新增webgl帮助类 用于自定义绘图

source/src/AI/Pathfinding/Dijkstra/WeightedPathfinder.ts

@@ -38,7 +38,7 @@ class WeightedPathfinder {
                 }
             });
         }
-
+        
         return foundPath ? this.recontructPath(cameFrom, start, goal) : null;
     }
 

source/src/Utils/WebGLUtils.ts

@@ -0,0 +1,44 @@
+class WebGLUtils {
+    public static getWebGL(): WebGLRenderingContext{
+        return document.querySelector("canvas").getContext("webgl");
+    }
+
+    public static drawUserIndexPrimitives<T>(primitiveType: number, vertexData: T[], vertexOffset: number, numVertices: number, indexData: number[], indexOffset: number, primitiveCount: number){
+        let GL = this.getWebGL();
+
+        GL.bindBuffer(GL.ARRAY_BUFFER, 0);
+        this.checkGLError();
+        GL.bindBuffer(GL.ELEMENT_ARRAY_BUFFER, 0);
+        this.checkGLError();
+
+        GL.drawElements(primitiveType, 
+            this.getElementCountArray(primitiveType, primitiveCount), 
+            GL.UNSIGNED_SHORT, 
+            indexOffset * 2);
+        this.checkGLError();
+    }
+
+    private static getElementCountArray(primitiveType: number, primitiveCount: number){
+        let GL = this.getWebGL();
+        switch (primitiveType){
+            case GL.LINES:
+                return primitiveCount * 2;
+            case GL.LINE_STRIP:
+                return primitiveCount + 1;
+            case GL.TRIANGLES:
+                return primitiveCount * 3;
+            case GL.TRIANGLE_STRIP:
+                return primitiveCount + 2;
+        }
+
+        throw new Error("not support");
+    }
+
+    public static checkGLError(){
+        let GL = this.getWebGL();
+        let error = GL.getError();
+        if (error != GL.NO_ERROR){
+            throw new Error("GL.GetError() returned" + error);
+        }
+    }
+}