GLFW demo

glfwtest.c

/* test GLFW */
#include <GLFW/glfw3.h>
#include <stdio.h>
#include <math.h>

#define WIDTH	1280
#define HEIGHT	720
#define TITLE	"glfw demo"

#define error_callback(err, descr) puts(descr);

#define get_t_angle(time, interv)\
(sinf((fmod(time,interv)/interv) * 2*M_PI))

int main(int argc, char *argv[])
{
	GLFWwindow *window;
	
	if (!glfwInit()
	 || !(window = glfwCreateWindow(WIDTH,HEIGHT,TITLE,NULL,NULL)))
		return -1;

	glfwMakeContextCurrent(window);
	/* render */
	while (!glfwWindowShouldClose(window)) {
		int width, height;
		double time;
		float ratio, angle;
		
		glfwGetFramebufferSize(window, &width, &height);
		glViewport(0, 0, width, height);
		time = glfwGetTime();
		ratio = width / (float) height;

		glClearColor(0.f, 0.f, 0.f, 1.f);
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glOrtho(-ratio, ratio, -1.f, 1.f, 1.f, -1.f);

		angle = -get_t_angle(glfwGetTime(), 20.f);
		glMatrixMode(GL_MODELVIEW);
		printf("angle: %f\n", angle);
		glRotatef(angle, 0.f, 0.f, 1.f);

		glBegin(GL_TRIANGLES);
		glColor3f(1.f, 0.f, 0.f);
		glVertex3f(-0.6f, -0.4f, 0.f);
		glColor3f(0.f, 1.f, 0.f);
		glVertex3f(0.6f, -0.4f, 0.f);
		glColor3f(0.f, 0.f, 1.f);
		glVertex3f(0.f, 0.6f, 0.f);
		glColor3f(0.7f, 0.3f, 0.5f);
		glVertex3f(0.7f, 0.3f, 0.f);
		glColor3f(0.7f, 0.3f, 0.5f);
		glVertex3f(-0.7f, -0.3f, 0.f);
		glColor3f(0.1f, 0.3f, 0.5f);
		glVertex3f(0.2f, 0.9f, 0.f);
		glEnd();

		glfwSwapBuffers(window);
		glfwPollEvents();
	}

	glfwDestroyWindow(window);	
	glfwTerminate();
}

Makefile

# makefile for glfw
CFLAGS=$(shell pkg-config --cflags glfw3)
LDFLAGS=$(shell pkg-config --libs glfw3) -lGL -lm

all:
	$(CC) $(CFLAGS) glfwtest.c -o glfw_test $(LDFLAGS)

clean:
	$(RM) glfw_test