src/mesa/tnl/t_vb_points.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.1
   4  *
   5  * Copyright (C) 1999-2004  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Brian Paul
  26  */
  27
  28 #include "mtypes.h"
  29 #include "imports.h"
  30 #include "t_context.h"
  31 #include "t_pipeline.h"
  32
  33
  34 struct point_stage_data {
  35    GLvector4f PointSize;
  36 };
  37
  38 #define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->privatePtr)
  39
  40
  41 /*
  42  * Compute attenuated point sizes
  43  */
  44 static GLboolean run_point_stage( GLcontext *ctx,
  45                                   struct tnl_pipeline_stage *stage )
  46 {
  47    struct point_stage_data *store = POINT_STAGE_DATA(stage);
  48    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
  49    const GLfloat (*eye)[4] = (const GLfloat (*)[4]) VB->EyePtr->data;
  50    const GLfloat p0 = ctx->Point.Params[0];
  51    const GLfloat p1 = ctx->Point.Params[1];
  52    const GLfloat p2 = ctx->Point.Params[2];
  53    const GLfloat pointSize = ctx->Point._Size;
  54    GLfloat (*size)[4] = store->PointSize.data;
  55    GLuint i;
  56
  57    if (stage->changed_inputs) {
  58       /* XXX do threshold and min/max clamping here? */
  59       for (i = 0; i < VB->Count; i++) {
  60          const GLfloat dist = -eye[i][2];
  61          /* GLfloat dist = SQRTF(pos[0]*pos[0]+pos[1]*pos[1]+pos[2]*pos[2]);*/
  62          size[i][0] = pointSize / (p0 + dist * (p1 + dist * p2));
  63       }
  64    }
  65
  66    VB->PointSizePtr = &store->PointSize;
  67    VB->AttribPtr[_TNL_ATTRIB_POINTSIZE] = &store->PointSize;
  68
  69    return GL_TRUE;
  70 }
  71
  72
  73 /* If point size attenuation is on we'll compute the point size for
  74  * each vertex in a special pipeline stage.
  75  */
  76 static void check_point_size( GLcontext *ctx, struct tnl_pipeline_stage *d )
  77 {
  78    d->active = ctx->Point._Attenuated && !ctx->VertexProgram._Enabled;
  79 }
  80
  81 static GLboolean alloc_point_data( GLcontext *ctx,
  82                                    struct tnl_pipeline_stage *stage )
  83 {
  84    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
  85    struct point_stage_data *store;
  86    stage->privatePtr = MALLOC(sizeof(*store));
  87    store = POINT_STAGE_DATA(stage);
  88    if (!store)
  89       return GL_FALSE;
  90
  91    _mesa_vector4f_alloc( &store->PointSize, 0, VB->Size, 32 );
  92
  93    /* Now run the stage.
  94     */
  95    stage->run = run_point_stage;
  96    return stage->run( ctx, stage );
  97 }
  98
  99
 100 static void free_point_data( struct tnl_pipeline_stage *stage )
 101 {
 102    struct point_stage_data *store = POINT_STAGE_DATA(stage);
 103    if (store) {
 104       _mesa_vector4f_free( &store->PointSize );
 105       FREE( store );
 106       stage->privatePtr = 0;
 107    }
 108 }
 109
 110 const struct tnl_pipeline_stage _tnl_point_attenuation_stage =
 111 {
 112    "point size attenuation",    /* name */
 113    _NEW_POINT|_NEW_PROGRAM,     /* check_state */
 114    _NEW_POINT,                  /* run_state */
 115    GL_FALSE,                    /* active */
 116    _TNL_BIT_POS,                /* inputs */
 117    _TNL_BIT_POS,                /* outputs */
 118    0,                           /* changed_inputs (temporary value) */
 119    NULL,                        /* stage private data */
 120    free_point_data,             /* destructor */
 121    check_point_size,            /* check */
 122    alloc_point_data             /* run -- initially set to alloc data */
 123 };