Fix silhouette sampling math

Author: adroitwhiz

src/Silhouette.js

@@ -126,8 +126,8 @@ class Silhouette {
     colorAtNearest (vec, dst) {
         return getColor4b(
             this,
-            Math.floor(vec[0] * (this._width - 1)),
-            Math.floor(vec[1] * (this._height - 1)),
+            Math.round(vec[0] * this._width),
+            Math.round(vec[1] * this._height),
             dst
         );
     }
@@ -140,8 +140,8 @@ class Silhouette {
      * @returns {Uint8ClampedArray} dst
      */
     colorAtLinear (vec, dst) {
-        const x = vec[0] * (this._width - 1);
-        const y = vec[1] * (this._height - 1);
+        const x = vec[0] * this._width;
+        const y = vec[1] * this._height;
 
         const x1D = x % 1;
         const y1D = y % 1;
@@ -173,8 +173,8 @@ class Silhouette {
         if (!this._colorData) return;
         return getPoint(
             this,
-            Math.floor(vec[0] * (this._width - 1)),
-            Math.floor(vec[1] * (this._height - 1))
+            Math.round(vec[0] * this._width),
+            Math.round(vec[1] * this._height)
         ) > 0;
     }
 
@@ -186,8 +186,8 @@ class Silhouette {
      */
     isTouchingLinear (vec) {
         if (!this._colorData) return;
-        const x = Math.floor(vec[0] * (this._width - 1));
-        const y = Math.floor(vec[1] * (this._height - 1));
+        const x = Math.round(vec[0] * this._width);
+        const y = Math.round(vec[1] * this._height);
         return getPoint(this, x, y) > 0 ||
             getPoint(this, x + 1, y) > 0 ||
             getPoint(this, x, y + 1) > 0 ||

src/playground/playground.js

@@ -5,6 +5,7 @@ const canvas = document.getElementById('scratch-stage');
 let fudge = 90;
 const renderer = new ScratchRender(canvas);
 renderer.setLayerGroupOrdering(['group1']);
+window.renderer = renderer;
 
 const drawableID = renderer.createDrawable('group1');
 renderer.updateDrawableProperties(drawableID, {
@@ -45,7 +46,7 @@ xhr.addEventListener('load', function () {
         });
     }
 });
-xhr.open('GET', 'https://cdn.assets.scratch.mit.edu/internalapi/asset/b7853f557e4426412e64bb3da6531a99.svg/get/');
+xhr.open('GET', 'https://cdn.assets.scratch.mit.edu/internalapi/asset/7e4d03ea982f865367dfc821108bf59f.svg/get/');
 xhr.send();
 
 if (wantedSkin === WantedSkinType.pen) {