1 /* $Id: clip.c,v 1.26 2002/10/24 23:57:19 brianp Exp $ */
4 * Mesa 3-D graphics library
7 * Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
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:
16 * The above copyright notice and this permission notice shall be included
17 * in all copies or substantial portions of the Software.
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.
35 #include "math/m_xform.h"
36 #include "math/m_matrix.h"
40 /**********************************************************************/
41 /* Get/Set User clip-planes. */
42 /**********************************************************************/
47 _mesa_ClipPlane( GLenum plane
, const GLdouble
*eq
)
49 GET_CURRENT_CONTEXT(ctx
);
52 ASSERT_OUTSIDE_BEGIN_END(ctx
);
54 p
= (GLint
) plane
- (GLint
) GL_CLIP_PLANE0
;
55 if (p
< 0 || p
>= (GLint
) ctx
->Const
.MaxClipPlanes
) {
56 _mesa_error( ctx
, GL_INVALID_ENUM
, "glClipPlane" );
60 equation
[0] = (GLfloat
) eq
[0];
61 equation
[1] = (GLfloat
) eq
[1];
62 equation
[2] = (GLfloat
) eq
[2];
63 equation
[3] = (GLfloat
) eq
[3];
66 * The equation is transformed by the transpose of the inverse of the
67 * current modelview matrix and stored in the resulting eye coordinates.
69 * KW: Eqn is then transformed to the current clip space, where user
70 * clipping now takes place. The clip-space equations are recalculated
71 * whenever the projection matrix changes.
73 if (ctx
->ModelviewMatrixStack
.Top
->flags
& MAT_DIRTY
)
74 _math_matrix_analyse( ctx
->ModelviewMatrixStack
.Top
);
76 _mesa_transform_vector( equation
, equation
,
77 ctx
->ModelviewMatrixStack
.Top
->inv
);
79 if (TEST_EQ_4V(ctx
->Transform
.EyeUserPlane
[p
], equation
))
82 FLUSH_VERTICES(ctx
, _NEW_TRANSFORM
);
83 COPY_4FV(ctx
->Transform
.EyeUserPlane
[p
], equation
);
85 /* Update derived state. This state also depends on the projection
86 * matrix, and is recalculated on changes to the projection matrix by
87 * code in _mesa_update_state().
89 if (ctx
->Transform
.ClipPlanesEnabled
& (1 << p
)) {
90 if (ctx
->ProjectionMatrixStack
.Top
->flags
& MAT_DIRTY
)
91 _math_matrix_analyse( ctx
->ProjectionMatrixStack
.Top
);
93 _mesa_transform_vector( ctx
->Transform
._ClipUserPlane
[p
],
94 ctx
->Transform
.EyeUserPlane
[p
],
95 ctx
->ProjectionMatrixStack
.Top
->inv
);
98 if (ctx
->Driver
.ClipPlane
)
99 ctx
->Driver
.ClipPlane( ctx
, plane
, equation
);
104 _mesa_GetClipPlane( GLenum plane
, GLdouble
*equation
)
106 GET_CURRENT_CONTEXT(ctx
);
108 ASSERT_OUTSIDE_BEGIN_END(ctx
);
110 p
= (GLint
) (plane
- GL_CLIP_PLANE0
);
111 if (p
< 0 || p
>= (GLint
) ctx
->Const
.MaxClipPlanes
) {
112 _mesa_error( ctx
, GL_INVALID_ENUM
, "glGetClipPlane" );
116 equation
[0] = (GLdouble
) ctx
->Transform
.EyeUserPlane
[p
][0];
117 equation
[1] = (GLdouble
) ctx
->Transform
.EyeUserPlane
[p
][1];
118 equation
[2] = (GLdouble
) ctx
->Transform
.EyeUserPlane
[p
][2];
119 equation
[3] = (GLdouble
) ctx
->Transform
.EyeUserPlane
[p
][3];