src/mesa/main/clip.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.3
   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 "clip.h"
  28 #include "context.h"
  29 #include "macros.h"
  30 #include "mtypes.h"
  31
  32 #include "math/m_matrix.h"
  33
  34
  35
  36 /**********************************************************************/
  37 /*                     Get/Set User clip-planes.                      */
  38 /**********************************************************************/
  39
  40
  41
  42 void GLAPIENTRY
  43 _mesa_ClipPlane( GLenum plane, const GLdouble *eq )
  44 {
  45    GET_CURRENT_CONTEXT(ctx);
  46    GLint p;
  47    GLfloat equation[4];
  48    ASSERT_OUTSIDE_BEGIN_END(ctx);
  49
  50    p = (GLint) plane - (GLint) GL_CLIP_PLANE0;
  51    if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
  52       _mesa_error( ctx, GL_INVALID_ENUM, "glClipPlane" );
  53       return;
  54    }
  55
  56    equation[0] = (GLfloat) eq[0];
  57    equation[1] = (GLfloat) eq[1];
  58    equation[2] = (GLfloat) eq[2];
  59    equation[3] = (GLfloat) eq[3];
  60
  61    /*
  62     * The equation is transformed by the transpose of the inverse of the
  63     * current modelview matrix and stored in the resulting eye coordinates.
  64     *
  65     * KW: Eqn is then transformed to the current clip space, where user
  66     * clipping now takes place.  The clip-space equations are recalculated
  67     * whenever the projection matrix changes.
  68     */
  69    if (_math_matrix_is_dirty(ctx->ModelviewMatrixStack.Top))
  70       _math_matrix_analyse( ctx->ModelviewMatrixStack.Top );
  71
  72    _mesa_transform_vector( equation, equation,
  73                            ctx->ModelviewMatrixStack.Top->inv );
  74
  75    if (TEST_EQ_4V(ctx->Transform.EyeUserPlane[p], equation))
  76       return;
  77
  78    FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
  79    COPY_4FV(ctx->Transform.EyeUserPlane[p], equation);
  80
  81    /* Update derived state.  This state also depends on the projection
  82     * matrix, and is recalculated on changes to the projection matrix by
  83     * code in _mesa_update_state().
  84     */
  85    if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
  86       if (_math_matrix_is_dirty(ctx->ProjectionMatrixStack.Top))
  87          _math_matrix_analyse( ctx->ProjectionMatrixStack.Top );
  88
  89       _mesa_transform_vector( ctx->Transform._ClipUserPlane[p],
  90                            ctx->Transform.EyeUserPlane[p],
  91                            ctx->ProjectionMatrixStack.Top->inv );
  92    }
  93
  94    if (ctx->Driver.ClipPlane)
  95       ctx->Driver.ClipPlane( ctx, plane, equation );
  96 }
  97
  98
  99 void GLAPIENTRY
 100 _mesa_GetClipPlane( GLenum plane, GLdouble *equation )
 101 {
 102    GET_CURRENT_CONTEXT(ctx);
 103    GLint p;
 104    ASSERT_OUTSIDE_BEGIN_END(ctx);
 105
 106    p = (GLint) (plane - GL_CLIP_PLANE0);
 107    if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
 108       _mesa_error( ctx, GL_INVALID_ENUM, "glGetClipPlane" );
 109       return;
 110    }
 111
 112    equation[0] = (GLdouble) ctx->Transform.EyeUserPlane[p][0];
 113    equation[1] = (GLdouble) ctx->Transform.EyeUserPlane[p][1];
 114    equation[2] = (GLdouble) ctx->Transform.EyeUserPlane[p][2];
 115    equation[3] = (GLdouble) ctx->Transform.EyeUserPlane[p][3];
 116 }
 117
 118 void GLAPIENTRY
 119 _mesa_CullParameterfvEXT (GLenum cap, GLfloat *v)
 120 {
 121    GET_CURRENT_CONTEXT(ctx);
 122    ASSERT_OUTSIDE_BEGIN_END(ctx);
 123
 124    switch (cap) {
 125    case GL_CULL_VERTEX_EYE_POSITION_EXT:
 126       FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
 127       COPY_4FV(ctx->Transform.CullEyePos, v);
 128
 129       _mesa_transform_vector( ctx->Transform.CullObjPos,
 130                               ctx->Transform.CullEyePos,
 131                               ctx->ModelviewMatrixStack.Top->inv );
 132       break;
 133
 134    case GL_CULL_VERTEX_OBJECT_POSITION_EXT:
 135       FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
 136       COPY_4FV(ctx->Transform.CullObjPos, v);
 137
 138       _mesa_transform_vector( ctx->Transform.CullEyePos,
 139                               ctx->Transform.CullObjPos,
 140                               ctx->ModelviewMatrixStack.Top->m );
 141      break;
 142    default:
 143       _mesa_error( ctx, GL_INVALID_ENUM, "glCullParameterfvEXT" );
 144    }
 145 }
 146
 147 void GLAPIENTRY
 148 _mesa_CullParameterdvEXT (GLenum cap, GLdouble *v)
 149 {
 150    GLfloat f[4];
 151
 152    f[0] = (GLfloat)v[0];
 153    f[1] = (GLfloat)v[1];
 154    f[2] = (GLfloat)v[2];
 155    f[3] = (GLfloat)v[3];
 156
 157    _mesa_CullParameterfvEXT(cap, f);
 158 }
 159