| /* |
| * 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; |
| } |