tests/spec/glsl-1.10/execution/linear-fog.c

   1 /*
   2  * Copyright © 2017 Fabian Bieler
   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 /**
  25  * @file linear-fog.c:  Draw using linear fog in GLSL.
  26  *
  27  * Simple fog test with constant fog coordinates.
  28  */
  29
  30 #include "piglit-util-gl.h"
  31
  32 PIGLIT_GL_TEST_CONFIG_BEGIN
  33
  34         config.supports_gl_compat_version = 20;
  35         config.window_visual = PIGLIT_GL_VISUAL_RGBA;
  36         config.khr_no_error_support = PIGLIT_NO_ERRORS;
  37
  38 PIGLIT_GL_TEST_CONFIG_END
  39
  40 static const char *vs_text =
  41         "void main() {\n"
  42         "   gl_Position = gl_Vertex; \n"
  43         "   gl_FogFragCoord = gl_MultiTexCoord0.x; \n"
  44         "   gl_FrontColor = gl_Color; \n"
  45         "}\n";
  46 static const char *fs_text =
  47         "void main() {\n"
  48         "   float bf = (gl_FogFragCoord - gl_Fog.start) * gl_Fog.scale; \n"
  49         "   gl_FragColor = mix(gl_Color, gl_Fog.color, bf); \n"
  50         "}\n";
  51
  52 static const float vertex_color[] = {.25, .5, .75, .25};
  53 static const float fog_color[] = {1, .5, 1, 0};
  54 static const float fog_start = 100;
  55 static const float fog_end = 200;
  56
  57 enum piglit_result
  58 piglit_display(void)
  59 {
  60         bool pass = true;
  61
  62         for (int j = 0; j < 5; ++j) {
  63                 const float fog_coord = 100 + j * 25;
  64                 const float bf =
  65                         (fog_coord - fog_start) / (fog_end - fog_start);
  66                 float expected_color[4];
  67                 for (int i = 0; i < 4; ++i)
  68                         expected_color[i] = bf * fog_color[i] +
  69                                             (1 - bf) * vertex_color[i];
  70
  71                 glClear(GL_COLOR_BUFFER_BIT);
  72
  73                 glTexCoord1f(fog_coord);
  74                 piglit_draw_rect(-1, -1, 2, 2);
  75
  76                 pass = piglit_probe_pixel_rgba(piglit_width / 2,
  77                                                piglit_height / 2,
  78                                                expected_color) &&
  79                        pass;
  80         }
  81
  82         return pass ? PIGLIT_PASS : PIGLIT_FAIL;
  83 }
  84
  85 void
  86 piglit_init(int argc, char **argv)
  87 {
  88         const int program = piglit_build_simple_program(vs_text, fs_text);
  89
  90         glUseProgram(program);
  91
  92         glColor4fv(vertex_color);
  93         glFogf(GL_FOG_START, fog_start);
  94         glFogf(GL_FOG_END, fog_end);
  95         glFogfv(GL_FOG_COLOR, fog_color);
  96 }