source: trunk/src/opengl/mesa/general_clip.h

Last change on this file was 2938, checked in by sandervl, 25 years ago

created
File size: 4.7 KB
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1/* $Id: general_clip.h,v 1.1 2000-02-29 00:48:31 sandervl Exp $ */
2
3/*
4 * Mesa 3-D graphics library
5 * Version: 3.1
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 * New (3.1) transformation code written by Keith Whitwell.
29 */
30
31
32
33/*
34 * Clip against +X
35 *
36 * The if conditions are known at compile time.
37 */
38#define PLANE (CLIP_RIGHT_BIT)
39#define INSIDE(K) (X(K) <= W(K))
40#define COMPUTE_INTERSECTION( in, out, new ) \
41 dx = X(out)-X(in); \
42 dw = W(out)-W(in); \
43 t = (X(in)-W(in)) / (dw-dx); \
44 neww = W(in) + t * dw; \
45 X(new) = neww; \
46 Y(new) = Y(in) + t * (Y(out) - Y(in)); \
47 if (SIZE>=3) coord[new][2] = Z(in) + t * (Z(out) - Z(in)); \
48 if (SIZE==4) coord[new][3] = neww;
49
50 GENERAL_CLIP
51
52#undef INSIDE
53#undef PLANE
54#undef COMPUTE_INTERSECTION
55
56
57/*
58 * Clip against -X
59 */
60#define PLANE (CLIP_LEFT_BIT)
61#define INSIDE(K) (X(K) >= -W(K))
62#define COMPUTE_INTERSECTION( in, out, new ) \
63 dx = X(out)-X(in); \
64 dw = W(out)-W(in); \
65 t = -(X(in)+W(in)) / (dw+dx); \
66 neww = W(in) + t * dw; \
67 X(new) = -neww; \
68 Y(new) = Y(in) + t * (Y(out) - Y(in)); \
69 if (SIZE>=3) coord[new][2] = Z(in) + t * (Z(out) - Z(in)); \
70 if (SIZE==4) coord[new][3] = neww;
71
72 GENERAL_CLIP
73
74#undef INSIDE
75#undef PLANE
76#undef COMPUTE_INTERSECTION
77
78
79/*
80 * Clip against +Y
81 */
82#define PLANE (CLIP_TOP_BIT)
83#define INSIDE(K) (Y(K) <= W(K))
84#define COMPUTE_INTERSECTION( in, out, new ) \
85 dy = Y(out)-Y(in); \
86 dw = W(out)-W(in); \
87 t = (Y(in)-W(in)) / (dw-dy); \
88 neww = W(in) + t * dw; \
89 X(new) = X(in) + t * (X(out) - X(in)); \
90 Y(new) = neww; \
91 if (SIZE>=3) coord[new][2] = Z(in) + t * (Z(out) - Z(in)); \
92 if (SIZE==4) coord[new][3] = neww;
93
94 GENERAL_CLIP
95
96#undef INSIDE
97#undef PLANE
98#undef COMPUTE_INTERSECTION
99
100
101/*
102 * Clip against -Y
103 */
104#define PLANE (CLIP_BOTTOM_BIT)
105#define INSIDE(K) (Y(K) >= -W(K))
106#define COMPUTE_INTERSECTION( in, out, new ) \
107 dy = Y(out)-Y(in); \
108 dw = W(out)-W(in); \
109 t = -(Y(in)+W(in)) / (dw+dy); \
110 neww = W(in) + t * dw; \
111 X(new) = X(in) + t * (X(out) - X(in)); \
112 Y(new) = -neww; \
113 if (SIZE>=3) coord[new][2] = Z(in) + t * (Z(out) - Z(in)); \
114 if (SIZE==4) coord[new][3] = neww;
115
116 GENERAL_CLIP
117
118#undef INSIDE
119#undef PLANE
120#undef COMPUTE_INTERSECTION
121
122
123
124/*
125 * Clip against +Z
126 */
127#define PLANE (CLIP_FAR_BIT)
128#define INSIDE(K) (Z(K) <= W(K))
129#define COMPUTE_INTERSECTION( in, out, new ) \
130 dz = Z(out)-Z(in); \
131 dw = W(out)-W(in); \
132 t = (Z(in)-W(in)) / (dw-dz); \
133 neww = W(in) + t * dw; \
134 X(new) = X(in) + t * (X(out) - X(in)); \
135 Y(new) = Y(in) + t * (Y(out) - Y(in)); \
136 coord[new][2] = neww; \
137 if (SIZE==4) coord[new][3] = neww;
138
139 if (SIZE>=3) {
140 GENERAL_CLIP
141 }
142
143#undef INSIDE
144#undef PLANE
145#undef COMPUTE_INTERSECTION
146
147
148/*
149 * Clip against -Z
150 */
151#define PLANE (CLIP_NEAR_BIT)
152#define INSIDE(K) (Z(K) >= -W(K))
153#define COMPUTE_INTERSECTION( in, out, new ) \
154 dz = Z(out)-Z(in); \
155 dw = W(out)-W(in); \
156 t = -(Z(in)+W(in)) / (dw+dz); \
157 neww = W(in) + t * dw; \
158 X(new) = X(in) + t * (X(out) - X(in)); \
159 Y(new) = Y(in) + t * (Y(out) - Y(in)); \
160 coord[new][2] = -neww; \
161 if (SIZE==4) coord[new][3] = neww;
162
163 if (SIZE>=3) {
164 GENERAL_CLIP
165 }
166
167#undef INSIDE
168#undef PLANE
169#undef COMPUTE_INTERSECTION
170#undef GENERAL_CLIP
171
172
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