[Piglit] [PATCH 4/4] Add test to verify sample alpha to one with multisample fbo

Paul Berry stereotype441 at gmail.com
Sat Jun 16 08:09:19 PDT 2012


On 8 June 2012 14:46, <anuj.phogat at gmail.com> wrote:

> From: Anuj Phogat <anuj.phogat at gmail.com>
>
> This test varifies that with GL_SAMPLE_ALPHA_TO_ONE enabled, each sample's
> alpha value is replaced by maximum alpha value i.e. 1.0.
>

This test is:

Reviewed-by: Paul Berry <stereotype441 at gmail.com>

I would recommend adding two additional tests, preferably in separate files:

1. We should make sure that when both GL_SAMPLE_ALPHA_TO_ONE and
GL_SAMPLE_ALPHA_TO_COVERAGE are enabled, GL_SAMPLE_ALPHA_TO_COVERAGE takes
effect first (that is, the coverage value needs to be computed from the
alpha value *before* the alpha value gets changed to 1).

2. We should make sure that if GL_SAMPLE_ALPHA_TO_ONE is enabled and
GL_MULTISAMPLE is disabled, alpha values are not modified.  Also, we should
make sure that if GL_SAMPLE_ALPHA_TO_ONE is enabled and the buffer is
single-sampled, alpha values are not modified.


