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_xform.h"
  33 #include "math/m_matrix.h"
  34
  35
  36
  37 /**********************************************************************/
  38 /*                     Get/Set User clip-planes.                      */
  39 /**********************************************************************/
  40
  41
  42
  43 void GLAPIENTRY
  44 _mesa_ClipPlane( GLenum plane, const GLdouble *eq )
  45 {
  46    GET_CURRENT_CONTEXT(ctx);
  47    GLint p;
  48    GLfloat equation[4];
  49    ASSERT_OUTSIDE_BEGIN_END(ctx);
  50
  51    p = (GLint) plane - (GLint) GL_CLIP_PLANE0;
  52    if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
  53       _mesa_error( ctx, GL_INVALID_ENUM, "glClipPlane" );
  54       return;
  55    }
  56
  57    equation[0] = (GLfloat) eq[0];
  58    equation[1] = (GLfloat) eq[1];
  59    equation[2] = (GLfloat) eq[2];
  60    equation[3] = (GLfloat) eq[3];
  61
  62    /*
  63     * The equation is transformed by the transpose of the inverse of the
  64     * current modelview matrix and stored in the resulting eye coordinates.
  65     *
  66     * KW: Eqn is then transformed to the current clip space, where user
  67     * clipping now takes place.  The clip-space equations are recalculated
  68     * whenever the projection matrix changes.
  69     */
  70    if (_math_matrix_is_dirty(ctx->ModelviewMatrixStack.Top))
  71       _math_matrix_analyse( ctx->ModelviewMatrixStack.Top );
  72
  73    _mesa_transform_vector( equation, equation,
  74                            ctx->ModelviewMatrixStack.Top->inv );
  75
  76    if (TEST_EQ_4V(ctx->Transform.EyeUserPlane[p], equation))
  77       return;
  78
  79    FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
  80    COPY_4FV(ctx->Transform.EyeUserPlane[p], equation);
  81
  82    /* Update derived state.  This state also depends on the projection
  83     * matrix, and is recalculated on changes to the projection matrix by
  84     * code in _mesa_update_state().
  85     */
  86    if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
  87       if (_math_matrix_is_dirty(ctx->ProjectionMatrixStack.Top))
  88          _math_matrix_analyse( ctx->ProjectionMatrixStack.Top );
  89
  90       _mesa_transform_vector( ctx->Transform._ClipUserPlane[p],
  91                            ctx->Transform.EyeUserPlane[p],
  92                            ctx->ProjectionMatrixStack.Top->inv );
  93    }
  94
  95    if (ctx->Driver.ClipPlane)
  96       ctx->Driver.ClipPlane( ctx, plane, equation );
  97 }
  98
  99
 100 void GLAPIENTRY
 101 _mesa_GetClipPlane( GLenum plane, GLdouble *equation )
 102 {
 103    GET_CURRENT_CONTEXT(ctx);
 104    GLint p;
 105    ASSERT_OUTSIDE_BEGIN_END(ctx);
 106
 107    p = (GLint) (plane - GL_CLIP_PLANE0);
 108    if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
 109       _mesa_error( ctx, GL_INVALID_ENUM, "glGetClipPlane" );
 110       return;
 111    }
 112
 113    equation[0] = (GLdouble) ctx->Transform.EyeUserPlane[p][0];
 114    equation[1] = (GLdouble) ctx->Transform.EyeUserPlane[p][1];
 115    equation[2] = (GLdouble) ctx->Transform.EyeUserPlane[p][2];
 116    equation[3] = (GLdouble) ctx->Transform.EyeUserPlane[p][3];
 117 }
 118
 119 void GLAPIENTRY
 120 _mesa_CullParameterfvEXT (GLenum cap, GLfloat *v)
 121 {
 122    GET_CURRENT_CONTEXT(ctx);
 123    ASSERT_OUTSIDE_BEGIN_END(ctx);
 124
 125    switch (cap) {
 126    case GL_CULL_VERTEX_EYE_POSITION_EXT:
 127       FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
 128       COPY_4FV(ctx->Transform.CullEyePos, v);
 129
 130       _mesa_transform_vector( ctx->Transform.CullObjPos,
 131                               ctx->Transform.CullEyePos,
 132                               ctx->ModelviewMatrixStack.Top->inv );
 133       break;
 134
 135    case GL_CULL_VERTEX_OBJECT_POSITION_EXT:
 136       FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
 137       COPY_4FV(ctx->Transform.CullObjPos, v);
 138
 139       _mesa_transform_vector( ctx->Transform.CullEyePos,
 140                               ctx->Transform.CullObjPos,
 141                               ctx->ModelviewMatrixStack.Top->m );
 142      break;
 143    default:
 144       _mesa_error( ctx, GL_INVALID_ENUM, "glCullParameterfvEXT" );
 145    }
 146 }
 147
 148 void GLAPIENTRY
 149 _mesa_CullParameterdvEXT (GLenum cap, GLdouble *v)
 150 {
 151    GLfloat f[4];
 152
 153    f[0] = (GLfloat)v[0];
 154    f[1] = (GLfloat)v[1];
 155    f[2] = (GLfloat)v[2];
 156    f[3] = (GLfloat)v[3];
 157
 158    _mesa_CullParameterfvEXT(cap, f);
 159 }
 160