aboutsummaryrefslogtreecommitdiff
path: root/mesalib/src/mesa/tnl/t_vb_cliptmp.h
blob: 8cc36e666dee01436eaecacdef75da8dd893b3e9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
/*
 * Mesa 3-D graphics library
 * Version:  6.5.2
 *
 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *    Keith Whitwell <keith@tungstengraphics.com>
 */


#define CLIP_DOTPROD(K, A, B, C, D) X(K)*A + Y(K)*B + Z(K)*C + W(K)*D

#define POLY_CLIP( PLANE_BIT, A, B, C, D )				\
do {									\
   if (mask & PLANE_BIT) {						\
      GLuint idxPrev = inlist[0];					\
      GLfloat dpPrev = CLIP_DOTPROD(idxPrev, A, B, C, D );		\
      GLuint outcount = 0;						\
      GLuint i;								\
									\
      inlist[n] = inlist[0]; /* prevent rotation of vertices */		\
      for (i = 1; i <= n; i++) {					\
	 GLuint idx = inlist[i];					\
	 GLfloat dp = CLIP_DOTPROD(idx, A, B, C, D );			\
									\
	 if (!IS_NEGATIVE(dpPrev)) {					\
	    outlist[outcount++] = idxPrev;				\
	 }								\
									\
	 if (DIFFERENT_SIGNS(dp, dpPrev)) {				\
	    if (IS_NEGATIVE(dp)) {					\
	       /* Going out of bounds.  Avoid division by zero as we	\
		* know dp != dpPrev from DIFFERENT_SIGNS, above.	\
		*/							\
	       GLfloat t = dp / (dp - dpPrev);				\
               INTERP_4F( t, coord[newvert], coord[idx], coord[idxPrev]); \
      	       interp( ctx, t, newvert, idx, idxPrev, GL_TRUE );	\
	    } else {							\
	       /* Coming back in.					\
		*/							\
	       GLfloat t = dpPrev / (dpPrev - dp);			\
               INTERP_4F( t, coord[newvert], coord[idxPrev], coord[idx]); \
	       interp( ctx, t, newvert, idxPrev, idx, GL_FALSE );	\
	    }								\
            outlist[outcount++] = newvert++;				\
	 }								\
									\
	 idxPrev = idx;							\
	 dpPrev = dp;							\
      }									\
									\
      if (outcount < 3)							\
	 return;							\
									\
      {									\
	 GLuint *tmp = inlist;						\
	 inlist = outlist;						\
	 outlist = tmp;							\
	 n = outcount;							\
      }									\
   }									\
} while (0)


#define LINE_CLIP(PLANE_BIT, A, B, C, D )				\
do {									\
   if (mask & PLANE_BIT) {						\
      const GLfloat dp0 = CLIP_DOTPROD( v0, A, B, C, D );		\
      const GLfloat dp1 = CLIP_DOTPROD( v1, A, B, C, D );		\
      const GLboolean neg_dp0 = IS_NEGATIVE(dp0);			\
      const GLboolean neg_dp1 = IS_NEGATIVE(dp1);			\
      									\
      /* For regular clipping, we know from the clipmask that one	\
       * (or both) of these must be negative (otherwise we wouldn't	\
       * be here).							\
       * For userclip, there is only a single bit for all active	\
       * planes, so we can end up here when there is nothing to do,	\
       * hence the second IS_NEGATIVE() test:				\
       */								\
      if (neg_dp0 && neg_dp1)						\
         return; /* both vertices outside clip plane: discard */	\
									\
      if (neg_dp1) {							\
	 GLfloat t = dp1 / (dp1 - dp0);					\
	 if (t > t1) t1 = t;						\
      } else if (neg_dp0) {						\
	 GLfloat t = dp0 / (dp0 - dp1);					\
	 if (t > t0) t0 = t;						\
      }									\
      if (t0 + t1 >= 1.0)						\
	 return; /* discard */						\
   }									\
} while (0)



