1.. _screen:
2
3Screen
4======
5
6A screen is an object representing the context-independent part of a device.
7
8Flags and enumerations
9----------------------
10
11XXX some of these don't belong in this section.
12
13
14.. _pipe_cap:
15
16PIPE_CAP_*
17^^^^^^^^^^
18
19Capability queries return information about the features and limits of the
20driver/GPU.  For floating-point values, use :ref:`get_paramf`, and for boolean
21or integer values, use :ref:`get_param`.
22
23The integer capabilities:
24
25* ``PIPE_CAP_GRAPHICS``: Whether graphics is supported. If not, contexts can
26  only be created with PIPE_CONTEXT_COMPUTE_ONLY.
27* ``PIPE_CAP_NPOT_TEXTURES``: Whether :term:`NPOT` textures may have repeat modes,
28  normalized coordinates, and mipmaps.
29* ``PIPE_CAP_MAX_DUAL_SOURCE_RENDER_TARGETS``: How many dual-source blend RTs are support.
30  :ref:`Blend` for more information.
31* ``PIPE_CAP_ANISOTROPIC_FILTER``: Whether textures can be filtered anisotropically.
32* ``PIPE_CAP_POINT_SPRITE``: Whether point sprites are available.
33* ``PIPE_CAP_MAX_RENDER_TARGETS``: The maximum number of render targets that may be
34  bound.
35* ``PIPE_CAP_OCCLUSION_QUERY``: Whether occlusion queries are available.
36* ``PIPE_CAP_QUERY_TIME_ELAPSED``: Whether PIPE_QUERY_TIME_ELAPSED queries are available.
37* ``PIPE_CAP_TEXTURE_SHADOW_MAP``: indicates whether the fragment shader hardware
38  can do the depth texture / Z comparison operation in TEX instructions
39  for shadow testing.
40* ``PIPE_CAP_TEXTURE_SWIZZLE``: Whether swizzling through sampler views is
41  supported.
42* ``PIPE_CAP_MAX_TEXTURE_2D_SIZE``: The maximum size of 2D (and 1D) textures.
43* ``PIPE_CAP_MAX_TEXTURE_3D_LEVELS``: The maximum number of mipmap levels available
44  for a 3D texture.
45* ``PIPE_CAP_MAX_TEXTURE_CUBE_LEVELS``: The maximum number of mipmap levels available
46  for a cubemap.
47* ``PIPE_CAP_TEXTURE_MIRROR_CLAMP_TO_EDGE``: Whether mirrored texture coordinates are
48  supported with the clamp-to-edge wrap mode.
49* ``PIPE_CAP_TEXTURE_MIRROR_CLAMP``: Whether mirrored texture coordinates are supported
50  with clamp or clamp-to-border wrap modes.
51* ``PIPE_CAP_BLEND_EQUATION_SEPARATE``: Whether alpha blend equations may be different
52  from color blend equations, in :ref:`Blend` state.
53* ``PIPE_CAP_MAX_STREAM_OUTPUT_BUFFERS``: The maximum number of stream buffers.
54* ``PIPE_CAP_PRIMITIVE_RESTART``: Whether primitive restart is supported.
55* ``PIPE_CAP_PRIMITIVE_RESTART_FIXED_INDEX``: Subset of
56  PRIMITIVE_RESTART where the restart index is always the fixed maximum
57  value for the index type.
58* ``PIPE_CAP_INDEP_BLEND_ENABLE``: Whether per-rendertarget blend enabling and channel
59  masks are supported. If 0, then the first rendertarget's blend mask is
60  replicated across all MRTs.
61* ``PIPE_CAP_INDEP_BLEND_FUNC``: Whether per-rendertarget blend functions are
62  available. If 0, then the first rendertarget's blend functions affect all
63  MRTs.
64* ``PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS``: The maximum number of texture array
65  layers supported. If 0, the array textures are not supported at all and
66  the ARRAY texture targets are invalid.
67* ``PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT``: Whether the TGSI property
68  FS_COORD_ORIGIN with value UPPER_LEFT is supported.
69* ``PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT``: Whether the TGSI property
70  FS_COORD_ORIGIN with value LOWER_LEFT is supported.
71* ``PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER``: Whether the TGSI
72  property FS_COORD_PIXEL_CENTER with value HALF_INTEGER is supported.
73* ``PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_INTEGER``: Whether the TGSI
74  property FS_COORD_PIXEL_CENTER with value INTEGER is supported.
75* ``PIPE_CAP_DEPTH_CLIP_DISABLE``: Whether the driver is capable of disabling
76  depth clipping (=1) (through pipe_rasterizer_state) or supports lowering
77  depth_clamp in the client shader code (=2), for this the driver must
78  currently use TGSI.
79* ``PIPE_CAP_DEPTH_CLIP_DISABLE_SEPARATE``: Whether the driver is capable of
80  disabling depth clipping (through pipe_rasterizer_state) separately for
81  the near and far plane. If not, depth_clip_near and depth_clip_far will be
82  equal.
83* ``PIPE_CAP_SHADER_STENCIL_EXPORT``: Whether a stencil reference value can be
84  written from a fragment shader.
85* ``PIPE_CAP_TGSI_INSTANCEID``: Whether TGSI_SEMANTIC_INSTANCEID is supported
86  in the vertex shader.
87* ``PIPE_CAP_VERTEX_ELEMENT_INSTANCE_DIVISOR``: Whether the driver supports
88  per-instance vertex attribs.
89* ``PIPE_CAP_FRAGMENT_COLOR_CLAMPED``: Whether fragment color clamping is
90  supported.  That is, is the pipe_rasterizer_state::clamp_fragment_color
91  flag supported by the driver?  If not, gallium frontends will insert
92  clamping code into the fragment shaders when needed.
93
94* ``PIPE_CAP_MIXED_COLORBUFFER_FORMATS``: Whether mixed colorbuffer formats are
95  supported, e.g. RGBA8 and RGBA32F as the first and second colorbuffer, resp.
96* ``PIPE_CAP_VERTEX_COLOR_UNCLAMPED``: Whether the driver is capable of
97  outputting unclamped vertex colors from a vertex shader. If unsupported,
98  the vertex colors are always clamped. This is the default for DX9 hardware.
99* ``PIPE_CAP_VERTEX_COLOR_CLAMPED``: Whether the driver is capable of
100  clamping vertex colors when they come out of a vertex shader, as specified
101  by the pipe_rasterizer_state::clamp_vertex_color flag.  If unsupported,
102  the vertex colors are never clamped. This is the default for DX10 hardware.
103  If both clamped and unclamped CAPs are supported, the clamping can be
104  controlled through pipe_rasterizer_state.  If the driver cannot do vertex
105  color clamping, gallium frontends may insert clamping code into the vertex
106  shader.
107* ``PIPE_CAP_GLSL_FEATURE_LEVEL``: Whether the driver supports features
108  equivalent to a specific GLSL version. E.g. for GLSL 1.3, report 130.
109* ``PIPE_CAP_GLSL_FEATURE_LEVEL_COMPATIBILITY``: Whether the driver supports
110  features equivalent to a specific GLSL version including all legacy OpenGL
111  features only present in the OpenGL compatibility profile.
112  The only legacy features that Gallium drivers must implement are
113  the legacy shader inputs and outputs (colors, texcoords, fog, clipvertex,
114  edgeflag).
115* ``PIPE_CAP_ESSL_FEATURE_LEVEL``: An optional cap to allow drivers to
116  report a higher GLSL version for GLES contexts.  This is useful when a
117  driver does not support all the required features for a higher GL version,
118  but does support the required features for a higher GLES version.  A driver
119  is allowed to return ``0`` in which case ``PIPE_CAP_GLSL_FEATURE_LEVEL`` is
120  used.
121  Note that simply returning the same value as the GLSL feature level cap is
122  incorrect.  For example, GLSL version 3.30 does not require ``ARB_gpu_shader5``,
123  but ESSL version 3.20 es does require ``EXT_gpu_shader5``
124* ``PIPE_CAP_QUADS_FOLLOW_PROVOKING_VERTEX_CONVENTION``: Whether quads adhere to
125  the flatshade_first setting in ``pipe_rasterizer_state``.
126* ``PIPE_CAP_USER_VERTEX_BUFFERS``: Whether the driver supports user vertex
127  buffers.  If not, gallium frontends must upload all data which is not in hw
128  resources.  If user-space buffers are supported, the driver must also still
129  accept HW resource buffers.
130* ``PIPE_CAP_VERTEX_BUFFER_OFFSET_4BYTE_ALIGNED_ONLY``: This CAP describes a hw
131  limitation.  If true, pipe_vertex_buffer::buffer_offset must always be aligned
132  to 4.  If false, there are no restrictions on the offset.
