src/mesa/main/depth.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  5.1
   4  *
   5  * Copyright (C) 1999-2003  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
  25
  26 #include "glheader.h"
  27 #include "imports.h"
  28 #include "context.h"
  29 #include "depth.h"
  30 #include "enums.h"
  31 #include "hash.h"
  32 #include "macros.h"
  33 #include "mtypes.h"
  34
  35
  36 /**********************************************************************/
  37 /*****                          API Functions                     *****/
  38 /**********************************************************************/
  39
  40
  41
  42 void
  43 _mesa_ClearDepth( GLclampd depth )
  44 {
  45    GET_CURRENT_CONTEXT(ctx);
  46    GLfloat tmp = (GLfloat) CLAMP( depth, 0.0, 1.0 );
  47    ASSERT_OUTSIDE_BEGIN_END(ctx);
  48
  49    if (ctx->Depth.Clear == tmp)
  50       return;
  51
  52    FLUSH_VERTICES(ctx, _NEW_DEPTH);
  53    ctx->Depth.Clear = tmp;
  54    if (ctx->Driver.ClearDepth)
  55       (*ctx->Driver.ClearDepth)( ctx, ctx->Depth.Clear );
  56 }
  57
  58
  59
  60 void
  61 _mesa_DepthFunc( GLenum func )
  62 {
  63    GET_CURRENT_CONTEXT(ctx);
  64    ASSERT_OUTSIDE_BEGIN_END(ctx);
  65
  66    if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
  67       _mesa_debug(ctx, "glDepthFunc %s\n", _mesa_lookup_enum_by_nr(func));
  68
  69    switch (func) {
  70    case GL_LESS:    /* (default) pass if incoming z < stored z */
  71    case GL_GEQUAL:
  72    case GL_LEQUAL:
  73    case GL_GREATER:
  74    case GL_NOTEQUAL:
  75    case GL_EQUAL:
  76    case GL_ALWAYS:
  77    case GL_NEVER:
  78       break;
  79    default:
  80       _mesa_error( ctx, GL_INVALID_ENUM, "glDepth.Func" );
  81       return;
  82    }
  83
  84    if (ctx->Depth.Func == func)
  85       return;
  86
  87    FLUSH_VERTICES(ctx, _NEW_DEPTH);
  88    ctx->Depth.Func = func;
  89
  90    if (ctx->Driver.DepthFunc)
  91       ctx->Driver.DepthFunc( ctx, func );
  92 }
  93
  94
  95
  96 void
  97 _mesa_DepthMask( GLboolean flag )
  98 {
  99    GET_CURRENT_CONTEXT(ctx);
 100    ASSERT_OUTSIDE_BEGIN_END(ctx);
 101
 102    if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
 103       _mesa_debug(ctx, "glDepthMask %d\n", flag);
 104
 105    /*
 106     * GL_TRUE indicates depth buffer writing is enabled (default)
 107     * GL_FALSE indicates depth buffer writing is disabled
 108     */
 109    if (ctx->Depth.Mask == flag)
 110       return;
 111
 112    FLUSH_VERTICES(ctx, _NEW_DEPTH);
 113    ctx->Depth.Mask = flag;
 114
 115    if (ctx->Driver.DepthMask)
 116       ctx->Driver.DepthMask( ctx, flag );
 117 }
 118
 119
 120
 121 /* GL_EXT_depth_bounds_test */
 122 void
 123 _mesa_DepthBoundsEXT( GLclampd zmin, GLclampd zmax )
 124 {
 125    GET_CURRENT_CONTEXT(ctx);
 126    ASSERT_OUTSIDE_BEGIN_END(ctx);
 127
 128    if (zmin > zmax) {
 129       _mesa_error(ctx, GL_INVALID_VALUE, "glDepthBoundsEXT(zmin > zmax)");
 130       return;
 131    }
 132
 133    zmin = CLAMP(zmin, 0.0, 1.0);
 134    zmax = CLAMP(zmax, 0.0, 1.0);
 135
 136    if (ctx->Depth.BoundsMin == zmin && ctx->Depth.BoundsMax == zmax)
 137       return;
 138
 139    FLUSH_VERTICES(ctx, _NEW_DEPTH);
 140    ctx->Depth.BoundsMin = (GLfloat) zmin;
 141    ctx->Depth.BoundsMax = (GLfloat) zmax;
 142 }
 143
 144
 145 /**********************************************************************/
 146 /*****                      Initialization                        *****/
 147 /**********************************************************************/
 148
 149 void _mesa_init_depth( GLcontext * ctx )
 150 {
 151    /* Depth buffer group */
 152    ctx->Depth.Test = GL_FALSE;
 153    ctx->Depth.Clear = 1.0;
 154    ctx->Depth.Func = GL_LESS;
 155    ctx->Depth.Mask = GL_TRUE;
 156    ctx->Depth.OcclusionTest = GL_FALSE;
 157
 158    /* Z buffer stuff */
 159    if (ctx->Visual.depthBits == 0) {
 160       /* Special case.  Even if we don't have a depth buffer we need
 161        * good values for DepthMax for Z vertex transformation purposes
 162        * and for per-fragment fog computation.
 163        */
 164       ctx->DepthMax = 1 << 16;
 165       ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
 166    }
 167    else if (ctx->Visual.depthBits < 32) {
 168       ctx->DepthMax = (1 << ctx->Visual.depthBits) - 1;
 169       ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
 170    }
 171    else {
 172       /* Special case since shift values greater than or equal to the
 173        * number of bits in the left hand expression's type are undefined.
 174        */
 175       ctx->DepthMax = 0xffffffff;
 176       ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
 177    }
 178    ctx->MRD = 1.0;  /* Minimum resolvable depth value, for polygon offset */
 179
 180 #if FEATURE_ARB_occlusion_query
 181    ctx->Occlusion.QueryObjects = _mesa_NewHashTable();
 182 #endif
 183    ctx->OcclusionResult = GL_FALSE;
 184    ctx->OcclusionResultSaved = GL_FALSE;
 185 }