2 * Mesa 3-D graphics library
4 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
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:
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
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.
25 * Keith Whitwell <keithw@vmware.com>
29 #define CLIP_DOTPROD(K, A, B, C, D) X(K)*A + Y(K)*B + Z(K)*C + W(K)*D
31 #define POLY_CLIP( PLANE_BIT, A, B, C, D ) \
33 if (mask & PLANE_BIT) { \
34 GLuint idxPrev = inlist[0]; \
35 GLfloat dpPrev = CLIP_DOTPROD(idxPrev, A, B, C, D ); \
36 GLuint outcount = 0; \
39 inlist[n] = inlist[0]; /* prevent rotation of vertices */ \
40 for (i = 1; i <= n; i++) { \
41 GLuint idx = inlist[i]; \
42 GLfloat dp = CLIP_DOTPROD(idx, A, B, C, D ); \
44 if (dpPrev >= 0.0f) { \
45 outlist[outcount++] = idxPrev; \
48 if (DIFFERENT_SIGNS(dp, dpPrev)) { \
50 /* Going out of bounds. Avoid division by zero as we \
51 * know dp != dpPrev from DIFFERENT_SIGNS, above. \
53 GLfloat t = dp / (dp - dpPrev); \
54 INTERP_4F( t, coord[newvert], coord[idx], coord[idxPrev]); \
55 interp( ctx, t, newvert, idx, idxPrev, GL_TRUE ); \
59 GLfloat t = dpPrev / (dpPrev - dp); \
60 INTERP_4F( t, coord[newvert], coord[idxPrev], coord[idx]); \
61 interp( ctx, t, newvert, idxPrev, idx, GL_FALSE ); \
63 outlist[outcount++] = newvert++; \
74 GLuint *tmp = inlist; \
83 #define LINE_CLIP(PLANE_BIT, A, B, C, D ) \
85 if (mask & PLANE_BIT) { \
86 const GLfloat dp0 = CLIP_DOTPROD( v0, A, B, C, D ); \
87 const GLfloat dp1 = CLIP_DOTPROD( v1, A, B, C, D ); \
88 const GLboolean neg_dp0 = dp0 < 0.0f; \
89 const GLboolean neg_dp1 = dp1 < 0.0f; \
91 /* For regular clipping, we know from the clipmask that one \
92 * (or both) of these must be negative (otherwise we wouldn't \
94 * For userclip, there is only a single bit for all active \
95 * planes, so we can end up here when there is nothing to do, \
96 * hence the second < 0.0f test: \
98 if (neg_dp0 && neg_dp1) \
99 return; /* both vertices outside clip plane: discard */ \
102 GLfloat t = dp1 / (dp1 - dp0); \
103 if (t > t1) t1 = t; \
104 } else if (neg_dp0) { \
105 GLfloat t = dp0 / (dp0 - dp1); \
106 if (t > t0) t0 = t; \
108 if (t0 + t1 >= 1.0) \
109 return; /* discard */ \
115 /* Clip a line against the viewport and user clip planes.
