[Piglit] [PATCH] fbo-tex-rgbx: test rendering to and texturing from an RGBx texture

Anuj Phogat anuj.phogat at gmail.com
Thu Mar 20 10:46:19 PDT 2014


On Thu, Mar 20, 2014 at 9:14 AM, Brian Paul <brianp at vmware.com> wrote:
> GL_RGB internal formats are usually stored as RGBx.  This test makes
> sure that the empty alpha channel is one when we sample from the texture.
> ---
>  tests/all.py                |    1 +
>  tests/fbo/CMakeLists.gl.txt |    1 +
>  tests/fbo/fbo-tex-rgbx.c    |  197 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 199 insertions(+)
>  create mode 100644 tests/fbo/fbo-tex-rgbx.c
>
> diff --git a/tests/all.py b/tests/all.py
> index 6ce459d..e15cbe9 100644
> --- a/tests/all.py
> +++ b/tests/all.py
> @@ -1673,6 +1673,7 @@ arb_framebuffer_object['FBO blit to missing attachment'] = concurrent_test('fbo-
>  arb_framebuffer_object['FBO blit from missing attachment'] = concurrent_test('fbo-missing-attachment-blit from')
>  arb_framebuffer_object['fbo-scissor-blit fbo'] = concurrent_test('fbo-scissor-blit fbo')
>  arb_framebuffer_object['fbo-scissor-blit window'] = plain_test('fbo-scissor-blit window')
> +arb_framebuffer_object['fbo-tex-rgbx'] = concurrent_test('fbo-tex-rgbx')
>  arb_framebuffer_object['negative-readpixels-no-rb'] = concurrent_test('arb_framebuffer_object-negative-readpixels-no-rb')
>  add_concurrent_test(arb_framebuffer_object, 'fbo-drawbuffers-none glClear')
>  add_concurrent_test(arb_framebuffer_object, 'fbo-drawbuffers-none glClearBuffer')
> diff --git a/tests/fbo/CMakeLists.gl.txt b/tests/fbo/CMakeLists.gl.txt
> index 588fe26..2b148ae 100644
> --- a/tests/fbo/CMakeLists.gl.txt
> +++ b/tests/fbo/CMakeLists.gl.txt
> @@ -90,6 +90,7 @@ piglit_add_executable (fbo-storage-formats fbo-storage-formats.c)
>  piglit_add_executable (fbo-storage-completeness fbo-storage-completeness.c)
>  piglit_add_executable (fbo-sys-blit fbo-sys-blit.c)
>  piglit_add_executable (fbo-sys-sub-blit fbo-sys-sub-blit.c)
> +piglit_add_executable (fbo-tex-rgbx fbo-tex-rgbx.c)
>  piglit_add_executable (fbo-pbo-readpixels-small fbo-pbo-readpixels-small.c)
>  piglit_add_executable (fbo-copyteximage fbo-copyteximage.c)
>  piglit_add_executable (fbo-copyteximage-simple fbo-copyteximage-simple.c)
> diff --git a/tests/fbo/fbo-tex-rgbx.c b/tests/fbo/fbo-tex-rgbx.c
> new file mode 100644
> index 0000000..61b8a80
> --- /dev/null
> +++ b/tests/fbo/fbo-tex-rgbx.c
> @@ -0,0 +1,197 @@
> +/*
> + * Copyright © 2014 VMware, Inc.
> + *
> + * 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 fbo-tex-rgbx.c
> + * \author Brian Paul
> + *
> + * Test texturing from an RGB texture after we've rendered some
> + * non-1 alpha values into it.  When we sample from an RGB texture,
> + * the alpha values should always be one.
> + * Many (most?) GL implementations store RGB textures as RGBx so there
> + * really is an alpha channel but it's supposed to be ignored when we
> + * sample from it.
> + */
> +
> +#include "piglit-util-gl-common.h"
> +
> +#define TEX_SIZE 256
> +
> +
> +PIGLIT_GL_TEST_CONFIG_BEGIN
> +       config.window_width = TEX_SIZE;
> +       config.window_height = TEX_SIZE;
> +       config.supports_gl_compat_version = 10;
> +       config.window_visual = PIGLIT_GL_VISUAL_RGBA | PIGLIT_GL_VISUAL_DOUBLE;
> +PIGLIT_GL_TEST_CONFIG_END
> +
> +
> +static const char *fragShaderText =
> +       "uniform sampler2D tex; \n"
> +       "void main() \n"
> +       "{ \n"
> +       "   gl_FragColor = texture2D(tex, gl_TexCoord[0].xy); \n"
> +       "} \n";
> +
> +static GLuint Program;
> +
> +
> +/* draw green quad with varying alpha values */
> +static void
> +draw_quad(void)
> +{
> +       static const float verts[4][2] = {
> +               { -1.0f, -1.0f },
> +               {  1.0f, -1.0f },
> +               {  1.0f,  1.0f },
> +               { -1.0f,  1.0f }
> +       };
> +       static const float colors[4][4] = {
> +               { 0.0f, 1.0f, 0.0f, 0.1f },
> +               { 0.0f, 1.0f, 0.0f, 0.2f },
> +               { 0.0f, 1.0f, 0.0f, 0.8f },
> +               { 0.0f, 1.0f, 0.0f, 0.9f }
> +       };
> +       glVertexPointer(2, GL_FLOAT, 0, verts);
> +       glColorPointer(4, GL_FLOAT, 0, colors);
> +       glEnableClientState(GL_VERTEX_ARRAY);
> +       glEnableClientState(GL_COLOR_ARRAY);
> +       glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
> +       glDisableClientState(GL_VERTEX_ARRAY);
> +       glDisableClientState(GL_COLOR_ARRAY);
> +}
> +
> +
> +/**
> + * Create texture with given internal format.  Render to it.  Then draw
> + * a test quad using that texture.  Check that all alpha values are one.
> + */
> +static bool
> +test_format(GLenum internalFormat)
> +{
> +       GLuint tex, fbo;
> +       GLenum status;
> +       bool pass = true;
> +       GLubyte *results;
> +       GLuint i;
> +
> +       /* Create (RGB) tex and FBO to render into it */
> +       glGenTextures(1, &tex);
> +       glBindTexture(GL_TEXTURE_2D, tex);
> +       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
> +       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
> +       glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, TEX_SIZE, TEX_SIZE, 0,
> +                    GL_RGB, GL_UNSIGNED_BYTE, NULL);
> +
> +       glGenFramebuffers(1, &fbo);
> +       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
> +
> +       glFramebufferTexture2D(GL_FRAMEBUFFER,
> +                              GL_COLOR_ATTACHMENT0,
> +                              GL_TEXTURE_2D, tex, 0);
> +       if (!piglit_check_gl_error(GL_NO_ERROR))
> +               return false;
> +
> +       status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
There is a 'Fbo' utility class in util/piglit-fbo.cpp which can setup
fbo for you. This is just for information in case you want to use it
in future.