133* ``PIPE_CAP_VERTEX_BUFFER_STRIDE_4BYTE_ALIGNED_ONLY``: This CAP describes a hw
134  limitation.  If true, pipe_vertex_buffer::stride must always be aligned to 4.
135  If false, there are no restrictions on the stride.
136* ``PIPE_CAP_VERTEX_ELEMENT_SRC_OFFSET_4BYTE_ALIGNED_ONLY``: This CAP describes
137  a hw limitation.  If true, pipe_vertex_element::src_offset must always be
138  aligned to 4.  If false, there are no restrictions on src_offset.
139* ``PIPE_CAP_COMPUTE``: Whether the implementation supports the
140  compute entry points defined in pipe_context and pipe_screen.
141* ``PIPE_CAP_CONSTANT_BUFFER_OFFSET_ALIGNMENT``: Describes the required
142  alignment of pipe_constant_buffer::buffer_offset.
143* ``PIPE_CAP_START_INSTANCE``: Whether the driver supports
144  pipe_draw_info::start_instance.
145* ``PIPE_CAP_QUERY_TIMESTAMP``: Whether PIPE_QUERY_TIMESTAMP and
146  the pipe_screen::get_timestamp hook are implemented.
147* ``PIPE_CAP_TEXTURE_MULTISAMPLE``: Whether all MSAA resources supported
148  for rendering are also supported for texturing.
149* ``PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT``: The minimum alignment that should be
150  expected for a pointer returned by transfer_map if the resource is
151  PIPE_BUFFER. In other words, the pointer returned by transfer_map is
152  always aligned to this value.
153* ``PIPE_CAP_TEXTURE_BUFFER_OFFSET_ALIGNMENT``: Describes the required
154  alignment for pipe_sampler_view::u.buf.offset, in bytes.
155  If a driver does not support offset/size, it should return 0.
156* ``PIPE_CAP_BUFFER_SAMPLER_VIEW_RGBA_ONLY``: Whether the driver only
157  supports R, RG, RGB and RGBA formats for PIPE_BUFFER sampler views.
158  When this is the case it should be assumed that the swizzle parameters
159  in the sampler view have no effect.
160* ``PIPE_CAP_TGSI_TEXCOORD``: This CAP describes a hw limitation.
161  If true, the hardware cannot replace arbitrary shader inputs with sprite
162  coordinates and hence the inputs that are desired to be replaceable must
163  be declared with TGSI_SEMANTIC_TEXCOORD instead of TGSI_SEMANTIC_GENERIC.
164  The rasterizer's sprite_coord_enable state therefore also applies to the
165  TEXCOORD semantic.
166  Also, TGSI_SEMANTIC_PCOORD becomes available, which labels a fragment shader
167  input that will always be replaced with sprite coordinates.
168* ``PIPE_CAP_PREFER_BLIT_BASED_TEXTURE_TRANSFER``: Whether it is preferable
169  to use a blit to implement a texture transfer which needs format conversions
170  and swizzling in gallium frontends. Generally, all hardware drivers with
171  dedicated memory should return 1 and all software rasterizers should return 0.
172* ``PIPE_CAP_QUERY_PIPELINE_STATISTICS``: Whether PIPE_QUERY_PIPELINE_STATISTICS
173  is supported.
174* ``PIPE_CAP_TEXTURE_BORDER_COLOR_QUIRK``: Bitmask indicating whether special
175  considerations have to be given to the interaction between the border color
176  in the sampler object and the sampler view used with it.
177  If PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_R600 is set, the border color
178  may be affected in undefined ways for any kind of permutational swizzle
179  (any swizzle XYZW where X/Y/Z/W are not ZERO, ONE, or R/G/B/A respectively)
180  in the sampler view.
181  If PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 is set, the border color
182  state should be swizzled manually according to the swizzle in the sampler
183  view it is intended to be used with, or herein undefined results may occur
184  for permutational swizzles.
185* ``PIPE_CAP_MAX_TEXTURE_BUFFER_SIZE``: The maximum accessible size with
186  a buffer sampler view, in texels.
187* ``PIPE_CAP_MAX_VIEWPORTS``: The maximum number of viewports (and scissors
188  since they are linked) a driver can support. Returning 0 is equivalent
189  to returning 1 because every driver has to support at least a single
190  viewport/scissor combination.
191* ``PIPE_CAP_ENDIANNESS``:: The endianness of the device.  Either
192  PIPE_ENDIAN_BIG or PIPE_ENDIAN_LITTLE.
193* ``PIPE_CAP_MIXED_FRAMEBUFFER_SIZES``: Whether it is allowed to have
194  different sizes for fb color/zs attachments. This controls whether
195  ARB_framebuffer_object is provided.
196* ``PIPE_CAP_TGSI_VS_LAYER_VIEWPORT``: Whether ``TGSI_SEMANTIC_LAYER`` and
197  ``TGSI_SEMANTIC_VIEWPORT_INDEX`` are supported as vertex shader
198  outputs. Note that the viewport will only be used if multiple viewports are
199  exposed.
200* ``PIPE_CAP_MAX_GEOMETRY_OUTPUT_VERTICES``: The maximum number of vertices
201  output by a single invocation of a geometry shader.
202* ``PIPE_CAP_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS``: The maximum number of
203  vertex components output by a single invocation of a geometry shader.
204  This is the product of the number of attribute components per vertex and
205  the number of output vertices.
206* ``PIPE_CAP_MAX_TEXTURE_GATHER_COMPONENTS``: Max number of components
207  in format that texture gather can operate on. 1 == RED, ALPHA etc,
208  4 == All formats.
209* ``PIPE_CAP_TEXTURE_GATHER_SM5``: Whether the texture gather
210  hardware implements the SM5 features, component selection,
211  shadow comparison, and run-time offsets.
212* ``PIPE_CAP_BUFFER_MAP_PERSISTENT_COHERENT``: Whether
213  PIPE_MAP_PERSISTENT and PIPE_MAP_COHERENT are supported
214  for buffers.
215* ``PIPE_CAP_TEXTURE_QUERY_LOD``: Whether the ``LODQ`` instruction is
216  supported.
217* ``PIPE_CAP_MIN_TEXTURE_GATHER_OFFSET``: The minimum offset that can be used
218  in conjunction with a texture gather opcode.
219* ``PIPE_CAP_MAX_TEXTURE_GATHER_OFFSET``: The maximum offset that can be used
220  in conjunction with a texture gather opcode.
221* ``PIPE_CAP_SAMPLE_SHADING``: Whether there is support for per-sample
222  shading. The context->set_min_samples function will be expected to be
223  implemented.
224* ``PIPE_CAP_TEXTURE_GATHER_OFFSETS``: Whether the ``TG4`` instruction can
225  accept 4 offsets.
226* ``PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION``: Whether
227  TGSI_PROPERTY_VS_WINDOW_SPACE_POSITION is supported, which disables clipping
228  and viewport transformation.
229* ``PIPE_CAP_MAX_VERTEX_STREAMS``: The maximum number of vertex streams
230  supported by the geometry shader. If stream-out is supported, this should be
231  at least 1. If stream-out is not supported, this should be 0.
232* ``PIPE_CAP_DRAW_INDIRECT``: Whether the driver supports taking draw arguments
233  { count, instance_count, start, index_bias } from a PIPE_BUFFER resource.
234  See pipe_draw_info.
235* ``PIPE_CAP_MULTI_DRAW_INDIRECT``: Whether the driver supports
236  pipe_draw_info::indirect_stride and ::indirect_count
237* ``PIPE_CAP_MULTI_DRAW_INDIRECT_PARAMS``: Whether the driver supports
238  taking the number of indirect draws from a separate parameter
239  buffer, see pipe_draw_indirect_info::indirect_draw_count.
240* ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE``: Whether the fragment shader supports
241  the FINE versions of DDX/DDY.
242* ``PIPE_CAP_VENDOR_ID``: The vendor ID of the underlying hardware. If it's
243  not available one should return 0xFFFFFFFF.
244* ``PIPE_CAP_DEVICE_ID``: The device ID (PCI ID) of the underlying hardware.
245  0xFFFFFFFF if not available.
246* ``PIPE_CAP_ACCELERATED``: Whether the renderer is hardware accelerated.
247* ``PIPE_CAP_VIDEO_MEMORY``: The amount of video memory in megabytes.
248* ``PIPE_CAP_UMA``: If the device has a unified memory architecture or on-card
249  memory and GART.
250* ``PIPE_CAP_CONDITIONAL_RENDER_INVERTED``: Whether the driver supports inverted
251  condition for conditional rendering.
