src/graphics/webgl-layer.js
function(offset) {
        var index = this._indexArray,
            l = this.index_pointer;
        index[0 + l] = 0 + offset;
        index[1 + l] = 1 + offset;
        index[2 + l] = 2 + offset;
        index[3 + l] = 1 + offset;
        index[4 + l] = 2 + offset;
        index[5 + l] = 3 + offset;
        this.index_pointer += 6;
    }
function(offset) {
        var index = this._indexArray,
            l = this.index_pointer;
        index[0 + l] = 0 + offset;
        index[1 + l] = 1 + offset;
        index[2 + l] = 2 + offset;
        index[3 + l] = 1 + offset;
        index[4 + l] = 2 + offset;
        index[5 + l] = 3 + offset;
        this.index_pointer += 6;
    }
function ( offset ) { var index = this . _indexArray , l = this . index_pointer ; index [ 0 + l ] = 0 + offset ; index [ 1 + l ] = 1 + offset ; index [ 2 + l ] = 2 + offset ; index [ 3 + l ] = 1 + offset ; index [ 4 + l ] = 2 + offset ; index [ 5 + l ] = 3 + offset ; this . index_pointer += 6 ; }
adds a set of 6 indices to the index array Corresponds to 2 triangles that make up a rectangle
adds a set of 6 indices to the index array Corresponds to 2 triangles that make up a rectangle