clip.c revision a864432fb4333dfbbe669554de7485d8426e1c38 
1/* $Id: clip.c,v 1.18 2000/11/27 18:22:13 brianp Exp $ */
2
3/*
4 * Mesa 3-D graphics library
5 * Version:  3.3
6 *
7 * Copyright (C) 1999  Brian Paul   All Rights Reserved.
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice shall be included
17 * in all copies or substantial portions of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
22 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
23 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 */
26
27
28#ifdef PC_HEADER
29#include "all.h"
30#else
31#include "glheader.h"
32#include "clip.h"
33#include "context.h"
34#include "macros.h"
35#include "mmath.h"
36#include "mtypes.h"
37
38#include "math/m_xform.h"
39#include "math/m_matrix.h"
40#endif
41
42
43
44
45
46
47/**********************************************************************/
48/*                     Get/Set User clip-planes.                      */
49/**********************************************************************/
50
51
52
53void
54_mesa_ClipPlane( GLenum plane, const GLdouble *eq )
55{
56   GET_CURRENT_CONTEXT(ctx);
57   GLint p;
58   GLfloat equation[4];
59   ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx, "glClipPlane");
60
61   p = (GLint) plane - (GLint) GL_CLIP_PLANE0;
62   if (p < 0 || p >= ctx->Const.MaxClipPlanes) {
63      gl_error( ctx, GL_INVALID_ENUM, "glClipPlane" );
64      return;
65   }
66
67   equation[0] = eq[0];
68   equation[1] = eq[1];
69   equation[2] = eq[2];
70   equation[3] = eq[3];
71
72   /*
73    * The equation is transformed by the transpose of the inverse of the
74    * current modelview matrix and stored in the resulting eye coordinates.
75    *
76    * KW: Eqn is then transformed to the current clip space, where user
77    * clipping now takes place.  The clip-space equations are recalculated
78    * whenever the projection matrix changes.
79    */
80   if (ctx->ModelView.flags & MAT_DIRTY)
81      _math_matrix_analyse( &ctx->ModelView );
82
83   gl_transform_vector( ctx->Transform.EyeUserPlane[p], equation,
84		        ctx->ModelView.inv );
85
86
87   /* Update derived state.  This state also depends on the projection
88    * matrix, and is recalculated on changes to the projection matrix by
89    * code in gl_update_state().
90    */
91   if (ctx->Transform.ClipEnabled[p]) {
92      if (ctx->ProjectionMatrix.flags & MAT_DIRTY)
93	 _math_matrix_analyse( &ctx->ProjectionMatrix );
94
95      gl_transform_vector( ctx->Transform._ClipUserPlane[p],
96			   ctx->Transform.EyeUserPlane[p],
97			   ctx->ProjectionMatrix.inv );
98   }
99
100   ctx->NewState |= _NEW_TRANSFORM;
101
102   if (ctx->Driver.ClipPlane)
103      ctx->Driver.ClipPlane( ctx, plane, equation );
104}
105
106
107void
108_mesa_GetClipPlane( GLenum plane, GLdouble *equation )
109{
110   GET_CURRENT_CONTEXT(ctx);
111   GLint p;
112
113   ASSERT_OUTSIDE_BEGIN_END(ctx, "glGetClipPlane");
114
115
116   p = (GLint) (plane - GL_CLIP_PLANE0);
117   if (p < 0 || p >= ctx->Const.MaxClipPlanes) {
118      gl_error( ctx, GL_INVALID_ENUM, "glGetClipPlane" );
119      return;
120   }
121
122   equation[0] = (GLdouble) ctx->Transform.EyeUserPlane[p][0];
123   equation[1] = (GLdouble) ctx->Transform.EyeUserPlane[p][1];
124   equation[2] = (GLdouble) ctx->Transform.EyeUserPlane[p][2];
125   equation[3] = (GLdouble) ctx->Transform.EyeUserPlane[p][3];
126}
127