252* ``PIPE_CAP_MAX_VERTEX_ATTRIB_STRIDE``: The maximum supported vertex stride.
253* ``PIPE_CAP_SAMPLER_VIEW_TARGET``: Whether the sampler view's target can be
254  different than the underlying resource's, as permitted by
255  ARB_texture_view. For example a 2d array texture may be reinterpreted as a
256  cube (array) texture and vice-versa.
257* ``PIPE_CAP_CLIP_HALFZ``: Whether the driver supports the
258  pipe_rasterizer_state::clip_halfz being set to true. This is required
259  for enabling ARB_clip_control.
260* ``PIPE_CAP_VERTEXID_NOBASE``: If true, the driver only supports
261  TGSI_SEMANTIC_VERTEXID_NOBASE (and not TGSI_SEMANTIC_VERTEXID). This means
262  gallium frontends for APIs whose vertexIDs are offset by basevertex (such as GL)
263  will need to lower TGSI_SEMANTIC_VERTEXID to TGSI_SEMANTIC_VERTEXID_NOBASE
264  and TGSI_SEMANTIC_BASEVERTEX, so drivers setting this must handle both these
265  semantics. Only relevant if geometry shaders are supported.
266  (BASEVERTEX could be exposed separately too via ``PIPE_CAP_DRAW_PARAMETERS``).
267* ``PIPE_CAP_POLYGON_OFFSET_CLAMP``: If true, the driver implements support
268  for ``pipe_rasterizer_state::offset_clamp``.
269* ``PIPE_CAP_MULTISAMPLE_Z_RESOLVE``: Whether the driver supports blitting
270  a multisampled depth buffer into a single-sampled texture (or depth buffer).
271  Only the first sampled should be copied.
272* ``PIPE_CAP_RESOURCE_FROM_USER_MEMORY``: Whether the driver can create
273  a pipe_resource where an already-existing piece of (malloc'd) user memory
274  is used as its backing storage. In other words, whether the driver can map
275  existing user memory into the device address space for direct device access.
276  The create function is pipe_screen::resource_from_user_memory. The address
277  and size must be page-aligned.
278* ``PIPE_CAP_RESOURCE_FROM_USER_MEMORY_COMPUTE_ONLY``: Same as
279  ``PIPE_CAP_RESOURCE_FROM_USER_MEMORY`` but indicates it is only supported from
280  the compute engines.
281* ``PIPE_CAP_DEVICE_RESET_STATUS_QUERY``:
282  Whether pipe_context::get_device_reset_status is implemented.
283* ``PIPE_CAP_MAX_SHADER_PATCH_VARYINGS``:
284  How many per-patch outputs and inputs are supported between tessellation
285  control and tessellation evaluation shaders, not counting in TESSINNER and
286  TESSOUTER. The minimum allowed value for OpenGL is 30.
287* ``PIPE_CAP_TEXTURE_FLOAT_LINEAR``: Whether the linear minification and
288  magnification filters are supported with single-precision floating-point
289  textures.
290* ``PIPE_CAP_TEXTURE_HALF_FLOAT_LINEAR``: Whether the linear minification and
291  magnification filters are supported with half-precision floating-point
292  textures.
293* ``PIPE_CAP_DEPTH_BOUNDS_TEST``: Whether bounds_test, bounds_min, and
294  bounds_max states of pipe_depth_stencil_alpha_state behave according
295  to the GL_EXT_depth_bounds_test specification.
296* ``PIPE_CAP_TGSI_TXQS``: Whether the `TXQS` opcode is supported
297* ``PIPE_CAP_FORCE_PERSAMPLE_INTERP``: If the driver can force per-sample
298  interpolation for all fragment shader inputs if
299  pipe_rasterizer_state::force_persample_interp is set. This is only used
300  by GL3-level sample shading (ARB_sample_shading). GL4-level sample shading
301  (ARB_gpu_shader5) doesn't use this. While GL3 hardware has a state for it,
302  GL4 hardware will likely need to emulate it with a shader variant, or by
303  selecting the interpolation weights with a conditional assignment
304  in the shader.
305* ``PIPE_CAP_SHAREABLE_SHADERS``: Whether shader CSOs can be used by any
306  pipe_context.
307* ``PIPE_CAP_COPY_BETWEEN_COMPRESSED_AND_PLAIN_FORMATS``:
308  Whether copying between compressed and plain formats is supported where
309  a compressed block is copied to/from a plain pixel of the same size.
310* ``PIPE_CAP_CLEAR_TEXTURE``: Whether `clear_texture` will be
311  available in contexts.
312* ``PIPE_CAP_CLEAR_SCISSORED``: Whether `clear` can accept a scissored
313  bounding box.
314* ``PIPE_CAP_DRAW_PARAMETERS``: Whether ``TGSI_SEMANTIC_BASEVERTEX``,
315  ``TGSI_SEMANTIC_BASEINSTANCE``, and ``TGSI_SEMANTIC_DRAWID`` are
316  supported in vertex shaders.
317* ``PIPE_CAP_TGSI_PACK_HALF_FLOAT``: Whether the ``UP2H`` and ``PK2H``
318  TGSI opcodes are supported.
319* ``PIPE_CAP_TGSI_FS_POSITION_IS_SYSVAL``: If gallium frontends should use
320  a system value for the POSITION fragment shader input.
321* ``PIPE_CAP_TGSI_FS_POINT_IS_SYSVAL``: If gallium frontends should use
322  a system value for the POINT fragment shader input.
323* ``PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL``: If gallium frontends should use
324  a system value for the FACE fragment shader input.
325  Also, the FACE system value is integer, not float.
326* ``PIPE_CAP_SHADER_BUFFER_OFFSET_ALIGNMENT``: Describes the required
327  alignment for pipe_shader_buffer::buffer_offset, in bytes. Maximum
328  value allowed is 256 (for GL conformance). 0 is only allowed if
329  shader buffers are not supported.
330* ``PIPE_CAP_INVALIDATE_BUFFER``: Whether the use of ``invalidate_resource``
331  for buffers is supported.
332* ``PIPE_CAP_GENERATE_MIPMAP``: Indicates whether pipe_context::generate_mipmap
333  is supported.
334* ``PIPE_CAP_STRING_MARKER``: Whether pipe->emit_string_marker() is supported.
335* ``PIPE_CAP_SURFACE_REINTERPRET_BLOCKS``: Indicates whether
336  pipe_context::create_surface supports reinterpreting a texture as a surface
337  of a format with different block width/height (but same block size in bits).
338  For example, a compressed texture image can be interpreted as a
339  non-compressed surface whose texels are the same number of bits as the
340  compressed blocks, and vice versa. The width and height of the surface is
341  adjusted appropriately.
342* ``PIPE_CAP_QUERY_BUFFER_OBJECT``: Driver supports
343  context::get_query_result_resource callback.
344* ``PIPE_CAP_PCI_GROUP``: Return the PCI segment group number.
345* ``PIPE_CAP_PCI_BUS``: Return the PCI bus number.
346* ``PIPE_CAP_PCI_DEVICE``: Return the PCI device number.
347* ``PIPE_CAP_PCI_FUNCTION``: Return the PCI function number.
348* ``PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT``:
349  If non-zero, rendering to framebuffers with no surface attachments
350  is supported. The context->is_format_supported function will be expected
351  to be implemented with PIPE_FORMAT_NONE yeilding the MSAA modes the hardware
352  supports. N.B., The maximum number of layers supported for rasterizing a
353  primitive on a layer is obtained from ``PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS``
354  even though it can be larger than the number of layers supported by either
355  rendering or textures.
356* ``PIPE_CAP_ROBUST_BUFFER_ACCESS_BEHAVIOR``: Implementation uses bounds
357  checking on resource accesses by shader if the context is created with
358  PIPE_CONTEXT_ROBUST_BUFFER_ACCESS. See the ARB_robust_buffer_access_behavior
359  extension for information on the required behavior for out of bounds accesses
360  and accesses to unbound resources.
361* ``PIPE_CAP_CULL_DISTANCE``: Whether the driver supports the arb_cull_distance
362  extension and thus implements proper support for culling planes.
363* ``PIPE_CAP_PRIMITIVE_RESTART_FOR_PATCHES``: Whether primitive restart is
364  supported for patch primitives.
365* ``PIPE_CAP_TGSI_VOTE``: Whether the ``VOTE_*`` ops can be used in shaders.
366* ``PIPE_CAP_MAX_WINDOW_RECTANGLES``: The maxium number of window rectangles
367  supported in ``set_window_rectangles``.
368* ``PIPE_CAP_POLYGON_OFFSET_UNITS_UNSCALED``: If true, the driver implements support
369  for ``pipe_rasterizer_state::offset_units_unscaled``.
