[Piglit] [PATCH V3 3/6] ARB_sample_shading: Add test to verify the functionality of gl_SampleID
Paul Berry
stereotype441 at gmail.com
Fri Dec 6 15:04:25 PST 2013
On 6 November 2013 17:20, Anuj Phogat <anuj.phogat at gmail.com> wrote:
> V2: Get rid of redundant projection matrix.
> V3: Draw to a multisample texture and use it later to verify
> the expected color of each sample.
> Use piglit_draw_rect() and get rid of redundant code.
>
> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> ---
> tests/all.tests | 5 +
> .../arb_sample_shading/execution/CMakeLists.gl.txt | 1 +
> .../execution/builtin-gl-sample-id.cpp | 216
> +++++++++++++++++++++
> 3 files changed, 222 insertions(+)
> create mode 100644
> tests/spec/arb_sample_shading/execution/builtin-gl-sample-id.cpp
>
> diff --git a/tests/all.tests b/tests/all.tests
> index 883fbec..5f66e43 100644
> --- a/tests/all.tests
> +++ b/tests/all.tests
> @@ -1342,6 +1342,11 @@ for num_samples in TEST_SAMPLE_COUNTS:
> executable = 'arb_sample_shading-{0} -auto'.format(test_name)
> arb_sample_shading[test_name] = PlainExecTest(executable)
>
> +for num_samples in TEST_SAMPLE_COUNTS:
> + test_name = 'builtin-gl-sample-id {0}'.format(num_samples)
> + executable = 'arb_sample_shading-{0} -auto'.format(test_name)
> + arb_sample_shading[test_name] = PlainExecTest(executable)
> +
> # Group ARB_debug_output
> arb_debug_output = Group()
> spec['ARB_debug_output'] = arb_debug_output
> diff --git a/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
> b/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
> index 56fa0da..35f2905 100644
> --- a/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
> +++ b/tests/spec/arb_sample_shading/execution/CMakeLists.gl.txt
> @@ -12,4 +12,5 @@ link_libraries (
>
> piglit_add_executable (arb_sample_shading-api api.c)
> piglit_add_executable (arb_sample_shading-builtin-gl-num-samples
> builtin-gl-num-samples.cpp)
> +piglit_add_executable (arb_sample_shading-builtin-gl-sample-id
> builtin-gl-sample-id.cpp)
> # vim: ft=cmake:
> diff --git
> a/tests/spec/arb_sample_shading/execution/builtin-gl-sample-id.cpp
> b/tests/spec/arb_sample_shading/execution/builtin-gl-sample-id.cpp
> new file mode 100644
> index 0000000..ebbb6a0
> --- /dev/null
> +++ b/tests/spec/arb_sample_shading/execution/builtin-gl-sample-id.cpp
> @@ -0,0 +1,216 @@
> +/*
> + * Copyright © 2013 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.
> + */
> +
> +/** \file builtin-gl-sample-id.cpp
> + * This test verifies that using gl_SampleID in fragment shader program
> + * works as per ARB_sample_shading specification.
> + *
> + **/
> +
> +#include "piglit-fbo.h"
> +using namespace piglit_util_fbo;
> +
> +const int pattern_width = 128; const int pattern_height = 128;
> +
> +PIGLIT_GL_TEST_CONFIG_BEGIN
> +
> + config.supports_gl_compat_version = 21;
> +
> + config.window_width = pattern_width;
> + config.window_height = pattern_height;
> + config.window_visual = PIGLIT_GL_VISUAL_DOUBLE |
> PIGLIT_GL_VISUAL_RGBA;
> +
> +PIGLIT_GL_TEST_CONFIG_END
> +
> +static int num_samples;
> +static unsigned prog_0, prog_1;
> +static Fbo multisampled_fbo, multisampled_tex;
> +
> +static void
> +print_usage_and_exit(char *prog_name)
> +{
> + printf("Usage: %s <num_samples>\n", prog_name);
> + piglit_report_result(PIGLIT_FAIL);
> +}
> +
> +void
> +compile_shader(void)
> +{
> + static const char *vert =
> + "#version 130\n"
> + "in vec2 pos;\n"
> + "void main()\n"
> + "{\n"
> + " gl_Position = gl_ModelViewProjectionMatrix *\n"
> + " vec4(pos, 0.0, 1.0);\n"
> + "}\n";
>
To interface properly with piglit_draw_rect, you really want your vertex
shader to look like this:
#version 130
in vec4 piglit_vertex;
void main()
{
gl_Position = piglit_vertex;
}
(the reason is that piglit_draw_rect specifically looks for a vertex shader
input called "piglit_vertex", and uses it if it finds it). I suspect that
the code you've written has undefined behaviour, and is working by luck.
