[Piglit] [PATCH 2/2] Add test to verify sample alpha to coverage with multisample fbo
Paul Berry
stereotype441 at gmail.com
Fri Jun 22 20:24:39 PDT 2012
On 22 June 2012 20:19, Paul Berry <stereotype441 at gmail.com> wrote:
> On 22 June 2012 14:40, Paul Berry <stereotype441 at gmail.com> wrote:
>
>> On 20 June 2012 19:01, Anuj Phogat <anuj.phogat at gmail.com> wrote:
>>
>>> This test varifies that with GL_SAMPLE_ALPHA_TO_COVERAGE enabled, the
>>> coverage
>>> value is set by fragment alpha value. Coverage value decides the number
>>> of
>>> samples in multisample buffer covered by an incoming fragment, which
>>> receive
>>> the fragment data.
>>>
>>> It also includes testing of GL_SAMPLE_ALPHA_TO_COVERAGE with
>>> GL_SAMPLE_ALPHA_TO_ONE
>>> enabled.
>>>
>>> V2: Add testing for coverage values which may result in dithering for
>>> all sample
>>> counts. Dropping the testing for multisample depth buffer.
>>>
>>
>> This patch is:
>>
>> Reviewed-by: Paul Berry <stereotype441 at gmail.com>
>>
>
> BTW, I just noticed that we don't yet have any tests for
> GL_SAMPLE_COVERAGE_INVERT. Would it be possible to add that to this test
> (preferably as a command line parameter)?
>
I'm sorry, please ignore this. I got confused between "sample coverage"
and "sample alpha to coverage".
>
>
>>
>>
>>>
>>> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
>>> ---
>>> This test fails on AMD's catalyst drivers with GL_SAMPLE_ALPHA_TO_ONE
>>> enabled. But
>>> as I remember it passed on NVIDIA last time. I will confirm it before
>>> pushing the
>>> test case.
>>>
>>> tests/all.tests | 6 +
>>> .../ext_framebuffer_multisample/CMakeLists.gl.txt | 1 +
>>> .../sample-alpha-to-coverage.cpp | 412
>>> ++++++++++++++++++++
>>> 3 files changed, 419 insertions(+), 0 deletions(-)
>>> create mode 100644
>>> tests/spec/ext_framebuffer_multisample/sample-alpha-to-coverage.cpp
>>>
>>> diff --git a/tests/all.tests b/tests/all.tests
>>> index 5fdc9e7..6745037 100644
>>> --- a/tests/all.tests
>>> +++ b/tests/all.tests
>>> @@ -1391,6 +1391,12 @@ 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-alpha-to-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 c746328..c6566be 100644
>>> --- a/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
>>> +++ b/tests/spec/ext_framebuffer_multisample/CMakeLists.gl.txt
>>> @@ -29,6 +29,7 @@ piglit_add_executable
>>> (ext_framebuffer_multisample-renderbuffer-samples renderbu
>>> 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-sample-alpha-to-coverage common.cpp
>>> sample-alpha-to-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-alpha-to-coverage.cpp
>>> b/tests/spec/ext_framebuffer_multisample/sample-alpha-to-coverage.cpp
>>> new file mode 100644
>>> index 0000000..540396b
>>> --- /dev/null
>>> +++ b/tests/spec/ext_framebuffer_multisample/sample-alpha-to-coverage.cpp
>>> @@ -0,0 +1,412 @@
>>> +/*
>>> + * 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-alpha-to-coverage.cpp
>>> + *
>>> + * Verify GL_SAMPLE_ALPHA_TO_COVERAGE with multisample FBO.
>>> + *
>>> + * This test operates by drawing a test pattern to multisample_fbo with
>>> + * GL_SAMPLE_ALPHA_TO_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 alpha to coverage value.
>>> + *
>>> + * Compute the expected color values based on the coverage value used to
>>> + * draw the test pattern.
>>> + *
>>> + * Clear the multisample framebuffer to a unique color. Draw the same
>>> test
>>> + * pattern in multisample buffer with GL_SAMPLE_ALPHA_TO_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 GL_SAMPLE_ALPHA_TO_ONE enabled /
>>> disabled.
