summaryrefslogtreecommitdiff
path: root/progs/tests/mapvbo.c
blob: 49e120de73c637aa22571bbb18fd29ce5222afe7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/*
 * Test glMapBuffer() call immediately after glDrawArrays().
 * See details below.
 *
 * NOTE: Do not use freeglut with this test!  It calls the Display()
 * callback twice right away instead of just once.
 *
 * Brian Paul
 * 27 Feb 2009
 */


#define GL_GLEXT_PROTOTYPES
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>

static GLuint BufferID;


static GLuint Win;




/*
 * Create VBO (position and color) and load with data.
 */
static void
SetupBuffers(void)
{
   static const GLfloat data[] = {
      /* vertex */     /* color */
      0, -1,  0,      1,    1,   0,
      1,  0,  0,      1,    1,   0,
      0,  1,  0,      1,    1,   0,
      -1, 0,  0,      1,    1,   0
   };

   glGenBuffersARB(1, &BufferID);
   glBindBufferARB(GL_ARRAY_BUFFER_ARB, BufferID);
   glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(data), data,
                   GL_STATIC_DRAW_ARB);
}


static void
Draw(void)
{
   static int count = 1;

   printf("Draw Frame %d\n", count);
   count++;

   glBindBufferARB(GL_ARRAY_BUFFER_ARB, BufferID);
   glVertexPointer(3, GL_FLOAT, 24, 0);
   glEnable(GL_VERTEX_ARRAY);

   glColorPointer(3, GL_FLOAT, 24, (void*) 12);
   glEnable(GL_COLOR_ARRAY);

   glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

   if (0)
      glFinish();

   /* Immediately map the color buffer and change something.
    * This should not effect the first glDrawArrays above, but the
    * next time we draw we should see a black vertex.
    */
   if (1) {
      GLfloat *m = (GLfloat *) glMapBufferARB(GL_ARRAY_BUFFER_ARB,
                                              GL_WRITE_ONLY_ARB);
      m[3] = m[4] = m[5] = 0.0f; /* black vertex */
      glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
   }
}


static void Display( void )
{
   glClear( GL_COLOR_BUFFER_BIT );
   Draw();
   glutSwapBuffers();
}


static void Reshape( int width, int height )
{
   float ar = (float) width / (float) height;
   glViewport( 0, 0, width, height );
   glMatrixMode( GL_PROJECTION );
   glLoadIdentity();
   glFrustum( -ar, ar, -1.0, 1.0, 5.0, 25.0 );
   glMatrixMode( GL_MODELVIEW );
   glLoadIdentity();
   glTranslatef( 0.0, 0.0, -15.0 );
}


static void Key( unsigned char key, int x, int y )
{
   (void) x;
   (void) y;
   if (key == 27) {
      glutDestroyWindow(Win);
      exit(0);
   }
   glutPostRedisplay();
}


static void Init( void )
{
   if (!glutExtensionSupported("GL_ARB_vertex_buffer_object")) {
      printf("GL_ARB_vertex_buffer_object not found!\n");
      exit(0);
   }
   printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));

   SetupBuffers();
}


int main( int argc, char *argv[] )
{
   glutInit( &argc, argv );
   glutInitWindowPosition( 0, 0 );
   glutInitWindowSize( 300, 300 );
   glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
   Win = glutCreateWindow(argv[0]);
   glutReshapeFunc( Reshape );
   glutKeyboardFunc( Key );
   glutDisplayFunc( Display );
   Init();
   glutMainLoop();
   return 0;
}