tests/shaders/glsl-fs-discard-02.c

   1 /*
   2  * Copyright © 2009 Marek Olšák (maraeo@gmail.com)
   3  * Copyright © 2010 Intel Corporation
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22  * IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Marek Olšák <mareao@gmail.com>
  26  *    Eric Anholt <eric@anholt.net>
  27  *
  28  */
  29
  30 /** @file glsl-fs-discard-02.c
  31  *
  32  * Tests that discarding fragments doesn't let early depth writes through.
  33  */
  34
  35 #include "piglit-util.h"
  36
  37 int piglit_width = 100, piglit_height = 100;
  38 int piglit_window_mode = GLUT_RGB | GLUT_ALPHA | GLUT_DOUBLE | GLUT_DEPTH;
  39
  40 static char vs_code[] =
  41         "varying vec4 color;"
  42         "\n"
  43         "void main()\n"
  44         "{\n"
  45         "       gl_Position = gl_Vertex;\n"
  46         "       if (gl_Vertex.z > 0.75)\n"
  47         "               color = vec4(1.0, 0.0, 0.0, gl_Vertex.z);\n"
  48         "       else if (gl_Vertex.z > 0.25)\n"
  49         "               color = vec4(0.0, 1.0, 0.0, gl_Vertex.z);\n"
  50         "       else\n"
  51         "               color = vec4(0.0, 0.0, 1.0, gl_Vertex.z);\n"
  52         "}\n";
  53
  54 static char fs_code[] =
  55         "varying vec4 color;\n"
  56         "\n"
  57         "void main()\n"
  58         "{\n"
  59         "       if (color.w < 0.25)\n"
  60         "               discard;"
  61         "    gl_FragColor = vec4(color.xyz, 0.0);\n"
  62         "}\n";
  63
  64 static GLuint setup_shaders()
  65 {
  66         GLuint vs, fs, prog;
  67
  68         vs = piglit_compile_shader_text(GL_VERTEX_SHADER, vs_code);
  69         fs = piglit_compile_shader_text(GL_FRAGMENT_SHADER, fs_code);
  70         prog = piglit_link_simple_program(vs, fs);
  71
  72         glUseProgram(prog);
  73         return prog;
  74 }
  75
  76 static GLboolean test()
  77 {
  78         GLint prog, location;
  79         GLboolean pass = GL_TRUE;
  80         int i;
  81         float red[4] =   {1, 0, 0, 0};
  82         float green[4] = {0, 1, 0, 0};
  83
  84         prog = setup_shaders();
  85
  86         glClear(GL_DEPTH_BUFFER_BIT);
  87
  88         glDepthFunc(GL_LEQUAL);
  89         glEnable(GL_DEPTH_TEST);
  90
  91         piglit_draw_rect_z(1.0, -1, -1, 2, 2); // red
  92         piglit_draw_rect_z(0.0, -1, -1, 2, 2); // discard
  93         piglit_draw_rect_z(0.5, -1, -1, 2, 2); // green
  94
  95         assert(glGetError() == 0);
  96
  97         piglit_probe_rect_rgba(0, 0, piglit_width, piglit_height, green);
  98
  99         return pass;
 100 }
 101
 102 enum piglit_result piglit_display(void)
 103 {
 104         GLboolean pass;
 105
 106         pass = test();
 107
 108         glutSwapBuffers();
 109
 110         return pass ? PIGLIT_SUCCESS : PIGLIT_FAILURE;
 111 }
 112
 113 void piglit_init(int argc, char **argv)
 114 {
 115         if (!GLEW_VERSION_2_0) {
 116                 printf("Requires OpenGL 2.0\n");
 117                 piglit_report_result(PIGLIT_SKIP);
 118         }
 119 }
 120