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/*
* Copyright © 2010 Intel Corporation
*
* 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, sublicense,
* 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 NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS 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:
* Eric Anholt <eric@anholt.net>
*
*/
/**
* @file line-aa-width.c
*
* Tests that width 1.0 AA lines are of the appropriate thickness.
*
* The 965 driver was rendering them so that when the line was
* centered on a pixel it was fullly lit and when it was off the pixel
* center neither of the neighbors would be lit at all. It's quite
* ugly.
*/
#ifdef _MSC_VER
#define _USE_MATH_DEFINES
#endif
#include "piglit-util.h"
int piglit_width = 300, piglit_height = 100;
int piglit_window_mode = GLUT_RGB | GLUT_DOUBLE;
static float
y_from_x(float x)
{
return 2.0 + (piglit_height - 4.0) *
(1.0 - cos(x / piglit_width * M_PI / 2));
}
/* Check that the color is approximately gray. There was a report that
* Gen3 Intel is failing at this.
*/
static GLboolean
check_color(float *color)
{
float max = 0.0;
static GLboolean reported = GL_FALSE;
if (fabs(color[1] - color[0]) > max)
max = fabs(color[1] - color[0]) > 0.01;
if (fabs(color[2] - color[0]) > max)
max = fabs(color[2] - color[0]) > 0.01;
if (max > 0.02) {
if (!reported) {
printf("Found color %f, %f, %f, expected %f, %f, %f\n",
color[0], color[1], color[2],
color[0], color[0], color[0]);
reported = GL_TRUE;
}
return GL_FALSE;
}
return GL_TRUE;
}
enum piglit_result
piglit_display(void)
{
int x1;
int seg_width = 30;
float *screen;
GLboolean pass = GL_TRUE;
/* The coverage checking assumes that we'll be sampling along
* the major axis, so a tall window will break that.
*/
if (piglit_width / piglit_height < 3)
return PIGLIT_SKIP;
piglit_ortho_projection(piglit_width, piglit_height, GL_FALSE);
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT);
glColor4f(1.0, 1.0, 1.0, 1.0);
glEnable(GL_LINE_SMOOTH);
/* GL AA lines produce an alpha value */
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ZERO);
/* Draw a bunch of line segments with varying slopes across
* the window. They're separated by a bit of space so that we
* can see which regions we're going to sample in while
* avoiding any need to worry about end caps. */
for (x1 = 0; x1 < piglit_width; x1 += seg_width) {
int x2 = x1 + seg_width - 2;
float y1, y2;
if (x2 > piglit_width)
x2 = piglit_width;
y1 = y_from_x(x1);
y2 = y_from_x(x2);
glBegin(GL_LINES);
glVertex2f(x1, y1);
glVertex2f(x2, y2);
glEnd();
}
screen = malloc(piglit_width * piglit_height * 4 * sizeof(float));
glReadPixels(0, 0, piglit_width, piglit_height,
GL_RGBA, GL_FLOAT, screen);
/* Now, sample the middles of the segments and compare the total
* coverage in each column
*/
for (x1 = 2; x1 < piglit_width; x1 += seg_width) {
int x2 = x1 + seg_width - 4;
int sample_x;
float y1, y2;
float avg = 0.0;
float min = 100.0;
float max = -100.0;
if (x2 > piglit_width - 4)
x2 = piglit_width - 4;
/* If we don't have a couple of pixels to sample because we've
* hit the edge of the window, we're done.
*/
if (x2 - x1 < 2)
break;
y1 = y_from_x(x1) - 2;
y2 = y_from_x(x2) + 2;
avg = 0;
for (sample_x = x1; sample_x < x2; sample_x++) {
int y;
float col_total = 0.0;
for (y = y1; y < y2; y++) {
if (y < 0 || y >= piglit_height)
continue;
pass = pass &&
check_color(&screen[(y * piglit_width +
sample_x) * 4]);
col_total += screen[(y * piglit_width +
sample_x) * 4];
}
if (col_total > max)
max = col_total;
if (col_total < min)
min = col_total;
avg += col_total / (x2 - x1);
}
if (min < 0.25 ||
avg / min > 2.0 ||
max / avg > 2.0 ||
max > 1.5) {
printf("Line from %d,%d-%d,%d had bad thickness:\n",
x1 - 2, (int)y_from_x(x1 - 2),
x2 + 2, (int)y_from_x(x2 + 2));
printf("min coverage: %f\n", min);
printf("avg coverage: %f\n", avg);
printf("max coverage: %f\n", max);
pass = GL_FALSE;
}
}
glutSwapBuffers();
return pass ? PIGLIT_SUCCESS : PIGLIT_FAILURE;
}
void
piglit_init(int argc, char **argv)
{
}
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