fix potential issue in case alpha is set to 0 (should not be rendered…

… at all)

Signed-off-by: Tim Deubler <tim.deubler@here.com>

packages/display/src/displays/webgl/buffer/FeatureFactory.ts

@@ -170,7 +170,7 @@ export class FeatureFactory {
 
     private toRGBA(color: Color, alpha: number = 1, premultiplyAlpha: boolean = true): RGBA {
         const rgba = Array.isArray(color)
-            ? [color[0], color[1], color[2], color[3]??1] as RGBA
+            ? [color[0], color[1], color[2], typeof color[3] == 'number' ? color[3] : 1] as RGBA
             : toRGB(color);
         if (rgba) {
             alpha = rgba[3] *= alpha;