1 /*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 1999-2005 Brian Paul All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * 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 */
38 void
_mesa_update_clip_plane(struct gl_context * ctx,GLuint plane)39 _mesa_update_clip_plane(struct gl_context *ctx, GLuint plane)
40 {
41 /* make sure the inverse is up to date */
42 if (_math_matrix_is_dirty(ctx->ProjectionMatrixStack.Top))
43 _math_matrix_analyse( ctx->ProjectionMatrixStack.Top );
44
45 /* Clip-Space Plane = Eye-Space Plane * Projection Matrix */
46 _mesa_transform_vector(ctx->Transform._ClipUserPlane[plane],
47 ctx->Transform.EyeUserPlane[plane],
48 ctx->ProjectionMatrixStack.Top->inv);
49 }
50
51
52 void GLAPIENTRY
_mesa_ClipPlane(GLenum plane,const GLdouble * eq)53 _mesa_ClipPlane( GLenum plane, const GLdouble *eq )
54 {
55 GET_CURRENT_CONTEXT(ctx);
56 GLint p;
57 GLfloat equation[4];
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 /* EyeUserPlane is used by program state constants. */
88 FLUSH_VERTICES(ctx, _NEW_TRANSFORM, GL_TRANSFORM_BIT);
89 ctx->NewDriverState |= ctx->DriverFlags.NewClipPlane;
90 COPY_4FV(ctx->Transform.EyeUserPlane[p], equation);
91
92 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
93 _mesa_update_clip_plane(ctx, p);
94 }
95
96 if (ctx->Driver.ClipPlane)
97 ctx->Driver.ClipPlane( ctx, plane, equation );
98 }
99
100
101 void GLAPIENTRY
_mesa_GetClipPlane(GLenum plane,GLdouble * equation)102 _mesa_GetClipPlane( GLenum plane, GLdouble *equation )
103 {
104 GET_CURRENT_CONTEXT(ctx);
105 GLint p;
106
107 p = (GLint) (plane - GL_CLIP_PLANE0);
108 if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
109 _mesa_error( ctx, GL_INVALID_ENUM, "glGetClipPlane" );
110 return;
111 }
112
113 equation[0] = (GLdouble) ctx->Transform.EyeUserPlane[p][0];
114 equation[1] = (GLdouble) ctx->Transform.EyeUserPlane[p][1];
115 equation[2] = (GLdouble) ctx->Transform.EyeUserPlane[p][2];
116 equation[3] = (GLdouble) ctx->Transform.EyeUserPlane[p][3];
117 }
118