depth.c revision 7117f1b4 
1/*
2 * Mesa 3-D graphics library
3 * Version:  6.5
4 *
5 * Copyright (C) 1999-2005  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
42void GLAPIENTRY
43_mesa_ClearDepth( GLclampd depth )
44{
45   GET_CURRENT_CONTEXT(ctx);
46   ASSERT_OUTSIDE_BEGIN_END(ctx);
47
48   depth = CLAMP( depth, 0.0, 1.0 );
49
50   if (ctx->Depth.Clear == depth)
51      return;
52
53   FLUSH_VERTICES(ctx, _NEW_DEPTH);
54   ctx->Depth.Clear = depth;
55   if (ctx->Driver.ClearDepth)
56      (*ctx->Driver.ClearDepth)( ctx, ctx->Depth.Clear );
57}
58
59
60
61void GLAPIENTRY
62_mesa_DepthFunc( GLenum func )
63{
64   GET_CURRENT_CONTEXT(ctx);
65   ASSERT_OUTSIDE_BEGIN_END(ctx);
66
67   if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
68      _mesa_debug(ctx, "glDepthFunc %s\n", _mesa_lookup_enum_by_nr(func));
69
70   switch (func) {
71   case GL_LESS:    /* (default) pass if incoming z < stored z */
72   case GL_GEQUAL:
73   case GL_LEQUAL:
74   case GL_GREATER:
75   case GL_NOTEQUAL:
76   case GL_EQUAL:
77   case GL_ALWAYS:
78   case GL_NEVER:
79      break;
80   default:
81      _mesa_error( ctx, GL_INVALID_ENUM, "glDepth.Func" );
82      return;
83   }
84
85   if (ctx->Depth.Func == func)
86      return;
87
88   FLUSH_VERTICES(ctx, _NEW_DEPTH);
89   ctx->Depth.Func = func;
90
91   if (ctx->Driver.DepthFunc)
92      ctx->Driver.DepthFunc( ctx, func );
93}
94
95
96
97void GLAPIENTRY
98_mesa_DepthMask( GLboolean flag )
99{
100   GET_CURRENT_CONTEXT(ctx);
101   ASSERT_OUTSIDE_BEGIN_END(ctx);
102
103   if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
104      _mesa_debug(ctx, "glDepthMask %d\n", flag);
105
106   /*
107    * GL_TRUE indicates depth buffer writing is enabled (default)
108    * GL_FALSE indicates depth buffer writing is disabled
109    */
110   if (ctx->Depth.Mask == flag)
111      return;
112
113   FLUSH_VERTICES(ctx, _NEW_DEPTH);
114   ctx->Depth.Mask = flag;
115
116   if (ctx->Driver.DepthMask)
117      ctx->Driver.DepthMask( ctx, flag );
118}
119
120
121
122/**
123 * Specified by the GL_EXT_depth_bounds_test extension.
124 */
125void GLAPIENTRY
126_mesa_DepthBoundsEXT( GLclampd zmin, GLclampd zmax )
127{
128   GET_CURRENT_CONTEXT(ctx);
129   ASSERT_OUTSIDE_BEGIN_END(ctx);
130
131   if (zmin > zmax) {
132      _mesa_error(ctx, GL_INVALID_VALUE, "glDepthBoundsEXT(zmin > zmax)");
133      return;
134   }
135
136   zmin = CLAMP(zmin, 0.0, 1.0);
137   zmax = CLAMP(zmax, 0.0, 1.0);
138
139   if (ctx->Depth.BoundsMin == zmin && ctx->Depth.BoundsMax == zmax)
140      return;
141
142   FLUSH_VERTICES(ctx, _NEW_DEPTH);
143   ctx->Depth.BoundsMin = (GLfloat) zmin;
144   ctx->Depth.BoundsMax = (GLfloat) zmax;
145}
146
147
148/**********************************************************************/
149/*****                      Initialization                        *****/
150/**********************************************************************/
151
152
153/**
154 * Initialize the depth buffer attribute group in the given context.
155 */
156void _mesa_init_depth( GLcontext * ctx )
157{
158   /* Depth buffer group */
159   ctx->Depth.Test = GL_FALSE;
160   ctx->Depth.Clear = 1.0;
161   ctx->Depth.Func = GL_LESS;
162   ctx->Depth.Mask = GL_TRUE;
163
164   /* XXX this is now per-framebuffer state */
165#if 00
166   /* Z buffer stuff */
167   if (ctx->Visual.depthBits == 0) {
168      /* Special case.  Even if we don't have a depth buffer we need
169       * good values for DepthMax for Z vertex transformation purposes
170       * and for per-fragment fog computation.
171       */
172      ctx->DepthMax = (1 << 16) - 1;
173      ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
174   }
175   else if (ctx->Visual.depthBits < 32) {
176      ctx->DepthMax = (1 << ctx->Visual.depthBits) - 1;
177      ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
178   }
179   else {
180      /* Special case since shift values greater than or equal to the
181       * number of bits in the left hand expression's type are undefined.
182       */
183      ctx->DepthMax = 0xffffffff;
184      ctx->DepthMaxF = (GLfloat) ctx->DepthMax;
185   }
186   ctx->MRD = 1.0;  /* Minimum resolvable depth value, for polygon offset */
187#endif
188}
189