don't set doubleSided=true when alpha<1 in getQualityProps

src/mol-repr/util.ts

@@ -51,6 +51,7 @@ export interface QualityProps {
     linearSegments: number
     resolution: number
     doubleSided: boolean
+    alpha: number
 }
 
 export const DefaultQualityThresholds = {
@@ -151,6 +152,10 @@ export function getQualityProps(props: Partial<QualityProps>, data?: any) {
             break;
     }
 
+    if (props.alpha !== undefined && props.alpha < 1) {
+        doubleSided = false;
+    }
+
     return {
         detail,
         radialSegments,