from OpenGL.GL import *
from OpenGL.arrays import vbo
from OpenGL.GL import shaders

import wx
import wx.glcanvas

class MyCanvas(wx.glcanvas.GLCanvas):
    def __init__(self, parent):
        wx.glcanvas.GLCanvas.__init__(self, parent)

        VERTEX_SHADER = shaders.compileShader("""#version 330
        void main() {
            gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
        }""", GL_VERTEX_SHADER)
        FRAGMENT_SHADER = shaders.compileShader("""#version 330
        void main() {
            gl_FragColor = vec4( 0, 1, 0, 1 );
        }""", GL_FRAGMENT_SHADER)
        self.shader = shaders.compileProgram(VERTEX_SHADER,FRAGMENT_SHADER)
        self.vbo = vbo.VBO(
            array( [
                [  0, 1, 0 ],
                [ -1,-1, 0 ],
                [  1,-1, 0 ],
                [  2,-1, 0 ],
                [  4,-1, 0 ],
                [  4, 1, 0 ],
                [  2,-1, 0 ],
                [  4, 1, 0 ],
                [  2, 1, 0 ],
            ],'f')
        )
        wx.EVT_PAINT(self, self.OnPaint)
        self.haveInited = False
        self.context = wx.glcanvas.GLContext(self)

    def OnPaint( self, mode):
        if not self.haveInited:
            self.SetCurrent(self.context)
            glClearColor(.3, .3, .3, 0)
            self.haveInited = True
        shaders.glUseProgram(self.shader)
        try:
            self.vbo.bind()
            try:
                glEnableClientState(GL_VERTEX_ARRAY);
                glVertexPointerf( self.vbo )
                glDrawArrays(GL_TRIANGLES, 0, 9)
            finally:
                self.vbo.unbind()
                glDisableClientState(GL_VERTEX_ARRAY);
        finally:
            shaders.glUseProgram( 0 )

class MyApp(wx.App):
    def OnInit(self):
        frame = wx.Frame(None)
        canvas = MyCanvas(frame)
        frame.Show()
        return True
MyApp(redirect = False).MainLoop()