tests/spec/ext_framebuffer_multisample/alpha-blending-after-rendering.c

   1 /*
   2  * Copyright © 2013 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 /** \file
  25  *
  26  * Verify that alpha blending works properly in multisample
  27  * framebuffers even if it is preceded by normal (non-blended)
  28  * rendering.
  29  *
  30  * In the fix for https://bugs.freedesktop.org/show_bug.cgi?id=53077,
  31  * Mesa's i965 driver must convert a compressed multisampled buffer to
  32  * an uncompressed buffer the first time it notices that alpha
  33  * blending is being performed on the buffer.  This test verifies that
  34  * the conversion happens correctly.  It specifically exercises pixels
  35  * that are in the following states at the time of conversion:
  36  *
  37  * - Clear
  38  * - Fully covered
  39  * - Partially covered, partially clear
  40  * - Partially covered by one color, partially by another color
  41  */
  42
  43 #include "piglit-util-gl.h"
  44
  45 PIGLIT_GL_TEST_CONFIG_BEGIN
  46
  47         config.supports_gl_compat_version = 30;
  48         config.supports_gl_core_version = 31;
  49         config.window_visual = PIGLIT_GL_VISUAL_RGBA | PIGLIT_GL_VISUAL_DOUBLE;
  50         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  51
  52 PIGLIT_GL_TEST_CONFIG_END
  53
  54 const char *vs_text =
  55         "#version 130\n"
  56         "in vec4 piglit_vertex;\n"
  57         "void main()\n"
  58         "{\n"
  59         "  gl_Position = piglit_vertex;\n"
  60         "}\n";
  61
  62 const char *fs_text =
  63         "#version 130\n"
  64         "uniform vec4 color;\n"
  65         "void main()\n"
  66         "{\n"
  67         "  gl_FragColor = color;\n"
  68         "}\n";
  69
  70 static GLuint prog, singlesampled_fbo;
  71 static GLint color_loc;
  72 static int num_samples;
  73
  74
  75 static void
  76 print_usage_and_exit(const char *prog_name)
  77 {
  78         printf("Usage: %s <num_samples>\n", prog_name);
  79         piglit_report_result(PIGLIT_FAIL);
  80 }
  81
  82
  83 void
  84 piglit_init(int argc, char **argv)
  85 {
  86         GLuint rb;
  87         char *endptr;
  88         GLint max_samples;
  89
  90         if (argc != 2)
  91                 print_usage_and_exit(argv[0]);
  92         endptr = NULL;
  93         num_samples = strtol(argv[1], &endptr, 0);
  94         if (endptr != argv[1] + strlen(argv[1]))
  95                 print_usage_and_exit(argv[0]);
  96
  97         /* Test assumes that glSampleCoverage(0.5) will yield exactly
  98          * 50% blending; this only works if num_samples is even and
  99          * greater than zero.
 100          */
 101         if (num_samples <= 0 || num_samples % 2 != 0) {
 102                 printf("num_samples must be even and greater than zero.\n");
 103                 piglit_report_result(PIGLIT_FAIL);
 104         }
 105
 106         /* Skip the test if num_samples > GL_MAX_SAMPLES */
 107         glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
 108         if (num_samples > max_samples) {
 109                 printf("num_samples = %d requested, but only %d supported.\n",
 110                        num_samples, max_samples);
 111                 piglit_report_result(PIGLIT_SKIP);
 112         }
 113
 114         prog = piglit_build_simple_program(vs_text, fs_text);
 115         color_loc = glGetUniformLocation(prog, "color");
 116
 117         /* Create the single-sampled fbo.  We only need to create this
 118          * once, since it isn't subject to the bugfix.
 119          */
 120         glGenFramebuffers(1, &singlesampled_fbo);
 121         glGenRenderbuffers(1, &rb);
 122         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, singlesampled_fbo);
 123         glBindRenderbuffer(GL_RENDERBUFFER, rb);
 124         glRenderbufferStorageMultisample(GL_RENDERBUFFER,
 125                                          0 /* samples */,
 126                                          GL_RGBA8 /* internalformat */,
 127                                          piglit_width, piglit_height);
 128         glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
 129                                   GL_RENDERBUFFER, rb);
 130         if (glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER)
 131             != GL_FRAMEBUFFER_COMPLETE) {
 132                 printf("Single-sampled framebuffer incomplete\n");
 133                 piglit_report_result(PIGLIT_FAIL);
 134         }
 135 }
 136
 137
 138 enum piglit_result
 139 piglit_display(void)
 140 {
 141         GLuint msaa_fbo, rb;
 142         bool pass = true;
 143         GLfloat expected_ul[] = { 0.25, 0.0,  0.25, 0.75 };
 144         GLfloat expected_ur[] = { 0.0,  0.25, 0.25, 0.75 };
 145         GLfloat expected_ll[] = { 0.5,  0.0,  0.0,  0.75 };
 146         GLfloat expected_lr[] = { 0.0,  0.5,  0.0,  0.75 };
 147
 148         /* Create a multisampled framebuffer.  We need to do this here
 149          * (rather than in piglit_init()) because the bugfix we are
 150          * verifying only converts any given buffer once; we want to
 151          * make sure we trigger the bugfix for every call to
 152          * piglit_display().