/* Clip a line against the viewport and user clip planes.
 */
static INLINE void
TAG(clip_line)( GLcontext *ctx, GLuint v0, GLuint v1, GLubyte mask )
{
   TNLcontext *tnl = TNL_CONTEXT(ctx);
   struct vertex_buffer *VB = &tnl->vb;
   tnl_interp_func interp = tnl->Driver.Render.Interp;
   GLfloat (*coord)[4] = VB->ClipPtr->data;
   GLuint newvert = VB->Count;
   GLfloat t0 = 0;
   GLfloat t1 = 0;
   GLuint p;
   const GLuint v0_orig = v0;

   if (mask & CLIP_FRUSTUM_BITS) {
      LINE_CLIP( CLIP_RIGHT_BIT,  -1,  0,  0, 1 );
      LINE_CLIP( CLIP_LEFT_BIT,    1,  0,  0, 1 );
      LINE_CLIP( CLIP_TOP_BIT,     0, -1,  0, 1 );
      LINE_CLIP( CLIP_BOTTOM_BIT,  0,  1,  0, 1 );
      LINE_CLIP( CLIP_FAR_BIT,     0,  0, -1, 1 );
      LINE_CLIP( CLIP_NEAR_BIT,    0,  0,  1, 1 );
   }

   if (mask & CLIP_USER_BIT) {
      for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
	 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
            const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
            const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
            const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
            const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
	    LINE_CLIP( CLIP_USER_BIT, a, b, c, d );
	 }
      }
   }

   if (VB->ClipMask[v0]) {
      INTERP_4F( t0, coord[newvert], coord[v0], coord[v1] );
      interp( ctx, t0, newvert, v0, v1, GL_FALSE );
      v0 = newvert;
      newvert++;
   }
   else {
      ASSERT(t0 == 0.0);
   }

   /* Note: we need to use vertex v0_orig when computing the new
    * interpolated/clipped vertex position, not the current v0 which
    * may have got set when we clipped the other end of the line!
    */
   if (VB->ClipMask[v1]) {
      INTERP_4F( t1, coord[newvert], coord[v1], coord[v0_orig] );
      interp( ctx, t1, newvert, v1, v0_orig, GL_FALSE );

      if (ctx->Light.ShadeModel == GL_FLAT)
	 tnl->Driver.Render.CopyPV( ctx, newvert, v1 );

      v1 = newvert;

      newvert++;
   }
   else {
      ASSERT(t1 == 0.0);
   }

   tnl->Driver.Render.ClippedLine( ctx, v0, v1 );
}


/* Clip a triangle against the viewport and user clip planes.
 */
static INLINE void
TAG(clip_tri)( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLubyte mask )
{
   TNLcontext *tnl = TNL_CONTEXT(ctx);
   struct vertex_buffer *VB = &tnl->vb;
   tnl_interp_func interp = tnl->Driver.Render.Interp;
   GLuint newvert = VB->Count;
   GLfloat (*coord)[4] = VB->ClipPtr->data;
   GLuint pv = v2;
   GLuint vlist[2][MAX_CLIPPED_VERTICES];
   GLuint *inlist = vlist[0], *outlist = vlist[1];
   GLuint p;
   GLuint n = 3;

   ASSIGN_3V(inlist, v2, v0, v1 ); /* pv rotated to slot zero */

   if (0) {
      /* print pre-clip vertex coords */
      GLuint i, j;
      printf("pre clip:\n");
      for (i = 0; i < n; i++) {
         j = inlist[i];
         printf("  %u: %u: %f, %f, %f, %f\n",
		i, j,
		coord[j][0], coord[j][1], coord[j][2], coord[j][3]);
         assert(!IS_INF_OR_NAN(coord[j][0]));
         assert(!IS_INF_OR_NAN(coord[j][1]));
         assert(!IS_INF_OR_NAN(coord[j][2]));
         assert(!IS_INF_OR_NAN(coord[j][3]));
      }
   }


