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* Copyright © 2008 Intel Corporation
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* Eric Anholt <eric@anholt.net>
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static int win_width, win_height;
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line(GLfloat x1, GLfloat y1, GLfloat x2, GLfloat y2)
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line3(GLfloat x1, GLfloat y1, GLfloat z1, GLfloat x2, GLfloat y2, GLfloat z2)
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glVertex3f(x1, y1, z1);
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glVertex3f(x2, y2, z2);
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glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
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glClearColor(0.0, 0.0, 0.0, 0.0);
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glClear(GL_COLOR_BUFFER_BIT);
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glColor3f(1.0, 0.0, 0.0);
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/* clipped along xmin */
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glBegin(GL_TRIANGLES);
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glVertex2f(-20, win_height / 2 - 20);
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glVertex2f(20, win_height / 2);
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glVertex2f(-20, win_height / 2 + 20);
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glColor3f(0.0, 1.0, 0.0);
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/* clipped along ymax */
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glBegin(GL_TRIANGLES);
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glVertex2f(win_height / 2 - 20, win_height + 20);
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glVertex2f(win_height / 2, win_height - 20);
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glVertex2f(win_height / 2 + 20, win_height + 20);
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glColor3f(0.0, 0.0, 1.0);
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/* clipped along xmax */
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glBegin(GL_TRIANGLES);
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glVertex2f(win_height + 20, win_height / 2 - 20);
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glVertex2f(win_height - 20, win_height / 2);
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glVertex2f(win_height + 20, win_height / 2 + 20);
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glColor3f(1.0, 1.0, 1.0);
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/* clipped along ymin */
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glBegin(GL_TRIANGLES);
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glVertex2f(win_height / 2 - 20, -20);
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glVertex2f(win_height / 2, 20);
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glVertex2f(win_height / 2 + 20, -20);
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/* clipped along near */
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glColor3f(1.0, 0.0, 1.0);
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glBegin(GL_TRIANGLES);
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glVertex3f(win_width / 2 - 20, win_height / 2 - 20, 0.5);
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glVertex3f(win_width / 2 - 40, win_height / 2, -0.5);
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glVertex3f(win_width / 2 - 20, win_height / 2 + 20, 0.5);
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/* clipped along far */
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glColor3f(0.0, 1.0, 1.0);
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glBegin(GL_TRIANGLES);
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glVertex3f(win_width / 2 + 20, win_height / 2 - 20, 0.5);
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glVertex3f(win_width / 2 + 40, win_height / 2, 1.5);
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glVertex3f(win_width / 2 + 20, win_height / 2 + 20, 0.5);
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/* entirely clipped along near/far */
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glColor3f(.5, .5, .5);
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glBegin(GL_TRIANGLES);
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glVertex3f(win_width / 2 - 20, win_height / 2 + 20, -0.5);
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glVertex3f(win_width / 2, win_height / 2 + 40, -0.5);
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glVertex3f(win_width / 2 + 20, win_height / 2 + 20, -0.5);
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glBegin(GL_TRIANGLES);
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glVertex3f(win_width / 2 - 20, win_height / 2 - 20, 1.5);
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glVertex3f(win_width / 2, win_height / 2 - 40, 1.5);
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glVertex3f(win_width / 2 + 20, win_height / 2 - 20, 1.5);
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glColor3f(.5, .5, .5);
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line3(win_width / 2, win_height / 2 - 20, 1.5,
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win_width / 2, win_height / 2 + 20, 1.5);
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glColor3f(1.0, 1.0, 0.0);
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/* clipped along both x and y limits */
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glBegin(GL_TRIANGLES); /* xmin, ymin */
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glBegin(GL_TRIANGLES); /* xmin, ymax */
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glVertex2f(-5, win_height - 20);
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glVertex2f(20, win_height - 20);
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glVertex2f(20, win_height + 5);
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glBegin(GL_TRIANGLES); /* xmax, ymax */
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glVertex2f(win_width - 20, win_height + 5);
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glVertex2f(win_width - 20, win_height - 20);
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glVertex2f(win_width + 5, win_height - 20);
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glBegin(GL_TRIANGLES); /* xmax, ymin */
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glVertex2f(win_width + 5, 20);
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glVertex2f(win_width - 20, 20);
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glVertex2f(win_width - 20, -5);
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reshape(int width, int height)
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glViewport(0, 0, width, height);
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glMatrixMode(GL_PROJECTION);
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glOrtho(0, win_width, 0, win_height, 0.0, -1.0);
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glMatrixMode(GL_MODELVIEW);
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glTranslatef(.25, .25, 0);
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static void key( unsigned char key, int x, int y )
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main(int argc, char *argv[])
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glutInit(&argc, argv);
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glutInitWindowPosition(0, 0);
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glutInitWindowSize(win_width, win_height);
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glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
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glutCreateWindow(argv[0]);
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glutReshapeFunc(reshape);
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glutKeyboardFunc(key);
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glutDisplayFunc(display);