370* ``PIPE_CAP_VIEWPORT_SUBPIXEL_BITS``: Number of bits of subpixel precision for
371  floating point viewport bounds.
372* ``PIPE_CAP_RASTERIZER_SUBPIXEL_BITS``: Number of bits of subpixel precision used
373  by the rasterizer.
374* ``PIPE_CAP_MIXED_COLOR_DEPTH_BITS``: Whether there is non-fallback
375  support for color/depth format combinations that use a different
376  number of bits. For the purpose of this cap, Z24 is treated as
377  32-bit. If set to off, that means that a B5G6R5 + Z24 or RGBA8 + Z16
378  combination will require a driver fallback, and should not be
379  advertised in the GLX/EGL config list.
380* ``PIPE_CAP_TGSI_ARRAY_COMPONENTS``: If true, the driver interprets the
381  UsageMask of input and output declarations and allows declaring arrays
382  in overlapping ranges. The components must be a contiguous range, e.g. a
383  UsageMask of  xy or yzw is allowed, but xz or yw isn't. Declarations with
384  overlapping locations must have matching semantic names and indices, and
385  equal interpolation qualifiers.
386  Components may overlap, notably when the gaps in an array of dvec3 are
387  filled in.
388* ``PIPE_CAP_STREAM_OUTPUT_INTERLEAVE_BUFFERS``: Whether interleaved stream
389  output mode is able to interleave across buffers. This is required for
390  ARB_transform_feedback3.
391* ``PIPE_CAP_TGSI_CAN_READ_OUTPUTS``: Whether every TGSI shader stage can read
392  from the output file.
393* ``PIPE_CAP_GLSL_OPTIMIZE_CONSERVATIVELY``: Tell the GLSL compiler to use
394  the minimum amount of optimizations just to be able to do all the linking
395  and lowering.
396* ``PIPE_CAP_FBFETCH``: The number of render targets whose value in the
397  current framebuffer can be read in the shader.  0 means framebuffer fetch
398  is not supported.  1 means that only the first render target can be read,
399  and a larger value would mean that multiple render targets are supported.
400* ``PIPE_CAP_FBFETCH_COHERENT``: Whether framebuffer fetches from the fragment
401  shader can be guaranteed to be coherent with framebuffer writes.
402* ``PIPE_CAP_TGSI_MUL_ZERO_WINS``: Whether TGSI shaders support the
403  ``TGSI_PROPERTY_MUL_ZERO_WINS`` shader property.
404* ``PIPE_CAP_DOUBLES``: Whether double precision floating-point operations
405  are supported.
406* ``PIPE_CAP_INT64``: Whether 64-bit integer operations are supported.
407* ``PIPE_CAP_INT64_DIVMOD``: Whether 64-bit integer division/modulo
408  operations are supported.
409* ``PIPE_CAP_TGSI_TEX_TXF_LZ``: Whether TEX_LZ and TXF_LZ opcodes are
410  supported.
411* ``PIPE_CAP_TGSI_CLOCK``: Whether the CLOCK opcode is supported.
412* ``PIPE_CAP_POLYGON_MODE_FILL_RECTANGLE``: Whether the
413  PIPE_POLYGON_MODE_FILL_RECTANGLE mode is supported for
414  ``pipe_rasterizer_state::fill_front`` and
415  ``pipe_rasterizer_state::fill_back``.
416* ``PIPE_CAP_SPARSE_BUFFER_PAGE_SIZE``: The page size of sparse buffers in
417  bytes, or 0 if sparse buffers are not supported. The page size must be at
418  most 64KB.
419* ``PIPE_CAP_TGSI_BALLOT``: Whether the BALLOT and READ_* opcodes as well as
420  the SUBGROUP_* semantics are supported.
421* ``PIPE_CAP_TGSI_TES_LAYER_VIEWPORT``: Whether ``TGSI_SEMANTIC_LAYER`` and
422  ``TGSI_SEMANTIC_VIEWPORT_INDEX`` are supported as tessellation evaluation
423  shader outputs.
424* ``PIPE_CAP_CAN_BIND_CONST_BUFFER_AS_VERTEX``: Whether a buffer with just
425  PIPE_BIND_CONSTANT_BUFFER can be legally passed to set_vertex_buffers.
426* ``PIPE_CAP_ALLOW_MAPPED_BUFFERS_DURING_EXECUTION``: As the name says.
427* ``PIPE_CAP_POST_DEPTH_COVERAGE``: whether
428  ``TGSI_PROPERTY_FS_POST_DEPTH_COVERAGE`` is supported.
429* ``PIPE_CAP_BINDLESS_TEXTURE``: Whether bindless texture operations are
430  supported.
431* ``PIPE_CAP_NIR_SAMPLERS_AS_DEREF``: Whether NIR tex instructions should
432  reference texture and sampler as NIR derefs instead of by indices.
433* ``PIPE_CAP_QUERY_SO_OVERFLOW``: Whether the
434  ``PIPE_QUERY_SO_OVERFLOW_PREDICATE`` and
435  ``PIPE_QUERY_SO_OVERFLOW_ANY_PREDICATE`` query types are supported. Note that
436  for a driver that does not support multiple output streams (i.e.,
437  ``PIPE_CAP_MAX_VERTEX_STREAMS`` is 1), both query types are identical.
438* ``PIPE_CAP_MEMOBJ``: Whether operations on memory objects are supported.
439* ``PIPE_CAP_LOAD_CONSTBUF``: True if the driver supports ``TGSI_OPCODE_LOAD`` use
440  with constant buffers.
441* ``PIPE_CAP_TGSI_ANY_REG_AS_ADDRESS``: Any TGSI register can be used as
442  an address for indirect register indexing.
443* ``PIPE_CAP_TILE_RASTER_ORDER``: Whether the driver supports
444  GL_MESA_tile_raster_order, using the tile_raster_order_* fields in
445  pipe_rasterizer_state.
446* ``PIPE_CAP_MAX_COMBINED_SHADER_OUTPUT_RESOURCES``: Limit on combined shader
447  output resources (images + buffers + fragment outputs). If 0 the state
448  tracker works it out.
449* ``PIPE_CAP_FRAMEBUFFER_MSAA_CONSTRAINTS``: This determines limitations
450  on the number of samples that framebuffer attachments can have.
451  Possible values:
452
453    0. color.nr_samples == zs.nr_samples == color.nr_storage_samples
454       (standard MSAA quality)
455    1. color.nr_samples >= zs.nr_samples == color.nr_storage_samples
456       (enhanced MSAA quality)
457    2. color.nr_samples >= zs.nr_samples >= color.nr_storage_samples
458       (full flexibility in tuning MSAA quality and performance)
459
460  All color attachments must have the same number of samples and the same
461  number of storage samples.
462* ``PIPE_CAP_SIGNED_VERTEX_BUFFER_OFFSET``:
463  Whether pipe_vertex_buffer::buffer_offset is treated as signed. The u_vbuf
464  module needs this for optimal performance in workstation applications.
465* ``PIPE_CAP_CONTEXT_PRIORITY_MASK``: For drivers that support per-context
466  priorities, this returns a bitmask of ``PIPE_CONTEXT_PRIORITY_x`` for the
467  supported priority levels.  A driver that does not support prioritized
468  contexts can return 0.
469* ``PIPE_CAP_FENCE_SIGNAL``: True if the driver supports signaling semaphores
470  using fence_server_signal().
471* ``PIPE_CAP_CONSTBUF0_FLAGS``: The bits of pipe_resource::flags that must be
472  set when binding that buffer as constant buffer 0. If the buffer doesn't have
473  those bits set, pipe_context::set_constant_buffer(.., 0, ..) is ignored
474  by the driver, and the driver can throw assertion failures.
475* ``PIPE_CAP_PACKED_UNIFORMS``: True if the driver supports packed uniforms
476  as opposed to padding to vec4s.
477* ``PIPE_CAP_CONSERVATIVE_RASTER_POST_SNAP_TRIANGLES``: Whether the
478  ``PIPE_CONSERVATIVE_RASTER_POST_SNAP`` mode is supported for triangles.
479  The post-snap mode means the conservative rasterization occurs after
480  the conversion from floating-point to fixed-point coordinates
481  on the subpixel grid.
482* ``PIPE_CAP_CONSERVATIVE_RASTER_POST_SNAP_POINTS_LINES``: Whether the
483  ``PIPE_CONSERVATIVE_RASTER_POST_SNAP`` mode is supported for points and lines.
