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#include "SDL/SDL.h"
#include "GL/glew.h"
#include <cmath>
#include <cstdlib>
const size_t size = 100;
GLuint pbo = 0;
GLfloat pixels[size*3];
void init_opengl()
{
glewInit();
glEnable( GL_TEXTURE_2D );
glEnable( GL_LIGHTING );
glEnable( GL_LIGHT0 );
glEnable( GL_COLOR_MATERIAL );
glEnableClientState( GL_VERTEX_ARRAY );
glGenBuffers(1, &pbo);
glBindBuffer(GL_PIXEL_PACK_BUFFER_ARB, pbo);
glBufferData(GL_PIXEL_PACK_BUFFER_ARB, size*3, NULL, GL_DYNAMIC_DRAW);
for ( size_t i = 0 ; i < 3*size; ) {
GLfloat theta = i*2*M_PI/(3*size);
pixels[i++] = cos(theta);
pixels[i++] = sin(theta);
pixels[i++] = 0.0;
}
}
void handle_event( const SDL_Event& event )
{
switch ( event.type ) {
case SDL_QUIT:
exit(0);
break;
case SDL_KEYDOWN:
if ( event.key.keysym.sym == SDLK_ESCAPE ) {
exit(0);
}
break;
default:
break;
}
}
void display()
{
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glDrawPixels(size, 1, GL_RGB, GL_FLOAT, pixels);
glReadPixels(0, 0, size, 1, GL_RGB, GL_FLOAT, 0);
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho(-1, 1, -1, 1, 0.1, 10.0);
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef(0,0,-1);
glBindBuffer(GL_ARRAY_BUFFER, pbo);
glVertexPointer(3, GL_FLOAT, 0, 0);
glDrawArrays(GL_POINTS, 0, size);
SDL_GL_SwapBuffers();
}
int main( int argc, char *argv[] )
{
SDL_Init( SDL_INIT_VIDEO|SDL_INIT_NOPARACHUTE );
atexit( SDL_Quit );
SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );
SDL_SetVideoMode( 512, 512, 32, SDL_OPENGL );
init_opengl();
while ( true ) {
SDL_Event event;
while ( SDL_PollEvent( &event ) ) {
handle_event( event );
}
display();
}
}
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