Refactor common layer code

Let individual layers define optional event callbacks in the events block. Trigger "LayerInit" and "LayerRemove" in the common layer's template init and remove method respectively.
craftyjs · May 17, 2017 · f215288 · f215288
1 parent 0bdae16
commit f215288
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Showing 4 changed files with 54 additions and 55 deletions.
diff --git a/src/graphics/canvas-layer.js b/src/graphics/canvas-layer.js
@@ -93,9 +93,21 @@ Crafty._registerLayerTemplate("Canvas", {
      */
      _canvas: null,
 
+    events: {
+        // Respond to init & remove events
+        "LayerInit": "layerInit",
+        "LayerRemove": "layerRemove",
+        // Bind scene rendering (see drawing.js)
+        "RenderScene": "_render",
+        // Listen for pixelart changes
+        "PixelartSet": "_setPixelart",
+        // Handle viewport modifications
+        "ViewportResize": "_resize"
+    },
+
     // When the system is first created, create the necessary canvas element and initial state
     // Bind to the necessary events
-    init: function () {
+    layerInit: function () {
         //check if canvas is supported
         if (!Crafty.support.canvas) {
             Crafty.trigger("NoCanvas");
@@ -133,7 +145,7 @@ Crafty._registerLayerTemplate("Canvas", {
     },
 
     // When the system is destroyed, remove related resources
-    remove: function() {
+    layerRemove: function() {
         this._canvas.parentNode.removeChild(this._canvas);
     },
 

diff --git a/src/graphics/dom-layer.js b/src/graphics/dom-layer.js
@@ -24,7 +24,20 @@ Crafty._registerLayerTemplate("DOM", {
      */
     _div: null,
 
-    init: function () {
+    events: {
+        // Respond to init & remove events
+        "LayerInit": "layerInit",
+        "LayerRemove": "layerRemove",
+        // Bind scene rendering (see drawing.js)
+        "RenderScene": "_render",
+        // Listen for pixelart changes
+        "PixelartSet": "_setPixelart"
+        // Layers should generally listen for resize events,
+        // but the DOM layers automatically inherit the stage's dimensions
+        //"ViewportResize": "_resize"
+    },
+
+    layerInit: function () {
         // Avoid shared state between systems
         this._changedObjs = [];
 
@@ -38,15 +51,10 @@ Crafty._registerLayerTemplate("DOM", {
     },
 
     // Cleanup the DOM when the layer is destroyed
-    remove: function() {
+    layerRemove: function() {
         this._div.parentNode.removeChild(this._div);
     },
 
-    // Layers should generally listen for resize events,
-    // but the DOM layers automatically inherit the stage's dimensions
-    _resize: function() {
-    },
-
     // Handle whether images should be smoothed or not
     _setPixelArt: function(enabled) {
         var style = this._div.style;

diff --git a/src/graphics/layers.js b/src/graphics/layers.js
@@ -20,24 +20,6 @@ Crafty.extend({
         this._drawLayerTemplates[type] = layerTemplate;
         var common = this._commonLayerProperties;
 
-        // merge inits
-        if (typeof layerTemplate.init === 'function') {
-            var layerInit = layerTemplate.init;
-            var commonInit = common.init;
-            layerTemplate.init = function() {
-                layerInit.call(this);
-                commonInit.call(this);
-            };
-        }
-        // merge removes
-        if (typeof layerTemplate.remove === 'function') {
-            var layerRemove = layerTemplate.remove;
-            var commonRemove = common.remove;
-            layerTemplate.remove = function() {
-                layerRemove.call(this);
-                commonRemove.call(this);
-            };
-        }
         // add common properties, don't overwrite existing ones
         for (var key in common) {
             if (layerTemplate[key]) continue;
@@ -63,41 +45,26 @@ Crafty.extend({
         // A cached version of the viewport rect
         _cachedViewportRect: null,
 
-        // This init code will be run after any other specific layer init code
+
         init: function() {
             this._cachedViewportRect = {};
 
-            // Handle viewport modifications
-            this.uniqueBind("ViewportResize", this._resize);
-            this.uniqueBind("InvalidateViewport", function () {
-                this._dirtyViewport = true;
-            });
+            // Trigger layer-specific init code
+            Crafty.trigger("LayerInit");
 
-            // Bind scene rendering (see drawing.js)
-            this.uniqueBind("RenderScene", this._render);
-
-            // Set pixelart to current status, and listen for changes
-            this._setPixelart(Crafty._pixelartEnabled);
-            this.uniqueBind("PixelartSet", this._setPixelart);
+            // Handle viewport invalidation
+            this.uniqueBind("InvalidateViewport", function () { this._dirtyViewport = true; });
+            // Set pixelart to current status
+            this.trigger("PixelartSet", Crafty._pixelartEnabled);
 
             Crafty._addDrawLayerInstance(this);
         },
-        // This remove code will be run after any other specific layer remove code
+
         remove: function() {
-            Crafty._removeDrawLayerInstance(this);
-        },
+            // Trigger layer-specific remove code
+            Crafty.trigger("LayerRemove");
 
-        _resize: function() {
-            // per default, do nothing
-            // specific layer should overwrite this method
-        },
-        _setPixelart: function(enabled) {
-            // per default, do nothing
-            // specific layer should overwrite this method
-        },
-        _render: function() {
-            // per default, render nothing
-            // specific layer should overwrite this method
+            Crafty._removeDrawLayerInstance(this);
         },
 
         // Sort function for rendering in the correct order

diff --git a/src/graphics/webgl-layer.js b/src/graphics/webgl-layer.js
@@ -256,7 +256,19 @@ Crafty._registerLayerTemplate("WebGL", {
         return this.texture_manager.makeTexture(url, image, repeating);
     },
 
-    init: function() {
+    events: {
+        // Respond to init & remove events
+        "LayerInit": "layerInit",
+        "LayerRemove": "layerRemove",
+        // Bind scene rendering (see drawing.js)
+        "RenderScene": "_render",
+        // Listen for pixelart changes
+        "PixelartSet": "_setPixelart",
+        // Handle viewport modifications
+        "ViewportResize": "_resize"
+    },
+
+    layerInit: function() {
 
         //check if we support webgl is supported
         if (!Crafty.support.webgl) {
@@ -311,7 +323,7 @@ Crafty._registerLayerTemplate("WebGL", {
     },
 
     // Cleanup the DOM when the system is destroyed
-    remove: function() {
+    layerRemove: function() {
         this._canvas.parentNode.removeChild(this._canvas);
     },