>>> + * when both GL_SAMPLE_ALPHA_TO_ONE and GL_SAMPLE_ALPHA_TO_COVERAGE are
>>> + * enabled, GL_SAMPLE_ALPHA_TO_COVERAGE takes effect first. i.e. the
>>> + * coverage value is computed from the alpha value before the alpha
>>> value
>>> + * is changed to 1.
>>> + *
>>> + * 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 ;
>>> +const int pattern_width = 512; const int pattern_height = 128;
>>> +
>>> +static Fbo ms_fbo, resolve_fbo;
>>> +static GLbitfield buffer_to_test;
>>> +
>>> +static float *coverage = 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_alpha_to_coverage, bool sample_alpha_to_one)
>>> +{
>>> + glUseProgram(prog);
>>> + glClearColor(bg_color[0], bg_color[1],
>>> + bg_color[2], bg_color[3]);
>>> + glClear(buffer_to_test);
>>> +
>>> + if (sample_alpha_to_coverage)
>>> + glEnable (GL_SAMPLE_ALPHA_TO_COVERAGE);
>>> +
>>> + if (sample_alpha_to_one)
>>> + glEnable (GL_SAMPLE_ALPHA_TO_ONE);
>>> +
>>> + 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);
>>> +
>>> + glUniform4fv(color_loc, 1, (color + i * 4));
>>> + glUniform1f(depth_loc, 0.0f);
>>> + glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT,
>>> + (void *) indices);
>>> + }
>>> + if (sample_alpha_to_coverage)
>>> + glDisable (GL_SAMPLE_ALPHA_TO_COVERAGE);
>>> +
>>> + if (sample_alpha_to_one)
>>> + glDisable (GL_SAMPLE_ALPHA_TO_ONE);
>>> +}
>>> +
>>> +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 sample_alpha_to_one)
>>> +{
>>> + int i, j;
>>> +
>>> + /* Sample alpha to coverage doesn't affect single sample FBO */
>>> + if(num_samples == 0) {
>>> + for(i = 0; i < 4; i++)
>>> + expected[i] = color[i];
>>> + return;
>>> + }
>>> +
>>> + /* Fragment's alpha value is directly used as coverage value */
>>> + for (i = 0; i < num_rects; i++)
>>> + coverage[i] = color[i * 4 + 3];
>>> +
>>> + /* 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]);
>>> +
>>> + if (sample_alpha_to_one)
>>> + expected[i * 4 + 3] =
>>> + 1.0 * coverage[i] +
>>> + bg_color[3] * (1 - coverage[i]);
>>> + }
>>> + }
>>> + }
>>> +}
>>> +
>>> +bool
>>> +probe_framebuffer_color(bool sample_alpha_to_one)
>>> +{
>>> + bool result = true;
>>> + 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_alpha_to_coverage(bool sample_alpha_to_one)
>>> +{
>>> + bool result = true;
>>> + compute_expected(sample_alpha_to_one);
>>> +
>>> + /* Draw test pattern in multisample ms_fbo with
>>> + * GL_SAMPLE_ALPHA_TO_COVERAGE enabled
>>> + */
>>> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
>>> + draw_pattern(true /* sample_alpha_to_coverage */ ,
>>> sample_alpha_to_one);
>>> +
>>> + /* 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(sample_alpha_to_one) &&
>>> 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));
>>> + coverage = (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;
>>> + /* Alpha value will be used as coverage */
>>> + color[i * 4 + 3] = i * (1.0 / (2 * num_samples));
>>> + }
>>> +}
>>> +
>>> +void
>>> +free_data_arrays(void)
>>> +{
>>> + if(color != NULL) {
>>> + free(color);
>>> + color = NULL;
>>> + }
>>> + if(coverage != NULL) {
>>> + free(coverage);
>>> + coverage = 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_ALPHA_TO_COVERAGE disabled.
>>> + */
>>> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
>>> + ms_fbo.set_viewport();
>>> + draw_pattern(false /* sample_alpha_to_coverage */,
>>> + false /* sample_alpha_to_one */ );
>>> +
>>> + /* 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 alpha to 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 sample_alpha_to_one = false */
>>> + pass = test_sample_alpha_to_coverage(false) && pass;
>>> +
>>> + /* Test sample alpha to coverage with sample_alpha_to_one = true
>>> */
>>> + pass = test_sample_alpha_to_coverage(true) && pass;
>>> +
>>> + /* 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
>>>
>>>
>>
>
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