src/mesa/tnl/t_vb_normals.c

   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
  42 struct 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
  50 static GLboolean
  51 run_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    VB->NormalPtr = &store->normal;
  83
  84    VB->NormalLengthPtr = NULL;  /* no longer valid */
  85    return GL_TRUE;
  86 }
  87
  88
  89 /**
  90  * Examine current GL state and set the store->NormalTransform pointer
  91  * to point to the appropriate normal transformation routine.
  92  */
  93 static void
  94 validate_normal_stage(GLcontext *ctx, struct tnl_pipeline_stage *stage)
  95 {
  96    struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
  97
  98    if (ctx->VertexProgram._Current ||
  99        (!ctx->Light.Enabled &&
 100         !(ctx->Texture._GenFlags & TEXGEN_NEED_NORMALS))) {
 101       store->NormalTransform = NULL;
 102       return;
 103    }
 104
 105    if (ctx->_NeedEyeCoords) {
 106       /* Eye coordinates are needed, for whatever reasons.
 107        * Do lighting in eye coordinates, as the GL spec says.
 108        */
 109       GLuint transform = NORM_TRANSFORM_NO_ROT;
 110
 111       if (_math_matrix_has_rotation(ctx->ModelviewMatrixStack.Top)) {
 112          /* need to do full (3x3) matrix transform */
 113          transform = NORM_TRANSFORM;
 114       }
 115
 116       if (ctx->Transform.Normalize) {
 117          store->NormalTransform = _mesa_normal_tab[transform | NORM_NORMALIZE];
 118       }
 119       else if (ctx->Transform.RescaleNormals &&
 120                ctx->_ModelViewInvScale != 1.0) {
 121          store->NormalTransform = _mesa_normal_tab[transform | NORM_RESCALE];
 122       }
 123       else {
 124          store->NormalTransform = _mesa_normal_tab[transform];
 125       }
 126    }
 127    else {
 128       /* We don't need eye coordinates.
 129        * Do lighting in object coordinates.  Thus, we don't need to fully
 130        * transform normal vectors (just leave them in object coordinates)
 131        * but we still need to do normalization/rescaling if enabled.
 132        */
 133       if (ctx->Transform.Normalize) {
 134          store->NormalTransform = _mesa_normal_tab[NORM_NORMALIZE];
 135       }
 136       else if (!ctx->Transform.RescaleNormals &&
 137                ctx->_ModelViewInvScale != 1.0) {
 138          store->NormalTransform = _mesa_normal_tab[NORM_RESCALE];
 139       }
 140       else {
 141          store->NormalTransform = NULL;
 142       }
 143    }
 144 }
 145
 146
 147 /**
 148  * Allocate stage's private data (storage for transformed normals).
 149  */
 150 static GLboolean
 151 alloc_normal_data(GLcontext *ctx, struct tnl_pipeline_stage *stage)
 152 {
 153    TNLcontext *tnl = TNL_CONTEXT(ctx);
 154    struct normal_stage_data *store;
 155
 156    stage->privatePtr = _mesa_malloc(sizeof(*store));
 157    store = NORMAL_STAGE_DATA(stage);
 158    if (!store)
 159       return GL_FALSE;
 160
 161    _mesa_vector4f_alloc( &store->normal, 0, tnl->vb.Size, 32 );
 162    return GL_TRUE;
 163 }
 164
 165
 166 /**
 167  * Free stage's private data.
 168  */
 169 static void
 170 free_normal_data(struct tnl_pipeline_stage *stage)
 171 {
 172    struct normal_stage_data *store = NORMAL_STAGE_DATA(stage);
 173    if (store) {
 174       _mesa_vector4f_free( &store->normal );
 175       _mesa_free( store );
 176       stage->privatePtr = NULL;
 177    }
 178 }
 179
 180
 181 const struct tnl_pipeline_stage _tnl_normal_transform_stage =
 182 {
 183    "normal transform",          /* name */
 184    NULL,                        /* privatePtr */
 185    alloc_normal_data,           /* create */
 186    free_normal_data,            /* destroy */
 187    validate_normal_stage,       /* validate */
 188    run_normal_stage             /* run */
 189 };