484* ``PIPE_CAP_CONSERVATIVE_RASTER_PRE_SNAP_TRIANGLES``: Whether the
485  ``PIPE_CONSERVATIVE_RASTER_PRE_SNAP`` mode is supported for triangles.
486  The pre-snap mode means the conservative rasterization occurs before
487  the conversion from floating-point to fixed-point coordinates.
488* ``PIPE_CAP_CONSERVATIVE_RASTER_PRE_SNAP_POINTS_LINES``: Whether the
489  ``PIPE_CONSERVATIVE_RASTER_PRE_SNAP`` mode is supported for points and lines.
490* ``PIPE_CAP_CONSERVATIVE_RASTER_POST_DEPTH_COVERAGE``: Whether
491  ``PIPE_CAP_POST_DEPTH_COVERAGE`` works with conservative rasterization.
492* ``PIPE_CAP_CONSERVATIVE_RASTER_INNER_COVERAGE``: Whether
493  inner_coverage from GL_INTEL_conservative_rasterization is supported.
494* ``PIPE_CAP_MAX_CONSERVATIVE_RASTER_SUBPIXEL_PRECISION_BIAS``: The maximum
495  subpixel precision bias in bits during conservative rasterization.
496* ``PIPE_CAP_PROGRAMMABLE_SAMPLE_LOCATIONS``: True is the driver supports
497  programmable sample location through ```get_sample_pixel_grid``` and
498  ```set_sample_locations```.
499* ``PIPE_CAP_MAX_GS_INVOCATIONS``: Maximum supported value of
500  TGSI_PROPERTY_GS_INVOCATIONS.
501* ``PIPE_CAP_MAX_SHADER_BUFFER_SIZE``: Maximum supported size for binding
502  with set_shader_buffers.
503* ``PIPE_CAP_MAX_COMBINED_SHADER_BUFFERS``: Maximum total number of shader
504  buffers. A value of 0 means the sum of all per-shader stage maximums (see
505  ``PIPE_SHADER_CAP_MAX_SHADER_BUFFERS``).
506* ``PIPE_CAP_MAX_COMBINED_HW_ATOMIC_COUNTERS``: Maximum total number of atomic
507  counters. A value of 0 means the default value (MAX_ATOMIC_COUNTERS = 4096).
508* ``PIPE_CAP_MAX_COMBINED_HW_ATOMIC_COUNTER_BUFFERS``: Maximum total number of
509  atomic counter buffers. A value of 0 means the sum of all per-shader stage
510  maximums (see ``PIPE_SHADER_CAP_MAX_HW_ATOMIC_COUNTER_BUFFERS``).
511* ``PIPE_CAP_MAX_TEXTURE_UPLOAD_MEMORY_BUDGET``: Maximum recommend memory size
512  for all active texture uploads combined. This is a performance hint.
513  0 means no limit.
514* ``PIPE_CAP_MAX_VERTEX_ELEMENT_SRC_OFFSET``: The maximum supported value for
515  of pipe_vertex_element::src_offset.
516* ``PIPE_CAP_SURFACE_SAMPLE_COUNT``: Whether the driver
517  supports pipe_surface overrides of resource nr_samples. If set, will
518  enable EXT_multisampled_render_to_texture.
519* ``PIPE_CAP_TGSI_ATOMFADD``: Atomic floating point adds are supported on
520  images, buffers, and shared memory.
521* ``PIPE_CAP_RGB_OVERRIDE_DST_ALPHA_BLEND``: True if the driver needs blend state to use zero/one instead of destination alpha for RGB/XRGB formats.
522* ``PIPE_CAP_GLSL_TESS_LEVELS_AS_INPUTS``: True if the driver wants TESSINNER and TESSOUTER to be inputs (rather than system values) for tessellation evaluation shaders.
523* ``PIPE_CAP_DEST_SURFACE_SRGB_CONTROL``: Indicates whether the drivers
524  supports switching the format between sRGB and linear for a surface that is
525  used as destination in draw and blit calls.
526* ``PIPE_CAP_NIR_COMPACT_ARRAYS``: True if the compiler backend supports NIR's compact array feature, for all shader stages.
527* ``PIPE_CAP_MAX_VARYINGS``: The maximum number of fragment shader
528  varyings. This will generally correspond to
529  ``PIPE_SHADER_CAP_MAX_INPUTS`` for the fragment shader, but in some
530  cases may be a smaller number.
531* ``PIPE_CAP_COMPUTE_GRID_INFO_LAST_BLOCK``: Whether pipe_grid_info::last_block
532  is implemented by the driver. See struct pipe_grid_info for more details.
533* ``PIPE_CAP_COMPUTE_SHADER_DERIVATIVE``: True if the driver supports derivatives (and texture lookups with implicit derivatives) in compute shaders.
534* ``PIPE_CAP_TGSI_SKIP_SHRINK_IO_ARRAYS``:  Whether the TGSI pass to shrink IO
535  arrays should be skipped and enforce keeping the declared array sizes instead.
536  A driver might rely on the input mapping that was defined with the original
537  GLSL code.
538* ``PIPE_CAP_IMAGE_LOAD_FORMATTED``: True if a format for image loads does not need to be specified in the shader IR
539* ``PIPE_CAP_THROTTLE``: Whether or not gallium frontends should throttle pipe_context
540  execution. 0 = throttling is disabled.
541* ``PIPE_CAP_DMABUF``: Whether Linux DMABUF handles are supported by
542  resource_from_handle and resource_get_handle.
543* ``PIPE_CAP_PREFER_COMPUTE_FOR_MULTIMEDIA``: Whether VDPAU, VAAPI, and
544  OpenMAX should use a compute-based blit instead of pipe_context::blit and compute pipeline for compositing images.
545* ``PIPE_CAP_FRAGMENT_SHADER_INTERLOCK``: True if fragment shader interlock
546  functionality is supported.
547* ``PIPE_CAP_CS_DERIVED_SYSTEM_VALUES_SUPPORTED``: True if driver handles
548  gl_LocalInvocationIndex and gl_GlobalInvocationID.  Otherwise, gallium frontends will
549  lower those system values.
550* ``PIPE_CAP_ATOMIC_FLOAT_MINMAX``: Atomic float point minimum,
551  maximum, exchange and compare-and-swap support to buffer and shared variables.
552* ``PIPE_CAP_TGSI_DIV``: Whether opcode DIV is supported
553* ``PIPE_CAP_FRAGMENT_SHADER_TEXTURE_LOD``: Whether texture lookups with
554  explicit LOD is supported in the fragment shader.
555* ``PIPE_CAP_FRAGMENT_SHADER_DERIVATIVES``: True if the driver supports
556  derivatives in fragment shaders.
557* ``PIPE_CAP_VERTEX_SHADER_SATURATE``: True if the driver supports saturate
558  modifiers in the vertex shader.
559* ``PIPE_CAP_TEXTURE_SHADOW_LOD``: True if the driver supports shadow sampler
560  types with texture functions having interaction with LOD of texture lookup.
561* ``PIPE_CAP_SHADER_SAMPLES_IDENTICAL``: True if the driver supports a shader query to tell whether all samples of a multisampled surface are definitely identical.
562* ``PIPE_CAP_TGSI_ATOMINC_WRAP``: Atomic increment/decrement + wrap around are supported.
563* ``PIPE_CAP_PREFER_IMM_ARRAYS_AS_CONSTBUF``: True if gallium frontends should
564  turn arrays whose contents can be deduced at compile time into constant
565  buffer loads, or false if the driver can handle such arrays itself in a more
566  efficient manner.
567* ``PIPE_CAP_GL_SPIRV``: True if the driver supports ARB_gl_spirv extension.
568* ``PIPE_CAP_GL_SPIRV_VARIABLE_POINTERS``: True if the driver supports Variable Pointers in SPIR-V shaders.
569* ``PIPE_CAP_DEMOTE_TO_HELPER_INVOCATION``: True if driver supports demote keyword in GLSL programs.
570* ``PIPE_CAP_TGSI_TG4_COMPONENT_IN_SWIZZLE``: True if driver wants the TG4 component encoded in sampler swizzle rather than as a separate source.
571* ``PIPE_CAP_FLATSHADE``: Driver supports pipe_rasterizer_state::flatshade.
572* ``PIPE_CAP_ALPHA_TEST``: Driver supports alpha-testing.
573* ``PIPE_CAP_POINT_SIZE_FIXED``: Driver supports point-sizes that are fixed,
574  as opposed to writing gl_PointSize for every point.
575* ``PIPE_CAP_TWO_SIDED_COLOR``: Driver supports two-sided coloring.
576* ``PIPE_CAP_CLIP_PLANES``: Driver supports user-defined clip-planes.
577* ``PIPE_CAP_MAX_VERTEX_BUFFERS``: Number of supported vertex buffers.
