_getWorldCoords() {
        const corners = [
            tempCorner1.set(-1, 1, 0), // plane's top left corner
            tempCorner2.set(1, 1, 0), // plane's top right corner
            tempCorner3.set(1, -1, 0), // plane's bottom right corner
            tempCorner4.set(-1, -1, 0), // plane's bottom left corner
        ];

        // corners with model view projection matrix applied
        let mvpCorners = [];
        // eventual clipped corners
        let clippedCorners = [];

        // we are going to get our plane's four corners relative to our model view projection matrix
        for(let i = 0; i < corners.length; i++) {
            const mvpCorner = corners[i].applyMat4(this._matrices.modelViewProjection.matrix);
            mvpCorners.push(mvpCorner);

            // Z position is > 1 or < -1 means the corner is clipped
            if(Math.abs(mvpCorner.z) > 1) {
                clippedCorners.push(i);
            }
        }

        // near plane is clipping, get intersections between plane and near plane
        if(clippedCorners.length) {
            mvpCorners = this._getNearPlaneIntersections(corners, mvpCorners, clippedCorners);
        }

        // we need to check for the X and Y min and max values
        // use arbitrary integers that will be overriden anyway
        let minX = Infinity;
        let maxX = -Infinity;

        let minY = Infinity;
        let maxY = -Infinity;

        for(let i = 0; i < mvpCorners.length; i++) {
            const corner = mvpCorners[i];

            if(corner.x < minX) {
                minX = corner.x;
            }
            if(corner.x > maxX) {
                maxX = corner.x;
            }

            if(corner.y < minY) {
                minY = corner.y;
            }
            if(corner.y > maxY) {
                maxY = corner.y;
            }
        }

        return {
            top: maxY,
            right: maxX,
            bottom: minY,
            left: minX,
        };
    }
Useful to get our WebGL plane bounding box in the world space
     Takes all transformations into account
     Used internally for frustum culling

     returns :
     @boundingRectangle (obj): an object containing our plane WebGL element 4 corners coordinates: top left corner is [-1, 1] and bottom right corner is [1, -1]
*