1 /* $Id: clip.c,v 1.20 2001/03/03 20:33:27 brianp Exp $ */
4 * Mesa 3-D graphics library
7 * Copyright (C) 1999 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.
38 #include "math/m_xform.h"
39 #include "math/m_matrix.h"
47 /**********************************************************************/
48 /* Get/Set User clip-planes. */
49 /**********************************************************************/
54 _mesa_ClipPlane( GLenum plane
, const GLdouble
*eq
)
56 GET_CURRENT_CONTEXT(ctx
);
59 ASSERT_OUTSIDE_BEGIN_END(ctx
);
61 p
= (GLint
) plane
- (GLint
) GL_CLIP_PLANE0
;
62 if (p
< 0 || p
>= ctx
->Const
.MaxClipPlanes
) {
63 _mesa_error( ctx
, GL_INVALID_ENUM
, "glClipPlane" );
73 * The equation is transformed by the transpose of the inverse of the
74 * current modelview matrix and stored in the resulting eye coordinates.
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.
80 if (ctx
->ModelView
.flags
& MAT_DIRTY
)
81 _math_matrix_analyse( &ctx
->ModelView
);
83 _mesa_transform_vector( equation
, equation
, ctx
->ModelView
.inv
);
85 if (TEST_EQ_4V(ctx
->Transform
.EyeUserPlane
[p
], equation
))
88 FLUSH_VERTICES(ctx
, _NEW_TRANSFORM
);
89 COPY_4FV(ctx
->Transform
.EyeUserPlane
[p
], equation
);
91 /* Update derived state. This state also depends on the projection
92 * matrix, and is recalculated on changes to the projection matrix by
93 * code in _mesa_update_state().
95 if (ctx
->Transform
.ClipEnabled
[p
]) {
96 if (ctx
->ProjectionMatrix
.flags
& MAT_DIRTY
)
97 _math_matrix_analyse( &ctx
->ProjectionMatrix
);
99 _mesa_transform_vector( ctx
->Transform
._ClipUserPlane
[p
],
100 ctx
->Transform
.EyeUserPlane
[p
],
101 ctx
->ProjectionMatrix
.inv
);
104 if (ctx
->Driver
.ClipPlane
)
105 ctx
->Driver
.ClipPlane( ctx
, plane
, equation
);
110 _mesa_GetClipPlane( GLenum plane
, GLdouble
*equation
)
112 GET_CURRENT_CONTEXT(ctx
);
114 ASSERT_OUTSIDE_BEGIN_END(ctx
);
116 p
= (GLint
) (plane
- GL_CLIP_PLANE0
);
117 if (p
< 0 || p
>= ctx
->Const
.MaxClipPlanes
) {
118 _mesa_error( ctx
, GL_INVALID_ENUM
, "glGetClipPlane" );
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];