118 TAG(clip_line
)( struct gl_context
*ctx
, GLuint v0
, GLuint v1
, GLubyte mask
)
120 TNLcontext
*tnl
= TNL_CONTEXT(ctx
);
121 struct vertex_buffer
*VB
= &tnl
->vb
;
122 tnl_interp_func interp
= tnl
->Driver
.Render
.Interp
;
123 GLfloat (*coord
)[4] = VB
->ClipPtr
->data
;
124 GLuint newvert
= VB
->Count
;
127 const GLuint v0_orig
= v0
;
129 if (mask
& CLIP_FRUSTUM_BITS
) {
130 LINE_CLIP( CLIP_RIGHT_BIT
, -1, 0, 0, 1 );
131 LINE_CLIP( CLIP_LEFT_BIT
, 1, 0, 0, 1 );
132 LINE_CLIP( CLIP_TOP_BIT
, 0, -1, 0, 1 );
133 LINE_CLIP( CLIP_BOTTOM_BIT
, 0, 1, 0, 1 );
134 LINE_CLIP( CLIP_FAR_BIT
, 0, 0, -1, 1 );
135 LINE_CLIP( CLIP_NEAR_BIT
, 0, 0, 1, 1 );
138 if (mask
& CLIP_USER_BIT
) {
139 GLbitfield enabled
= ctx
->Transform
.ClipPlanesEnabled
;
141 const int p
= u_bit_scan(&enabled
);
142 const GLfloat a
= ctx
->Transform
._ClipUserPlane
[p
][0];
143 const GLfloat b
= ctx
->Transform
._ClipUserPlane
[p
][1];
144 const GLfloat c
= ctx
->Transform
._ClipUserPlane
[p
][2];
145 const GLfloat d
= ctx
->Transform
._ClipUserPlane
[p
][3];
146 LINE_CLIP( CLIP_USER_BIT
, a
, b
, c
, d
);
150 if (VB
->ClipMask
[v0
]) {
151 INTERP_4F( t0
, coord
[newvert
], coord
[v0
], coord
[v1
] );
152 interp( ctx
, t0
, newvert
, v0
, v1
, GL_FALSE
);
160 /* Note: we need to use vertex v0_orig when computing the new
161 * interpolated/clipped vertex position, not the current v0 which
162 * may have got set when we clipped the other end of the line!
164 if (VB
->ClipMask
[v1
]) {
165 INTERP_4F( t1
, coord
[newvert
], coord
[v1
], coord
[v0_orig
] );
166 interp( ctx
, t1
, newvert
, v1
, v0_orig
, GL_FALSE
);
168 if (ctx
->Light
.ShadeModel
== GL_FLAT
)
169 tnl
->Driver
.Render
.CopyPV( ctx
, newvert
, v1
);
179 tnl
->Driver
.Render
.ClippedLine( ctx
, v0
, v1
);
183 /* Clip a triangle against the viewport and user clip planes.
186 TAG(clip_tri
)( struct gl_context
*ctx
, GLuint v0
, GLuint v1
, GLuint v2
, GLubyte mask
)
188 TNLcontext
*tnl
= TNL_CONTEXT(ctx
);
189 struct vertex_buffer
*VB
= &tnl
->vb
;
190 tnl_interp_func interp
= tnl
->Driver
.Render
.Interp
;
191 GLuint newvert
= VB
->Count
;
192 GLfloat (*coord
)[4] = VB
->ClipPtr
->data
;
194 GLuint vlist
[2][MAX_CLIPPED_VERTICES
];
195 GLuint
*inlist
= vlist
[0], *outlist
= vlist
[1];
198 ASSIGN_3V(inlist
, v2
, v0
, v1
); /* pv rotated to slot zero */
201 /* print pre-clip vertex coords */
203 printf("pre clip:\n");
204 for (i
= 0; i
< n
; i
++) {
206 printf(" %u: %u: %f, %f, %f, %f\n",
208 coord
[j
][0], coord
[j
][1], coord
[j
][2], coord
[j
][3]);
209 assert(!util_is_inf_or_nan(coord
[j
][0]));
210 assert(!util_is_inf_or_nan(coord
[j
][1]));
211 assert(!util_is_inf_or_nan(coord
[j
][2]));
212 assert(!util_is_inf_or_nan(coord
[j
][3]));
