src/mesa/tnl/t_vb_points.c

   1 /* $Id: t_vb_points.c,v 1.9 2002/10/24 23:57:25 brianp Exp $ */
   2
   3 /*
   4  * Mesa 3-D graphics library
   5  * Version:  4.1
   6  *
   7  * Copyright (C) 1999-2002  Brian Paul   All Rights Reserved.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included
  17  * in all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  22  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  23  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  24  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * Authors:
  27  *    Brian Paul <brian@valinux.com>
  28  */
  29
  30 #include "mtypes.h"
  31 #include "imports.h"
  32 #include "t_context.h"
  33 #include "t_pipeline.h"
  34
  35
  36 struct point_stage_data {
  37    GLvector4f PointSize;
  38 };
  39
  40 #define POINT_STAGE_DATA(stage) ((struct point_stage_data *)stage->privatePtr)
  41
  42
  43 /*
  44  * Compute attenuated point sizes
  45  */
  46 static GLboolean run_point_stage( GLcontext *ctx,
  47                                   struct gl_pipeline_stage *stage )
  48 {
  49    struct point_stage_data *store = POINT_STAGE_DATA(stage);
  50    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
  51    const GLfloat (*eye)[4] = (const GLfloat (*)[4]) VB->EyePtr->data;
  52    const GLfloat p0 = ctx->Point.Params[0];
  53    const GLfloat p1 = ctx->Point.Params[1];
  54    const GLfloat p2 = ctx->Point.Params[2];
  55    const GLfloat pointSize = ctx->Point._Size;
  56    GLfloat (*size)[4] = store->PointSize.data;
  57    GLuint i;
  58
  59    if (stage->changed_inputs) {
  60       /* XXX do threshold and min/max clamping here? */
  61       for (i = 0; i < VB->Count; i++) {
  62          const GLfloat dist = -eye[i][2];
  63          /* GLfloat dist = GL_SQRT(pos[0]*pos[0]+pos[1]*pos[1]+pos[2]*pos[2]);*/
  64          size[i][0] = pointSize / (p0 + dist * (p1 + dist * p2));
  65       }
  66    }
  67
  68    VB->PointSizePtr = &store->PointSize;
  69
  70    return GL_TRUE;
  71 }
  72
  73
  74 /* If point size attenuation is on we'll compute the point size for
  75  * each vertex in a special pipeline stage.
  76  */
  77 static void check_point_size( GLcontext *ctx, struct gl_pipeline_stage *d )
  78 {
  79    d->active = ctx->Point._Attenuated && !ctx->VertexProgram.Enabled;
  80 }
  81
  82 static GLboolean alloc_point_data( GLcontext *ctx,
  83                                    struct gl_pipeline_stage *stage )
  84 {
  85    struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
  86    struct point_stage_data *store;
  87    stage->privatePtr = MALLOC(sizeof(*store));
  88    store = POINT_STAGE_DATA(stage);
  89    if (!store)
  90       return GL_FALSE;
  91
  92    _mesa_vector4f_alloc( &store->PointSize, 0, VB->Size, 32 );
  93
  94    /* Now run the stage.
  95     */
  96    stage->run = run_point_stage;
  97    return stage->run( ctx, stage );
  98 }
  99
 100
 101 static void free_point_data( struct gl_pipeline_stage *stage )
 102 {
 103    struct point_stage_data *store = POINT_STAGE_DATA(stage);
 104    if (store) {
 105       _mesa_vector4f_free( &store->PointSize );
 106       FREE( store );
 107       stage->privatePtr = 0;
 108    }
 109 }
 110
 111 const struct gl_pipeline_stage _tnl_point_attenuation_stage =
 112 {
 113    "point size attenuation",    /* name */
 114    _NEW_POINT,                  /* build_state_change */
 115    _NEW_POINT,                  /* run_state_change */
 116    GL_FALSE,                    /* active */
 117    VERT_BIT_EYE,                        /* inputs */
 118    VERT_BIT_POINT_SIZE,         /* outputs */
 119    0,                           /* changed_inputs (temporary value) */
 120    NULL,                        /* stage private data */
 121    free_point_data,             /* destructor */
 122    check_point_size,            /* check */
 123    alloc_point_data             /* run -- initially set to alloc data */
 124 };