Simple SDL2 OpenGL 1.1 demo

gistfile1.c

#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>

 
void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1,0,0);

	GLfloat i;
	/*
	for(i=-0.8;i<=0.8;)
	{
		glBegin(GL_LINES);
		glVertex3f(0+i,-0.8,0);
		glVertex3f(0+i,0.8,0); 
		glEnd();
		i+=0.2;
	}
	for(i=-0.8;i<=0.8;)
	{
		glBegin(GL_LINES);
		glVertex3f(-0.8,i,0);
		glVertex3f(0.8,i,0); 
		glEnd();
		i+=0.2;
	}
	*/

	for(i=-2;i<=2;i+=0.25)
	{
		glBegin(GL_LINES);
		glVertex3f(i,0,2);
		glVertex3f(i,0,-2);
		glVertex3f(2,0,i);
		glVertex3f(-2,0,i);
		glEnd();
	}
				   

	glColor3f(1,0,1);
	glBegin(GL_TRIANGLE_STRIP);
	glVertex3f(0,2,0);
	glVertex3f(-1,0,1);
	glVertex3f(1,0,1);
	glColor3f(0,1,1);
	glVertex3f(0,0,-1);
	glColor3f(0,0,1);
	glVertex3f(0,2,0);
	glColor3f(0,1,0);
	glVertex3f(-1,0,1);
	glEnd();


	glFlush();
}

void init()
{
	glClearColor(0.1,0.3,0.8,1.0);
	glColor3f(1,1,1);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glFrustum(-2,2,-1.5,1.5,1,40);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glTranslatef(0,0,-3);
	glRotatef(50,1,0,0);
	glRotatef(70,0,1,0);
}

int main()
{
	SDL_Init(SDL_INIT_VIDEO);
	SDL_Window *window = SDL_CreateWindow("SDL2 OpenGL", 100, 100, 500, 500, SDL_WINDOW_OPENGL);
	SDL_GLContext ctx = SDL_GL_CreateContext(window);
	
	init();
	while (1)
	{
		SDL_Event event;
		if (SDL_PollEvent(&event))
		{
			if (event.type == SDL_QUIT)
			{
				break;
			}
		}
		
		display();
		SDL_GL_SwapWindow(window);
	}
	SDL_GL_DeleteContext(ctx);
	SDL_Quit();
	return 0;
}