1/*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
23 *
24 * Authors:
25 *    Keith Whitwell <keithw@vmware.com>
26 */
27
28
29#include "main/glheader.h"
30#include "main/macros.h"
31#include "main/imports.h"
32#include "main/mtypes.h"
33
34#include "math/m_xform.h"
35
36#include "t_context.h"
37#include "t_pipeline.h"
38
39
40struct normal_stage_data {
41   normal_func NormalTransform;
42   GLvector4f normal;
43};
44
45#define NORMAL_STAGE_DATA(stage) ((struct normal_stage_data *)stage->privatePtr)
46
47
48static GLboolean
49run_normal_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
50{
51   struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
52   struct vertex_buffer *VB = &TNL_CONTEXT(ctx)->vb;
53   const GLfloat *lengths;
54
55   if (!store->NormalTransform)
56      return GL_TRUE;
57
58   /* We can only use the display list's saved normal lengths if we've
59    * got a transformation matrix with uniform scaling.
60    */
61   if (_math_matrix_is_general_scale(ctx->ModelviewMatrixStack.Top))
62      lengths = NULL;
63   else
64      lengths = VB->NormalLengthPtr;
65
66   store->NormalTransform( ctx->ModelviewMatrixStack.Top,
67			   ctx->_ModelViewInvScale,
68			   VB->AttribPtr[_TNL_ATTRIB_NORMAL],  /* input normals */
69			   lengths,
70			   &store->normal ); /* resulting normals */
71
72   if (VB->AttribPtr[_TNL_ATTRIB_NORMAL]->count > 1) {
73      store->normal.stride = 4 * sizeof(GLfloat);
74   }
75   else {
76      store->normal.stride = 0;
77   }
78
79   VB->AttribPtr[_TNL_ATTRIB_NORMAL] = &store->normal;
80
81   VB->NormalLengthPtr = NULL;	/* no longer valid */
82   return GL_TRUE;
83}
84
85
86/**
87 * Examine current GL state and set the store->NormalTransform pointer
88 * to point to the appropriate normal transformation routine.
89 */
90static void
91validate_normal_stage(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
92{
93   struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
94
95   if (ctx->VertexProgram._Current ||
96       (!ctx->Light.Enabled &&
97	!(ctx->Texture._GenFlags & TEXGEN_NEED_NORMALS))) {
98      store->NormalTransform = NULL;
99      return;
100   }
101
102   if (ctx->_NeedEyeCoords) {
103      /* Eye coordinates are needed, for whatever reasons.
104       * Do lighting in eye coordinates, as the GL spec says.
105       */
106      GLuint transform = NORM_TRANSFORM_NO_ROT;
107
108      if (_math_matrix_has_rotation(ctx->ModelviewMatrixStack.Top)) {
109         /* need to do full (3x3) matrix transform */
110	 transform = NORM_TRANSFORM;
111      }
112
113      if (ctx->Transform.Normalize) {
114	 store->NormalTransform = _mesa_normal_tab[transform | NORM_NORMALIZE];
115      }
116      else if (ctx->Transform.RescaleNormals &&
117               ctx->_ModelViewInvScale != 1.0F) {
118	 store->NormalTransform = _mesa_normal_tab[transform | NORM_RESCALE];
119      }
120      else {
121	 store->NormalTransform = _mesa_normal_tab[transform];
122      }
123   }
124   else {
125      /* We don't need eye coordinates.
126       * Do lighting in object coordinates.  Thus, we don't need to fully
127       * transform normal vectors (just leave them in object coordinates)
128       * but we still need to do normalization/rescaling if enabled.
129       */
130      if (ctx->Transform.Normalize) {
131	 store->NormalTransform = _mesa_normal_tab[NORM_NORMALIZE];
132      }
133      else if (!ctx->Transform.RescaleNormals &&
134	       ctx->_ModelViewInvScale != 1.0F) {
135	 store->NormalTransform = _mesa_normal_tab[NORM_RESCALE];
136      }
137      else {
138	 store->NormalTransform = NULL;
139      }
140   }
141}
142
143
144/**
145 * Allocate stage's private data (storage for transformed normals).
146 */
147static GLboolean
148alloc_normal_data(struct gl_context *ctx, struct tnl_pipeline_stage *stage)
149{
150   TNLcontext *tnl = TNL_CONTEXT(ctx);
151   struct normal_stage_data *store;
152
153   stage->privatePtr = malloc(sizeof(*store));
154   store = NORMAL_STAGE_DATA(stage);
155   if (!store)
156      return GL_FALSE;
157
158   _mesa_vector4f_alloc( &store->normal, 0, tnl->vb.Size, 32 );
159   return GL_TRUE;
160}
161
162
163/**
164 * Free stage's private data.
165 */
166static void
167free_normal_data(struct tnl_pipeline_stage *stage)
168{
169   struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
170   if (store) {
171      _mesa_vector4f_free( &store->normal );
172      free( store );
173      stage->privatePtr = NULL;
174   }
175}
176
177
178const struct tnl_pipeline_stage _tnl_normal_transform_stage =
179{
180   "normal transform",		/* name */
181   NULL,			/* privatePtr */
182   alloc_normal_data,		/* create */
183   free_normal_data,		/* destroy */
184   validate_normal_stage,	/* validate */
185   run_normal_stage             /* run */
186};
187