[Piglit] [PATCH 1/2] Add test to verify glSampleCoverage with multisample fbo
Paul Berry
stereotype441 at gmail.com
Fri Jun 22 14:31:22 PDT 2012
On 20 June 2012 18:52, Anuj Phogat <anuj.phogat at gmail.com> wrote:
> This test varifies that the coverage value set by glSampleCoverage()
> decides
> the number of samples in multisample buffer covered by an incoming
> fragment,
> which will receive the fragment data.
>
> V2: Add the testing for glSampleCoverage() with coverage mask invert
> enabled
> / disabled. Resolve the multisample FBO to a single sample FBO in place
> of doing it on window system framebuffer. This fixes the color buffer
> failures on NVIDIA due to sRGB.
>
> V3: Add testing for coverage values which may result in dithering for all
> sample counts. Dropping the testing for multisample depth buffer.
>
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
> tests/all.tests | 6 +
> .../ext_framebuffer_multisample/CMakeLists.gl.txt | 1 +
> .../sample-coverage.cpp | 420
> ++++++++++++++++++++
> 3 files changed, 427 insertions(+), 0 deletions(-)
> create mode 100644
> tests/spec/ext_framebuffer_multisample/sample-coverage.cpp
>
> diff --git a/tests/all.tests b/tests/all.tests
> index 754a7e5..5fdc9e7 100644
> --- a/tests/all.tests
> +++ b/tests/all.tests
> @@ -1385,6 +1385,12 @@ for num_samples in (2, 4, 8, 16, 32):
> test_name)
> ext_framebuffer_multisample[test_name] = PlainExecTest(executable)
>
> +for num_samples in (2, 4, 8, 16, 32):
> + test_name = ' '.join(['sample-coverage', str(num_samples)])
> + executable = 'ext_framebuffer_multisample-{0} -auto'.format(
> + test_name)
> + ext_framebuffer_multisample[test_name] = PlainExecTest(executable)
> +
> ext_framebuffer_object = Group()
> spec['EXT_framebuffer_object'] = ext_framebuffer_object
> add_fbo_stencil_tests(ext_framebuffer_object, 'GL_STENCIL_INDEX1')
> diff --git a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
> b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
> index 7e37787..c746328 100644
> --- a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
> +++ b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
> @@ -28,6 +28,7 @@ piglit_add_executable
> (ext_framebuffer_multisample-polygon-smooth common.cpp pol
> piglit_add_executable (ext_framebuffer_multisample-renderbuffer-samples
> renderbuffer-samples.c)
> piglit_add_executable
> (ext_framebuffer_multisample-renderbufferstorage-samples
> renderbufferstorage-samples.c)
> piglit_add_executable (ext_framebuffer_multisample-samples samples.c)
> +piglit_add_executable (ext_framebuffer_multisample-sample-coverage
> common.cpp sample-coverage.cpp)
> piglit_add_executable (ext_framebuffer_multisample-turn-on-off common.cpp
> turn-on-off.cpp)
> piglit_add_executable (ext_framebuffer_multisample-unaligned-blit
> common.cpp unaligned-blit.cpp)
> piglit_add_executable (ext_framebuffer_multisample-upsample common.cpp
> upsample.cpp)
> diff --git a/tests/spec/ext_framebuffer_multisample/sample-coverage.cpp
> b/tests/spec/ext_framebuffer_multisample/sample-coverage.cpp
> new file mode 100644
> index 0000000..2f510c6
> --- /dev/null
> +++ b/tests/spec/ext_framebuffer_multisample/sample-coverage.cpp
> @@ -0,0 +1,420 @@
> +/*
> + * 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 "common.h"
> +
> +/**
> + * \file sample-coverage.cpp
> + *
> + * Verify glSampleCoverage() with and without coverage mask invert.
> + *
> + * This test operates by drawing a test pattern to multisample_fbo with
> + * GL_SAMPLE_COVERAGE disabled.
> + *
> + * Blit the multisample_fbo to top half of window system framebuffer. This
> + * is used as reference image to visually compare the difference caused by
> + * sample coverage value.
> + *
> + * Compute the expected color values based on the coverage value used to
> + * draw the test pattern and status of coverage mask invert flag.
> + *
> + * Clear the multisample framebuffer to a unique color. Draw the
> + * same test pattern in multisample buffer with GL_SAMPLE_COVERAGE
> enabled.
> + * Resolve the multisample FBO by blitting it to a single sample FBO.
> Blit
> + * the resolve_fbo to bottom half of window system framebuffer. This is
> our
> + * test image.
