Determine pixel-to-texel ratio for each sprite individually.

This fixes rendering artifacts when sprites are scaled > 1.

OpenRA.Game/Graphics/SpriteRenderer.cs

@@ -253,9 +253,9 @@ namespace OpenRA.Graphics
 			shader.SetVec("DepthPreviewParams", contrast, offset);
 		}
 
-		public void SetAntialiasingPixelsPerTexel(float pxPerTx)
+		public void EnablePixelArtScaling(bool enabled)
 		{
-			shader.SetVec("AntialiasPixelsPerTexel", pxPerTx);
+			shader.SetBool("EnablePixelArtScaling", enabled);
 		}
 	}
 }