1 /*
2 * Copyright (C) 2008 Brian Paul All Rights Reserved.
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 shall be included
12 * in all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
18 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
19 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
20 */
21
22 /*
23 * Draw a triangle with X/EGL.
24 * Brian Paul
25 * 3 June 2008
26 */
27
28
29 #include <math.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include "gl_wrap.h"
33
34 #include "eglut.h"
35
36
37 static GLfloat view_rotx = 0.0, view_roty = 0.0, view_rotz = 0.0;
38
39
40 static void
draw(void)41 draw(void)
42 {
43 static const GLfloat verts[3][2] = {
44 { -1, -1 },
45 { 1, -1 },
46 { 0, 1 }
47 };
48 static const GLfloat colors[3][3] = {
49 { 1, 0, 0 },
50 { 0, 1, 0 },
51 { 0, 0, 1 }
52 };
53
54 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
55
56 glPushMatrix();
57 glRotatef(view_rotx, 1, 0, 0);
58 glRotatef(view_roty, 0, 1, 0);
59 glRotatef(view_rotz, 0, 0, 1);
60
61 {
62 glVertexPointer(2, GL_FLOAT, 0, verts);
63 glColorPointer(3, GL_FLOAT, 0, colors);
64 glEnableClientState(GL_VERTEX_ARRAY);
65 glEnableClientState(GL_COLOR_ARRAY);
66
67 glDrawArrays(GL_TRIANGLES, 0, 3);
68
69 glDisableClientState(GL_VERTEX_ARRAY);
70 glDisableClientState(GL_COLOR_ARRAY);
71 }
72
73 glPopMatrix();
74 }
75
76
77 /* new window size or exposure */
78 static void
reshape(int width,int height)79 reshape(int width, int height)
80 {
81 GLfloat ar = (GLfloat) width / (GLfloat) height;
82
83 glViewport(0, 0, (GLint) width, (GLint) height);
84
85 glMatrixMode(GL_PROJECTION);
86 glLoadIdentity();
87 glFrustum(-ar, ar, -1, 1, 5.0, 60.0);
88
89 glMatrixMode(GL_MODELVIEW);
90 glLoadIdentity();
91 glTranslatef(0.0, 0.0, -10.0);
92 }
93
94
95 static void
init(void)96 init(void)
97 {
98 glClearColor(0.4, 0.4, 0.4, 0.0);
99 }
100
101
102 static void
special_key(int special)103 special_key(int special)
104 {
105 switch (special) {
106 case EGLUT_KEY_LEFT:
107 view_roty += 5.0;
108 break;
109 case EGLUT_KEY_RIGHT:
110 view_roty -= 5.0;
111 break;
112 case EGLUT_KEY_UP:
113 view_rotx += 5.0;
114 break;
115 case EGLUT_KEY_DOWN:
116 view_rotx -= 5.0;
117 break;
118 default:
119 break;
120 }
121 }
122
123 int
main(int argc,char * argv[])124 main(int argc, char *argv[])
125 {
126 eglutInitWindowSize(300, 300);
127 eglutInitAPIMask(EGLUT_OPENGL_BIT);
128 eglutInit(argc, argv);
129
130 eglutCreateWindow("egltri");
131
132 eglutReshapeFunc(reshape);
133 eglutDisplayFunc(draw);
134 eglutSpecialFunc(special_key);
135
136 init();
137
138 eglutMainLoop();
139
140 return 0;
141 }
142