fix gpupick when map devicePixelRatio!==window.devicePixelRatio (#567)

* fix gpupick when map devicePixelRatio!==window.devicePixelRatio

* baseobject support cofnig pick weight

Author: deyihu

src/BaseObject.ts

@@ -11,7 +11,8 @@ const OPTIONS = {
     minZoom: 0,
     maxZoom: 30,
     asynchronous: false,
-    bloom: false
+    bloom: false,
+    pickWeight: -1
 };
 
 /**

src/GPUPick.ts

@@ -115,7 +115,11 @@ class GPUPick {
 
         //read the pixel
         const { x, y } = pixel;
-        const devicePixelRatio = window.devicePixelRatio;
+        let devicePixelRatio = window.devicePixelRatio;
+        const map = layer.getMap();
+        if (map) {
+            devicePixelRatio = map.getDevicePixelRatio ? map.getDevicePixelRatio() : map.options.devicePixelRatio;
+        }
         const offsetX = (x * devicePixelRatio), offsetY = (pickingTexture.height - y * devicePixelRatio);
         renderer.readRenderTargetPixels(pickingTexture, Math.round(offsetX), Math.round(offsetY), 1, 1, pixelBuffer);
 

src/index.ts

@@ -933,9 +933,20 @@ class ThreeLayer extends maptalks.CanvasLayer {
                 }
             }
         }
+        let pickResult = baseObjects.filter(mesh => {
+            return mesh instanceof BaseObject;
+        });
+        pickResult = pickResult.sort((a, b) => {
+            return a['options'].pickWeight - b['options'].pickWeight;
+        });
+        baseObjects.forEach(mesh => {
+            if (!(mesh instanceof BaseObject)) {
+                pickResult.push(mesh);
+            }
+        })
         options = maptalks.Util.extend({}, options);
         const count = options['count'];
-        return (maptalks.Util.isNumber(count) && count > 0 ? baseObjects.slice(0, count) : baseObjects);
+        return (maptalks.Util.isNumber(count) && count > 0 ? pickResult.slice(0, count) : baseObjects);
     }
 
     /**

src/type/BaseOption.ts

@@ -18,6 +18,7 @@ export type BaseLayerOptionType = {
 };
 
 export type BaseObjectOptionType = {
+    pickWeight?: number,
     interactive?: boolean,
     altitude?: number,
     minZoom?: number,