> + *
> + * Probe the rectangles in bottom half of window system framebuffer and
> + * compare with expected color values. OpenGL 3.0 specification intends
> + * to allow (but not require) the implementation to produce a dithering
> + * effect when the coverage value is not a strict multiple of
> 1/num_samples.
> + * We will skip computing expected values and probing for such rectangles.
> + * They are drawn just to look for dithering by human inspection.
> + *
> + * Repeat the above testing with coverage mask invert enabled / disabled.
> + *
> + * Note: glSampleCoverage() takes effect in the graphics pipeline before
> + * the point where the output of the fragment shader is split into the
> + * various buffers. So it's very likely that if glSampleCoverage() works
> + * properly for color buffers, it will work properly for depth and stencil
> + * buffers too.
> + *
> + * Author: Anuj Phogat <anuj.phogat at gmail.com>
> + */
> +
> +int piglit_width = 512; int piglit_height = 256;
> +int piglit_window_mode = GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA;
>
FYI, because of commit 29bbf12, this needs to change to
PIGLIT_GL_TEST_MAIN(
512 /*window_width*/,
256 /*window_height*/,
GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA)
See Chad's email "NOTICE: piglit_{width, height, window_mode} are no longer
used".
> +const int pattern_width = 512; const int pattern_height = 128;
> +
> +static Fbo ms_fbo, resolve_fbo;
> +static GLbitfield buffer_to_test;
> +
> +static float *cov = NULL;
> +static float *color = NULL;
> +static float *expected = NULL;
> +
> +static int num_samples;
> +static int num_rects;
> +static int prog;
> +static int color_loc;
> +static int depth_loc;
> +
> +static const float bg_color[4] = { 0.4, 0.6, 0.0, 0.8 };
> +
> +static const char *vert =
> + "#version 130\n"
> + "in vec2 pos;\n"
> + "uniform float depth;\n"
> + "void main()\n"
> + "{\n"
> + " vec4 eye_pos = gl_ModelViewProjectionMatrix * vec4(pos, 0.0,
> 1.0);\n"
> + " gl_Position = vec4(eye_pos.xy, depth, 1.0);\n"
> + "}\n";
> +
> +static const char *frag =
> + "#version 130\n"
> + "uniform vec4 color;\n"
> + "void main()\n"
> + "{\n"
> + " gl_FragColor = color;\n"
> + "}\n";
> +
> +void
> +shader_compile()
> +{
> + /* Compile program */
> + GLint vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vert);
> + GLint fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, frag);
> + prog = piglit_link_simple_program(vs, fs);
> +
> + if (!piglit_link_check_status(prog)) {
> + piglit_report_result(PIGLIT_FAIL);
> + }
> +
> + glBindAttribLocation(prog, 0, "pos");
> + glEnableVertexAttribArray(0);
> +
> + /* Set up uniforms */
> + glUseProgram(prog);
> + color_loc = glGetUniformLocation(prog, "color");
> + depth_loc = glGetUniformLocation(prog, "depth");
> +}
> +
> +void
> +draw_pattern(bool sample_coverage, bool coverage_invert)
> +{
> + glUseProgram(prog);
> + glClearColor(bg_color[0], bg_color[1],
> + bg_color[2], bg_color[3]);
> +
> + glClear(buffer_to_test);
> + if (sample_coverage)
> + glEnable (GL_SAMPLE_COVERAGE);
> +
> + unsigned int indices[6] = {0, 1, 2, 0, 2, 3};
> +
> + for (int i = 0; i < num_rects; ++i) {
> +
> + float vertex_data[4][2] = {
> + { 0.0f + i * (pattern_width / num_rects), 0.0f
> },
> + { 0.0f + i * (pattern_width / num_rects), pattern_height
> },
> + { (i + 1.0f) * (pattern_width / num_rects), pattern_height
> },
> + { (i + 1.0f) * (pattern_width / num_rects), 0.0f
> } };
> +
> + glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
> + sizeof(vertex_data[0]),
> + (void *) vertex_data);
> +
> + if(sample_coverage) {
> + if(coverage_invert)
> + glSampleCoverage (cov[i], GL_TRUE);
> + else
> + glSampleCoverage (cov[i], GL_FALSE);
> + }
> +
> + glUniform4fv(color_loc, 1, (color + i * 4));
> + glUniform1f(depth_loc, 0.0f);
> + glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT,
> + (void *) indices);
> + }
> + if(sample_coverage)
> + glDisable (GL_SAMPLE_COVERAGE);
> +}
> +
> +void
> +print_usage_and_exit(char *prog_name)
> +{
> + printf("Usage: %s <num_samples>\n", prog_name);
> + piglit_report_result(PIGLIT_FAIL);
> +}
> +
> +void
> +compute_expected(bool coverage_invert)
> +{
> + int i, j;
> + float coverage[num_rects];
> +
> + /* Sample coverage doesn't affect single sample FBO */
> + if(num_samples == 0) {
> + for(i = 0; i < 4; i++)
> + expected[i] = color[i];
> + return;
> + }
> +
> + if(coverage_invert) {
> + for (i = 0; i < num_rects; i++)
> + coverage[i] = 1 - cov[i];
> + }
> + else
> + for (i = 0; i < num_rects; i++)
> + coverage[i] = cov[i];
> +
> + /* Coverage value decides the number of samples in multisample
> buffer
> + * covered by an incoming fragment, which will then receive the
> fragment
> + * data. When the multisample buffer is resolved it will be blended
> + * with the background color which will be written to the remaining
> + * samples.
