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-rw-r--r--src/mesa/pipe/draw/draw_clip.c429
1 files changed, 429 insertions, 0 deletions
diff --git a/src/mesa/pipe/draw/draw_clip.c b/src/mesa/pipe/draw/draw_clip.c
new file mode 100644
index 00000000000..304c43c3f48
--- /dev/null
+++ b/src/mesa/pipe/draw/draw_clip.c
@@ -0,0 +1,429 @@
+/**************************************************************************
+ *
+ * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * 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, sub license, 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 (including the
+ * next paragraph) 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 NON-INFRINGEMENT.
+ * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS 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 <[email protected]>
+ */
+
+#include "imports.h"
+#include "macros.h"
+
+#include "sp_context.h"
+#include "sp_prim.h"
+
+struct clipper {
+ struct prim_stage stage;
+
+ GLuint active_user_planes;
+};
+
+/* This is a bit confusing:
+ */
+static INLINE struct clipper *clipper_stage( struct prim_stage *stage )
+{
+ return (struct clipper *)stage;
+}
+
+
+#define LINTERP(T, OUT, IN) ((OUT) + (T) * ((IN) - (OUT)))
+
+
+/* All attributes are float[4], so this is easy:
+ */
+static void interp_attr( GLfloat *fdst,
+ GLfloat t,
+ const GLfloat *fin,
+ const GLfloat *fout )
+{
+ fdst[0] = LINTERP( t, fout[0], fin[0] );
+ fdst[1] = LINTERP( t, fout[1], fin[1] );
+ fdst[2] = LINTERP( t, fout[2], fin[2] );
+ fdst[3] = LINTERP( t, fout[3], fin[3] );
+}
+
+
+
+
+/* Interpolate between two vertices to produce a third.
+ */
+static void interp( struct clipper *clip,
+ struct vertex_header *dst,
+ GLfloat t,
+ const struct vertex_header *out,
+ const struct vertex_header *in )
+{
+ const GLuint nr_attrs = clip->stage.softpipe->nr_attrs;
+ GLuint j;
+
+ /* Vertex header.
+ */
+ {
+ dst->clipmask = 0;
+ dst->edgeflag = 0;
+ dst->pad = 0;
+ }
+
+ /* Clip coordinates: interpolate normally
+ */
+ {
+ interp_attr(dst->clip, t, in->clip, out->clip);
+ }
+
+ /* Do the projective divide and insert window coordinates:
+ */
+ {
+ const GLfloat *pos = dst->clip;
+ const GLfloat *scale = clip->stage.softpipe->viewport.scale;
+ const GLfloat *trans = clip->stage.softpipe->viewport.translate;
+ GLfloat oow;
+
+ oow = 1.0 / pos[3];
+
+ dst->data[0][0] = pos[0] * oow * scale[0] + trans[0];
+ dst->data[0][1] = pos[1] * oow * scale[1] + trans[1];
+ dst->data[0][2] = pos[2] * oow * scale[2] + trans[2];
+ dst->data[0][3] = oow;
+ }
+
+
+ /* Other attributes
+ */
+ for (j = 1; j < nr_attrs-1; j++) {
+ interp_attr(dst->data[j], t, in->data[j], out->data[j]);
+ }
+}
+
+
+#define CLIP_USER_BIT 0x40
+#define CLIP_CULL_BIT 0x80
+
+
+static INLINE GLfloat dot4( const GLfloat *a,
+ const GLfloat *b )
+{
+ GLfloat result = (a[0]*b[0] +
+ a[1]*b[1] +
+ a[2]*b[2] +
+ a[3]*b[3]);
+
+ return result;
+}
+
+
+#if 0
+static INLINE void do_tri( struct prim_stage *next,
+ struct prim_header *header )
+{
+ GLuint i;
+ for (i = 0; i < 3; i++) {
+ GLfloat *ndc = header->v[i]->data[0];
+ _mesa_printf("ndc %f %f %f\n", ndc[0], ndc[1], ndc[2]);
+ assert(ndc[0] >= -1 && ndc[0] <= 641);
+ assert(ndc[1] >= 30 && ndc[1] <= 481);
+ }
+ _mesa_printf("\n");
+ next->tri(next, header);
+}
+#endif
+
+
+static void emit_poly( struct prim_stage *stage,
+ struct vertex_header **inlist,
+ GLuint n )
+{
+ struct prim_header header;
+ GLuint i;
+
+ for (i = 2; i < n; i++) {
+ header.v[0] = inlist[0];
+ header.v[1] = inlist[i-1];
+ header.v[2] = inlist[i];
+
+ {
+ GLuint tmp0 = header.v[0]->edgeflag;
+ GLuint tmp2 = header.v[2]->edgeflag;
+
+ if (i != 2) header.v[0]->edgeflag = 0;
+ if (i != n-1) header.v[2]->edgeflag = 0;
+
+ stage->next->tri( stage->next, &header );
+
+ header.v[0]->edgeflag = tmp0;
+ header.v[2]->edgeflag = tmp2;
+ }
+ }
+}
+
+
+#if 0
+static void emit_poly( struct prim_stage *stage )
+{
+ GLuint i;
+
+ for (i = 2; i < n; i++) {
+ header->v[0] = inlist[0];
+ header->v[1] = inlist[i-1];
+ header->v[2] = inlist[i];
+
+ stage->next->tri( stage->next, header );
+ }
+}
+#endif
+
+
+/* Clip a triangle against the viewport and user clip planes.
