OpenGL Spinning Triangle With GLFW

From IronPython Cookbook

This example demonstrates how to use Tao with the GLFW binding to initialize an OpenGL context and render a spinning triangle. This example has been adapted from the Tao example which lies under a MIT license.

This has been tested with:

• IronPython 2.0Alpha8 (the original distribution)
• mono 1.2.6 under Ubuntu
• tao 2.0.0 (binary distribution deployed in the gac)
• GLFW 2.6

# -*- coding: utf-8 -*-
import clr
clr.AddReference('Tao.Glfw')
clr.AddReference('Tao.OpenGl')
from Tao.Glfw import Glfw
from Tao.OpenGl import Gl, Glu

def run():
    Glfw.glfwInit()
    
    if not Glfw.glfwOpenWindow(640, 480, 0, 0, 0, 0, 0, 0, Glfw.GLFW_WINDOW):
        Glfw.glfwTerminate()
        return 2
    
    Glfw.glfwEnable(Glfw.GLFW_STICKY_KEYS)
    Glfw.glfwSwapInterval(0)

    running = True
    frame_count = 0
    start_time = Glfw.glfwGetTime()

    while running:
        current_time = Glfw.glfwGetTime()
        coordinates = Glfw.glfwGetMousePos()

        #Calculate and display FPS (frames per second)
        if (current_time - start_time) > 1 or frame_count == 0:
            frame_rate = frame_count / (current_time - start_time);
            Glfw.glfwSetWindowTitle("Spinning Triangle (%d FPS)" % frame_rate)
            start_time = current_time
            frame_count = 0
                
        frame_count = frame_count + 1

        window_dim = Glfw.glfwGetWindowSize()
        if window_dim[1] > 0:
            height = window_dim[1]
        else:
            height = 1

        # Set viewport
        Gl.glViewport(0, 0, window_dim[0], height)

        # Clear color buffer
        Gl.glClearColor(0, 0, 0, 0)
        Gl.glClear(Gl.GL_COLOR_BUFFER_BIT)

        # Select and setup the projection matrix
        Gl.glMatrixMode(Gl.GL_PROJECTION)
        Gl.glLoadIdentity()
        Glu.gluPerspective(65, window_dim[0]/height, 1, 100)

        # Select and setup the modelview matrix
        Gl.glMatrixMode(Gl.GL_MODELVIEW)
        Gl.glLoadIdentity()
        Glu.gluLookAt(0, 1, 0, 0, 20, 0, 0, 0, 1)

        # Draw a rotating colorful triangle
        Gl.glTranslatef(0, 14, 0)
        Gl.glRotatef(1/3 * float(coordinates[0]) + float(current_time) * 100,
                     0, 0, 1)
        Gl.glBegin(Gl.GL_TRIANGLES)
        Gl.glColor3f(1, 0, 0)
        Gl.glVertex3f(-5, 0, -4)
        Gl.glColor3f(0, 1, 0)
        Gl.glVertex3f(5, 0, -4)
        Gl.glColor3f(0, 0, 1)
        Gl.glVertex3f(0, 0, 6)
        Gl.glEnd();

        Glfw.glfwSwapBuffers()
        running = ((Glfw.glfwGetKey(Glfw.GLFW_KEY_ESC) == Glfw.GLFW_RELEASE) and
                   Glfw.glfwGetWindowParam(Glfw.GLFW_OPENED) == Gl.GL_TRUE)

    
    Glfw.glfwTerminate()

if __name__ == '__main__':
    run()

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