> + * Page 254 (page 270 of the PDF) of the OpenGL 3.0 spec says:
> + * "The method of combination is not specified, though a simple
> average
> + * computed independently for each color component is recommended."
> + */
> + if(buffer_to_test == GL_COLOR_BUFFER_BIT) {
> + for (i = 0; i < num_rects; i++) {
> +
> + float samples_used = coverage[i] * num_samples;
> + /* Exepected color values are computed only for
> integer
> + * number of samples_used
> + */
> + if(samples_used == (int)samples_used) {
> +
> + for(j =0; j < 4; j++)
> + expected[i * 4 + j] =
> + color[i * 4 + j] * coverage[i] +
> + bg_color[j] * (1 - coverage[i]);
> + }
> + }
> + }
> +}
> +
> +bool
> +probe_framebuffer_color(bool coverage_invert)
> +{
> + bool result = true;
> + float coverage[num_rects];
> +
> + if(coverage_invert) {
> + for (int i = 0; i < num_rects; i++)
> + coverage[i] = 1 - cov[i];
> + }
> + else
> + for (int i = 0; i < num_rects; i++)
> + coverage[i] = cov[i];
> +
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
> +
> + for (int i = 0; i < num_rects; i++) {
> + float samples_used = coverage[i] * num_samples;
> +
> + /* Only probe rectangles with coverage value which is a
> strict
> + * multiple of 1 / num_samples.
> + */
> + if(samples_used == (int)samples_used) {
> + result = piglit_probe_rect_rgba(
> + i * (pattern_width / num_rects),
> + 0,
> + pattern_width / num_rects,
> + pattern_height,
> + expected + i * 4)
> + && result;
> + }
> + }
> + return result;
> +}
> +
> +bool
> +test_sample_coverage(bool coverage_invert)
> +{
> + bool result = true;
> + compute_expected(coverage_invert);
> +
> + /* Now draw test pattern in multisample ms_fbo with
> GL_SAMPLE_COVERAGE
> + * enabled
> + */
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
> + draw_pattern(true /* sample_coverage */ , coverage_invert);
> +
> + /* Blit ms_fbo to resolve_fbo to resolve multisample buffer */
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, ms_fbo.handle);
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, resolve_fbo.handle);
> + glBlitFramebuffer(0, 0, pattern_width, pattern_height,
> + 0, 0, pattern_width, pattern_height,
> + buffer_to_test, GL_NEAREST);
> +
> + /* Blit resolve_fbo to the bottom half of window system
> framebuffer.
> + * This is the test image.