 153          */
 154         glGenFramebuffers(1, &msaa_fbo);
 155         glGenRenderbuffers(1, &rb);
 156         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, msaa_fbo);
 157         glBindRenderbuffer(GL_RENDERBUFFER, rb);
 158         glRenderbufferStorageMultisample(GL_RENDERBUFFER,
 159                                          num_samples,
 160                                          GL_RGBA8 /* internalformat */,
 161                                          piglit_width, piglit_height);
 162         glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
 163                                   GL_RENDERBUFFER, rb);
 164         if (glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER)
 165             != GL_FRAMEBUFFER_COMPLETE) {
 166                 printf("MSAA framebuffer incomplete\n");
 167                 pass = false;
 168         }
 169
 170         /* Clear the framebuffer to red. */
 171         glClearColor(1, 0, 0, 1);
 172         glClear(GL_COLOR_BUFFER_BIT);
 173
 174         /* Paint the right half of the framebuffer green. */
 175         glUseProgram(prog);
 176         glDisable(GL_SAMPLE_COVERAGE);
 177         glDisable(GL_BLEND);
 178         glUniform4f(color_loc, 0, 1, 0, 1);
 179         piglit_draw_rect(0, -1, 1, 2);
 180
 181         /* Paint the top half of the framebuffer blue, using 50%
 182          * sample coverage.
 183          */
 184         glEnable(GL_SAMPLE_COVERAGE);
 185         glSampleCoverage(0.5, GL_FALSE);
 186         glUniform4f(color_loc, 0, 0, 1, 1);
 187         piglit_draw_rect(-1, 0, 2, 1);
 188
 189         /* Paint black over the entire framebuffer, using 50% alpha
 190          * blending.
 191          */
 192         glDisable(GL_SAMPLE_COVERAGE);
 193         glEnable(GL_BLEND);
 194         glBlendEquation(GL_FUNC_ADD);
 195         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 196         glUniform4f(color_loc, 0, 0, 0, 0.5);
 197         piglit_draw_rect(-1, -1, 2, 2);
 198
 199         /* Blit to the single-sampled fbo to force a multisample
 200          * resolve.  Note that we don't blit directly to the screen
 201          * because the screen may be using SRGB, which might trigger
 202          * the driver to do something other than linear averaging when
 203          * resolving the samples.
 204          */
 205         glBindFramebuffer(GL_READ_FRAMEBUFFER, msaa_fbo);
 206         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, singlesampled_fbo);
 207         glBlitFramebuffer(0, 0, piglit_width, piglit_height,
 208                           0, 0, piglit_width, piglit_height,
 209                           GL_COLOR_BUFFER_BIT, GL_NEAREST);
 210
 211         /* Blit to the screen for ease in diagnosing failures. */
 212         glBindFramebuffer(GL_READ_FRAMEBUFFER, singlesampled_fbo);
 213         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
 214         glBlitFramebuffer(0, 0, piglit_width, piglit_height,
 215                           0, 0, piglit_width, piglit_height,
 216                           GL_COLOR_BUFFER_BIT, GL_NEAREST);
 217
 218         /* Check that the color is correct in each quadrant. */
 219         pass = piglit_probe_rect_rgba(0, 0, piglit_width / 2,
 220                                       piglit_height / 2, expected_ll) && pass;
 221         pass = piglit_probe_rect_rgba(piglit_width - piglit_width / 2, 0,
 222                                       piglit_width / 2, piglit_height / 2,
 223                                       expected_lr) && pass;
 224         pass = piglit_probe_rect_rgba(0, piglit_height - piglit_height / 2,
 225                                       piglit_width / 2, piglit_height / 2,
 226                                       expected_ul) && pass;
 227         pass = piglit_probe_rect_rgba(piglit_width - piglit_width / 2,
 228                                       piglit_height - piglit_height / 2,
 229                                       piglit_width / 2, piglit_height / 2,
 230                                       expected_ur) && pass;
 231
 232         piglit_present_results();
 233
 234         /* Clean up */
 235         glDeleteRenderbuffers(1, &rb);
 236         glDeleteFramebuffers(1, &msaa_fbo);
 237
 238         return pass ? PIGLIT_PASS : PIGLIT_FAIL;
 239 }