tests/spec/ext_framebuffer_multisample/alpha-blending.c

   1 /*
   2  * Copyright © 2012 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 DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 /** \file alpha-blending.c
  25  *
  26  * This test checks for Mesa bug 53077 (Output error with msaa when
  27  * both of framebuffer and source color's alpha are not 1).  The test
  28  * operates by drawing a partially transparent non-square rectangle to
  29  * a multisampled buffer (using a triangle fan) and then blitting the
  30  * result to the screen.  If the bug is present, artifacts will appear
  31  * along the rectangle diagonal due to alpha blending being performed
  32  * incorrectly while drawing the first triangle of the fan.
  33  *
  34  * See also https://bugs.freedesktop.org/show_bug.cgi?id=53077
  35  *
  36  * Note: when fast color clears are implemented for MSAA buffers, it's
  37  * possible that they will cover up this bug.  To avoid that, the test
  38  * can be supplied a command-line option of "slow_cc", which causes it
  39  * to use a clear color that cannot be fast cleared.
  40  */
  41
  42 #include "piglit-util-gl.h"
  43
  44 GLuint framebuffer, renderbuffer;
  45 #define WIDTH 300
  46 #define HEIGHT 350
  47 int numSamples;
  48 static bool slow_color_clear = false;
  49
  50 PIGLIT_GL_TEST_CONFIG_BEGIN
  51
  52         config.supports_gl_compat_version = 10;
  53
  54         config.window_width = WIDTH;
  55         config.window_height = HEIGHT;
  56         config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGBA;
  57         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  58         slow_color_clear = PIGLIT_STRIP_ARG("slow_cc");
  59
  60 PIGLIT_GL_TEST_CONFIG_END
  61
  62 void
  63 piglit_init(int argc, char **argv)
  64 {
  65         glGetIntegerv(GL_MAX_SAMPLES_EXT, &numSamples);
  66
  67         glGenFramebuffersEXT(1, &framebuffer);
  68         glGenRenderbuffersEXT(1, &renderbuffer);
  69         glBindFramebufferEXT(GL_FRAMEBUFFER, framebuffer);
  70         glBindRenderbufferEXT(GL_RENDERBUFFER, renderbuffer);
  71         glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, numSamples, GL_RGBA, WIDTH, HEIGHT);
  72         glFramebufferRenderbufferEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);
  73         glEnable (GL_MULTISAMPLE);
  74 }
  75
  76 enum piglit_result
  77 piglit_display()
  78 {
  79         GLenum src_factor, dst_factor;
  80         float expected_color[] = { 0.0, 0.7, 0.0, 0.79 };
  81         int x0 = 140;
  82         int x1 = 220;
  83         int y0 = 55;
  84         int y1 = 165;
  85         bool pass = true;
  86         float vertex_data[][2] = {
  87                 { ((float) x0)/WIDTH * 2.0 - 1.0, ((float) y0)/HEIGHT * 2.0 - 1.0 },
  88                 { ((float) x1)/WIDTH * 2.0 - 1.0, ((float) y0)/HEIGHT * 2.0 - 1.0 },
  89                 { ((float) x1)/WIDTH * 2.0 - 1.0, ((float) y1)/HEIGHT * 2.0 - 1.0 },
  90                 { ((float) x0)/WIDTH * 2.0 - 1.0, ((float) y1)/HEIGHT * 2.0 - 1.0 },
  91         };
  92
  93         glBindFramebufferEXT(GL_FRAMEBUFFER,framebuffer);
  94
  95         if (slow_color_clear) {
  96                 glColor4f (0.0, 1.0, 0.5, 0.7);
  97                 glClearColor(0.0, 0.0, 0.5, 1.0);
  98                 expected_color[2] = 0.5;
  99         } else {
 100                 glColor4f (0.0, 1.0, 0.0, 0.7);
 101                 glClearColor(0.0, 0.0, 0.0, 1.0);
 102         }
 103         glClear(GL_COLOR_BUFFER_BIT);
 104
 105         glEnable(GL_BLEND);
 106         src_factor = GL_SRC_ALPHA;
 107         dst_factor = GL_ONE_MINUS_SRC_ALPHA;
 108         glBlendFunc (src_factor, dst_factor);
 109         glVertexPointer(2, GL_FLOAT, 0, vertex_data);
 110         glEnableClientState(GL_VERTEX_ARRAY);
 111         glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
 112
 113         glBindFramebufferEXT(GL_READ_FRAMEBUFFER, framebuffer);
 114         glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
 115         glBlitFramebuffer(0, 0, WIDTH, HEIGHT, 0, 0, WIDTH, HEIGHT, GL_COLOR_BUFFER_BIT, GL_NEAREST);
 116         glBindFramebuffer(GL_FRAMEBUFFER, piglit_winsys_fbo);
 117
 118         pass = piglit_probe_rect_rgba(x0, y0, x1 - x0, y1 - y0, expected_color)
 119                 && pass;
 120
 121         piglit_present_results();
 122
 123         return pass ? PIGLIT_PASS : PIGLIT_FAIL;
 124 }