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diff --git a/src/gallium/aux/draw/draw_clip.c b/src/gallium/aux/draw/draw_clip.c
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+/**************************************************************************
+ *
+ * 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.
+ *
+ **************************************************************************/
+
+/**
+ * \brief Clipping stage
+ *
+ * \author Keith Whitwell <[email protected]>
+ */
+
+
+#include "pipe/p_util.h"
+#include "pipe/p_shader_tokens.h"
+
+#include "draw_context.h"
+#include "draw_private.h"
+
+
+#ifndef IS_NEGATIVE
+#define IS_NEGATIVE(X) ((X) < 0.0)
+#endif
+
+#ifndef DIFFERENT_SIGNS
+#define DIFFERENT_SIGNS(x, y) ((x) * (y) <= 0.0F && (x) - (y) != 0.0F)
+#endif
+
+#ifndef MAX_CLIPPED_VERTICES
+#define MAX_CLIPPED_VERTICES ((2 * (6 + PIPE_MAX_CLIP_PLANES))+1)
+#endif
+
+
+
+struct clipper {
+ struct draw_stage stage; /**< base class */
+
+ /* Basically duplicate some of the flatshading logic here:
+ */
+ boolean flat;
+ uint num_color_attribs;
+ uint color_attribs[4]; /* front/back primary/secondary colors */
+
+ float (*plane)[4];
+};
+
+
+/* This is a bit confusing:
+ */
+static INLINE struct clipper *clipper_stage( struct draw_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( float *fdst,
+ float t,
+ const float *fin,
+ const float *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] );
+}
+
+static void copy_colors( struct draw_stage *stage,
+ struct vertex_header *dst,
+ const struct vertex_header *src )
+{
+ const struct clipper *clipper = clipper_stage(stage);
+ uint i;
+ for (i = 0; i < clipper->num_color_attribs; i++) {
+ const uint attr = clipper->color_attribs[i];
+ COPY_4FV(dst->data[attr], src->data[attr]);
+ }
+}
+
+
+
+/* Interpolate between two vertices to produce a third.
+ */
+static void interp( const struct clipper *clip,
+ struct vertex_header *dst,
+ float t,
+ const struct vertex_header *out,
+ const struct vertex_header *in )
+{
+ const unsigned nr_attrs = clip->stage.draw->num_vs_outputs;
+ unsigned j;
+
+ /* Vertex header.
+ */
+ {
+ dst->clipmask = 0;
+ dst->edgeflag = 0;
+ dst->pad = 0;
+ dst->vertex_id = UNDEFINED_VERTEX_ID;
+ }
+
+ /* Clip coordinates: interpolate normally
+ */
+ {
+ interp_attr(dst->clip, t, in->clip, out->clip);
+ }
+
+ /* Do the projective divide and insert window coordinates:
+ */
+ {
+ const float *pos = dst->clip;
+ const float *scale = clip->stage.draw->viewport.scale;
+ const float *trans = clip->stage.draw->viewport.translate;
+ const float oow = 1.0f / 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
+ * Note: start at 1 to skip winpos (data[0]) since we just computed
+ * it above.
+ */
+ for (j = 1; j < nr_attrs; j++) {
+ interp_attr(dst->data[j], t, in->data[j], out->data[j]);
+ }
+}
+
+
+static void emit_poly( struct draw_stage *stage,
+ struct vertex_header **inlist,
+ unsigned n,
+ const struct prim_header *origPrim)
+{
+ struct prim_header header;
+ unsigned i;
+
+ /* later stages may need the determinant, but only the sign matters */
+ header.det = origPrim->det;
+
+ for (i = 2; i < n; i++) {
+ header.v[0] = inlist[i-1];
+ header.v[1] = inlist[i];
+ header.v[2] = inlist[0]; /* keep in v[2] for flatshading */
+
+ {
+ unsigned tmp1 = header.v[1]->edgeflag;
+ unsigned tmp2 = header.v[2]->edgeflag;
+
+ if (i != n-1) header.v[1]->edgeflag = 0;
+ if (i != 2) header.v[2]->edgeflag = 0;
+
+ header.edgeflags = ((header.v[0]->edgeflag << 0) |
+ (header.v[1]->edgeflag << 1) |
+ (header.v[2]->edgeflag << 2));
+
+ stage->next->tri( stage->next, &header );
+
+ header.v[1]->edgeflag = tmp1;
+ header.v[2]->edgeflag = tmp2;
+ }
+ }
+}
+
+
+
+
+/* Clip a triangle against the viewport and user clip planes.
+ */
+static void
+do_clip_tri( struct draw_stage *stage,
+ struct prim_header *header,
+ unsigned 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;
+ unsigned tmpnr = 0;
+ unsigned n = 3;
+ unsigned i;
+
+ inlist[0] = header->v[0];
+ inlist[1] = header->v[1];
+ inlist[2] = header->v[2];
+
+ while (clipmask && n >= 3) {
+ const unsigned plane_idx = ffs(clipmask)-1;
+ const float *plane = clipper->plane[plane_idx];
+ struct vertex_header *vert_prev = inlist[0];
+ float dp_prev = dot4( vert_prev->clip, plane );
+ unsigned 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];
+
+ float 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.
+ */
+ float 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.
+ */
+ float 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;
+ }
+ }
+
+ /* If flat-shading, copy color to new provoking vertex.