>
> Verified the test case using proprietary NVIDIA drivers.
>
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
>  tests/all.tests                                    |    6 +
>  .../ext_framebuffer_multisample/CMakeLists.gl.txt  |    1 +
>  .../sample-alpha-to-one.cpp                        |  287
> ++++++++++++++++++++
>  3 files changed, 294 insertions(+), 0 deletions(-)
>  create mode 100644
> tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp
>
> diff --git a/tests/all.tests b/tests/all.tests
> index 0e531b8..946874c 100644
> --- a/tests/all.tests
> +++ b/tests/all.tests
> @@ -1400,6 +1400,12 @@ 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-one', 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 a6595fa..f482581 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-renderbufferstorage-samples r
>  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-sample-alpha-to-one
> common.cpp sample-alpha-to-one.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-one.cpp
> b/tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp
> new file mode 100644
> index 0000000..76d288b
> --- /dev/null
> +++ b/tests/spec/ext_framebuffer_multisample/sample-alpha-to-one.cpp
> @@ -0,0 +1,287 @@
> +/*
> + * 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:
> +static float coverage[4];
> + *
> + * 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-one.cpp
> + *
> + * This test operates by computing the expected color values when
> + * GL_SAMPLE_ALPHA_TO_ONE is disabled.
> + *
> + * Draw a test pattern with GL_SAMPLE_ALPHA_TO_ONE disabled and blit it to
> + * the right half of window system framebuffer. Probe the right half of
> + * framebuffer and compare with expected values.
> + *
> + * Compute the expected color values when GL_SAMPLE_ALPHA_TO_ONE is
> enabled.
> + * Draws the same test pattern for the second time in multisample buffer
> with
> + * GL_SAMPLE_ALPHA_TO_ONE enabled. Blits it in to left half of window
> system
> + * framebuffer.
> + *
> + * Probe the left half of window syetem framebuffer and compare with
> expected
> + * color values.
> + *
> + * 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 | GLUT_DEPTH;
> +const int pattern_width = 256; const int pattern_height = 256;
> +
> +static Fbo ms_fbo;
> +static GLint num_samples;
> +static float expected[4][4];
> +static GLbitfield buffer_to_test;
> +
> +static const float bg_color[4] =
> +       {0.0, 0.0, 1.0, 0.8};
> +
> +static const float color[4][4] = {
> +       /* Red */
> +       {1.0, 0.0, 0.0, 0.0},
> +       /* Green */
> +       {0.0, 1.0, 0.0, 0.25},
> +       /* Yellow */
> +       {1.0, 1.0, 0.0, 0.75},
> +       /* Cyan */
> +       {0.0, 1.0, 1.0, 1.0} };
> +
> +static GLint prog;
> +static GLint color_loc;
> +static GLint depth_loc;
> +
> +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_one)
> +{
> +       float vertex_data[10][2] = {
> +               { 0,                     0 },
> +               { 0,                     pattern_height },
> +               { pattern_width / 4,     pattern_height },
> +               { pattern_width / 4,     0 },
> +               { pattern_width / 2,     pattern_height },
> +               { pattern_width / 2,     0 },
> +               { 3 * pattern_width / 4, pattern_height },
> +               { 3 * pattern_width / 4, 0 },
> +               { pattern_width,         pattern_height },
> +               { pattern_width,         0 },
> +       };
> +
> +       unsigned int indices[24] = {0, 1, 2, 0, 2, 3,
> +                                   3, 2, 4, 3, 4, 5,
> +                                   5, 4, 6, 5, 6, 7,
> +                                   7, 6, 8, 7, 8, 9};
> +       glUseProgram(prog);
> +
> +       glClearColor(bg_color[0], bg_color[1],
> +                    bg_color[2], bg_color[3]);
> +       glClear(buffer_to_test);
> +
> +       if (sample_alpha_to_one)
> +               glEnable(GL_SAMPLE_ALPHA_TO_ONE);
> +
> +       glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
> sizeof(vertex_data[0]),
> +                             (void *) vertex_data);
> +
> +       for (int i = 0; i < 4; ++i) {
> +               glUniform4fv(color_loc, 1, color[i]);
> +               glUniform1f(depth_loc, 0.0);
> +               glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT,
> +                              (void *) (indices + 6 * i));
> +
> +       }
> +       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(void)
> +{
> +
> +       /* Page 242 (page 258 of the PDF) of the OpenGL 3.0 spec says:
> +        * Next, if SAMPLE ALPHA TO ONE is enabled, each alpha value is
> +        * replaced by the maximum representable alpha value. Otherwise,
> +        * the alpha values are not changed.
> +        */
> +       for(int i = 0; i < 4; i++) {
> +               expected[i][0] = color[i][0];
> +               expected[i][1] = color[i][1];
> +               expected[i][2] = color[i][2];
> +               expected[i][3] = 1.0 ;
> +       }
> +}
> +
> +bool probe_framebuffer_color(GLint x_offset, const float *expected)
> +{
> +       bool result = true;
> +
> +       glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
> +       for(int i = 0; i< 4; i++) {
> +               result = piglit_probe_rect_rgba(x_offset + i *
> (pattern_width / 4),
> +                                               0,
> +                                               pattern_width / 4,
> +                                               pattern_height,
> +                                               expected + 4 * i)
> +                        && result;
> +       }
> +       return result;
> +}
> +
> +bool
> +test_sample_alpha_to_one(void)
> +{
> +       bool result = true;
> +       compute_expected();
> +       /* Now draw test pattern in mulisample ms_fbo with
> GL_SAMPLE_COVERAGE
> +        * enabled
> +        */
> +       glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
> +       draw_pattern(true);
> +
> +       /* Blit ms_fbo to the left half of window system framebuffer. This
> +        * is the test image.
> +        */
> +       glBindFramebuffer(GL_READ_FRAMEBUFFER, ms_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 left half of default framebuffer and compare to the
> +        * expected values */
> +       if (buffer_to_test == GL_COLOR_BUFFER_BIT)
> +               result = probe_framebuffer_color(0, expected[0]) && result;
> +
> +       result = piglit_check_gl_error(GL_NO_ERROR) && result;
> +       return result;
> +}
> +void
> +piglit_init(int argc, char **argv)
> +{
> +       if (argc < 2)
> +               print_usage_and_exit(argv[0]);
> +       {
> +               char *endptr = NULL;
> +               num_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 num_samples > GL_MAX_SAMPLES or num_samples =
> 0 */
> +       GLint max_samples;
> +       glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
> +
> +       if (num_samples > max_samples ||
> +           num_samples == 0)
> +               piglit_report_result(PIGLIT_SKIP);
> +
> +       ms_fbo.setup(FboConfig(num_samples, pattern_width,
> pattern_height));
> +       buffer_to_test = GL_COLOR_BUFFER_BIT;
> +       shader_compile();
> +}
> +
> +enum piglit_result
> +piglit_display()
> +{
> +       bool pass = true;
> +       glClearColor(0.0, 0.0, 0.0, 1.0);
> +       glClear(GL_COLOR_BUFFER_BIT);
> +
> +       /* Draw test pattern in  multisample ms_fbo with
> GL_SAMPLE_ALPHA_TO_ONE
> +        * disabled.
> +        */
> +       glBindFramebuffer(GL_DRAW_FRAMEBUFFER, ms_fbo.handle);
> +       ms_fbo.set_viewport();
> +       draw_pattern(false);
> +
> +       /* Blit ms_fbo to the right half of window system framebuffer. This
> +        * is a reference image to see the visual difference when compared
> +        * to the test image.
> +        */
> +       glBindFramebuffer(GL_READ_FRAMEBUFFER, ms_fbo.handle);
> +       glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
> +       glBlitFramebuffer(0, 0, pattern_width, pattern_height,
> +                         pattern_width, 0, 2 * pattern_width,
> pattern_height,
> +                         buffer_to_test, GL_NEAREST);
> +       /* Probe the right half of default framebuffer and compare to the
> +        * expected values */
> +       pass = probe_framebuffer_color(pattern_width, color[0]) && pass;
> +
> +       /* Now test multisample fbo with GL_SAMPLE_ALPHA_TO_ONE enabled */
> +       pass = test_sample_alpha_to_one() && pass;
> +
> +       if (!piglit_automatic)
> +               piglit_present_results();
> +
> +       return pass ? PIGLIT_PASS : PIGLIT_FAIL;
> +}
> --
> 1.7.7.6
>
>
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