+ */
+static void
+do_clip_tri( struct prim_stage *stage,
+ struct prim_header *header,
+ GLuint clipmask )
+{
+ struct clipper *clipper = clipper_stage( stage );
+ struct vertex_header *a[MAX_CLIPPED_VERTICES];
+ struct vertex_header *b[MAX_CLIPPED_VERTICES];
+ struct vertex_header **inlist = a;
+ struct vertex_header **outlist = b;
+ GLuint tmpnr = 0;
+ GLuint n = 3;
+ GLuint i;
+
+ inlist[0] = header->v[0];
+ inlist[1] = header->v[1];
+ inlist[2] = header->v[2];
+
+ /* XXX: Note stupid hack to deal with tnl's 8-bit clipmask. Remove
+ * this once we correctly use 16bit masks for userclip planes.
+ */
+ clipmask &= ~CLIP_CULL_BIT;
+ if (clipmask & CLIP_USER_BIT) {
+ clipmask &= ~CLIP_USER_BIT;
+ clipmask |= clipper->active_user_planes;
+ }
+
+ while (clipmask && n >= 3) {
+ GLuint plane_idx = ffs(clipmask)-1;
+ const GLfloat *plane = clipper->stage.softpipe->plane[plane_idx];
+ struct vertex_header *vert_prev = inlist[0];
+ GLfloat dp_prev = dot4( vert_prev->clip, plane );
+ GLuint outcount = 0;
+
+ clipmask &= ~(1<<plane_idx);
+
+ inlist[n] = inlist[0]; /* prevent rotation of vertices */
+
+ for (i = 1; i <= n; i++) {
+ struct vertex_header *vert = inlist[i];
+
+ GLfloat dp = dot4( vert->clip, plane );
+
+ if (!IS_NEGATIVE(dp_prev)) {
+ outlist[outcount++] = vert_prev;
+ }
+
+ if (DIFFERENT_SIGNS(dp, dp_prev)) {
+ struct vertex_header *new_vert = clipper->stage.tmp[tmpnr++];
+ outlist[outcount++] = new_vert;
+
+ if (IS_NEGATIVE(dp)) {
+ /* Going out of bounds. Avoid division by zero as we
+ * know dp != dp_prev from DIFFERENT_SIGNS, above.
+ */
+ GLfloat t = dp / (dp - dp_prev);
+ interp( clipper, new_vert, t, vert, vert_prev );
+
+ /* Force edgeflag true in this case:
+ */
+ new_vert->edgeflag = 1;
+ } else {
+ /* Coming back in.
+ */
+ GLfloat t = dp_prev / (dp_prev - dp);
+ interp( clipper, new_vert, t, vert_prev, vert );
+
+ /* Copy starting vert's edgeflag:
+ */
+ new_vert->edgeflag = vert_prev->edgeflag;
+ }
+ }
+
+ vert_prev = vert;
+ dp_prev = dp;
+ }
+
+ {
+ struct vertex_header **tmp = inlist;
+ inlist = outlist;
+ outlist = tmp;
+ n = outcount;
+ }
+ }
+
+ /* Emit the polygon as triangles to the setup stage:
+ */
+ if (n >= 3)
+ emit_poly( stage, inlist, n );
+}
+
+
+/* Clip a line against the viewport and user clip planes.
