tests/general/line-smooth-coverage.c

   1 /*
   2  * Copyright © 2022 Collabora Ltd
   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  * Authors:
  24  *    Erik Faye-Lund <erik.faye-lund@collabora.com>
  25  *
  26  */
  27
  28 /*
  29  * Test that the coverage of multiple line-segments split at various positions
  30  * adds up to one.
  31  */
  32
  33 #include "piglit-util-gl.h"
  34
  35 PIGLIT_GL_TEST_CONFIG_BEGIN
  36
  37         config.supports_gl_compat_version = 10;
  38
  39         config.window_width = 300;
  40         config.window_height = 100;
  41         config.window_visual = PIGLIT_GL_VISUAL_RGB | PIGLIT_GL_VISUAL_DOUBLE;
  42
  43 PIGLIT_GL_TEST_CONFIG_END
  44
  45 enum piglit_result
  46 piglit_display(void)
  47 {
  48         glClearColor(0.0, 0.0, 0.0, 0.0);
  49         glClear(GL_COLOR_BUFFER_BIT);
  50
  51         glColor4f(0.5, 0.5, 0.5, 1.0);
  52         glEnable(GL_LINE_SMOOTH);
  53         /* GL AA lines produce an alpha value */
  54         glEnable(GL_BLEND);
  55         glBlendFunc(GL_SRC_ALPHA, GL_ONE);
  56
  57         glLineWidth(3.0f);
  58
  59         int y;
  60         for (y = 0; y * 4 < piglit_height; y++) {
  61                 float seg_width = 0.25 + y * 0.25;
  62                 float x1;
  63                 for (x1 = 0; x1 < piglit_width; x1 += seg_width) {
  64                         float x2 = x1 + seg_width;
  65
  66                         glBegin(GL_LINES);
  67                         glVertex2f(x1, 1.5 + y * 4);
  68                         glVertex2f(x2, 1.5 + y * 4);
  69                         glEnd();
  70                 }
  71         }
  72
  73         GLboolean pass = GL_TRUE;
  74         for (y = 1; y < piglit_height; y += 4) {
  75                 float expected[4] = { 0.5, 0.5, 0.5, 1.0 };
  76                 pass = pass && piglit_probe_rect_rgb(0, y, piglit_width, 1, expected);
  77         }
  78
  79         piglit_present_results();
  80
  81         return pass ? PIGLIT_PASS : PIGLIT_FAIL;
  82 }
  83
  84 void
  85 piglit_init(int argc, char **argv)
  86 {
  87         piglit_ortho_projection(piglit_width, piglit_height, GL_FALSE);
  88 }