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 * Update derived clip plane state.
37 */
38void
39_mesa_update_clip_plane(struct gl_context *ctx, GLuint plane)
40{
41   if (_math_matrix_is_dirty(ctx->ProjectionMatrixStack.Top))
42      _math_matrix_analyse( ctx->ProjectionMatrixStack.Top );
43
44   /* Clip-Space Plane = Eye-Space Plane * Projection Matrix */
45   _mesa_transform_vector(ctx->Transform._ClipUserPlane[plane],
46                          ctx->Transform.EyeUserPlane[plane],
47                          ctx->ProjectionMatrixStack.Top->inv);
48}
49
50
51void GLAPIENTRY
52_mesa_ClipPlane( GLenum plane, const GLdouble *eq )
53{
54   GET_CURRENT_CONTEXT(ctx);
55   GLint p;
56   GLfloat equation[4];
57   ASSERT_OUTSIDE_BEGIN_END(ctx);
58
59   p = (GLint) plane - (GLint) GL_CLIP_PLANE0;
60   if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
61      _mesa_error( ctx, GL_INVALID_ENUM, "glClipPlane" );
62      return;
63   }
64
65   equation[0] = (GLfloat) eq[0];
66   equation[1] = (GLfloat) eq[1];
67   equation[2] = (GLfloat) eq[2];
68   equation[3] = (GLfloat) eq[3];
69
70   /*
71    * The equation is transformed by the transpose of the inverse of the
72    * current modelview matrix and stored in the resulting eye coordinates.
73    *
74    * KW: Eqn is then transformed to the current clip space, where user
75    * clipping now takes place.  The clip-space equations are recalculated
76    * whenever the projection matrix changes.
77    */
78   if (_math_matrix_is_dirty(ctx->ModelviewMatrixStack.Top))
79      _math_matrix_analyse( ctx->ModelviewMatrixStack.Top );
80
81   _mesa_transform_vector( equation, equation,
82                           ctx->ModelviewMatrixStack.Top->inv );
83
84   if (TEST_EQ_4V(ctx->Transform.EyeUserPlane[p], equation))
85      return;
86
87   FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
88   COPY_4FV(ctx->Transform.EyeUserPlane[p], equation);
89
90   if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
91      _mesa_update_clip_plane(ctx, p);
92   }
93
94   if (ctx->Driver.ClipPlane)
95      ctx->Driver.ClipPlane( ctx, plane, equation );
96}
97
98
99void 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