DerelictGL program draw nothing

[Zhenya]

Why this simple program don't show white square?

import std.stdio;

import derelict.opengl3.gl;
import derelict.glfw3.glfw3;

const uint width = 200;
const uint height = 200;

void init()
{
	glViewport(0,0,width,height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-width,width,-height,height,-1,1);
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glBegin(GL_POLYGON);
		glVertex2d(0,0);
		glVertex2d(0,height);
		glVertex2d(width,height);
		glVertex2d(height,0);
	glEnd();
}

void main()
{
	DerelictGL.load();
	DerelictGLFW3.load();
	glfwInit();
	GLFWwindow window;
	window = glfwCreateWindow(width,height,GLFW_WINDOWED,"Hello 
DerelictGLFW3",null);
	init();
	bool opened = true;
	while(opened)
	{
		opened = !glfwGetWindowParam(window,GLFW_CLOSE_REQUESTED) && 
!glfwGetKey(window,GLFW_KEY_ESC);
		display();
		glfwSwapBuffers(window);
		glfwWaitEvents();
	}
	glfwTerminate();
}