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/*
* Copyright © 2013 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.
*/
/** @file fbo-front-invalidate-back.c
*
* This test validates a corner case in the Intel mesa driver: if GL
* calls that require access to the front buffer are followed by GL
* calls that don't require access to the front buffer, and an
* invalidate event is received from the server in between, then
* before the driver responds to the invalidate event by requesting a
* new back buffer, it needs to flush the pending front buffer
* rendering. Otherwise the front buffer rendering will be lost.
*
* Unfortunately, we can't force the server to send an invalidate
* event to the driver at a specific time; however, thanks to a quirk
* in the driver, we can simulate one using a sequence of
* glDrawBuffer() calls.
*/
#include "piglit-util-gl.h"
PIGLIT_GL_TEST_CONFIG_BEGIN
config.supports_gl_compat_version = 10;
config.requires_displayed_window = true;
config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGB;
PIGLIT_GL_TEST_CONFIG_END
void
piglit_init(int argc, char **argv)
{
}
enum piglit_result
piglit_display(void)
{
const float green[] = {0.0f, 1.0f, 0.0f};
bool pass;
/* Do some rendering that requires access to the front buffer
* (clear it to green).
*/
glDrawBuffer(GL_FRONT);
glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
/* Simulate an invalidate event using a sequence of
* glDrawBuffer() calls. This takes advantage of a quirk of
* the Intel driver: when glDrawBuffer() is used to switch
* from back buffer to front buffer rendering, the driver acts
* as though a buffer invalidate event has occurred, so that
* when the next draw operation occurs, it will be sure to
* pick up a valid front buffer. Therefore, we can simulate
* an invalidate event by switching to GL_BACK and then to
* GL_FRONT again.
*/
glDrawBuffer(GL_BACK);
glDrawBuffer(GL_FRONT);
/* Do some rendering that doesn't require access to the front
* buffer (clear the back buffer to red). Note:
* gl_ReadBuffer(GL_BACK) ensures that the driver doesn't try
* to maintain access to the front buffer.
*/
glReadBuffer(GL_BACK);
glDrawBuffer(GL_BACK);
glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
/* Check that the front buffer rendering was not lost. */
glReadBuffer(GL_FRONT);
pass = piglit_probe_rect_rgb(0, 0, piglit_width, piglit_height,
green);
/* Since we don't do a buffer swap, flush to make sure
* rendering gets to the screen.
*/
glFlush();
return pass ? PIGLIT_PASS : PIGLIT_FAIL;
}
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