[Piglit] [PATCH 4/4] Test blending a fast clear color with GL_FRAMEBUFFER_SRGB enabled

Pohjolainen, Topi topi.pohjolainen at intel.com
Tue Dec 1 01:13:39 PST 2015


On Wed, Nov 25, 2015 at 06:11:53PM +0100, Neil Roberts wrote:
> On SKL in the i965 driver there is some special handling of the fast
> clear optimisation when GL_FRAMEBUFFER_SRGB is enabled because the
> hardware can't cope with the fast clear buffer in that case and the
> color buffer needs to be resolved. This test just tries varies
> different clear colors and enabling at GL_FRAMEBUFFER_SRGB at
> different points to make sure this resolving works correctly.
> ---
>  tests/all.py                                       |   1 +
>  tests/spec/arb_framebuffer_srgb/CMakeLists.gl.txt  |   1 +
>  tests/spec/arb_framebuffer_srgb/fast-clear-blend.c | 238 +++++++++++++++++++++
>  3 files changed, 240 insertions(+)
>  create mode 100644 tests/spec/arb_framebuffer_srgb/fast-clear-blend.c
> 
> diff --git a/tests/all.py b/tests/all.py
> index ab9f181..425f301 100644
> --- a/tests/all.py
> +++ b/tests/all.py
> @@ -2052,6 +2052,7 @@ with profile.group_manager(
>         'enable-fb-srgb',
>         'single-sample'],
>        'fbo-fast-clear')
> +    g(['arb_framebuffer_srgb-fast-clear-blend'])
>  
>  with profile.group_manager(
>          PiglitGLTest,
> diff --git a/tests/spec/arb_framebuffer_srgb/CMakeLists.gl.txt b/tests/spec/arb_framebuffer_srgb/CMakeLists.gl.txt
> index 04609b8..fc1eb57 100644
> --- a/tests/spec/arb_framebuffer_srgb/CMakeLists.gl.txt
> +++ b/tests/spec/arb_framebuffer_srgb/CMakeLists.gl.txt
> @@ -12,4 +12,5 @@ piglit_add_executable (arb_framebuffer_srgb-pushpop pushpop.c)
>  piglit_add_executable (arb_framebuffer_srgb-blit blit.c)
>  piglit_add_executable (arb_framebuffer_srgb-clear clear.c)
>  piglit_add_executable (arb_framebuffer_srgb-srgb_conformance srgb_conformance.c)
> +piglit_add_executable (arb_framebuffer_srgb-fast-clear-blend fast-clear-blend.c)
>  
> diff --git a/tests/spec/arb_framebuffer_srgb/fast-clear-blend.c b/tests/spec/arb_framebuffer_srgb/fast-clear-blend.c
> new file mode 100644
> index 0000000..c8fe723
> --- /dev/null
> +++ b/tests/spec/arb_framebuffer_srgb/fast-clear-blend.c
> @@ -0,0 +1,238 @@
> +/*
> + * Copyright © 2015 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 fast-clear-blend.c
> + *
> + * Enables GL_FRAMEBUFFER_SRGB, clears the buffer to a color and then
> + * blends it with a rectangle in another color before verifying the
> + * result. This is mainly to test fast clears on SKL in the i965
> + * driver because in that case fast clears can't be used with