578* ``PIPE_CAP_OPENCL_INTEGER_FUNCTIONS``: Driver supports extended OpenCL-style integer functions.  This includes averge, saturating additiong, saturating subtraction, absolute difference, count leading zeros, and count trailing zeros.
579* ``PIPE_CAP_INTEGER_MULTIPLY_32X16``: Driver supports integer multiplication between a 32-bit integer and a 16-bit integer.  If the second operand is 32-bits, the upper 16-bits are ignored, and the low 16-bits are possibly sign extended as necessary.
580* ``PIPE_CAP_NIR_IMAGES_AS_DEREF``: Whether NIR image load/store intrinsics should be nir_intrinsic_image_deref_* instead of nir_intrinsic_image_*.  Defaults to true.
581* ``PIPE_CAP_PACKED_STREAM_OUTPUT``: Driver supports packing optimization for stream output (e.g. GL transform feedback captured variables). Defaults to true.
582* ``PIPE_CAP_VIEWPORT_TRANSFORM_LOWERED``: Driver needs the nir_lower_viewport_transform pass to be enabled. This also means that the gl_Position value is modified and should be lowered for transform feedback, if needed. Defaults to false.
583* ``PIPE_CAP_PSIZ_CLAMPED``: Driver needs for the point size to be clamped. Additionally, the gl_PointSize has been modified and its value should be lowered for transform feedback, if needed. Defaults to false.
584* ``PIPE_CAP_DRAW_INFO_START_WITH_USER_INDICES``: pipe_draw_info::start can be non-zero with user indices.
585* ``PIPE_CAP_GL_BEGIN_END_BUFFER_SIZE``: Buffer size used to upload vertices for glBegin/glEnd.
586* ``PIPE_CAP_VIEWPORT_SWIZZLE``: Whether pipe_viewport_state::swizzle can be used to specify pre-clipping swizzling of coordinates (see GL_NV_viewport_swizzle).
587* ``PIPE_CAP_SYSTEM_SVM``: True if all application memory can be shared with the GPU without explicit mapping.
588* ``PIPE_CAP_VIEWPORT_MASK``: Whether ``TGSI_SEMANTIC_VIEWPORT_MASK`` and ``TGSI_PROPERTY_LAYER_VIEWPORT_RELATIVE`` are supported (see GL_NV_viewport_array2).
589* ``PIPE_CAP_MAP_UNSYNCHRONIZED_THREAD_SAFE``: Whether mapping a buffer as unsynchronized from any thread is safe.
590* ``PIPE_CAP_GLSL_ZERO_INIT``: Choose a default zero initialization some glsl variables. If `1`, then all glsl shader variables and gl_FragColor are initialized to zero. If `2`, then shader out variables are not initialized but function out variables are.
591* ``PIPE_CAP_BLEND_EQUATION_ADVANCED``: Driver supports blend equation advanced without necessarily supporting FBFETCH.
592* ``PIPE_CAP_NIR_ATOMICS_AS_DEREF``: Whether NIR atomics instructions should reference atomics as NIR derefs instead of by indices.
593* ``PIPE_CAP_NO_CLIP_ON_COPY_TEX``: Driver doesn't want x/y/width/height clipped based on src size when doing a copy texture operation (eg: may want out-of-bounds reads that produce 0 instead of leaving the texture content undefined)
594* ``PIPE_CAP_MAX_TEXTURE_MB``: Maximum texture size in MB (default is 1024)
595* ``PIPE_CAP_DEVICE_PROTECTED_CONTENT``: Whether the device support protected / encrypted content.
596
597.. _pipe_capf:
598
599PIPE_CAPF_*
600^^^^^^^^^^^^^^^^
601
602The floating-point capabilities are:
603
604* ``PIPE_CAPF_MAX_LINE_WIDTH``: The maximum width of a regular line.
605* ``PIPE_CAPF_MAX_LINE_WIDTH_AA``: The maximum width of a smoothed line.
606* ``PIPE_CAPF_MAX_POINT_WIDTH``: The maximum width and height of a point.
607* ``PIPE_CAPF_MAX_POINT_WIDTH_AA``: The maximum width and height of a smoothed point.
608* ``PIPE_CAPF_MAX_TEXTURE_ANISOTROPY``: The maximum level of anisotropy that can be
609  applied to anisotropically filtered textures.
610* ``PIPE_CAPF_MAX_TEXTURE_LOD_BIAS``: The maximum :term:`LOD` bias that may be applied
611  to filtered textures.
612* ``PIPE_CAPF_MIN_CONSERVATIVE_RASTER_DILATE``: The minimum conservative rasterization
613  dilation.
614* ``PIPE_CAPF_MAX_CONSERVATIVE_RASTER_DILATE``: The maximum conservative rasterization
615  dilation.
616* ``PIPE_CAPF_CONSERVATIVE_RASTER_DILATE_GRANULARITY``: The conservative rasterization
617  dilation granularity for values relative to the minimum dilation.
618
619
620.. _pipe_shader_cap:
621
622PIPE_SHADER_CAP_*
623^^^^^^^^^^^^^^^^^
624
625These are per-shader-stage capabitity queries. Different shader stages may
626support different features.
627
628* ``PIPE_SHADER_CAP_MAX_INSTRUCTIONS``: The maximum number of instructions.
629* ``PIPE_SHADER_CAP_MAX_ALU_INSTRUCTIONS``: The maximum number of arithmetic instructions.
630* ``PIPE_SHADER_CAP_MAX_TEX_INSTRUCTIONS``: The maximum number of texture instructions.
631* ``PIPE_SHADER_CAP_MAX_TEX_INDIRECTIONS``: The maximum number of texture indirections.
632* ``PIPE_SHADER_CAP_MAX_CONTROL_FLOW_DEPTH``: The maximum nested control flow depth.
633* ``PIPE_SHADER_CAP_MAX_INPUTS``: The maximum number of input registers.
634* ``PIPE_SHADER_CAP_MAX_OUTPUTS``: The maximum number of output registers.
635  This is valid for all shaders except the fragment shader.
636* ``PIPE_SHADER_CAP_MAX_CONST_BUFFER_SIZE``: The maximum size per constant buffer in bytes.
637* ``PIPE_SHADER_CAP_MAX_CONST_BUFFERS``: Maximum number of constant buffers that can be bound
638  to any shader stage using ``set_constant_buffer``. If 0 or 1, the pipe will
639  only permit binding one constant buffer per shader.
640
641If a value greater than 0 is returned, the driver can have multiple
642constant buffers bound to shader stages. The CONST register file is
643accessed with two-dimensional indices, like in the example below.
644
645DCL CONST[0][0..7]       # declare first 8 vectors of constbuf 0
646DCL CONST[3][0]          # declare first vector of constbuf 3
647MOV OUT[0], CONST[0][3]  # copy vector 3 of constbuf 0
648
649* ``PIPE_SHADER_CAP_MAX_TEMPS``: The maximum number of temporary registers.
650* ``PIPE_SHADER_CAP_TGSI_CONT_SUPPORTED``: Whether the continue opcode is supported.
651* ``PIPE_SHADER_CAP_INDIRECT_INPUT_ADDR``: Whether indirect addressing
652  of the input file is supported.
653* ``PIPE_SHADER_CAP_INDIRECT_OUTPUT_ADDR``: Whether indirect addressing
654  of the output file is supported.
655* ``PIPE_SHADER_CAP_INDIRECT_TEMP_ADDR``: Whether indirect addressing
656  of the temporary file is supported.
657* ``PIPE_SHADER_CAP_INDIRECT_CONST_ADDR``: Whether indirect addressing
658  of the constant file is supported.
659* ``PIPE_SHADER_CAP_SUBROUTINES``: Whether subroutines are supported, i.e.
660  BGNSUB, ENDSUB, CAL, and RET, including RET in the main block.
661* ``PIPE_SHADER_CAP_INTEGERS``: Whether integer opcodes are supported.
662  If unsupported, only float opcodes are supported.
663* ``PIPE_SHADER_CAP_INT64_ATOMICS``: Whether int64 atomic opcodes are supported. The device needs to support add, sub, swap, cmpswap, and, or, xor, min, and max.
664* ``PIPE_SHADER_CAP_FP16``: Whether half precision floating-point opcodes are supported.
665   If unsupported, half precision ops need to be lowered to full precision.
666* ``PIPE_SHADER_CAP_FP16_DERIVATIVES``: Whether half precision floating-point
667  DDX and DDY opcodes are supported.
668* ``PIPE_SHADER_CAP_INT16``: Whether 16-bit signed and unsigned integer types
669  are supported.
