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 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
51 void GLAPIENTRY
_mesa_ClipPlane(GLenum plane,const GLdouble * eq)52 _mesa_ClipPlane( GLenum plane, const GLdouble *eq )
53 {
54 GET_CURRENT_CONTEXT(ctx);
55 GLint p;
56 GLfloat equation[4];
57
58 p = (GLint) plane - (GLint) GL_CLIP_PLANE0;
59 if (p < 0 || p >= (GLint) ctx->Const.MaxClipPlanes) {
60 _mesa_error( ctx, GL_INVALID_ENUM, "glClipPlane" );
61 return;
62 }
63
64 equation[0] = (GLfloat) eq[0];
65 equation[1] = (GLfloat) eq[1];
66 equation[2] = (GLfloat) eq[2];
67 equation[3] = (GLfloat) eq[3];
68
69 /*
70 * The equation is transformed by the transpose of the inverse of the
71 * current modelview matrix and stored in the resulting eye coordinates.
72 *
73 * KW: Eqn is then transformed to the current clip space, where user
74 * clipping now takes place. The clip-space equations are recalculated
75 * whenever the projection matrix changes.
76 */
77 if (_math_matrix_is_dirty(ctx->ModelviewMatrixStack.Top))
78 _math_matrix_analyse( ctx->ModelviewMatrixStack.Top );
79
80 _mesa_transform_vector( equation, equation,
81 ctx->ModelviewMatrixStack.Top->inv );
82
83 if (TEST_EQ_4V(ctx->Transform.EyeUserPlane[p], equation))
84 return;
85
86 /* EyeUserPlane is used by program state constants. */
87 FLUSH_VERTICES(ctx, _NEW_TRANSFORM);
88 ctx->NewDriverState |= ctx->DriverFlags.NewClipPlane;
89 COPY_4FV(ctx->Transform.EyeUserPlane[p], equation);
90
91 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
92 _mesa_update_clip_plane(ctx, p);
93 }
94
95 if (ctx->Driver.ClipPlane)
96 ctx->Driver.ClipPlane( ctx, plane, equation );
97 }
98
99
100 void GLAPIENTRY
_mesa_GetClipPlane(GLenum plane,GLdouble * equation)101 _mesa_GetClipPlane( GLenum plane, GLdouble *equation )
102 {
103 GET_CURRENT_CONTEXT(ctx);
104 GLint p;
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