+ */
+ if (clipper->flat && inlist[0] != header->v[2]) {
+ if (1) {
+ inlist[0] = dup_vert(stage, inlist[0], tmpnr++);
+ }
+
+ copy_colors(stage, inlist[0], header->v[2]);
+ }
+
+
+
+ /* Emit the polygon as triangles to the setup stage:
+ */
+ if (n >= 3)
+ emit_poly( stage, inlist, n, header );
+}
+
+
+/* Clip a line against the viewport and user clip planes.
+ */
+static void
+do_clip_line( struct draw_stage *stage,
+ struct prim_header *header,
+ unsigned clipmask )
+{
+ const struct clipper *clipper = clipper_stage( stage );
+ struct vertex_header *v0 = header->v[0];
+ struct vertex_header *v1 = header->v[1];
+ const float *pos0 = v0->clip;
+ const float *pos1 = v1->clip;
+ float t0 = 0.0F;
+ float t1 = 0.0F;
+ struct prim_header newprim;
+
+ while (clipmask) {
+ const unsigned plane_idx = ffs(clipmask)-1;
+ const float *plane = clipper->plane[plane_idx];
+ const float dp0 = dot4( pos0, plane );
+ const float dp1 = dot4( pos1, plane );
+
+ if (dp1 < 0.0F) {
+ float t = dp1 / (dp1 - dp0);
+ t1 = MAX2(t1, t);
+ }
+
+ if (dp0 < 0.0F) {
+ float t = dp0 / (dp0 - dp1);
+ t0 = MAX2(t0, t);
+ }
+
+ if (t0 + t1 >= 1.0F)
+ return; /* discard */
+
+ clipmask &= ~(1 << plane_idx); /* turn off this plane's bit */
+ }
+
+ if (v0->clipmask) {
+ interp( clipper, stage->tmp[0], t0, v0, v1 );
+
+ if (clipper->flat)
+ copy_colors(stage, stage->tmp[0], v0);
+
+ newprim.v[0] = stage->tmp[0];
+ }
+ else {
+ newprim.v[0] = v0;
+ }
+
+ if (v1->clipmask) {
+ interp( clipper, stage->tmp[1], t1, v1, v0 );
+ newprim.v[1] = stage->tmp[1];
+ }
+ else {
+ newprim.v[1] = v1;
+ }
+
+ stage->next->line( stage->next, &newprim );
+}
+
+
+static void
+clip_point( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ if (header->v[0]->clipmask == 0)
+ stage->next->point( stage->next, header );
+}
+
+
+static void
+clip_line( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ unsigned clipmask = (header->v[0]->clipmask |
+ header->v[1]->clipmask);
+
+ if (clipmask == 0) {
+ /* no clipping needed */
+ stage->next->line( stage->next, header );
+ }
+ else if ((header->v[0]->clipmask &
+ header->v[1]->clipmask) == 0) {
+ do_clip_line(stage, header, clipmask);
+ }
+ /* else, totally clipped */
+}
+
+
+static void
+clip_tri( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ unsigned clipmask = (header->v[0]->clipmask |
+ header->v[1]->clipmask |
+ header->v[2]->clipmask);
+
+ if (clipmask == 0) {
+ /* no clipping needed */
+ 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);
+ }
+}
+
+/* Update state. Could further delay this until we hit the first
+ * primitive that really requires clipping.
+ */
+static void
+clip_init_state( struct draw_stage *stage )
+{
+ struct clipper *clipper = clipper_stage( stage );
+
+ clipper->flat = stage->draw->rasterizer->flatshade ? TRUE : FALSE;
+
+ if (clipper->flat) {
+ const struct pipe_shader_state *vs = stage->draw->vertex_shader->state;
+ uint i;
+
+ clipper->num_color_attribs = 0;
+ for (i = 0; i < vs->num_outputs; i++) {
+ if (vs->output_semantic_name[i] == TGSI_SEMANTIC_COLOR ||
+ vs->output_semantic_name[i] == TGSI_SEMANTIC_BCOLOR) {
+ clipper->color_attribs[clipper->num_color_attribs++] = i;
+ }
+ }
+ }
+
+ stage->tri = clip_tri;
+ stage->line = clip_line;
+}
+
+
+
+static void clip_first_tri( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ clip_init_state( stage );
+ stage->tri( stage, header );
+}
+
+static void clip_first_line( struct draw_stage *stage,
+ struct prim_header *header )
+{
+ clip_init_state( stage );
+ stage->line( stage, header );
+}
+
+
+static void clip_flush( struct draw_stage *stage,
+ unsigned flags )
+{
+ stage->tri = clip_first_tri;
+ stage->line = clip_first_line;
+ stage->next->flush( stage->next, flags );
+}
+
+
+static void clip_reset_stipple_counter( struct draw_stage *stage )
+{
+ stage->next->reset_stipple_counter( stage->next );
+}
+
+
+static void clip_destroy( struct draw_stage *stage )
+{
+ draw_free_temp_verts( stage );
+ FREE( stage );
+}
+
+
+/**
+ * Allocate a new clipper stage.
+ * \return pointer to new stage object
+ */
+struct draw_stage *draw_clip_stage( struct draw_context *draw )
+{
+ struct clipper *clipper = CALLOC_STRUCT(clipper);
+
+ draw_alloc_temp_verts( &clipper->stage, MAX_CLIPPED_VERTICES+1 );
+
+ clipper->stage.draw = draw;
+ clipper->stage.point = clip_point;
+ clipper->stage.line = clip_first_line;
+ clipper->stage.tri = clip_first_tri;
+ clipper->stage.flush = clip_flush;
+ clipper->stage.reset_stipple_counter = clip_reset_stipple_counter;
+ clipper->stage.destroy = clip_destroy;
+
+ clipper->plane = draw->plane;
+
+ return &clipper->stage;
+}
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