140 lines
2.9 KiB
C
140 lines
2.9 KiB
C
/*
|
|
* 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
|
|
*/
|
|
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <GL/glew.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);
|
|
glEnableClientState(GL_VERTEX_ARRAY);
|
|
|
|
glColorPointer(3, GL_FLOAT, 24, (void*) 12);
|
|
glEnableClientState(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]);
|
|
glewInit();
|
|
glutReshapeFunc( Reshape );
|
|
glutKeyboardFunc( Key );
|
|
glutDisplayFunc( Display );
|
|
Init();
|
|
glutMainLoop();
|
|
return 0;
|
|
}
|