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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 <keith@tungstengraphics.com>
*/
#include "pipe/p_util.h"
#include "pipe/p_defines.h"
#include "pipe/p_shader_tokens.h"
#include "draw_private.h"
#include "draw_pipe.h"
struct wideline_stage {
struct draw_stage stage;
float half_line_width;
};
static INLINE struct wideline_stage *wideline_stage( struct draw_stage *stage )
{
return (struct wideline_stage *)stage;
}
/**
* Draw a wide line by drawing a quad (two triangles).
* XXX need to disable polygon stipple.
*/
static void wideline_line( struct draw_stage *stage,
struct prim_header *header )
{
/*const struct wideline_stage *wide = wideline_stage(stage);*/
const unsigned pos = stage->draw->vs.position_output;
const float half_width = 0.5f * stage->draw->rasterizer->line_width;
struct prim_header tri;
struct vertex_header *v0 = dup_vert(stage, header->v[0], 0);
struct vertex_header *v1 = dup_vert(stage, header->v[0], 1);
struct vertex_header *v2 = dup_vert(stage, header->v[1], 2);
struct vertex_header *v3 = dup_vert(stage, header->v[1], 3);
float *pos0 = v0->data[pos];
float *pos1 = v1->data[pos];
float *pos2 = v2->data[pos];
float *pos3 = v3->data[pos];
const float dx = FABSF(pos0[0] - pos2[0]);
const float dy = FABSF(pos0[1] - pos2[1]);
/* small tweak to meet GL specification */
const float bias = 0.125f;
/*
* Draw wide line as a quad (two tris) by "stretching" the line along
* X or Y.
* We need to tweak coords in several ways to be conformant here.
*/
if (dx > dy) {
/* x-major line */
pos0[1] = pos0[1] - half_width - bias;
pos1[1] = pos1[1] + half_width - bias;
pos2[1] = pos2[1] - half_width - bias;
pos3[1] = pos3[1] + half_width - bias;
if (pos0[0] < pos2[0]) {
/* left to right line */
pos0[0] -= 0.5f;
pos1[0] -= 0.5f;
pos2[0] -= 0.5f;
pos3[0] -= 0.5f;
}
else {
/* right to left line */
pos0[0] += 0.5f;
pos1[0] += 0.5f;
pos2[0] += 0.5f;
pos3[0] += 0.5f;
}
}
else {
/* y-major line */
pos0[0] = pos0[0] - half_width + bias;
pos1[0] = pos1[0] + half_width + bias;
pos2[0] = pos2[0] - half_width + bias;
pos3[0] = pos3[0] + half_width + bias;
if (pos0[1] < pos2[1]) {
/* top to bottom line */
pos0[1] -= 0.5f;
pos1[1] -= 0.5f;
pos2[1] -= 0.5f;
pos3[1] -= 0.5f;
}
else {
/* bottom to top line */
pos0[1] += 0.5f;
pos1[1] += 0.5f;
pos2[1] += 0.5f;
pos3[1] += 0.5f;
}
}
tri.det = header->det; /* only the sign matters */
tri.v[0] = v0;
tri.v[1] = v2;
tri.v[2] = v3;
stage->next->tri( stage->next, &tri );
tri.v[0] = v0;
tri.v[1] = v3;
tri.v[2] = v1;
stage->next->tri( stage->next, &tri );
}
static void wideline_flush( struct draw_stage *stage, unsigned flags )
{
stage->next->flush( stage->next, flags );
}
static void wideline_reset_stipple_counter( struct draw_stage *stage )
{
stage->next->reset_stipple_counter( stage->next );
}
static void wideline_destroy( struct draw_stage *stage )
{
draw_free_temp_verts( stage );
FREE( stage );
}
struct draw_stage *draw_wide_line_stage( struct draw_context *draw )
{
struct wideline_stage *wide = CALLOC_STRUCT(wideline_stage);
draw_alloc_temp_verts( &wide->stage, 4 );
wide->stage.draw = draw;
wide->stage.next = NULL;
wide->stage.point = draw_pipe_passthrough_point;
wide->stage.line = wideline_line;
wide->stage.tri = draw_pipe_passthrough_tri;
wide->stage.flush = wideline_flush;
wide->stage.reset_stipple_counter = wideline_reset_stipple_counter;
wide->stage.destroy = wideline_destroy;
return &wide->stage;
}
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