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-rw-r--r--src/gallium/auxiliary/draw/draw_stipple.c239
1 files changed, 239 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/draw/draw_stipple.c b/src/gallium/auxiliary/draw/draw_stipple.c
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+++ b/src/gallium/auxiliary/draw/draw_stipple.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.
+ *
+ **************************************************************************/
+
+/* Authors: Keith Whitwell <[email protected]>
+ */
+
+/* Implement line stipple by cutting lines up into smaller lines.
+ * There are hundreds of ways to implement line stipple, this is one
+ * choice that should work in all situations, requires no state
+ * manipulations, but with a penalty in terms of large amounts of
+ * generated geometry.
+ */
+
+
+#include "pipe/p_util.h"
+#include "pipe/p_defines.h"
+#include "pipe/p_shader_tokens.h"
+#include "draw_private.h"
+
+
+/** Subclass of draw_stage */
+struct stipple_stage {
+ struct draw_stage stage;
+ float counter;
+ uint pattern;
+ uint factor;
+};
+
+
+static INLINE struct stipple_stage *
+stipple_stage(struct draw_stage *stage)
+{
+ return (struct stipple_stage *) stage;
+}
+
+
+/**
+ * Compute interpolated vertex attributes for 'dst' at position 't'
+ * between 'v0' and 'v1'.
+ * XXX using linear interpolation for all attribs at this time.
+ */
+static void
+screen_interp( struct draw_context *draw,
+ struct vertex_header *dst,
+ float t,
+ const struct vertex_header *v0,
+ const struct vertex_header *v1 )
+{
+ uint attr;
+ for (attr = 0; attr < draw->num_vs_outputs; attr++) {
+ const float *val0 = v0->data[attr];
+ const float *val1 = v1->data[attr];
+ float *newv = dst->data[attr];
+ uint i;
+ for (i = 0; i < 4; i++) {
+ newv[i] = val0[i] + t * (val1[i] - val0[i]);
+ }
+ }
+}
+
+
+static void
+emit_segment(struct draw_stage *stage, struct prim_header *header,
+ float t0, float t1)
+{
+ struct vertex_header *v0new = dup_vert(stage, header->v[0], 0);
+ struct vertex_header *v1new = dup_vert(stage, header->v[1], 1);
+ struct prim_header newprim = *header;
+
+ if (t0 > 0.0) {
+ screen_interp( stage->draw, v0new, t0, header->v[0], header->v[1] );
+ newprim.v[0] = v0new;
+ }
+
+ if (t1 < 1.0) {
+ screen_interp( stage->draw, v1new, t1, header->v[0], header->v[1] );
+ newprim.v[1] = v1new;
+ }
+
+ stage->next->line( stage->next, &newprim );
+}
+
+
+static INLINE unsigned
+stipple_test(int counter, ushort pattern, int factor)
+{
+ int b = (counter / factor) & 0xf;
+ return (1 << b) & pattern;
+}
+
+
+static void
+stipple_line(struct draw_stage *stage, struct prim_header *header)
+{
+ struct stipple_stage *stipple = stipple_stage(stage);
+ struct vertex_header *v0 = header->v[0];
+ struct vertex_header *v1 = header->v[1];
+ const float *pos0 = v0->data[0];
+ const float *pos1 = v1->data[0];
+ float start = 0;
+ int state = 0;
+
+ float x0 = pos0[0];
+ float x1 = pos1[0];
+ float y0 = pos0[1];
+ float y1 = pos1[1];
+
+ float dx = x0 > x1 ? x0 - x1 : x1 - x0;
+ float dy = y0 > y1 ? y0 - y1 : y1 - y0;
+
+ float length = MAX2(dx, dy);
+ int i;
+
+ /* XXX ToDo: intead of iterating pixel-by-pixel, use a look-up table.
+ */
+ for (i = 0; i < length; i++) {
+ int result = stipple_test( (int) stipple->counter+i,
+ (ushort) stipple->pattern, stipple->factor );
+ if (result != state) {
+ /* changing from "off" to "on" or vice versa */
+ if (state) {
+ if (start != i) {
+ /* finishing an "on" segment */
+ emit_segment( stage, header, start / length, i / length );
+ }
+ }
+ else {
+ /* starting an "on" segment */
+ start = (float) i;
+ }
+ state = result;
+ }
+ }
+
+ if (state && start < length)
+ emit_segment( stage, header, start / length, 1.0 );
+
+ stipple->counter += length;
+}
+
+
+static void
+reset_stipple_counter(struct draw_stage *stage)
+{
+ struct stipple_stage *stipple = stipple_stage(stage);
+ stipple->counter = 0;
+ stage->next->reset_stipple_counter( stage->next );
+}
+
+
+static void
+stipple_first_line(struct draw_stage *stage,
+ struct prim_header *header)
+{
+ struct stipple_stage *stipple = stipple_stage(stage);
+ struct draw_context *draw = stage->draw;
+
+ stipple->pattern = draw->rasterizer->line_stipple_pattern;
+ stipple->factor = draw->rasterizer->line_stipple_factor + 1;
+
+ stage->line = stipple_line;
+ stage->line( stage, header );
+}
+
+
+static void
+stipple_flush(struct draw_stage *stage, unsigned flags)
+{
+ stage->line = stipple_first_line;
+ stage->next->flush( stage->next, flags );
+}
+
+
+static void
+passthrough_point(struct draw_stage *stage, struct prim_header *header)
+{
+ stage->next->point( stage->next, header );
+}
+
+
+static void
+passthrough_tri(struct draw_stage *stage, struct prim_header *header)
+{
+ stage->next->tri(stage->next, header);
+}
+
+
+static void
+stipple_destroy( struct draw_stage *stage )
+{
+ draw_free_temp_verts( stage );
+ FREE( stage );
+}
+
+
+/**
+ * Create line stippler stage
+ */
+struct draw_stage *draw_stipple_stage( struct draw_context *draw )
+{
+ struct stipple_stage *stipple = CALLOC_STRUCT(stipple_stage);
+
+ draw_alloc_temp_verts( &stipple->stage, 2 );
+
+ stipple->stage.draw = draw;
+ stipple->stage.next = NULL;
+ stipple->stage.point = passthrough_point;
+ stipple->stage.line = stipple_first_line;
+ stipple->stage.tri = passthrough_tri;
+ stipple->stage.reset_stipple_counter = reset_stipple_counter;
+ stipple->stage.flush = stipple_flush;
+ stipple->stage.destroy = stipple_destroy;
+
+ return &stipple->stage;
+}
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