1
2 /*
3 * Example of how to use the GL_MESA_window_pos extension.
4 * Brian Paul This file is in the public domain.
5 */
6
7 #include <math.h>
8 #include <string.h>
9 #include <stdlib.h>
10 #include <stdio.h>
11 #ifdef _WIN32
12 #include <windows.h>
13 #endif
14 #include "glad/glad.h"
15 #include "glut_wrap.h"
16
17 #include "readtex.h"
18
19 #define IMAGE_FILE DEMOS_DATA_DIR "girl.rgb"
20
21
22 #ifndef M_PI
23 # define M_PI 3.14159265
24 #endif
25
26
27
28 static GLubyte *Image;
29 static int ImgWidth, ImgHeight;
30 static GLenum ImgFormat;
31
32 static PFNGLWINDOWPOS2FPROC WindowPosFunc;
33
draw(void)34 static void draw( void )
35 {
36 GLfloat angle;
37
38 glClear( GL_COLOR_BUFFER_BIT );
39
40 for (angle = -45.0; angle <= 135.0; angle += 10.0) {
41 GLfloat x = 50.0 + 200.0 * cos( angle * M_PI / 180.0 );
42 GLfloat y = 50.0 + 200.0 * sin( angle * M_PI / 180.0 );
43
44 /* Don't need to worry about the modelview or projection matrices!!! */
45 (*WindowPosFunc)( x, y );
46
47 glDrawPixels( ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image );
48 }
49 glFinish();
50 }
51
52
key(unsigned char key,int x,int y)53 static void key( unsigned char key, int x, int y )
54 {
55 (void) x;
56 (void) y;
57 switch (key) {
58 case 27:
59 exit(0);
60 }
61 }
62
63
64 /* new window size or exposure */
reshape(int width,int height)65 static void reshape( int width, int height )
66 {
67 glViewport(0, 0, (GLint)width, (GLint)height);
68 }
69
70
init(void)71 static void init( void )
72 {
73 if (GLAD_GL_ARB_window_pos) {
74 printf("Using GL_ARB_window_pos\n");
75 WindowPosFunc = glWindowPos2fARB;
76 }
77 else
78 if (GLAD_GL_MESA_window_pos) {
79 printf("Using GL_MESA_window_pos\n");
80 WindowPosFunc = glWindowPos2fMESA;
81 }
82 else
83 {
84 printf("Sorry, GL_ARB/MESA_window_pos extension not available.\n");
85 exit(1);
86 }
87
88 Image = LoadRGBImage( IMAGE_FILE, &ImgWidth, &ImgHeight, &ImgFormat );
89 if (!Image) {
90 printf("Couldn't read %s\n", IMAGE_FILE);
91 exit(0);
92 }
93 glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
94 }
95
96
main(int argc,char * argv[])97 int main( int argc, char *argv[] )
98 {
99 glutInitWindowSize(500, 500);
100 glutInit(&argc, argv);
101 glutInitDisplayMode( GLUT_RGB );
102
103 if (glutCreateWindow("winpos") <= 0) {
104 exit(0);
105 }
106
107 gladLoadGL();
108
109 init();
110
111 glutReshapeFunc( reshape );
112 glutKeyboardFunc( key );
113 glutDisplayFunc( draw );
114 glutMainLoop();
115 return 0;
116 }
117