+ */
+static void
+do_clip_line( struct prim_stage *stage,
+ struct prim_header *header,
+ GLuint clipmask )
+{
+ struct clipper *clipper = clipper_stage( stage );
+ struct vertex_header *v0 = header->v[0];
+ struct vertex_header *v1 = header->v[1];
+ const GLfloat *pos0 = v0->clip;
+ const GLfloat *pos1 = v1->clip;
+ GLfloat t0 = 0;
+ GLfloat t1 = 0;
+
+ /* XXX: Note stupid hack to deal with tnl's 8-bit clipmask. Remove
+ * this once we correctly use 16bit masks for userclip planes.
+ */
+ clipmask &= ~CLIP_CULL_BIT;
+ if (clipmask & CLIP_USER_BIT) {
+ clipmask &= ~CLIP_USER_BIT;
+ clipmask |= clipper->active_user_planes;
+ }
+
+ while (clipmask) {
+ GLuint plane_idx = ffs(clipmask)-1;
+ const GLfloat *plane = clipper->stage.softpipe->plane[plane_idx];
+
+ clipmask &= ~(1<<plane_idx);
+
+ const GLfloat dp0 = dot4( pos0, plane );
+ const GLfloat dp1 = dot4( pos1, plane );
+
+ if (dp1 < 0) {
+ GLfloat t = dp1 / (dp1 - dp0);
+ if (t > t1) t1 = t;
+ }
+
+ if (dp0 < 0) {
+ GLfloat t = dp0 / (dp0 - dp1);
+ if (t > t0) t0 = t;
+ }
+
+ if (t0 + t1 >= 1.0)
+ return; /* discard */
+ }
+
+ if (v0->clipmask) {
+ interp( clipper, stage->tmp[0], t0, v0, v1 );
+ header->v[0] = stage->tmp[0];
+ }
+
+ if (v1->clipmask) {
+ interp( clipper, stage->tmp[1], t1, v1, v0 );
+ header->v[1] = stage->tmp[1];
+ }
+
+ stage->next->line( stage->next, header );
+}
+
+
+
+static void clip_begin( struct prim_stage *stage )
+{
+ struct clipper *clipper = clipper_stage(stage);
+ GLuint nr = stage->softpipe->nr_planes;
+
+ /* Hacky bitmask to use when we hit CLIP_USER_BIT:
+ */
+ clipper->active_user_planes = ((1<<nr)-1) & ~((1<<6)-1);
+
+ stage->next->begin( stage->next );
+}
+
+static void
+clip_point( struct prim_stage *stage,
+ struct prim_header *header )
+{
+ if (header->v[0]->clipmask == 0)
+ stage->next->point( stage->next, header );
+}
+
+
+static void
+clip_line( struct prim_stage *stage,
+ struct prim_header *header )
+{
+ GLuint clipmask = (header->v[0]->clipmask |
+ header->v[1]->clipmask);
+
+ if (clipmask == 0) {
+ stage->next->line( stage->next, header );
+ }
+ else if ((header->v[0]->clipmask &
+ header->v[1]->clipmask) == 0) {
+ do_clip_line(stage, header, clipmask);
+ }
+}
+
+
+static void
+clip_tri( struct prim_stage *stage,
+ struct prim_header *header )
+{
+ GLuint clipmask = (header->v[0]->clipmask |
+ header->v[1]->clipmask |
+ header->v[2]->clipmask);
+
+ if (clipmask == 0) {
+ stage->next->tri( stage->next, header );
+ }
+ else if ((header->v[0]->clipmask &
+ header->v[1]->clipmask &
+ header->v[2]->clipmask) == 0) {
+ do_clip_tri(stage, header, clipmask);
+ }
+}
+
+static void clip_end( struct prim_stage *stage )
+{
+ stage->next->end( stage->next );
+}
+
+
+struct prim_stage *prim_clip( struct softpipe_context *softpipe )
+{
+ struct clipper *clipper = CALLOC_STRUCT(clipper);
+
+ prim_alloc_tmps( &clipper->stage, MAX_CLIPPED_VERTICES );
+
+ clipper->stage.softpipe = softpipe;
+ clipper->stage.begin = clip_begin;
+ clipper->stage.point = clip_point;
+ clipper->stage.line = clip_line;
+ clipper->stage.tri = clip_tri;
+ clipper->stage.end = clip_end;
+
+ return &clipper->stage;
+}
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