> + */
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, resolve_fbo.handle);
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
> + glBlitFramebuffer(0, 0, pattern_width, pattern_height,
> + 0, 0, pattern_width, pattern_height,
> + buffer_to_test, GL_NEAREST);
> +
> + /* Probe the bottom half of default framebuffer and compare to the
> + * expected values */
> + if (buffer_to_test == GL_COLOR_BUFFER_BIT)
> + result = probe_framebuffer_color(coverage_invert) &&
> result;
> +
> + result = piglit_check_gl_error(GL_NO_ERROR) && result;
> + return result;
> +}
> +
> +void
> +allocate_data_arrays(void)
> +{
> + /* Draw 2N + 1 rectangles for N samples, each with a unique color
> + * and coverage value
> + */
> + num_rects = 2 * num_samples + 1;
> +
> + /* Allocate data arrays based on number of samples used */
> + color = (float *) malloc(num_rects * 4 * sizeof(float));
> + cov = (float *) malloc(num_rects * sizeof(float));
> + expected = (float *) malloc(num_rects * 4 * sizeof(float));
> +
> + for(int i = 0; i < num_rects; i++) {
> + /* Randomly select color for each rectangle */
> + color[i * 4 + 0] = (rand() % 1000) * .001;
> + color[i * 4 + 1] = (rand() % 1000) * .001;
> + color[i * 4 + 2] = (rand() % 1000) * .001;
> + color[i * 4 + 3] = (rand() % 1000) * .001;
>
Generally I try to shy away from piglit tests that call rand(), because
they don't always have reproducible results. I don't think it's going to
be a problem for this test, but in the future you might want to consider
something deteministic. For example, you could do something like this:
color[i * 4 + 0] = (sin(i * 4 + 0)+1)/2;
color[i * 4 + 1] = (sin(i * 4 + 1)+1)/2;
color[i * 4 + 2] = (sin(i * 4 + 2)+1)/2;
color[i * 4 + 3] = (sin(i * 4 + 3)+1)/2;
But I won't make a fuss about it if you want to leave it as is.
> +
> + cov[i] = i * (1.0 / (2 * num_samples));
> + }
> +}
> +
> +void
> +free_data_arrays(void)
> +{
> + if(color != NULL) {
> + free(color);
> + color = NULL;
> + }
> + if(cov != NULL) {
> + free(cov);
> + cov = NULL;
> + }
> + if(expected != NULL) {
> + free(expected);
> + expected = NULL;
> + }
> +}
> +
> +void
> +piglit_init(int argc, char **argv)
> +{
> + int samples;
> + 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);
> + 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);
> +
> + /* Setup frame buffer objects with required configuration */
> + ms_fbo.setup(FboConfig(samples, pattern_width, pattern_height));
> + resolve_fbo.setup(FboConfig(0, pattern_width, pattern_height));
> +
> + if (!piglit_check_gl_error(GL_NO_ERROR)) {
> + printf("Error setting up frame buffer objects\n");
> + piglit_report_result(PIGLIT_FAIL);
> + }
> +
> + /* Query the number of samples used in ms_fbo. OpenGL
> implementation
> + * may create FBO with more samples per pixel than what is
> requested.
> + */
> + glBindRenderbuffer(GL_RENDERBUFFER, ms_fbo.color_rb);
> + glGetRenderbufferParameteriv(GL_RENDERBUFFER,
> + GL_RENDERBUFFER_SAMPLES,
> + &num_samples);
> +
> + buffer_to_test = GL_COLOR_BUFFER_BIT;
> + shader_compile();
> +}
> +
> +enum piglit_result
> +piglit_display()
> +{
> + bool pass = true;
> + allocate_data_arrays();
> +
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
> + glClearColor(0.0, 0.0, 0.0, 1.0);
> + glClear(buffer_to_test);
> +
> + /* Draw test pattern in multisample ms_fbo with GL_SAMPLE_COVERAGE
> + * disabled.
> + */
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
> + ms_fbo.set_viewport();
> + draw_pattern(false /* sample_coverage */,
> + false /* coverage_invert */ );
> +
> + /* Blit ms_fbo to the top half of window system framebuffer. This
> + * is our reference image to visually compare the effect of MSAA
> with
> + * sample coverage.
> + */
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, ms_fbo.handle);
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
> + glBlitFramebuffer(0, 0,
> + pattern_width, pattern_height,
> + 0, pattern_height,
> + pattern_width, 2 * pattern_height,
> + buffer_to_test, GL_NEAREST);
> +
> + /* Test with coverage_invert = false */
> + pass = test_sample_coverage(false) && pass;
> +
> + /* Test with coverage_invert = true */
> + pass = test_sample_coverage(true) && pass;
>
What's unfortunate about this is that the user only gets to see the results
of test_sample_coverage(true). Could we add a command-line parameter to
choose between testing "inverted" and "non-inverted" modes? Or,
alternatively, make the output window taller so that then reference image,
the inverted output, and the non-inverted outputs can all be seen at the
same time?
> +
> + /* Free the memory allocated for data arrays */
> + free_data_arrays();
> +
> + if (!piglit_automatic &&
> + buffer_to_test != GL_DEPTH_BUFFER_BIT)
> + piglit_present_results();
> +
> + return pass ? PIGLIT_PASS : PIGLIT_FAIL;
> +}
> --
> 1.7.7.6
>
>
My suggestions are pretty nit-picky, so regardless of whether you take my
suggestions, you can consider this patch
Reviewed-by: Paul Berry <stereotype441 at gmail.com>
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