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 <[email protected]>
---
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 <[email protected]>
+ */
+
+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 *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;
+
+ 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;
+
+ /* 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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