reactos/dll/opengl/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 #include <precomp.h>
  26
  27 /**
  28  * Update derived clip plane state.
  29  */
  30 void
  31 _mesa_update_clip_plane(struct gl_context *ctx, GLuint plane)
  32 {
  33    if (_math_matrix_is_dirty(ctx->ProjectionMatrixStack.Top))
  34       _math_matrix_analyse( ctx->ProjectionMatrixStack.Top );
  35
  36    /* Clip-Space Plane = Eye-Space Plane * Projection Matrix */
  37    _mesa_transform_vector(ctx->Transform._ClipUserPlane[plane],
  38                           ctx->Transform.EyeUserPlane[plane],
  39                           ctx->ProjectionMatrixStack.Top->inv);
  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    if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
  83       _mesa_update_clip_plane(ctx, p);
  84    }
  85
  86    if (ctx->Driver.ClipPlane)
  87       ctx->Driver.ClipPlane( ctx, plane, equation );
  88 }
  89
  90
  91 void GLAPIENTRY
  92 _mesa_GetClipPlane( GLenum plane, GLdouble *equation )
  93 {
  94    GET_CURRENT_CONTEXT(ctx);
  95    GLint p;
  96    ASSERT_OUTSIDE_BEGIN_END(ctx);
  97
  98    p = (GLint) (plane - GL_CLIP_PLANE0);
  99    if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
 100       _mesa_error( ctx, GL_INVALID_ENUM, "glGetClipPlane" );
 101       return;
 102    }
 103
 104    equation[0] = (GLdouble) ctx->Transform.EyeUserPlane[p][0];
 105    equation[1] = (GLdouble) ctx->Transform.EyeUserPlane[p][1];
 106    equation[2] = (GLdouble) ctx->Transform.EyeUserPlane[p][2];
 107    equation[3] = (GLdouble) ctx->Transform.EyeUserPlane[p][3];
 108 }