670* ``PIPE_SHADER_CAP_GLSL_16BIT_CONSTS``: Lower mediump constants to 16-bit.
671  Note that 16-bit constants are not lowered to uniforms in GLSL.
672* ``PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLERS``: The maximum number of texture
673  samplers.
674* ``PIPE_SHADER_CAP_PREFERRED_IR``: Preferred representation of the
675  program.  It should be one of the ``pipe_shader_ir`` enum values.
676* ``PIPE_SHADER_CAP_MAX_SAMPLER_VIEWS``: The maximum number of texture
677  sampler views. Must not be lower than PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLERS.
678* ``PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED``: Whether double precision rounding
679  is supported. If it is, DTRUNC/DCEIL/DFLR/DROUND opcodes may be used.
680* ``PIPE_SHADER_CAP_TGSI_DFRACEXP_DLDEXP_SUPPORTED``: Whether DFRACEXP and
681  DLDEXP are supported.
682* ``PIPE_SHADER_CAP_TGSI_LDEXP_SUPPORTED``: Whether LDEXP is supported.
683* ``PIPE_SHADER_CAP_TGSI_FMA_SUPPORTED``: Whether FMA and DFMA (doubles only)
684  are supported.
685* ``PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE``: Whether the driver doesn't
686  ignore tgsi_declaration_range::Last for shader inputs and outputs.
687* ``PIPE_SHADER_CAP_MAX_UNROLL_ITERATIONS_HINT``: This is the maximum number
688  of iterations that loops are allowed to have to be unrolled. It is only
689  a hint to gallium frontends. Whether any loops will be unrolled is not
690  guaranteed.
691* ``PIPE_SHADER_CAP_MAX_SHADER_BUFFERS``: Maximum number of memory buffers
692  (also used to implement atomic counters). Having this be non-0 also
693  implies support for the ``LOAD``, ``STORE``, and ``ATOM*`` TGSI
694  opcodes.
695* ``PIPE_SHADER_CAP_SUPPORTED_IRS``: Supported representations of the
696  program.  It should be a mask of ``pipe_shader_ir`` bits.
697* ``PIPE_SHADER_CAP_MAX_SHADER_IMAGES``: Maximum number of image units.
698* ``PIPE_SHADER_CAP_LOWER_IF_THRESHOLD``: IF and ELSE branches with a lower
699  cost than this value should be lowered by gallium frontends for better
700  performance. This is a tunable for the GLSL compiler and the behavior is
701  specific to the compiler.
702* ``PIPE_SHADER_CAP_TGSI_SKIP_MERGE_REGISTERS``: Whether the merge registers
703  TGSI pass is skipped. This might reduce code size and register pressure if
704  the underlying driver has a real backend compiler.
705* ``PIPE_SHADER_CAP_MAX_HW_ATOMIC_COUNTERS``: If atomic counters are separate,
706  how many HW counters are available for this stage. (0 uses SSBO atomics).
707* ``PIPE_SHADER_CAP_MAX_HW_ATOMIC_COUNTER_BUFFERS``: If atomic counters are
708  separate, how many atomic counter buffers are available for this stage.
709
710.. _pipe_compute_cap:
711
712PIPE_COMPUTE_CAP_*
713^^^^^^^^^^^^^^^^^^
714
715Compute-specific capabilities. They can be queried using
716pipe_screen::get_compute_param.
717
718* ``PIPE_COMPUTE_CAP_IR_TARGET``: A description of the target of the form
719  ``processor-arch-manufacturer-os`` that will be passed on to the compiler.
720  This CAP is only relevant for drivers that specify PIPE_SHADER_IR_NATIVE for
721  their preferred IR.
722  Value type: null-terminated string. Shader IR type dependent.
723* ``PIPE_COMPUTE_CAP_GRID_DIMENSION``: Number of supported dimensions
724  for grid and block coordinates.  Value type: ``uint64_t``. Shader IR type dependent.
725* ``PIPE_COMPUTE_CAP_MAX_GRID_SIZE``: Maximum grid size in block
726  units.  Value type: ``uint64_t []``.  Shader IR type dependent.
727* ``PIPE_COMPUTE_CAP_MAX_BLOCK_SIZE``: Maximum block size in thread
728  units.  Value type: ``uint64_t []``. Shader IR type dependent.
729* ``PIPE_COMPUTE_CAP_MAX_THREADS_PER_BLOCK``: Maximum number of threads that
730  a single block can contain.  Value type: ``uint64_t``. Shader IR type dependent.
731  This may be less than the product of the components of MAX_BLOCK_SIZE and is
732  usually limited by the number of threads that can be resident simultaneously
733  on a compute unit.
734* ``PIPE_COMPUTE_CAP_MAX_GLOBAL_SIZE``: Maximum size of the GLOBAL
735  resource.  Value type: ``uint64_t``. Shader IR type dependent.
736* ``PIPE_COMPUTE_CAP_MAX_LOCAL_SIZE``: Maximum size of the LOCAL
737  resource.  Value type: ``uint64_t``. Shader IR type dependent.
738* ``PIPE_COMPUTE_CAP_MAX_PRIVATE_SIZE``: Maximum size of the PRIVATE
739  resource.  Value type: ``uint64_t``. Shader IR type dependent.
740* ``PIPE_COMPUTE_CAP_MAX_INPUT_SIZE``: Maximum size of the INPUT
741  resource.  Value type: ``uint64_t``. Shader IR type dependent.
742* ``PIPE_COMPUTE_CAP_MAX_MEM_ALLOC_SIZE``: Maximum size of a memory object
743  allocation in bytes.  Value type: ``uint64_t``.
744* ``PIPE_COMPUTE_CAP_MAX_CLOCK_FREQUENCY``: Maximum frequency of the GPU
745  clock in MHz. Value type: ``uint32_t``
746* ``PIPE_COMPUTE_CAP_MAX_COMPUTE_UNITS``: Maximum number of compute units
747  Value type: ``uint32_t``
748* ``PIPE_COMPUTE_CAP_IMAGES_SUPPORTED``: Whether images are supported
749  non-zero means yes, zero means no. Value type: ``uint32_t``
750* ``PIPE_COMPUTE_CAP_SUBGROUP_SIZE``: The size of a basic execution unit in
751  threads. Also known as wavefront size, warp size or SIMD width.
752* ``PIPE_COMPUTE_CAP_ADDRESS_BITS``: The default compute device address space
753  size specified as an unsigned integer value in bits.
754* ``PIPE_COMPUTE_CAP_MAX_VARIABLE_THREADS_PER_BLOCK``: Maximum variable number
755  of threads that a single block can contain. This is similar to
756  PIPE_COMPUTE_CAP_MAX_THREADS_PER_BLOCK, except that the variable size is not
757  known a compile-time but at dispatch-time.
758
759.. _pipe_bind:
760
761PIPE_BIND_*
762^^^^^^^^^^^
763
764These flags indicate how a resource will be used and are specified at resource
765creation time. Resources may be used in different roles
766during their lifecycle. Bind flags are cumulative and may be combined to create
767a resource which can be used for multiple things.
768Depending on the pipe driver's memory management and these bind flags,
769resources might be created and handled quite differently.
770
771* ``PIPE_BIND_RENDER_TARGET``: A color buffer or pixel buffer which will be
772  rendered to.  Any surface/resource attached to pipe_framebuffer_state::cbufs
773  must have this flag set.
774* ``PIPE_BIND_DEPTH_STENCIL``: A depth (Z) buffer and/or stencil buffer. Any
775  depth/stencil surface/resource attached to pipe_framebuffer_state::zsbuf must
776  have this flag set.
777* ``PIPE_BIND_BLENDABLE``: Used in conjunction with PIPE_BIND_RENDER_TARGET to
778  query whether a device supports blending for a given format.
779  If this flag is set, surface creation may fail if blending is not supported
780  for the specified format. If it is not set, a driver may choose to ignore
781  blending on surfaces with formats that would require emulation.
782* ``PIPE_BIND_DISPLAY_TARGET``: A surface that can be presented to screen. Arguments to
783  pipe_screen::flush_front_buffer must have this flag set.
784* ``PIPE_BIND_SAMPLER_VIEW``: A texture that may be sampled from in a fragment
785  or vertex shader.
786* ``PIPE_BIND_VERTEX_BUFFER``: A vertex buffer.
787* ``PIPE_BIND_INDEX_BUFFER``: An vertex index/element buffer.
788* ``PIPE_BIND_CONSTANT_BUFFER``: A buffer of shader constants.
789* ``PIPE_BIND_STREAM_OUTPUT``: A stream output buffer.
790* ``PIPE_BIND_CUSTOM``:
791* ``PIPE_BIND_SCANOUT``: A front color buffer or scanout buffer.
