t_vb_normals.c revision 32f2fd1c5d6088692551c80352b7d6fa35b0cd09 
1/*
2 * Mesa 3-D graphics library
3 * Version:  6.5
4 *
5 * Copyright (C) 1999-2006  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 *    Keith Whitwell <keith@tungstengraphics.com>
26 */
27
28
29#include "main/glheader.h"
30#include "main/colormac.h"
31#include "main/context.h"
32#include "main/macros.h"
33#include "main/imports.h"
34#include "main/mtypes.h"
35
36#include "math/m_xform.h"
37
38#include "t_context.h"
39#include "t_pipeline.h"
40
41
42struct normal_stage_data {
43   normal_func NormalTransform;
44   GLvector4f normal;
45};
46
47#define NORMAL_STAGE_DATA(stage) ((struct normal_stage_data *)stage->privatePtr)
48
49
50static GLboolean
51run_normal_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage)
52{
53   struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
54   struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
55   const GLfloat *lengths;
56
57   if (!store->NormalTransform)
58      return GL_TRUE;
59
60   /* We can only use the display list's saved normal lengths if we've
61    * got a transformation matrix with uniform scaling.
62    */
63   if (_math_matrix_is_general_scale(ctx->ModelviewMatrixStack.Top))
64      lengths = NULL;
65   else
66      lengths = VB->NormalLengthPtr;
67
68   store->NormalTransform( ctx->ModelviewMatrixStack.Top,
69			   ctx->_ModelViewInvScale,
70			   VB->AttribPtr[_TNL_ATTRIB_NORMAL],  /* input normals */
71			   lengths,
72			   &store->normal ); /* resulting normals */
73
74   if (VB->AttribPtr[_TNL_ATTRIB_NORMAL]->count > 1) {
75      store->normal.stride = 4 * sizeof(GLfloat);
76   }
77   else {
78      store->normal.stride = 0;
79   }
80
81   VB->AttribPtr[_TNL_ATTRIB_NORMAL] = &store->normal;
82
83   VB->NormalLengthPtr = NULL;	/* no longer valid */
84   return GL_TRUE;
85}
86
87
88/**
89 * Examine current GL state and set the store->NormalTransform pointer
90 * to point to the appropriate normal transformation routine.
91 */
92static void
93validate_normal_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage)
94{
95   struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
96
97   if (ctx->VertexProgram._Current ||
98       (!ctx->Light.Enabled &&
99	!(ctx->Texture._GenFlags & TEXGEN_NEED_NORMALS))) {
100      store->NormalTransform = NULL;
101      return;
102   }
103
104   if (ctx->_NeedEyeCoords) {
105      /* Eye coordinates are needed, for whatever reasons.
106       * Do lighting in eye coordinates, as the GL spec says.
107       */
108      GLuint transform = NORM_TRANSFORM_NO_ROT;
109
110      if (_math_matrix_has_rotation(ctx->ModelviewMatrixStack.Top)) {
111         /* need to do full (3x3) matrix transform */
112	 transform = NORM_TRANSFORM;
113      }
114
115      if (ctx->Transform.Normalize) {
116	 store->NormalTransform = _mesa_normal_tab[transform | NORM_NORMALIZE];
117      }
118      else if (ctx->Transform.RescaleNormals &&
119               ctx->_ModelViewInvScale != 1.0) {
120	 store->NormalTransform = _mesa_normal_tab[transform | NORM_RESCALE];
121      }
122      else {
123	 store->NormalTransform = _mesa_normal_tab[transform];
124      }
125   }
126   else {
127      /* We don't need eye coordinates.
128       * Do lighting in object coordinates.  Thus, we don't need to fully
129       * transform normal vectors (just leave them in object coordinates)
130       * but we still need to do normalization/rescaling if enabled.
131       */
132      if (ctx->Transform.Normalize) {
133	 store->NormalTransform = _mesa_normal_tab[NORM_NORMALIZE];
134      }
135      else if (!ctx->Transform.RescaleNormals &&
136	       ctx->_ModelViewInvScale != 1.0) {
137	 store->NormalTransform = _mesa_normal_tab[NORM_RESCALE];
138      }
139      else {
140	 store->NormalTransform = NULL;
141      }
142   }
143}
144
145
146/**
147 * Allocate stage's private data (storage for transformed normals).
148 */
149static GLboolean
150alloc_normal_data(GLcontext *ctx, struct tnl_pipeline_stage *stage)
151{
152   TNLcontext *tnl = TNL_CONTEXT(ctx);
153   struct normal_stage_data *store;
154
155   stage->privatePtr = malloc(sizeof(*store));
156   store = NORMAL_STAGE_DATA(stage);
157   if (!store)
158      return GL_FALSE;
159
160   _mesa_vector4f_alloc( &store->normal, 0, tnl->vb.Size, 32 );
161   return GL_TRUE;
162}
163
164
165/**
166 * Free stage's private data.
167 */
168static void
169free_normal_data(struct tnl_pipeline_stage *stage)
170{
171   struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
172   if (store) {
173      _mesa_vector4f_free( &store->normal );
174      free( store );
175      stage->privatePtr = NULL;
176   }
177}
178
179
180const struct tnl_pipeline_stage _tnl_normal_transform_stage =
181{
182   "normal transform",		/* name */
183   NULL,			/* privatePtr */
184   alloc_normal_data,		/* create */
185   free_normal_data,		/* destroy */
186   validate_normal_stage,	/* validate */
187   run_normal_stage             /* run */
188};
189