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path: root/src/mesa/pipe/draw/draw_linestipple.c
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Diffstat (limited to 'src/mesa/pipe/draw/draw_linestipple.c')
-rw-r--r--src/mesa/pipe/draw/draw_linestipple.c266
1 files changed, 266 insertions, 0 deletions
diff --git a/src/mesa/pipe/draw/draw_linestipple.c b/src/mesa/pipe/draw/draw_linestipple.c
new file mode 100644
index 0000000000..1fac1ebe66
--- /dev/null
+++ b/src/mesa/pipe/draw/draw_linestipple.c
@@ -0,0 +1,266 @@
+/**************************************************************************
+ *
+ * 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 <keith@tungstengraphics.com>
+ */
+
+/* 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 "imports.h"
+#include "macros.h"
+
+#define CLIP_PRIVATE
+#include "clip/clip_context.h"
+
+#define CLIP_PIPE_PRIVATE
+#include "clip/clip_pipe.h"
+
+
+
+struct stipple_stage {
+ struct clip_pipe_stage stage;
+
+ GLuint hw_data_offset;
+
+ GLfloat counter;
+ GLuint pattern;
+ GLuint factor;
+};
+
+
+
+
+static INLINE struct stipple_stage *stipple_stage( struct clip_pipe_stage *stage )
+{
+ return (struct stipple_stage *)stage;
+}
+
+
+
+
+static void interp_attr( const struct vf_attr *a,
+ GLubyte *vdst,
+ GLfloat t,
+ const GLubyte *vin,
+ const GLubyte *vout )
+{
+ GLuint offset = a->vertoffset;
+ GLfloat fin[4], fout[4], fdst[4];
+
+ a->extract( a, fin, vin + offset );
+ a->extract( a, fout, vout + offset );
+
+ 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] );
+
+ a->insert[4-1]( a, vdst + offset, fdst );
+}
+
+
+
+
+/* Weird screen-space interpolation?? Otherwise do something special
+ * with pos.w or fix vertices to always have clip coords available.
+ */
+static void screen_interp( struct vertex_fetch *vf,
+ struct vertex_header *dst,
+ GLfloat t,
+ const struct vertex_header *out,
+ const struct vertex_header *in )
+{
+ GLubyte *vdst = (GLubyte *)dst;
+ const GLubyte *vin = (const GLubyte *)in;
+ const GLubyte *vout = (const GLubyte *)out;
+
+ const struct vf_attr *a = vf->attr;
+ const GLuint attr_count = vf->attr_count;
+ GLuint j;
+
+ /* Vertex header.
+ */
+ {
+ assert(a[0].attrib == VF_ATTRIB_VERTEX_HEADER);
+ dst->clipmask = 0;
+ dst->edgeflag = 0;
+ dst->pad = 0;
+ dst->index = 0xffff;
+ }
+
+
+ /* Other attributes
+ */
+ for (j = 1; j < attr_count; j++) {
+ interp_attr(&a[j], vdst, t, vin, vout);
+ }
+}
+
+
+
+/* Clip a line against the viewport and user clip planes.
+ */
+static void draw_line_segment( struct clip_pipe_stage *stage,
+ struct prim_header *header,
+ GLfloat t0,
+ GLfloat t1 )
+{
+ struct vertex_fetch *vf = stage->pipe->draw->vb.vf;
+ struct vertex_header *v0 = header->v[0];
+ struct vertex_header *v1 = header->v[1];
+
+ struct prim_header newprim = *header;
+ header = &newprim;
+
+ _mesa_printf("%s %f %f\n", __FUNCTION__, t0, t1);
+
+ if (t0 > 0.0) {
+ screen_interp( vf, stage->tmp[0], t0, v0, v1 );
+ header->v[0] = stage->tmp[0];
+ }
+
+ if (t1 < 1.0) {
+ screen_interp( vf, stage->tmp[1], t1, v0, v1 );
+ header->v[1] = stage->tmp[1];
+ }
+
+ stage->next->line( stage->next, header );
+}
+
+
+
+/* XXX: don't really want to iterate like this.
+ */
+static INLINE unsigned
+stipple_test(int counter, ushort pattern, int factor)
+{
+ int b = (counter / factor) & 0xf;
+ return (1 << b) & pattern;
+}
+
+
+
+/* XXX: Need to have precalculated flatshading already.
+ */
+static void stipple_line( struct clip_pipe_stage *stage,
+ struct prim_header *header )
+{
+ struct stipple_stage *stipple = stipple_stage(stage);
+ GLuint hw_data_offset = stipple->hw_data_offset;
+ const GLfloat *pos0 = (GLfloat *)&(header->v[0]->data[hw_data_offset]);
+ const GLfloat *pos1 = (GLfloat *)&(header->v[1]->data[hw_data_offset]);
+ GLfloat start = 0;
+ int state = 0;
+
+ GLfloat x0 = (GLfloat)pos0[0];
+ GLfloat x1 = (GLfloat)pos1[0];
+ GLfloat y0 = (GLfloat)pos0[1];
+ GLfloat y1 = (GLfloat)pos1[1];
+
+ GLfloat dx = x0 > x1 ? x0 - x1 : x1 - x0;
+ GLfloat dy = y0 > y1 ? y0 - y1 : y1 - y0;
+
+ GLfloat length = MAX2(dx, dy);
+ GLint i;
+
+ if (header->reset_line_stipple)
+ stipple->counter = 0;
+
+ /* XXX: iterating like this is lame
+ */
+ for (i = 0; i < length; i++) {
+ int result = !!stipple_test( stipple->counter+i, stipple->pattern, stipple->factor );
+// _mesa_printf("%d %f %d\n", i, length, result);
+ if (result != state) {
+ if (state) {
+ if (start != i)
+ draw_line_segment( stage, header, start / length, i / length );
+ }
+ else {
+ start = i;
+ }
+ state = result;
+ }
+ }
+
+ if (state && start < length)
+ draw_line_segment( stage, header, start / length, 1.0 );
+
+ stipple->counter += length;
+}
+
+
+
+static void stipple_begin( struct clip_pipe_stage *stage )
+{
+ struct stipple_stage *stipple = stipple_stage(stage);
+ struct clip_context *draw = stage->pipe->draw;
+
+ if (stage->pipe->draw->vb_state.clipped_prims)
+ stipple->hw_data_offset = 16;
+ else
+ stipple->hw_data_offset = 0;
+
+ stipple->stage.tri = clip_passthrough_tri;
+ stipple->stage.point = clip_passthrough_point;
+
+ stipple->stage.line = stipple_line;
+ stipple->factor = draw->state.line_stipple_factor + 1;
+ stipple->pattern = draw->state.line_stipple_pattern;
+
+ stage->next->begin( stage->next );
+}
+
+
+
+static void stipple_end( struct clip_pipe_stage *stage )
+{
+ stage->next->end( stage->next );
+}
+
+struct clip_pipe_stage *clip_pipe_stipple( struct clip_pipeline *pipe )
+{
+ struct stipple_stage *stipple = CALLOC_STRUCT(stipple_stage);
+
+ clip_pipe_alloc_tmps( &stipple->stage, 4 );
+
+ stipple->stage.pipe = pipe;
+ stipple->stage.next = NULL;
+ stipple->stage.begin = stipple_begin;
+ stipple->stage.point = clip_passthrough_point;
+ stipple->stage.line = stipple_line;
+ stipple->stage.tri = clip_passthrough_tri;
+ stipple->stage.reset_tmps = clip_pipe_reset_tmps;
+ stipple->stage.end = stipple_end;
+
+ return &stipple->stage;
+}
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