Added a very simple light source so the 3D models now have simple shading applied to them.

engine.py

@@ -1,5 +1,6 @@
 from vectors import Vector2d, Vector3d, Vector4d
 from matrix import Matrix3x3
+from triangle import Triangle
 
 class Engine:
 	def __init__(self, width, height):
@@ -40,7 +41,5 @@ class Mesh:
 				row0 = self.vertices[int(tmp[1]) - 1]
 				row1 = self.vertices[int(tmp[2]) - 1]
 				row2 = self.vertices[int(tmp[3]) - 1]
-				
-				tri = Matrix3x3(row0, row1, row2)
 
-				self.triangles.append(tri)#Vector3d(x - 1, y - 1, z - 1))				
+				self.triangles.append(Triangle(Matrix3x3(row0, row1, row2)))