1 /*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 1999-2007 Brian Paul 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 "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * Authors:
25 * Brian Paul
26 */
27
28 #include "c99_math.h"
29 #include "main/glheader.h"
30 #include "main/mtypes.h"
31 #include "main/dd.h"
32 #include "main/imports.h"
33 #include "t_context.h"
34 #include "t_pipeline.h"
35
36
37 struct point_stage_data {
38 GLvector4f PointSize;
39 };
40
41 #define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->privatePtr)
42
43
44 /**
45 * Compute point size for each vertex from the vertex eye-space Z
46 * coordinate and the point size attenuation factors.
47 * Only done when point size attenuation is enabled and vertex program is
48 * disabled.
49 */
50 static GLboolean
run_point_stage(struct gl_context * ctx,struct tnl_pipeline_stage * stage)51 run_point_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
52 {
53 if (ctx->Point._Attenuated && !ctx->VertexProgram._Current) {
54 struct point_stage_data *store = POINT_STAGE_DATA(stage);
55 struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
56 const GLfloat *eyeCoord = (GLfloat *) VB->EyePtr->data + 2;
57 const GLint eyeCoordStride = VB->EyePtr->stride / sizeof(GLfloat);
58 const GLfloat p0 = ctx->Point.Params[0];
59 const GLfloat p1 = ctx->Point.Params[1];
60 const GLfloat p2 = ctx->Point.Params[2];
61 const GLfloat pointSize = ctx->Point.Size;
62 GLfloat (*size)[4] = store->PointSize.data;
63 GLuint i;
64
65 for (i = 0; i < VB->Count; i++) {
66 const GLfloat dist = fabsf(*eyeCoord);
67 const GLfloat q = p0 + dist * (p1 + dist * p2);
68 const GLfloat atten = (q != 0.0F) ? (1.0f / sqrtf(q)) : 1.0F;
69 size[i][0] = pointSize * atten; /* clamping done in rasterization */
70 eyeCoord += eyeCoordStride;
71 }
72
73 VB->AttribPtr[_TNL_ATTRIB_POINTSIZE] = &store->PointSize;
74 }
75
76 return GL_TRUE;
77 }
78
79
80 static GLboolean
alloc_point_data(struct gl_context * ctx,struct tnl_pipeline_stage * stage)81 alloc_point_data(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
82 {
83 struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
84 struct point_stage_data *store;
85 stage->privatePtr = malloc(sizeof(*store));
86 store = POINT_STAGE_DATA(stage);
87 if (!store)
88 return GL_FALSE;
89
90 _mesa_vector4f_alloc( &store->PointSize, 0, VB->Size, 32 );
91 return GL_TRUE;
92 }
93
94
95 static void
free_point_data(struct tnl_pipeline_stage * stage)96 free_point_data(struct tnl_pipeline_stage *stage)
97 {
98 struct point_stage_data *store = POINT_STAGE_DATA(stage);
99 if (store) {
100 _mesa_vector4f_free( &store->PointSize );
101 free( store );
102 stage->privatePtr = NULL;
103 }
104 }
105
106
107 const struct tnl_pipeline_stage _tnl_point_attenuation_stage =
108 {
109 "point size attenuation", /* name */
110 NULL, /* stage private data */
111 alloc_point_data, /* alloc data */
112 free_point_data, /* destructor */
113 NULL,
114 run_point_stage /* run */
115 };
116