Fix syntax and bump the error allowance

Author: DD Liu

src/Drawable.js

@@ -13,6 +13,7 @@ const log = require('./util/log');
  * @type {twgl.v3}
  */
 const __isTouchingPosition = twgl.v3.create();
+const FLOATING_POINT_ERROR_ALLOWANCE = 1e-6;
 
 /**
  * Convert a scratch space location into a texture space float.  Uses the
@@ -37,6 +38,10 @@ const getLocalPosition = (drawable, vec) => {
     // localPosition matches that transformation.
     localPosition[0] = 0.5 - (((v0 * m[0]) + (v1 * m[4]) + m[12]) / d);
     localPosition[1] = (((v0 * m[1]) + (v1 * m[5]) + m[13]) / d) + 0.5;
+    // Fix floating point issues near 0.
+    // TODO: Check if this can be removed after render pull 479 is merged
+    if (Math.abs(localPosition[0]) < FLOATING_POINT_ERROR_ALLOWANCE) localPosition[0] = 0;
+    if (Math.abs(localPosition[1]) < FLOATING_POINT_ERROR_ALLOWANCE) localPosition[1] = 0;
     // Apply texture effect transform if the localPosition is within the drawable's space,
     // and any effects are currently active.
     if (drawable.enabledEffects !== 0 &&