792* ``PIPE_BIND_SHARED``: A sharable buffer that can be given to another
793  process.
794* ``PIPE_BIND_GLOBAL``: A buffer that can be mapped into the global
795  address space of a compute program.
796* ``PIPE_BIND_SHADER_BUFFER``: A buffer without a format that can be bound
797  to a shader and can be used with load, store, and atomic instructions.
798* ``PIPE_BIND_SHADER_IMAGE``: A buffer or texture with a format that can be
799  bound to a shader and can be used with load, store, and atomic instructions.
800* ``PIPE_BIND_COMPUTE_RESOURCE``: A buffer or texture that can be
801  bound to the compute program as a shader resource.
802* ``PIPE_BIND_COMMAND_ARGS_BUFFER``: A buffer that may be sourced by the
803  GPU command processor. It can contain, for example, the arguments to
804  indirect draw calls.
805
806.. _pipe_usage:
807
808PIPE_USAGE_*
809^^^^^^^^^^^^
810
811The PIPE_USAGE enums are hints about the expected usage pattern of a resource.
812Note that drivers must always support read and write CPU access at any time
813no matter which hint they got.
814
815* ``PIPE_USAGE_DEFAULT``: Optimized for fast GPU access.
816* ``PIPE_USAGE_IMMUTABLE``: Optimized for fast GPU access and the resource is
817  not expected to be mapped or changed (even by the GPU) after the first upload.
818* ``PIPE_USAGE_DYNAMIC``: Expect frequent write-only CPU access. What is
819  uploaded is expected to be used at least several times by the GPU.
820* ``PIPE_USAGE_STREAM``: Expect frequent write-only CPU access. What is
821  uploaded is expected to be used only once by the GPU.
822* ``PIPE_USAGE_STAGING``: Optimized for fast CPU access.
823
824
825Methods
826-------
827
828XXX to-do
829
830get_name
831^^^^^^^^
832
833Returns an identifying name for the screen.
834
835The returned string should remain valid and immutable for the lifetime of
836pipe_screen.
837
838get_vendor
839^^^^^^^^^^
840
841Returns the screen vendor.
842
843The returned string should remain valid and immutable for the lifetime of
844pipe_screen.
845
846get_device_vendor
847^^^^^^^^^^^^^^^^^
848
849Returns the actual vendor of the device driving the screen
850(as opposed to the driver vendor).
851
852The returned string should remain valid and immutable for the lifetime of
853pipe_screen.
854
855.. _get_param:
856
857get_param
858^^^^^^^^^
859
860Get an integer/boolean screen parameter.
861
862**param** is one of the :ref:`PIPE_CAP` names.
863
864.. _get_paramf:
865
866get_paramf
867^^^^^^^^^^
868
869Get a floating-point screen parameter.
870
871**param** is one of the :ref:`PIPE_CAPF` names.
872
873context_create
874^^^^^^^^^^^^^^
875
876Create a pipe_context.
877
878**priv** is private data of the caller, which may be put to various
879unspecified uses, typically to do with implementing swapbuffers
880and/or front-buffer rendering.
881
882is_format_supported
883^^^^^^^^^^^^^^^^^^^
884
885Determine if a resource in the given format can be used in a specific manner.
886
887**format** the resource format
888
889**target** one of the PIPE_TEXTURE_x flags
890
891**sample_count** the number of samples. 0 and 1 mean no multisampling,
892the maximum allowed legal value is 32.
893
894**storage_sample_count** the number of storage samples. This must be <=
895sample_count. See the documentation of ``pipe_resource::nr_storage_samples``.
896
897**bindings** is a bitmask of :ref:`PIPE_BIND` flags.
898
899Returns TRUE if all usages can be satisfied.
900
901
902can_create_resource
903^^^^^^^^^^^^^^^^^^^
904
905Check if a resource can actually be created (but don't actually allocate any
906memory).  This is used to implement OpenGL's proxy textures.  Typically, a
907driver will simply check if the total size of the given resource is less than
908some limit.
909
910For PIPE_TEXTURE_CUBE, the pipe_resource::array_size field should be 6.
911
912
913.. _resource_create:
914
915resource_create
916^^^^^^^^^^^^^^^
917
918Create a new resource from a template.
919The following fields of the pipe_resource must be specified in the template:
920
921**target** one of the pipe_texture_target enums.
922Note that PIPE_BUFFER and PIPE_TEXTURE_X are not really fundamentally different.
923Modern APIs allow using buffers as shader resources.
924
925**format** one of the pipe_format enums.
926
927**width0** the width of the base mip level of the texture or size of the buffer.
928
929**height0** the height of the base mip level of the texture
930(1 for 1D or 1D array textures).
931
932**depth0** the depth of the base mip level of the texture
933(1 for everything else).
934
935**array_size** the array size for 1D and 2D array textures.
936For cube maps this must be 6, for other textures 1.
937
938**last_level** the last mip map level present.
939
940**nr_samples**: Number of samples determining quality, driving the rasterizer,
941shading, and framebuffer. It is the number of samples seen by the whole
942graphics pipeline. 0 and 1 specify a resource which isn't multisampled.
943
944**nr_storage_samples**: Only color buffers can set this lower than nr_samples.
945Multiple samples within a pixel can have the same color. ``nr_storage_samples``
946determines how many slots for different colors there are per pixel.
947If there are not enough slots to store all sample colors, some samples will
948have an undefined color (called "undefined samples").
949
950The resolve blit behavior is driver-specific, but can be one of these two:
951
9521. Only defined samples will be averaged. Undefined samples will be ignored.
9532. Undefined samples will be approximated by looking at surrounding defined
954   samples (even in different pixels).
955
956Blits and MSAA texturing: If the sample being fetched is undefined, one of
957the defined samples is returned instead.
958
959Sample shading (``set_min_samples``) will operate at a sample frequency that
960is at most ``nr_storage_samples``. Greater ``min_samples`` values will be
961replaced by ``nr_storage_samples``.
962
963**usage** one of the :ref:`PIPE_USAGE` flags.
964
965**bind** bitmask of the :ref:`PIPE_BIND` flags.
966
967**flags** bitmask of PIPE_RESOURCE_FLAG flags.
968
969**next**: Pointer to the next plane for resources that consist of multiple
970memory planes.
971
972As a corollary, this mean resources for an image with multiple planes have
973to be created starting from the highest plane.
974
975resource_changed
976^^^^^^^^^^^^^^^^
977
978Mark a resource as changed so derived internal resources will be recreated
979on next use.
980
981When importing external images that can't be directly used as texture sampler
982source, internal copies may have to be created that the hardware can sample
983from. When those resources are reimported, the image data may have changed, and
984the previously derived internal resources must be invalidated to avoid sampling
985from old copies.
986
987
988
989resource_destroy
990^^^^^^^^^^^^^^^^
991
992Destroy a resource. A resource is destroyed if it has no more references.
993
994
995
996get_timestamp
997^^^^^^^^^^^^^
998
999Query a timestamp in nanoseconds. The returned value should match
1000PIPE_QUERY_TIMESTAMP. This function returns immediately and doesn't
1001wait for rendering to complete (which cannot be achieved with queries).
1002
1003
1004
1005get_driver_query_info
1006^^^^^^^^^^^^^^^^^^^^^
1007
1008Return a driver-specific query. If the **info** parameter is NULL,
1009the number of available queries is returned.  Otherwise, the driver
1010query at the specified **index** is returned in **info**.
1011The function returns non-zero on success.
1012The driver-specific query is described with the pipe_driver_query_info
1013structure.
1014
1015get_driver_query_group_info
1016^^^^^^^^^^^^^^^^^^^^^^^^^^^
1017
1018Return a driver-specific query group. If the **info** parameter is NULL,
1019the number of available groups is returned.  Otherwise, the driver
1020query group at the specified **index** is returned in **info**.
1021The function returns non-zero on success.
1022The driver-specific query group is described with the
1023pipe_driver_query_group_info structure.
1024
1025
1026
1027get_disk_shader_cache
1028^^^^^^^^^^^^^^^^^^^^^
1029
1030Returns a pointer to a driver-specific on-disk shader cache. If the driver
1031failed to create the cache or does not support an on-disk shader cache NULL is
1032returned. The callback itself may also be NULL if the driver doesn't support
1033an on-disk shader cache.
1034
1035
1036Thread safety
1037-------------
1038
1039Screen methods are required to be thread safe. While gallium rendering
1040contexts are not required to be thread safe, it is required to be safe to use
1041different contexts created with the same screen in different threads without
1042locks. It is also required to be safe using screen methods in a thread, while
1043using one of its contexts in another (without locks).
1044