/**************************************************************************
*
* 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_context.h"
#include "pipe/p_defines.h"
#include "pipe/p_shader_tokens.h"
#include "util/u_math.h"
#include "util/u_memory.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).
*/
static void wideline_line( struct draw_stage *stage,
struct prim_header *header )
{
/*const struct wideline_stage *wide = wideline_stage(stage);*/
const unsigned pos = draw_current_shader_position_output(stage->draw);
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]);
const boolean half_pixel_center =
stage->draw->rasterizer->half_pixel_center;
/* small tweak to meet GL specification */
const float bias = half_pixel_center ? 0.125f : 0.0f;
/*
* 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 (half_pixel_center) {
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 (half_pixel_center) {
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_first_line( struct draw_stage *stage,
struct prim_header *header )
{
struct draw_context *draw = stage->draw;
struct pipe_context *pipe = draw->pipe;
const struct pipe_rasterizer_state *rast = draw->rasterizer;
void *r;
/* Disable triangle culling, stippling, unfilled mode etc. */
r = draw_get_rasterizer_no_cull(draw, rast->scissor, rast->flatshade);
draw->suspend_flushing = TRUE;
pipe->bind_rasterizer_state(pipe, r);
draw->suspend_flushing = FALSE;
stage->line = wideline_line;
wideline_line(stage, header);
}
static void wideline_flush( struct draw_stage *stage, unsigned flags )
{
struct draw_context *draw = stage->draw;
struct pipe_context *pipe = draw->pipe;
stage->line = wideline_first_line;
stage->next->flush( stage->next, flags );
/* restore original rasterizer state */
if (draw->rast_handle) {
draw->suspend_flushing = TRUE;
pipe->bind_rasterizer_state(pipe, draw->rast_handle);
draw->suspend_flushing = FALSE;
}
}
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);
if (wide == NULL)
goto fail;
wide->stage.draw = draw;
wide->stage.name = "wide-line";
wide->stage.next = NULL;
wide->stage.point = draw_pipe_passthrough_point;
wide->stage.line = wideline_first_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;
if (!draw_alloc_temp_verts( &wide->stage, 4 ))
goto fail;
return &wide->stage;
fail:
if (wide)
wide->stage.destroy( &wide->stage );
return NULL;
}