Convenience functions for creating matrices

kitty/shaders.py

@@ -18,6 +18,42 @@ def array(*args, dtype=gl.GLfloat):
     return (dtype * len(args))(*args)
 
 
+def translation_matrix(x, y):
+    return array(
+        1, 0, x,
+        0, 1, y,
+        0, 0, 1
+    )
+
+
+def scaling_matrix(x, y):
+    return array(
+        x, 0, 0,
+        0, y, 0,
+        0, 0, 1
+    )
+
+
+def multiply(a, b):
+    # 0 1 2
+    # 3 4 5
+    # 6 7 8
+    return array(
+        # Row 1
+        a[0] * b[0] + a[1] * b[3] + a[2] * b[6],
+        a[0] * b[1] + a[1] * b[4] + a[2] * b[7],
+        a[0] * b[2] + a[1] * b[5] + a[2] * b[8],
+        # Row 2
+        a[3] * b[0] + a[4] * b[3] + a[5] * b[6],
+        a[3] * b[1] + a[4] * b[4] + a[5] * b[7],
+        a[3] * b[2] + a[4] * b[5] + a[5] * b[8],
+        # Row 3
+        a[6] * b[0] + a[7] * b[3] + a[8] * b[6],
+        a[6] * b[1] + a[7] * b[4] + a[8] * b[7],
+        a[6] * b[2] + a[7] * b[5] + a[8] * b[8]
+    )
+
+
 class Sprites:
     ''' Maintain sprite sheets of all rendered characters on the GPU as a texture
     array with each texture being a sprite sheet. '''