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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
|
/*
* Test GL_ARB_vertex_buffer_object
*
* Brian Paul
* 16 Sep 2003
*/
#define GL_GLEXT_PROTOTYPES
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
#define NUM_OBJECTS 10
struct object
{
GLuint BufferID;
GLuint ElementsBufferID;
GLuint NumVerts;
GLuint VertexOffset;
GLuint ColorOffset;
GLuint NumElements;
};
static struct object Objects[NUM_OBJECTS];
static GLuint NumObjects;
static GLfloat Xrot = 0, Yrot = 0, Zrot = 0;
static GLboolean Anim = GL_TRUE;
static void CheckError(int line)
{
GLenum err = glGetError();
if (err) {
printf("GL Error %d at line %d\n", (int) err, line);
}
}
static void DrawObject( const struct object *obj )
{
glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
glVertexPointer(3, GL_FLOAT, 0, (void *) obj->VertexOffset);
glEnable(GL_VERTEX_ARRAY);
glColorPointer(3, GL_FLOAT, 0, (void *) obj->ColorOffset);
glEnable(GL_COLOR_ARRAY);
if (obj->NumElements > 0) {
/* indexed arrays */
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, obj->ElementsBufferID);
glDrawElements(GL_LINE_LOOP, obj->NumElements, GL_UNSIGNED_INT, NULL);
}
else {
/* non-indexed arrays */
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
glDrawArrays(GL_LINE_LOOP, 0, obj->NumVerts);
}
}
static void Idle( void )
{
Zrot = 0.05 * glutGet(GLUT_ELAPSED_TIME);
glutPostRedisplay();
}
static void Display( void )
{
int i;
glClear( GL_COLOR_BUFFER_BIT );
for (i = 0; i < NumObjects; i++) {
float x = 5.0 * ((float) i / (NumObjects-1) - 0.5);
glPushMatrix();
glTranslatef(x, 0, 0);
glRotatef(Xrot, 1, 0, 0);
glRotatef(Yrot, 0, 1, 0);
glRotatef(Zrot, 0, 0, 1);
DrawObject(Objects + i);
glPopMatrix();
}
CheckError(__LINE__);
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 )
{
const GLfloat step = 3.0;
(void) x;
(void) y;
switch (key) {
case 'a':
Anim = !Anim;
if (Anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
case 'z':
Zrot -= step;
break;
case 'Z':
Zrot += step;
break;
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void SpecialKey( int key, int x, int y )
{
const GLfloat step = 3.0;
(void) x;
(void) y;
switch (key) {
case GLUT_KEY_UP:
Xrot -= step;
break;
case GLUT_KEY_DOWN:
Xrot += step;
break;
case GLUT_KEY_LEFT:
Yrot -= step;
break;
case GLUT_KEY_RIGHT:
Yrot += step;
break;
}
glutPostRedisplay();
}
static void MakeObject1(struct object *obj)
{
GLfloat *v, *c;
glGenBuffersARB(1, &obj->BufferID);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, 1000, NULL, GL_STATIC_DRAW_ARB);
v = (GLfloat *) glMapBufferARB(GL_ARRAY_BUFFER_ARB, GL_READ_WRITE_ARB);
/* Make rectangle */
v[0] = -1; v[1] = -1; v[2] = 0;
v[3] = 1; v[4] = -1; v[5] = 0;
v[6] = 1; v[7] = 1; v[8] = 0;
v[9] = -1; v[10] = 1; v[11] = 0;
c = v + 12;
c[0] = 1; c[1] = 0; c[2] = 0;
c[3] = 1; c[4] = 0; c[5] = 0;
c[6] = 1; c[7] = 0; c[8] = 1;
c[9] = 1; c[10] = 0; c[11] = 1;
obj->NumVerts = 4;
obj->VertexOffset = 0;
obj->ColorOffset = 3 * sizeof(GLfloat) * obj->NumVerts;
obj->NumElements = 0;
glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
}
static void MakeObject2(struct object *obj)
{
GLfloat *v, *c;
glGenBuffersARB(1, &obj->BufferID);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, 1000, NULL, GL_STATIC_DRAW_ARB);
v = (GLfloat *) glMapBufferARB(GL_ARRAY_BUFFER_ARB, GL_READ_WRITE_ARB);
/* Make triangle */
v[0] = -1; v[1] = -1; v[2] = 0;
v[3] = 1; v[4] = -1; v[5] = 0;
v[6] = 0; v[7] = 1; v[8] = 0;
c = v + 9;
c[0] = 0; c[1] = 1; c[2] = 0;
c[3] = 0; c[4] = 1; c[5] = 0;
c[6] = 1; c[7] = 1; c[8] = 0;
obj->NumVerts = 3;
obj->VertexOffset = 0;
obj->ColorOffset = 3 * sizeof(GLfloat) * obj->NumVerts;
obj->NumElements = 0;
glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
}
static void MakeObject3(struct object *obj)
{
GLfloat *v, *c;
GLuint *i;
glGenBuffersARB(1, &obj->BufferID);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, 1000, NULL, GL_STATIC_DRAW_ARB);
v = (GLfloat *) glMapBufferARB(GL_ARRAY_BUFFER_ARB, GL_READ_WRITE_ARB);
/* Make rectangle */
v[0] = -1; v[1] = -0.5; v[2] = 0;
v[3] = 1; v[4] = -0.5; v[5] = 0;
v[6] = 1; v[7] = 0.5; v[8] = 0;
v[9] = -1; v[10] = 0.5; v[11] = 0;
c = v + 12;
c[0] = 0; c[1] = 0; c[2] = 1;
c[3] = 0; c[4] = 0; c[5] = 1;
c[6] = 0; c[7] = 1; c[8] = 1;
c[9] = 0; c[10] = 1; c[11] = 1;
obj->NumVerts = 4;
obj->VertexOffset = 0;
obj->ColorOffset = 3 * sizeof(GLfloat) * obj->NumVerts;
glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
/* Setup a buffer of indices to test the ELEMENTS path */
glGenBuffersARB(1, &obj->ElementsBufferID);
glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, obj->ElementsBufferID);
glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 100, NULL, GL_STATIC_DRAW_ARB);
i = (GLuint *) glMapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, GL_READ_WRITE_ARB);
i[0] = 0;
i[1] = 1;
i[2] = 2;
i[3] = 3;
glUnmapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB);
obj->NumElements = 4;
}
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));
MakeObject1(Objects + 0);
MakeObject2(Objects + 1);
MakeObject3(Objects + 2);
NumObjects = 3;
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 600, 300 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutDisplayFunc( Display );
if (Anim)
glutIdleFunc(Idle);
Init();
glutMainLoop();
return 0;
}
|
