vbo-drawelements.c revision 7ec3b29a 
1/* Basic VBO */
2
3#include <assert.h>
4#include <string.h>
5#include <stdio.h>
6#include <stdlib.h>
7#include <math.h>
8#include <GL/glew.h>
9#include "glut_wrap.h"
10
11struct {
12   GLfloat pos[3];
13   GLubyte color[4];
14} verts[] =
15{
16   { {  0.9, -0.9, 0.0 },
17     { 0x00, 0x00, 0xff, 0x00 }
18   },
19
20   { {  0.9,  0.9, 0.0 },
21     { 0x00, 0xff, 0x00, 0x00 }
22   },
23
24   { { -0.9,  0.9, 0.0 },
25     { 0xff, 0x00, 0x00, 0x00 }
26   },
27
28   { { -0.9, -0.9, 0.0 },
29     { 0xff, 0xff, 0xff, 0x00 }
30   },
31};
32
33GLuint indices[] = { 0, 1, 2, 3 };
34
35GLuint arrayObj, elementObj;
36
37static void Init( void )
38{
39   GLint errnum;
40   GLuint prognum;
41
42   static const char *prog1 =
43      "!!ARBvp1.0\n"
44      "MOV  result.color, vertex.color;\n"
45      "MOV  result.position, vertex.position;\n"
46      "END\n";
47
48   glGenProgramsARB(1, &prognum);
49   glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
50   glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
51		      strlen(prog1), (const GLubyte *) prog1);
52
53   assert(glIsProgramARB(prognum));
54   errnum = glGetError();
55   printf("glGetError = %d\n", errnum);
56   if (errnum != GL_NO_ERROR)
57   {
58      GLint errorpos;
59
60      glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
61      printf("errorpos: %d\n", errorpos);
62      printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
63   }
64
65
66   glEnableClientState( GL_VERTEX_ARRAY );
67   glEnableClientState( GL_COLOR_ARRAY );
68
69   glGenBuffersARB(1, &arrayObj);
70   glGenBuffersARB(1, &elementObj);
71
72   glBindBufferARB(GL_ARRAY_BUFFER_ARB, arrayObj);
73   glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, elementObj);
74
75   glBufferDataARB(GL_ARRAY_BUFFER_ARB, sizeof(verts), verts, GL_STATIC_DRAW_ARB);
76   glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, sizeof(indices), indices, GL_STATIC_DRAW_ARB);
77
78   glVertexPointer( 3, GL_FLOAT, sizeof(verts[0]), 0 );
79   glColorPointer( 4, GL_UNSIGNED_BYTE, sizeof(verts[0]), (void *)(3*sizeof(float)) );
80
81}
82
83
84
85static void Display( void )
86{
87   glClearColor(0.3, 0.3, 0.3, 1);
88   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
89
90   glEnable(GL_VERTEX_PROGRAM_ARB);
91   glDrawElements( GL_TRIANGLES, 3, GL_UNSIGNED_INT, NULL );
92
93   glFlush();
94}
95
96
97static void Reshape( int width, int height )
98{
99   glViewport( 0, 0, width, height );
100   glMatrixMode( GL_PROJECTION );
101   glLoadIdentity();
102   glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
103   glMatrixMode( GL_MODELVIEW );
104   glLoadIdentity();
105   /*glTranslatef( 0.0, 0.0, -15.0 );*/
106}
107
108
109static void Key( unsigned char key, int x, int y )
110{
111   (void) x;
112   (void) y;
113   switch (key) {
114      case 27:
115         exit(0);
116         break;
117   }
118   glutPostRedisplay();
119}
120
121
122
123
124int main( int argc, char *argv[] )
125{
126   glutInit( &argc, argv );
127   glutInitWindowPosition( 0, 0 );
128   glutInitWindowSize( 250, 250 );
129   glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
130   glutCreateWindow(argv[0]);
131   glewInit();
132   glutReshapeFunc( Reshape );
133   glutKeyboardFunc( Key );
134   glutDisplayFunc( Display );
135   Init();
136   glutMainLoop();
137   return 0;
138}
139