Transform shadow casters correctly in 3d

 */

void ShadowTessellator::generateCasterPolygon(float width, float height,

        const mat4& casterTransform, int vertexCount, Vector3* polygon) {

    Vector3 pivot(width / 2, height / 2, 0.0f);

    casterTransform.mapPoint3d(pivot);

    // TODO: The zScaleFactor need to be mapped to the screen.

    float zScaleFactor = 0.5;

    Rect blockRect(pivot.x - width * zScaleFactor, pivot.y - height * zScaleFactor,

            pivot.x + width * zScaleFactor, pivot.y + height * zScaleFactor);

    // Generate the caster's polygon from the rect.

    Rect blockRect(0, 0, width, height);

    polygon[0].x = blockRect.left;

    polygon[0].y = blockRect.top;

    polygon[0].z = pivot.z;

    polygon[0].z = 0;

    polygon[1].x = blockRect.right;

    polygon[1].y = blockRect.top;

    polygon[1].z = pivot.z;

    polygon[1].z = 0;

    polygon[2].x = blockRect.right;

    polygon[2].y = blockRect.bottom;

    polygon[2].z = pivot.z;

    polygon[2].z = 0;

    polygon[3].x = blockRect.left;

    polygon[3].y = blockRect.bottom;

    polygon[3].z = pivot.z;

    polygon[3].z = 0;

    casterTransform.mapPoint3d(polygon[0]);

    casterTransform.mapPoint3d(polygon[1]);

    casterTransform.mapPoint3d(polygon[2]);

    casterTransform.mapPoint3d(polygon[3]);

}

void ShadowTessellator::tessellateAmbientShadow(float width, float height,