etX, offsetY);
					// Canvas has changed, so flag that THREE needs to copy the new texture back to the GPU
					displacementMap.needsUpdate = true;
				}

				const terrainHeightFieldShape = Jolt.castObject(terrain.GetShape(), Jolt.HeightFieldShape);
				// Given a percentage X,Y, alter the HeightField by a fixed float amount
				function changeTerrainShape(fractionX, fractionY, amount) {
					// offset left of click and make multiple of block size
					const offsetX = Math.min(Math.max((Math.floor(fractio