> +       if (status != GL_FRAMEBUFFER_COMPLETE) {
> +               fprintf(stderr, "incomplete fbo (status 0x%x)\n", status);
> +               return true; /* this isn't necessarily a failure */
> +       }
> +
> +       /* Draw into tex, constant green and varying alpha */
> +       glUseProgram(0);
> +       draw_quad();
> +
> +       /* Now draw a textured quad in the window using the texture that we
> +        * just rendered to.
> +        */
> +       glBindFramebuffer(GL_FRAMEBUFFER, 0);
> +       glUseProgram(Program);
> +
> +       piglit_draw_rect_tex(-1.0f, -1.0f, 2.0f, 2.0f,
> +                            0.0f, 0.0f, 1.0f, 1.0f);
> +
> +       /* Now read back the rendering and check that alpha is always one */
> +       results = malloc(TEX_SIZE * TEX_SIZE * 4);
> +       glReadPixels(0, 0, TEX_SIZE, TEX_SIZE,
> +                    GL_RGBA, GL_UNSIGNED_BYTE, results);
> +
> +       for (i = 0; i < TEX_SIZE * TEX_SIZE; i++) {
> +               if (results[i*4+3] != 255) {
> +                       fprintf(stderr,
> +                               "Bad alpha value at texel [%d]: %d."
> +                               "  Should be 255."
> +                               "  Texture format %s\n",
> +                               i, results[i*4+3],
> +                               piglit_get_gl_enum_name(internalFormat));
> +                       pass = false;
> +                       break;
> +               }
> +       }
> +
> +       free(results);
> +
> +       piglit_present_results();
> +
> +       glDeleteFramebuffers(1, &fbo);
> +       glDeleteTextures(1, &tex);
> +
> +       return pass;
> +}
> +
> +
> +void
> +piglit_init(int argc, char **argv)
> +{
> +       piglit_require_extension("GL_ARB_framebuffer_object");
> +       piglit_require_gl_version(20);
> +
> +       Program = piglit_build_simple_program(NULL, fragShaderText);
> +       assert(Program);
> +}
> +
> +
> +enum piglit_result
> +piglit_display(void)
> +{
> +       bool pass = true;
> +
> +       pass = test_format(GL_RGB) && pass;
> +       pass = test_format(GL_RGB4) && pass;
> +       pass = test_format(GL_RGB5) && pass;
> +       pass = test_format(GL_RGB8) && pass;
> +       pass = test_format(GL_RGB10) && pass;
> +       pass = test_format(GL_RGB12) && pass;
> +       pass = test_format(GL_RGB16) && pass;
> +
> +       if (piglit_is_extension_supported("GL_ARB_ES2_compatibility")) {
> +               pass = test_format(GL_RGB565) && pass;
> +       }
> +
> +       if (piglit_is_extension_supported("GL_EXT_texture_sRGB")) {
> +               pass = test_format(GL_SRGB) && pass;
> +               pass = test_format(GL_SRGB8) && pass;
> +       }
> +
> +       return pass ? PIGLIT_PASS : PIGLIT_FAIL;
> +}

Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>
> --
> 1.7.10.4
>
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