You also need to link the program using piglit_link_simple_program(),
piglit_build_simple_program(),
piglit_link_simple_program_multiple_shaders(), or
piglit_build_simple_program_multiple_shaders(). Those functions ensure
that piglit_vertex gets assigned to the proper attribute slot.
An additional advantage of writing the vertex shader like this is that you
won't have to call piglit_ortho_projection() anymore, which means you can
add:
config.supports_gl_core_version = 31;
to the test config.
> + static const char *frag_0 =
> + "#version 130\n"
> + "#extension GL_ARB_sample_shading : enable\n"
> + "uniform int samples;\n"
> + "out vec4 out_color;\n"
> + "void main()\n"
> + "{\n"
> + " if(samples == 0)\n"
> + " out_color = vec4(0.0, 1.0, 0.0, 1.0);\n"
> + " else\n"
> + " out_color = vec4(0.0, float(gl_SampleID) / samples,
> 0.0, 1.0);\n"
>
+ "}\n";
> +
> + static const char *frag_1 =
> + "#version 130\n"
> + "#extension GL_ARB_texture_multisample : require\n"
> + "uniform sampler2DMS ms_tex;\n"
> + "uniform int samples;\n"
> + "out vec4 out_color;\n"
> + "void main()\n"
> + "{\n"
> + " int i;\n"
> + " bool pass = true;\n"
> + /* Use a small tolerance value to account for the
> precision
> + * loss in floating point color values.
> + */
> + " float color_tolerance = 0.02;\n"
> + " for (i = 0; i < samples; i++) {\n"
> + " vec4 sample_color =\n"
> + " texelFetch(ms_tex, ivec2(gl_FragCoord.xy), i);\n"
> + " float sample_id_float = sample_color.g * samples;\n"
> + " int sample_id_int = int(round(sample_id_float));\n"
> + " if (sample_id_int != i ||\n"
> + " abs(sample_id_int - sample_id_float) >
> color_tolerance)\n"
>
The second condition (abs(sample_id_int - sample_id_float) >
color_tolerance) seems wrong for two reasons:
1. It shouldn't be necessary. Any rounding errors that happen should be
far smaller than 1/samples, so when you compute int(round(sample_id_float))
it shoud always be exactly correct.
2. The expression abs(sample_id_int - sample_id_float) doesn't do anything
with the expected value (i). This means that if the distance between
sample_id_int and sample_id_float is ever larger than 0.02, the test will
pass, even if sample_id_float is so wrong that it can't be explained by
rounding error.
I'd recommend simplifying the if test to just "if (sample_id_int != i)".
If that causes the test to fail, then I think we should suspect a genuine
bug rather than a rounding error.
Unrelated: the contents of the "for" loop aren't uniformly indented, making
it hard to read.
> + " pass = false;\n"
> + " }\n"
> + "\n"
> + " if(pass)\n"
> + " out_color = vec4(0.0, 1.0, 0.0, 1.0);\n"
> + " else\n"
> + " out_color = vec4(1.0, 0.0, 0.0, 1.0);\n"
> + "}\n";
> +
> + /* Compile program */
> + prog_0 = glCreateProgram();
> + GLint vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vert);
> + glAttachShader(prog_0, vs);
> + piglit_check_gl_error(GL_NO_ERROR);
> + GLint fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, frag_0);
> + glAttachShader(prog_0, fs);
> + glBindAttribLocation(prog_0, 0, "pos");
>
Once you're using piglit_vertex in your vertex shader, it won't be
necessary to make this call to glBindAttribLocation() anymore.
