// A window that slowly changes color. Needs GLFW and OpenGL
// (on Nix they are in shell.nix: run this inside nix-shell).
import "GLFW/glfw3.h"
import "GL/gl.h"
import "math.h"
link "glfw"
link "GL"

fn main() {
    if glfwInit() == 0 {
        print("could not start GLFW")
        return
    }

    window := glfwCreateWindow(800, 600, "Finch", null, null)
    if window == null {
        print("could not open a window")
        glfwTerminate()
        return
    }
    glfwMakeContextCurrent(window)

    while glfwWindowShouldClose(window) == 0 {
        t := glfwGetTime()
        glClearColor(f32(sin(t) * 0.5 + 0.5), 0.3, 0.6, 1.0)
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

        glfwSwapBuffers(window)
        glfwPollEvents()
    }

    glfwDestroyWindow(window)
    glfwTerminate()
}