src/mesa/tnl/t_vb_normals.c

   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
  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
  40 struct 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
  48 static GLboolean
  49 run_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  */
  90 static void
  91 validate_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  */
 147 static GLboolean
 148 alloc_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  */
 166 static void
 167 free_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
 178 const 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 };