piglit_draw_rect() will
> + glLinkProgram(prog_0);
> + if (!piglit_link_check_status(prog_0)) {
> + piglit_report_result(PIGLIT_FAIL);
> + }
> +
> + prog_1 = glCreateProgram();
> + vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vert);
> + glAttachShader(prog_1, vs);
> + piglit_check_gl_error(GL_NO_ERROR);
> + fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, frag_1);
> + glAttachShader(prog_1, fs);
> + glBindAttribLocation(prog_1, 0, "pos");
> + glLinkProgram(prog_1);
> + if (!piglit_link_check_status(prog_1)) {
> + piglit_report_result(PIGLIT_FAIL);
> + }
> +}
> +
> +void
> +piglit_init(int argc, char **argv)
> +{
> + if (argc != 2)
> + print_usage_and_exit(argv[0]);
> +
> + /* 1st arg: num_samples */
> + 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_extension("GL_ARB_texture_multisample");
> + piglit_require_extension("GL_ARB_sample_shading");
> +
> + /* Skip the test if num_samples > GL_MAX_SAMPLES */
> + GLint max_samples;
> + glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
> + if (num_samples > max_samples)
> + piglit_report_result(PIGLIT_SKIP);
> +
> + piglit_ortho_projection(pattern_width, pattern_height, false);
> + FboConfig msConfig(num_samples, pattern_width, pattern_height);
> + multisampled_fbo.setup(msConfig);
> + msConfig.attach_texture = true;
> + multisampled_tex.setup(msConfig);
> +
> + compile_shader();
> + if (!piglit_check_gl_error(GL_NO_ERROR)) {
> + piglit_report_result(PIGLIT_FAIL);
> + }
> +}
> +
> +enum piglit_result
> +piglit_display()
> +{
> + bool pass = true;
> + int samples;
> + float expected[4] = {0.0, 1.0, 0.0, 1.0};
> +
> + glUseProgram(prog_0);
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, multisampled_fbo.handle);
> + glGetIntegerv(GL_SAMPLES, &samples);
> + glClear(GL_COLOR_BUFFER_BIT);
> + glUniform1i(glGetUniformLocation(prog_0, "samples"), samples);
> + piglit_draw_rect(0, 0, pattern_width, pattern_height);
> +
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, multisampled_fbo.handle);
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, multisampled_tex.handle);
> + glClear(GL_COLOR_BUFFER_BIT);
> + glBlitFramebuffer(0, 0,
> + pattern_width, pattern_height,
> + 0, 0,
> + pattern_width, pattern_height,
> + GL_COLOR_BUFFER_BIT,
> + GL_NEAREST);
>
It looks like you're drawing into an FBO that's backed by a multisampled
renderbuffer, then blitting that to an FBO that's backed by a multisampled
texture, then checking the result. Why not just drop the first FBO and
draw directly into the second?
> +
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, multisampled_tex.handle);
> + glBindFramebuffer(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
> + glClear(GL_COLOR_BUFFER_BIT);
> + if (samples == 0) {
> + glBlitFramebuffer(0, 0,
> + pattern_width, pattern_height,
> + 0, 0,
> + pattern_width, pattern_height,
> + GL_COLOR_BUFFER_BIT,
> + GL_NEAREST);
> + } else {
> + glUseProgram(prog_1);
> + glUniform1i(glGetUniformLocation(prog_1, "ms_tex"), 0);
> + glUniform1i(glGetUniformLocation(prog_1, "samples"),
> samples);
> + piglit_draw_rect_tex(0, 0, pattern_width, pattern_height,
> + 0, 0, pattern_width, pattern_height);
>
Since your vertex shader doesn't use piglit_texcoord, you should just call
piglit_draw_rect() here.
> + }
> + glBindFramebuffer(GL_READ_FRAMEBUFFER, piglit_winsys_fbo);
> + pass = piglit_probe_rect_rgba(0, 0, pattern_width,
> + pattern_width, expected)
> + && pass;
> + piglit_present_results();
> + return pass ? PIGLIT_PASS : PIGLIT_FAIL;
> +}
> --
> 1.8.1.4
>
>
With those changes, this patch is:
Reviewed-by: Paul Berry <stereotype441 at gmail.com>
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