tests/spec/arb_sample_shading/execution/builtin-gl-sample-mask-mrt-alpha.cpp

   1 /*
   2  * Copyright (c) 2015 Intel Corporation
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  23
  24 /** \file builtin-gl-sample-mask-mrt-alpha.cpp
  25  *
  26  *  This test verifies that assigning gl_SampleMask[] from the
  27  *  fragment shader works as expected in cases where the
  28  *  implementation is required to supply an additional alpha component
  29  *  previously written to a different color attachment to render to a
  30  *  non-zero attachment of a multisample FBO (e.g. while using
  31  *  alpha-to-coverage).
  32  */
  33
  34 #include "piglit-fbo.h"
  35 using namespace piglit_util_fbo;
  36
  37 #define NUM_SAMPLES 4
  38
  39 PIGLIT_GL_TEST_CONFIG_BEGIN
  40
  41         config.supports_gl_compat_version = 21;
  42         config.supports_gl_core_version = 31;
  43
  44         config.window_visual = PIGLIT_GL_VISUAL_DOUBLE | PIGLIT_GL_VISUAL_RGBA;
  45         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  46
  47 PIGLIT_GL_TEST_CONFIG_END
  48
  49 static Fbo
  50 make_fbo()
  51 {
  52         FboConfig config(NUM_SAMPLES, piglit_width, piglit_height);
  53         config.num_rb_attachments = 0;
  54         config.num_tex_attachments = 2;
  55         config.tex_attachment[0] = GL_COLOR_ATTACHMENT0;
  56         config.tex_attachment[1] = GL_COLOR_ATTACHMENT1;
  57
  58         Fbo fbo;
  59         fbo.setup(config);
  60
  61         if (!piglit_check_gl_error(GL_NO_ERROR))
  62                 piglit_report_result(PIGLIT_FAIL);
  63
  64         return fbo;
  65 }
  66
  67 /**
  68  * Render to both texture attachments of the multisample fbo enabling
  69  * alpha-to-coverage to make the implementation pass the additional
  70  * alpha component from the first attachment when rendering into the
  71  * second.  The resulting sample mask will still be 5 as specified in
  72  * the fragment shader because an alpha value of 1.0 maps to the
  73  * coverage mask ~0.
  74  */
  75 static bool
  76 run_test(Fbo &fbo)
  77 {
  78         const GLuint prog = piglit_build_simple_program(
  79                 "#version 130\n"
  80                 "in vec4 piglit_vertex;\n"
  81                 "\n"
  82                 "void main()\n"
  83                 "{\n"
  84                 "   gl_Position = piglit_vertex;\n"
  85                 "}\n",
  86                 "#version 130\n"
  87                 "#extension GL_ARB_sample_shading : enable\n"
  88                 "\n"
  89                 "out vec4 out_color[2];"
  90                 "\n"
  91                 "void main()\n"
  92                 "{\n"
  93                 "   gl_SampleMask[0] = 5;\n"
  94                 "   out_color[0] = vec4(1.0, 0.0, 0.0, 1.0);\n"
  95                 "   out_color[1] = vec4(1.0, 0.0, 0.0, 0.0);\n"
  96                 "}\n");
  97
  98         glUseProgram(prog);
  99
 100         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo.handle);
 101         glDrawBuffers(fbo.config.num_tex_attachments,
 102                       fbo.config.tex_attachment);
 103         glEnable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 104         fbo.set_viewport();
 105
 106         glClear(GL_COLOR_BUFFER_BIT);
 107         piglit_draw_rect(-1, -1, 2, 2);
 108
 109         glDisable(GL_SAMPLE_ALPHA_TO_COVERAGE);
 110         glDeleteProgram(prog);
 111
 112         return piglit_check_gl_error(GL_NO_ERROR);
 113 }
 114
 115 /**
 116  * Resolve the red component of each sample from the texture
 117  * previously bound to color attachment i as the RGBA components of
 118  * the actual framebuffer.  Return true if only the first and third
 119  * samples were written according to the coverage mask set by the
 120  * shader.
 121  */
 122 static bool
 123 check(const Fbo &fbo, unsigned i)
 124 {
 125         const float expected[] = { 1, 0, 1, 0 };
 126         const GLuint prog = piglit_build_simple_program(
 127                 "#version 130\n"
 128                 "in vec4 piglit_vertex;\n"
 129                 "\n"
 130                 "void main()\n"
 131                 "{\n"
 132                 "   gl_Position = piglit_vertex;\n"
 133                 "}\n",
 134                 "#version 130\n"
 135                 "#extension GL_ARB_texture_multisample : require\n"
 136                 "\n"
 137                 "uniform sampler2DMS tex;\n"
 138                 "out vec4 out_color;\n"
 139                 "\n"
 140                 "void main()\n"
 141                 "{\n"
 142                 "   vec4 v;\n"
 143                 "\n"
 144                 "   for (int i = 0; i < 4; i++)\n"
 145                 "      v[i] = texelFetch(tex, ivec2(gl_FragCoord.x,\n"
 146                 "                                   gl_FragCoord.y), i).x;\n"
 147                 "\n"
 148                 "   out_color = v;\n"
 149                 "}\n");
 150
 151         glUseProgram(prog);
 152         glUniform1i(glGetUniformLocation(prog, "tex"), 0);
 153
 154         glBindFramebuffer(GL_DRAW_FRAMEBUFFER, piglit_winsys_fbo);
 155         glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, fbo.color_tex[i]);
 156         glViewport(0, 0, piglit_width, piglit_height);
 157
 158         glClear(GL_COLOR_BUFFER_BIT);
 159         piglit_draw_rect(-1, -1, 2, 2);
 160
 161         glDeleteProgram(prog);
 162
 163         if (!piglit_check_gl_error(GL_NO_ERROR))
 164                 return false;
 165
 166         if (!piglit_probe_rect_rgba(0, 0, piglit_width, piglit_height,
 167                                     expected)) {
 168                 printf("  Attachment: %d\n", i);
 169                 return false;
 170         }
 171
 172         return true;
 173 }
 174
 175 void
 176 piglit_init(int argc, char **argv)
 177 {
 178         piglit_require_extension("GL_ARB_texture_multisample");
 179         piglit_require_extension("GL_ARB_sample_shading");
 180         piglit_require_GLSL_version(130);
 181
 182         Fbo fbo = make_fbo();
 183
 184         if (run_test(fbo) && check(fbo, 0) && check(fbo, 1))
 185                 piglit_report_result(PIGLIT_PASS);
 186         else
 187                 piglit_report_result(PIGLIT_FAIL);
 188 }
 189
 190 piglit_result
 191 piglit_display()
 192 {
 193         return PIGLIT_FAIL;
 194 }