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/*
* Copyright © 2012 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.
*/
#include "draw-buffers-common.h"
/**
* \file draw-buffers-alpha-to-one.cpp
*
* Verify sample alpha to one with multiple draw buffers
*
* When rendering to multiple draw buffers, GL_SAMPLE_ALPHA_TO_ONE should
* modify the alpha values sent to each draw buffer. OpenGL 3.3 specification's
* section 4.1.3 (page 196 of pdf) is little unclear about the exact behavior
* in above mentioned case:
*
* "All alpha values in this section refer only to the alpha component of the
* fragment shader output linked to color number zero, index zero (see section
* 3.9.2) if a fragment shader is in use, or the alpha component of the result
* of fixed-function fragment shading. If the fragment shader does not write to
* this output, the alpha value is undefined."
*
* And later in the same section it is stated that:
*
* "Next, if SAMPLE_ALPHA_TO_ONE is enabled, each alpha value is replaced by
* the maximum representable alpha value for fixed-point color buffers, or by
* 1.0 for floating-point buffers. Otherwise, the alpha values are not changed."
*
* By reading above two references together, specification seems to suggest that
* alpha values for only draw buffer zero will be modified when GL_SAMPLE_TO_ONE.
* is enabled. But with NVIDIA's proprietary drivers this test verifies that
* alpha values for all the draw buffers will be modified. In my opinion, this
* section needs clarification from khronos.
*
* At present test is based on the behavior observed with NVIDIA's proprietary
* drivers.
*
* This test operates by drawing a pattern in multisample FBO to generate
* reference and test images for all the draw buffers. Reference images are drawn
* to right half of window system draw buffer and test images to left half.
*
* Compare the left and right halves of window system frame buffer to verify
* the test image.
*
* Author: Anuj Phogat <anuj.phogat@gmail.com>
*/
PIGLIT_GL_TEST_MAIN(512 /*window_width*/,
768 /*window_height*/,
PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGBA | PIGLIT_GL_VISUAL_ALPHA)
static int samples;
void
print_usage_and_exit(char *prog_name)
{
printf("Usage: %s <num_samples>\n", prog_name);
piglit_report_result(PIGLIT_FAIL);
}
void
piglit_init(int argc, char **argv)
{
/* At present fragment shader supports only fixed number of
* attachments (3)
*/
int num_attachments = 3;
if (argc < 2)
print_usage_and_exit(argv[0]);
{
char *endptr = NULL;
samples = strtol(argv[1], &endptr, 0);
if (endptr != argv[1] + strlen(argv[1]))
print_usage_and_exit(argv[0]);
}
piglit_require_gl_version(30);
int pattern_width = piglit_width / 2;
int pattern_height = piglit_height / num_attachments;
piglit_ortho_projection(pattern_width,
pattern_height,
GL_TRUE);
/* Skip the test if samples > GL_MAX_SAMPLES */
GLint max_samples;
glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
if (samples > max_samples)
piglit_report_result(PIGLIT_SKIP);
ms_fbo_and_draw_buffers_setup(samples,
pattern_width,
pattern_height,
num_attachments,
GL_COLOR_BUFFER_BIT,
GL_RGBA);
shader_compile(false /* sample_alpha_to_coverage */,
false /* dual_src_blend */);
}
enum piglit_result
piglit_display()
{
bool pass = true;
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
glClearColor(0.0, 0.0, 0.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
allocate_data_arrays();
draw_reference_image(false /* sample_alpha_to_coverage */,
true /* sample_alpha_to_one */);
draw_test_image(false /* sample_alpha_to_coverage */,
true /* sample_alpha_to_one */);
pass = piglit_check_gl_error(GL_NO_ERROR) && pass;
glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
pass = piglit_probe_rect_halves_equal_rgba(0, 0,
piglit_width,
piglit_height)
&& pass;
/* Free the memory allocated for data arrays */
free_data_arrays();
if (!piglit_automatic)
piglit_present_results();
return pass ? PIGLIT_PASS : PIGLIT_FAIL;
}
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