2 * smooth_opengl3.c, based on smooth.c, which is (c) by SGI, see below.
3 * This program demonstrates smooth shading in a way which is fully
4 * OpenGL-3.0-compliant.
5 * A smooth shaded polygon is drawn in a 2-D projection.
9 * Original copyright notice from smooth.c:
11 * License Applicability. Except to the extent portions of this file are
12 * made subject to an alternative license as permitted in the SGI Free
13 * Software License B, Version 1.1 (the "License"), the contents of this
14 * file are subject only to the provisions of the License. You may not use
15 * this file except in compliance with the License. You may obtain a copy
16 * of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
17 * Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
19 * http://oss.sgi.com/projects/FreeB
21 * Note that, as provided in the License, the Software is distributed on an
22 * "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
23 * DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
24 * CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
25 * PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
27 * Original Code. The Original Code is: OpenGL Sample Implementation,
28 * Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
29 * Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
30 * Copyright in any portions created by third parties is as indicated
31 * elsewhere herein. All Rights Reserved.
33 * Additional Notice Provisions: The application programming interfaces
34 * established by SGI in conjunction with the Original Code are The
35 * OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
36 * April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
37 * 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
38 * Window System(R) (Version 1.3), released October 19, 1998. This software
39 * was created using the OpenGL(R) version 1.2.1 Sample Implementation
40 * published by SGI, but has not been independently verified as being
41 * compliant with the OpenGL(R) version 1.2.1 Specification.
45 #include <GL/freeglut.h>
49 void reportErrors(const char *message)
52 while (( error = glGetError() ) != GL_NO_ERROR) {
53 fprintf (stderr, "GL error 0x%X %s\n", error, message);
59 reportErrors ("at start of init");
60 glClearColor (0.0, 0.0, 0.0, 0.0);
61 glShadeModel (GL_SMOOTH);
62 reportErrors ("at end of init");
67 reportErrors ("at start of triangle");
68 glBegin (GL_TRIANGLES);
69 glColor3f (1.0, 0.0, 0.0);
70 glVertex2f (5.0, 5.0);
71 glColor3f (0.0, 1.0, 0.0);
72 glVertex2f (25.0, 5.0);
73 glColor3f (0.0, 0.0, 1.0);
74 glVertex2f (5.0, 25.0);
76 reportErrors ("at end of triangle");
81 reportErrors ("at start of display");
82 glClear (GL_COLOR_BUFFER_BIT);
85 reportErrors ("at end of display");
88 void loadOrthof(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t,
91 m[ 0] = 2.0f / (r - l);
97 m[ 5] = 2.0f / (t - b);
103 m[10] = -2.0f / (f - n);
106 m[12] = -(r + l) / (r - l);
107 m[13] = -(t + b) / (t - b);
108 m[14] = -(f + n) / (f - n);
112 void loadOrtho2Df(GLfloat *m, GLfloat l, GLfloat r, GLfloat b, GLfloat t)
114 loadOrthof (m, l, r, b, t, -1.0f, 1.0f);
117 void reshape (int w, int h)
120 reportErrors ("at start of reshape");
121 glViewport (0, 0, (GLsizei) w, (GLsizei) h);
122 glMatrixMode (GL_PROJECTION);
124 loadOrtho2Df (m, 0.0, 30.0, 0.0, 30.0 * (GLfloat) h/(GLfloat) w);
126 loadOrtho2Df (m, 0.0, 30.0 * (GLfloat) w/(GLfloat) h, 0.0, 30.0);
129 glMatrixMode (GL_MODELVIEW);
130 reportErrors ("at end of reshape");
133 void keyboard(unsigned char key, int x, int y)
142 int main(int argc, char** argv)
144 glutInit(&argc, argv);
145 glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
146 glutInitContextVersion(3, 0);
147 // glutInitContextFlags(GLUT_FORWARD_COMPATIBLE | GLUT_DEBUG);
148 glutInitWindowSize (500, 500);
149 glutInitWindowPosition (100, 100);
150 glutCreateWindow (argv[0]);
152 glutDisplayFunc(display);
153 glutReshapeFunc(reshape);
154 glutKeyboardFunc (keyboard);