   if (mask & CLIP_FRUSTUM_BITS) {
      POLY_CLIP( CLIP_RIGHT_BIT,  -1,  0,  0, 1 );
      POLY_CLIP( CLIP_LEFT_BIT,    1,  0,  0, 1 );
      POLY_CLIP( CLIP_TOP_BIT,     0, -1,  0, 1 );
      POLY_CLIP( CLIP_BOTTOM_BIT,  0,  1,  0, 1 );
      POLY_CLIP( CLIP_FAR_BIT,     0,  0, -1, 1 );
      POLY_CLIP( CLIP_NEAR_BIT,    0,  0,  1, 1 );
   }

   if (mask & CLIP_USER_BIT) {
      for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
         if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
            const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
            const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
            const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
            const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
            POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
         }
      }
   }

   if (ctx->Light.ShadeModel == GL_FLAT) {
      if (pv != inlist[0]) {
	 ASSERT( inlist[0] >= VB->Count );
	 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
      }
   }

   if (0) {
      /* print post-clip vertex coords */
      GLuint i, j;
      printf("post clip:\n");
      for (i = 0; i < n; i++) {
         j = inlist[i];
         printf("  %u: %u: %f, %f, %f, %f\n",
		i, j,
		coord[j][0], coord[j][1], coord[j][2], coord[j][3]);
      }
   }

   tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
}


/* Clip a quad against the viewport and user clip planes.
 */
static INLINE void
TAG(clip_quad)( GLcontext *ctx, GLuint v0, GLuint v1, GLuint v2, GLuint v3,
                GLubyte mask )
{
   TNLcontext *tnl = TNL_CONTEXT(ctx);
   struct vertex_buffer *VB = &tnl->vb;
   tnl_interp_func interp = tnl->Driver.Render.Interp;
   GLuint newvert = VB->Count;
   GLfloat (*coord)[4] = VB->ClipPtr->data;
   GLuint pv = v3;
   GLuint vlist[2][MAX_CLIPPED_VERTICES];
   GLuint *inlist = vlist[0], *outlist = vlist[1];
   GLuint p;
   GLuint n = 4;

   ASSIGN_4V(inlist, v3, v0, v1, v2 ); /* pv rotated to slot zero */

   if (mask & CLIP_FRUSTUM_BITS) {
      POLY_CLIP( CLIP_RIGHT_BIT,  -1,  0,  0, 1 );
      POLY_CLIP( CLIP_LEFT_BIT,    1,  0,  0, 1 );
      POLY_CLIP( CLIP_TOP_BIT,     0, -1,  0, 1 );
      POLY_CLIP( CLIP_BOTTOM_BIT,  0,  1,  0, 1 );
      POLY_CLIP( CLIP_FAR_BIT,     0,  0, -1, 1 );
      POLY_CLIP( CLIP_NEAR_BIT,    0,  0,  1, 1 );
   }

   if (mask & CLIP_USER_BIT) {
      for (p = 0; p < ctx->Const.MaxClipPlanes; p++) {
	 if (ctx->Transform.ClipPlanesEnabled & (1 << p)) {
            const GLfloat a = ctx->Transform._ClipUserPlane[p][0];
            const GLfloat b = ctx->Transform._ClipUserPlane[p][1];
            const GLfloat c = ctx->Transform._ClipUserPlane[p][2];
            const GLfloat d = ctx->Transform._ClipUserPlane[p][3];
	    POLY_CLIP( CLIP_USER_BIT, a, b, c, d );
	 }
      }
   }

   if (ctx->Light.ShadeModel == GL_FLAT) {
      if (pv != inlist[0]) {
	 ASSERT( inlist[0] >= VB->Count );
	 tnl->Driver.Render.CopyPV( ctx, inlist[0], pv );
      }
   }

   tnl->Driver.Render.ClippedPolygon( ctx, inlist, n );
}

#undef W
#undef Z
#undef Y
#undef X
#undef SIZE
#undef TAG
#undef POLY_CLIP
#undef LINE_CLIP