1 /**************************************************************************
2 *
3 * Copyright 2010, VMware, inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 #include "util/u_bitcast.h"
29
TAG(do_cliptest)30 static boolean TAG(do_cliptest)( struct pt_post_vs *pvs,
31 struct draw_vertex_info *info,
32 const struct draw_prim_info *prim_info )
33 {
34 struct vertex_header *out = info->verts;
35 /* const */ float (*plane)[4] = pvs->draw->plane;
36 const unsigned pos = draw_current_shader_position_output(pvs->draw);
37 const unsigned cv = draw_current_shader_clipvertex_output(pvs->draw);
38 unsigned cd[2];
39 const unsigned ef = pvs->draw->vs.edgeflag_output;
40 unsigned ucp_enable = pvs->draw->rasterizer->clip_plane_enable;
41 unsigned flags = (FLAGS);
42 unsigned need_pipeline = 0;
43 unsigned j;
44 unsigned i;
45 bool have_cd = false;
46 unsigned viewport_index_output =
47 draw_current_shader_viewport_index_output(pvs->draw);
48 int viewport_index =
49 draw_current_shader_uses_viewport_index(pvs->draw) ?
50 u_bitcast_f2u(out->data[viewport_index_output][0]): 0;
51 int num_written_clipdistance =
52 draw_current_shader_num_written_clipdistances(pvs->draw);
53
54 cd[0] = draw_current_shader_ccdistance_output(pvs->draw, 0);
55 cd[1] = draw_current_shader_ccdistance_output(pvs->draw, 1);
56
57 if (cd[0] != pos || cd[1] != pos)
58 have_cd = true;
59
60 /* If clipdistance semantic has been written by the shader
61 * that means we're expected to do 'user plane clipping' */
62 if (num_written_clipdistance && !(flags & DO_CLIP_USER)) {
63 flags |= DO_CLIP_USER;
64 ucp_enable = (1 << num_written_clipdistance) - 1;
65 }
66
67 assert(pos != -1);
68 for (j = 0; j < info->count; j++) {
69 float *position = out->data[pos];
70 unsigned mask = 0x0;
71 float *scale = pvs->draw->viewports[0].scale;
72 float *trans = pvs->draw->viewports[0].translate;
73 if (draw_current_shader_uses_viewport_index(pvs->draw)) {
74 unsigned verts_per_prim = u_vertices_per_prim(prim_info->prim);
75 /* only change the viewport_index for the leading vertex */
76 if (!(j % verts_per_prim)) {
77 viewport_index = u_bitcast_f2u(out->data[viewport_index_output][0]);
78 viewport_index = draw_clamp_viewport_idx(viewport_index);
79 }
80 scale = pvs->draw->viewports[viewport_index].scale;
81 trans = pvs->draw->viewports[viewport_index].translate;
82 }
83
84 initialize_vertex_header(out);
85
86 if (flags & (DO_CLIP_XY | DO_CLIP_XY_GUARD_BAND |
87 DO_CLIP_FULL_Z | DO_CLIP_HALF_Z | DO_CLIP_USER)) {
88 float *clipvertex = position;
89
90 if ((flags & DO_CLIP_USER) && cv != pos) {
91 assert(cv != -1);
92 clipvertex = out->data[cv];
93 }
94
95 for (i = 0; i < 4; i++) {
96 out->clip_pos[i] = position[i];
97 }
98
99 /* Be careful with NaNs. Comparisons must be true for them. */
100 /* Do the hardwired planes first:
101 */
102 if (flags & DO_CLIP_XY_GUARD_BAND) {
103 if (!(-0.50 * position[0] + position[3] >= 0)) mask |= (1<<0);
104 if (!( 0.50 * position[0] + position[3] >= 0)) mask |= (1<<1);
105 if (!(-0.50 * position[1] + position[3] >= 0)) mask |= (1<<2);
106 if (!( 0.50 * position[1] + position[3] >= 0)) mask |= (1<<3);
107 }
108 else if (flags & DO_CLIP_XY) {
109 if (!(-position[0] + position[3] >= 0)) mask |= (1<<0);
110 if (!( position[0] + position[3] >= 0)) mask |= (1<<1);
111 if (!(-position[1] + position[3] >= 0)) mask |= (1<<2);
112 if (!( position[1] + position[3] >= 0)) mask |= (1<<3);
113 }
114
115 /* Clip Z planes according to full cube, half cube or none.
116 */
117 if (flags & DO_CLIP_FULL_Z) {
118 if (!( position[2] + position[3] >= 0)) mask |= (1<<4);
119 if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
120 }
121 else if (flags & DO_CLIP_HALF_Z) {
122 if (!( position[2] >= 0)) mask |= (1<<4);
123 if (!(-position[2] + position[3] >= 0)) mask |= (1<<5);
124 }
125
126 if (flags & DO_CLIP_USER) {
127 unsigned ucp_mask = ucp_enable;
128
129 while (ucp_mask) {
130 unsigned plane_idx = ffs(ucp_mask)-1;
131 ucp_mask &= ~(1 << plane_idx);
132 plane_idx += 6;
133
134 /*
135 * for user clipping check if we have a clip distance output
136 * and the shader has written to it, otherwise use clipvertex
137 * to decide when the plane is clipping.
138 */
139 if (have_cd && num_written_clipdistance) {
140 float clipdist;
141 i = plane_idx - 6;
142 /* first four clip distance in first vector etc. */
143 if (i < 4)
144 clipdist = out->data[cd[0]][i];
145 else
146 clipdist = out->data[cd[1]][i-4];
147 if (clipdist < 0 || util_is_inf_or_nan(clipdist))
148 mask |= 1 << plane_idx;
149 } else {
150 if (!(dot4(clipvertex, plane[plane_idx]) >= 0))
151 mask |= 1 << plane_idx;
152 }
153 }
154 }
155
156 out->clipmask = mask;
157 need_pipeline |= out->clipmask;
158 }
159
160 /*
161 * Transform the vertex position from clip coords to window coords,
162 * if the vertex is unclipped.
163 */
164 if ((flags & DO_VIEWPORT) && mask == 0)
165 {
166 /* divide by w */
167 float w = 1.0f / position[3];
168
169 /* Viewport mapping */
170 position[0] = position[0] * w * scale[0] + trans[0];
171 position[1] = position[1] * w * scale[1] + trans[1];
172 position[2] = position[2] * w * scale[2] + trans[2];
173 position[3] = w;
174 }
175 #ifdef DEBUG
176 /* For debug builds, set the clipped vertex's window coordinate
177 * to NaN to help catch potential errors later.
178 */
179 else {
180 float zero = 0.0f;
181 position[0] =
182 position[1] =
183 position[2] =
184 position[3] = zero / zero; /* MSVC doesn't accept 0.0 / 0.0 */
185 }
186 #endif
187
188 if ((flags & DO_EDGEFLAG) && ef) {
189 const float *edgeflag = out->data[ef];
190 out->edgeflag = !(edgeflag[0] != 1.0f);
191 need_pipeline |= !out->edgeflag;
192 }
193
194 out = (struct vertex_header *)( (char *)out + info->stride );
195 }
196 return need_pipeline != 0;
197 }
198
199
200 #undef FLAGS
201 #undef TAG
202