2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
21 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 * Keith Whitwell <keith@tungstengraphics.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 (!IS_NEGATIVE(dpPrev)) { \
45 outlist[outcount++] = idxPrev; \
48 if (DIFFERENT_SIGNS(dp, dpPrev)) { \
49 if (IS_NEGATIVE(dp)) { \
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 = IS_NEGATIVE(dp0); \
89 const GLboolean neg_dp1 = IS_NEGATIVE(dp1); \
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 IS_NEGATIVE() 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)( GLcontext *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;
128 const GLuint v0_orig = v0;
130 if (mask & CLIP_FRUSTUM_BITS) {
131 LINE_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 );
132 LINE_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 );
133 LINE_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 );
134 LINE_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 );
135 LINE_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 );
136 LINE_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 );
139 if (mask & CLIP_USER_BIT) {
140 for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
141 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
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 );
151 if (VB->ClipMask[v0]) {
152 INTERP_4F( t0, coord[newvert], coord[v0], coord[v1] );
153 interp( ctx, t0, newvert, v0, v1, GL_FALSE );
161 /* Note: we need to use vertex v0_orig when computing the new
162 * interpolated/clipped vertex position, not the current v0 which
163 * may have got set when we clipped the other end of the line!
165 if (VB->ClipMask[v1]) {
166 INTERP_4F( t1, coord[newvert], coord[v1], coord[v0_orig] );
167 interp( ctx, t1, newvert, v1, v0_orig, GL_FALSE );
169 if (ctx->Light.ShadeModel == GL_FLAT)
170 tnl->Driver.Render.CopyPV( ctx, newvert, v1 );
180 tnl->Driver.Render.ClippedLine( ctx, v0, v1 );
184 /* Clip a triangle against the viewport and user clip planes.
187 TAG(clip_tri)( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLubyte mask )
189 TNLcontext *tnl = TNL_CONTEXT(ctx);
190 struct vertex_buffer *VB = &tnl->vb;
191 tnl_interp_func interp = tnl->Driver.Render.Interp;
192 GLuint newvert = VB->Count;
193 GLfloat (*coord)[4] = VB->ClipPtr->data;
195 GLuint vlist[2][MAX_CLIPPED_VERTICES];
196 GLuint *inlist = vlist[0], *outlist = vlist[1];
200 ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */
202 if (mask & CLIP_FRUSTUM_BITS) {
203 POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 );
204 POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 );
205 POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 );
206 POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 );
207 POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 );
208 POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 );
211 if (mask & CLIP_USER_BIT) {
212 for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
213 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
214 const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
215 const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
216 const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
217 const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
218 POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
223 if (ctx->Light.ShadeModel == GL_FLAT) {
224 if (pv != inlist[0]) {
225 ASSERT( inlist[0] >= VB->Count );
226 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
230 tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
234 /* Clip a quad against the viewport and user clip planes.
237 TAG(clip_quad)( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint v3,
240 TNLcontext *tnl = TNL_CONTEXT(ctx);
241 struct vertex_buffer *VB = &tnl->vb;
242 tnl_interp_func interp = tnl->Driver.Render.Interp;
243 GLuint newvert = VB->Count;
244 GLfloat (*coord)[4] = VB->ClipPtr->data;
246 GLuint vlist[2][MAX_CLIPPED_VERTICES];
247 GLuint *inlist = vlist[0], *outlist = vlist[1];
251 ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */
253 if (mask & CLIP_FRUSTUM_BITS) {
254 POLY_CLIP( CLIP_RIGHT_BIT, -1, 0, 0, 1 );
255 POLY_CLIP( CLIP_LEFT_BIT, 1, 0, 0, 1 );
256 POLY_CLIP( CLIP_TOP_BIT, 0, -1, 0, 1 );
257 POLY_CLIP( CLIP_BOTTOM_BIT, 0, 1, 0, 1 );
258 POLY_CLIP( CLIP_FAR_BIT, 0, 0, -1, 1 );
259 POLY_CLIP( CLIP_NEAR_BIT, 0, 0, 1, 1 );
262 if (mask & CLIP_USER_BIT) {
263 for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
264 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
265 const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
266 const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
267 const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
268 const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
269 POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
274 if (ctx->Light.ShadeModel == GL_FLAT) {
275 if (pv != inlist[0]) {
276 ASSERT( inlist[0] >= VB->Count );
277 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
281 tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );