Friday, November 15, 2013

Complete Minimal SDL2 OpenGL Animation Program with no memory leaks


#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>
#include <iostream>
using std::cout;

int main()
{
  int width = 640, height = 480;
  SDL_Init(SDL_INIT_VIDEO);
  SDL_Window *window = SDL_CreateWindow( "Grapics Application", 0, 0, width, height, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
  SDL_GLContext glcontext = SDL_GL_CreateContext(window);
  cout << "OpenGL Version " << glGetString(GL_VERSION) << "\n";
  glClearColor(0,0,0,1);
  glViewport( 0, 0, width, height );
  glFrustum( -1, 1, -(float)height/width, (float)height/width, 1, 500 );
  SDL_Event event;
  while( 1 )
  {
    while( SDL_PollEvent( &event ) )
    {
      switch( event.type )
      {
        case SDL_WINDOWEVENT:
          if( event.window.event == SDL_WINDOWEVENT_RESIZED )
          {
            glViewport( 0, 0, event.window.data1, event.window.data2 );
            glLoadIdentity();
            glFrustum( -1, 1, -(float)event.window.data2/event.window.data1, (float)event.window.data2/event.window.data1, 1, 500 );
          }
          break;
        case SDL_QUIT: SDL_GL_DeleteContext(glcontext); SDL_DestroyWindow(window);SDL_Quit(); return 0;
      }
    }
  static float delta = 0;
  delta += 0.002;
  glClear(GL_COLOR_BUFFER_BIT);
  glBegin(GL_TRIANGLES);
  glVertex3f( delta, 0, -5 );
  glVertex3f( 1+delta, 0, -5 );
  glVertex3f( delta, 1, -5 );
  glEnd();
  SDL_GL_SwapWindow(window);
  SDL_Delay(20);
  }
}

2 comments:

  1. The code intentionally prints the version string to help you replace the given OpenGL commands with those used by the version supported by your hardware.

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