diff --git a/src/runtime/colour.ts b/src/runtime/colour.ts
index 382d03c..b2a6b63 100644
--- a/src/runtime/colour.ts
+++ b/src/runtime/colour.ts
@@ -88,11 +88,12 @@ export namespace RGBAUtil {
     }
 
     export function lerp(a: RGBA, b: RGBA, alpha: number) {
+        const invAlpha = 1 - alpha;
         return {
-            r: a.r * (1 - alpha) + b.r * alpha,
-            g: a.g * (1 - alpha) + b.g * alpha,
-            b: a.b * (1 - alpha) + b.b * alpha,
-            a: a.a * (1 - alpha) + b.a * alpha,
+            r: a.r * invAlpha + b.r * alpha,
+            g: a.g * invAlpha + b.g * alpha,
+            b: a.b * invAlpha + b.b * alpha,
+            a: a.a * invAlpha + b.a * alpha,
         };
     }
 
diff --git a/src/runtime/texture.ts b/src/runtime/texture.ts
index e7d4e1d..cb84143 100644
--- a/src/runtime/texture.ts
+++ b/src/runtime/texture.ts
@@ -143,13 +143,15 @@ export class Texture {
             return RGBAColours.MAGENTA;
         }
 
-        const A = Texture._sampleImage(xLeft, yUp, image);
-        const B = Texture._sampleImage(xRight, yUp, image);
-        const AB = RGBAUtil.lerp(A, B, u);
+        const top = Texture._sampleImagePair(xLeft, yUp, image);
+        //const A = Texture._sampleImage(xLeft, yUp, image);
+        //const B = Texture._sampleImage(xRight, yUp, image);
+        const AB = RGBAUtil.lerp(top.left, top.right, u);
 
-        const C = Texture._sampleImage(xLeft, yDown, image);
-        const D = Texture._sampleImage(xRight, yDown, image);
-        const CD = RGBAUtil.lerp(C, D, u);
+        const bottom = Texture._sampleImagePair(xLeft, yDown, image);
+        //const C = Texture._sampleImage(xLeft, yDown, image);
+        //const D = Texture._sampleImage(xRight, yDown, image);
+        const CD = RGBAUtil.lerp(bottom.left, bottom.right, u);
 
         return RGBAUtil.lerp(AB, CD, v);
     }
@@ -209,6 +211,30 @@ export class Texture {
             a: image.data[index + 3] / 255,
         };
     }
+
+    private static _sampleImagePair(x: number, y: number, image: ImageData) {
+        const cx1 = clamp(x, 0, image.width - 1);
+        const cx2 = clamp(x + 1, 0, image.width - 1);
+        const cy = clamp(y, 0, image.height - 1);
+
+        const index1 = 4 * (image.width * cy + cx1);
+        const index2 = 4 * (image.width * cy + cx2);
+
+        return {
+            left: {
+                r: image.data[index1 + 0] / 255,
+                g: image.data[index1 + 1] / 255,
+                b: image.data[index1 + 2] / 255,
+                a: image.data[index1 + 3] / 255,
+            },
+            right: {
+                r: image.data[index2 + 0] / 255,
+                g: image.data[index2 + 1] / 255,
+                b: image.data[index2 + 2] / 255,
+                a: image.data[index2 + 3] / 255,
+            }
+        };
+    }
 }
 
 export class TextureConverter {