[Piglit] [PATCH 2/2] Add test to verify sample alpha to coverage with multisample fbo
Paul Berry
stereotype441 at gmail.com
Fri Jun 22 20:19:10 PDT 2012
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)?
>
>
>>
>> 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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