Fix LegacyGrid Opacity and Color

materialsLibrary/materials/grid/legacygrid.fragment.fx

@@ -1,3 +1,14 @@
-void main(void) {
+uniform vec3 mainColor;
+uniform vec4 gridControl;
+
+void main(void) {
     gl_FragColor = vec4(1, 1, 1, 0.1);
+    
+    #ifdef TRANSPARENT
+        // Min opacity as if there were no lines.
+        gl_FragColor = vec4(mainColor.rgb, 0.08);
+    #else
+        // Apply the color.
+        gl_FragColor = vec4(mainColor.rgb, 1.0);
+    #endif
 }