> + * GL_FRAMEBUFFER_SRGB so it internally needs to resolve the color
> + * buffer.
> + */
> +
> +#include "piglit-util-gl.h"
> +
> +PIGLIT_GL_TEST_CONFIG_BEGIN
> +
> +	config.supports_gl_compat_version = 21;
> +	config.window_visual = PIGLIT_GL_VISUAL_RGBA | PIGLIT_GL_VISUAL_DOUBLE;
> +
> +PIGLIT_GL_TEST_CONFIG_END
> +
> +static const char
> +vertex_source[] =
> +	"attribute vec4 piglit_vertex;\n"
> +	"\n"
> +	"void\n"
> +	"main()\n"
> +	"{\n"
> +	"	 gl_Position = piglit_vertex;\n"
> +	"}\n";
> +
> +static const char
> +fragment_source[] =
> +	"uniform vec4 color;\n"
> +	"\n"
> +	"void\n"
> +	"main()\n"
> +	"{\n"
> +	"	 gl_FragColor = color;\n"
> +	"}\n";
> +
> +static GLuint prog;
> +static GLuint fbo;
> +static GLint color_location;
> +
> +static const float
> +clear_colors[][4] = {
> +	{ 0.0f, 0.0f, 0.0f, 0.0f },
> +	{ 1.0f, 1.0f, 1.0f, 1.0f },
> +	{ 0.0f, 0.0f, 1.0f, 0.0f },
> +	{ 1.0f, 0.0f, 0.0f, 1.0f },
> +
> +	{ 0.25f, 0.5f, 0.75f, 1.0f },
> +	{ 0.75f, 0.5f, 0.25f, 0.0f },
> +	{ 0.5f, 0.25f, 0.75f, 0.5f },
> +};
> +
> +static bool
> +probe_srgb_color(int x, int y, int w, int h,
> +		 const GLfloat *color)
> +{
> +	GLfloat srgb_color[4];
> +	int i;
> +
> +	/* The value in the framebuffer is stored in SRGB space so we
> +	 * need to convert to that.
> +	 */
> +	for (i = 0; i < 3; i++)
> +		srgb_color[i] = piglit_linear_to_srgb(color[i]);
> +	srgb_color[3] = color[3];
> +
> +	return piglit_probe_rect_rgba(x, y, w, h, srgb_color);
> +}
> +
> +static bool
> +test_color(bool srgb_before_clear,
> +	   const GLfloat *clear_color)
> +{
> +	static const GLfloat rect_color[] = {
> +		0.0f, 0.75f, 1.0f, 0.5f
> +	};
> +	GLfloat expected_color[4];
> +	GLfloat fb_color;
> +	bool pass = true;
> +	int i;
> +
> +	printf("Clear to %f,%f,%f,%f - SRGB enabled %s clear\n",
> +	       clear_color[0],
> +	       clear_color[1],
> +	       clear_color[2],
> +	       clear_color[3],
> +	       srgb_before_clear ? "before" : "after");
> +
> +	if (srgb_before_clear)
> +		glEnable(GL_FRAMEBUFFER_SRGB);
> +
> +	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
> +	glClearColor(clear_color[0],
> +		     clear_color[1],
> +		     clear_color[2],
> +		     clear_color[3]);
> +	glClear(GL_COLOR_BUFFER_BIT);
> +
> +	if (!srgb_before_clear)
> +		glEnable(GL_FRAMEBUFFER_SRGB);
> +
> +	glUseProgram(prog);
> +	glUniform4fv(color_location, 1, rect_color);
> +
> +	glEnable(GL_BLEND);
> +	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
> +
> +	/* Blend a rectangle into the right-hand half of the framebuffer */
> +	piglit_draw_rect(0.0f, -1.0f, 1.0f, 2.0f);
> +
> +	glDisable(GL_BLEND);
> +	glDisable(GL_FRAMEBUFFER_SRGB);
> +

