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 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 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 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