217 if (mask
& CLIP_FRUSTUM_BITS
) {
218 POLY_CLIP( CLIP_RIGHT_BIT
, -1, 0, 0, 1 );
219 POLY_CLIP( CLIP_LEFT_BIT
, 1, 0, 0, 1 );
220 POLY_CLIP( CLIP_TOP_BIT
, 0, -1, 0, 1 );
221 POLY_CLIP( CLIP_BOTTOM_BIT
, 0, 1, 0, 1 );
222 POLY_CLIP( CLIP_FAR_BIT
, 0, 0, -1, 1 );
223 POLY_CLIP( CLIP_NEAR_BIT
, 0, 0, 1, 1 );
226 if (mask
& CLIP_USER_BIT
) {
227 GLbitfield enabled
= ctx
->Transform
.ClipPlanesEnabled
;
229 const int p
= u_bit_scan(&enabled
);
230 const GLfloat a
= ctx
->Transform
._ClipUserPlane
[p
][0];
231 const GLfloat b
= ctx
->Transform
._ClipUserPlane
[p
][1];
232 const GLfloat c
= ctx
->Transform
._ClipUserPlane
[p
][2];
233 const GLfloat d
= ctx
->Transform
._ClipUserPlane
[p
][3];
234 POLY_CLIP( CLIP_USER_BIT
, a
, b
, c
, d
);
238 if (ctx
->Light
.ShadeModel
== GL_FLAT
) {
239 if (pv
!= inlist
[0]) {
240 assert( inlist
[0] >= VB
->Count
);
241 tnl
->Driver
.Render
.CopyPV( ctx
, inlist
[0], pv
);
246 /* print post-clip vertex coords */
248 printf("post clip:\n");
249 for (i
= 0; i
< n
; i
++) {
251 printf(" %u: %u: %f, %f, %f, %f\n",
253 coord
[j
][0], coord
[j
][1], coord
[j
][2], coord
[j
][3]);
257 tnl
->Driver
.Render
.ClippedPolygon( ctx
, inlist
, n
);
261 /* Clip a quad against the viewport and user clip planes.
264 TAG(clip_quad
)( struct gl_context
*ctx
, GLuint v0
, GLuint v1
, GLuint v2
, GLuint v3
,
267 TNLcontext
*tnl
= TNL_CONTEXT(ctx
);
268 struct vertex_buffer
*VB
= &tnl
->vb
;
269 tnl_interp_func interp
= tnl
->Driver
.Render
.Interp
;
270 GLuint newvert
= VB
->Count
;
271 GLfloat (*coord
)[4] = VB
->ClipPtr
->data
;
273 GLuint vlist
[2][MAX_CLIPPED_VERTICES
];
274 GLuint
*inlist
= vlist
[0], *outlist
= vlist
[1];
277 ASSIGN_4V(inlist
, v3
, v0
, v1
, v2
); /* pv rotated to slot zero */
279 if (mask
& CLIP_FRUSTUM_BITS
) {
280 POLY_CLIP( CLIP_RIGHT_BIT
, -1, 0, 0, 1 );
281 POLY_CLIP( CLIP_LEFT_BIT
, 1, 0, 0, 1 );
282 POLY_CLIP( CLIP_TOP_BIT
, 0, -1, 0, 1 );
283 POLY_CLIP( CLIP_BOTTOM_BIT
, 0, 1, 0, 1 );
284 POLY_CLIP( CLIP_FAR_BIT
, 0, 0, -1, 1 );
285 POLY_CLIP( CLIP_NEAR_BIT
, 0, 0, 1, 1 );
288 if (mask
& CLIP_USER_BIT
) {
289 GLbitfield enabled
= ctx
->Transform
.ClipPlanesEnabled
;
291 const int p
= u_bit_scan(&enabled
);
292 const GLfloat a
= ctx
->Transform
._ClipUserPlane
[p
][0];
293 const GLfloat b
= ctx
->Transform
._ClipUserPlane
[p
][1];
294 const GLfloat c
= ctx
->Transform
._ClipUserPlane
[p
][2];
295 const GLfloat d
= ctx
->Transform
._ClipUserPlane
[p
][3];
296 POLY_CLIP( CLIP_USER_BIT
, a
, b
, c
, d
);
300 if (ctx
->Light
.ShadeModel
== GL_FLAT
) {
301 if (pv
!= inlist
[0]) {
302 assert( inlist
[0] >= VB
->Count
);
303 tnl
->Driver
.Render
.CopyPV( ctx
, inlist
[0], pv
);
307 tnl
->Driver
.Render
.ClippedPolygon( ctx
, inlist
, n
);