Below we check the pixel values in the left-hand side, this is to check that
the blending (and hence the implied resolving of the buffer) in the
right-hand side didn't alter the values in the left-hand side, right? If so,
perhaps a small comment?

> +	if (srgb_before_clear) {
> +		pass = probe_srgb_color(0, 0,
> +					piglit_width / 2, piglit_height,
> +					clear_color) && pass;
> +	} else {
> +		pass = piglit_probe_rect_rgba(0, 0,
> +					      piglit_width / 2, piglit_height,
> +					      clear_color) && pass;
> +	}
> +
> +	/* Calculate the expected blended color. The blending will be
> +	 * done in linear space so if GL_FRAMEBUFFER_SRGB was enabled
> +	 * before the clear then the SRGB conversions cancel out and
> +	 * don't affect the result. However if it wasn't enabled then
> +	 * the clear color will go through an SRGB???linear conversion
> +	 * before being used as one of the sources for the blend.
> +	 */
> +	for (i = 0; i < 4; i++) {
> +		if (i >= 3 || srgb_before_clear)
> +			fb_color = clear_color[i];
> +		else
> +			fb_color = piglit_srgb_to_linear(clear_color[i]);
> +
> +		expected_color[i] = (fb_color * (1.0f - rect_color[3]) +
> +				     rect_color[i] * rect_color[3]);
> +	}
> +
> +	pass = probe_srgb_color(piglit_width / 2, 0,
> +				piglit_width / 2, piglit_height,
> +				expected_color) && pass;
> +
> +	/* Copy the test framebuffer into the winsys framebuffer so
> +	 * that something will be visible */
> +	glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
> +	glBindFramebuffer(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
> +	glBlitFramebuffer(0, 0, piglit_width, piglit_height,
> +			  0, 0, piglit_width, piglit_height,
> +			  GL_COLOR_BUFFER_BIT,
> +			  GL_NEAREST);
> +
> +	glBindFramebuffer(GL_FRAMEBUFFER, piglit_winsys_fbo);
> +
> +	piglit_present_results();
> +
> +	return pass;
> +}
> +
> +enum piglit_result
> +piglit_display()
> +{
> +	bool pass = true;
> +	int srgb_before_clear;
> +	int i;
> +
> +	for (srgb_before_clear = 0;
> +	     srgb_before_clear < 2;
> +	     srgb_before_clear++) {
> +		for (i = 0; i < ARRAY_SIZE(clear_colors); i++) {
> +			pass = test_color(srgb_before_clear,
> +					  clear_colors[i]) && pass;
> +		}
> +	}

Iterating over false-true looks a little strange. Could we just open code
the two cases? Or perhaps:

        for (i = 0; i < ARRAY_SIZE(clear_colors); i++) {
                pass = test_color(false, clear_colors[i]) && pass;
                pass = test_color(true, clear_colors[i]) && pass;
        }

> +
> +	return pass ? PIGLIT_PASS : PIGLIT_FAIL;
> +}
> +
> +void
> +piglit_init(int argc, char **argv)
> +{
> +	GLuint rb;
> +
> +	piglit_require_extension("GL_EXT_framebuffer_sRGB");
> +	piglit_require_extension("GL_ARB_framebuffer_sRGB");
> +
> +	prog = piglit_build_simple_program(vertex_source, fragment_source);
> +
> +	color_location = glGetUniformLocation(prog, "color");
> +
> +	glGenFramebuffers(1, &fbo);
> +	glBindFramebuffer(GL_FRAMEBUFFER, fbo);
> +	glGenRenderbuffers(1, &rb);
> +	glBindRenderbuffer(GL_RENDERBUFFER, rb);
> +	glRenderbufferStorage(GL_RENDERBUFFER,
> +			      GL_SRGB8_ALPHA8,
> +			      piglit_width, piglit_height);
> +	glFramebufferRenderbuffer(GL_FRAMEBUFFER,
> +				  GL_COLOR_ATTACHMENT0,
> +				  GL_RENDERBUFFER,
> +				  rb);
> +
> +	if (glCheckFramebufferStatus(GL_FRAMEBUFFER) !=
> +	    GL_FRAMEBUFFER_COMPLETE) {
> +		fprintf(stderr, "FBO incomplete\n");
> +		piglit_report_result(PIGLIT_SKIP);
> +	}
> +
> +	glBindFramebuffer(GL_FRAMEBUFFER, piglit_winsys_fbo);
> +}
> -- 
> 1.9.3
> 
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