add allowTransparentBackfaces parameter

- for mesh, spheres, cylinders, texture-mesh geometries

CHANGELOG.md

@@ -12,6 +12,7 @@ Note that since we don't clearly distinguish between a public and private interf
 - Fix unit mapping in bondedAtomicPairs MolScript query
 - Improve pdb parsing: handle non unique atom and chain names (fixes #156)
 - Fix volume streaming for entries with multiple contour lists
+- Add ``allowTransparentBackfaces`` parameter to support double-sided rendering of transparent geometries
 
 ## [v3.5.0] - 2022-03-25
 

src/mol-geo/geometry/cylinders/cylinders.ts

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2020 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ * Copyright (c) 2020-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  */
@@ -157,6 +157,7 @@ export namespace Cylinders {
         doubleSided: PD.Boolean(false, BaseGeometry.CustomQualityParamInfo),
         ignoreLight: PD.Boolean(false, BaseGeometry.ShadingCategory),
         xrayShaded: PD.Boolean(false, BaseGeometry.ShadingCategory),
+        allowTransparentBackfaces: PD.Boolean(false, BaseGeometry.ShadingCategory),
         bumpFrequency: PD.Numeric(0, { min: 0, max: 10, step: 0.1 }, BaseGeometry.ShadingCategory),
         bumpAmplitude: PD.Numeric(1, { min: 0, max: 5, step: 0.1 }, BaseGeometry.ShadingCategory),
     };

src/mol-geo/geometry/mesh/mesh.ts

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2018-2021 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ * Copyright (c) 2018-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  * @author David Sehnal <david.sehnal@gmail.com>
@@ -625,6 +625,7 @@ export namespace Mesh {
         flatShaded: PD.Boolean(false, BaseGeometry.ShadingCategory),
         ignoreLight: PD.Boolean(false, BaseGeometry.ShadingCategory),
         xrayShaded: PD.Boolean(false, BaseGeometry.ShadingCategory),
+        allowTransparentBackfaces: PD.Boolean(false, BaseGeometry.ShadingCategory),
         bumpFrequency: PD.Numeric(0, { min: 0, max: 10, step: 0.1 }, BaseGeometry.ShadingCategory),
         bumpAmplitude: PD.Numeric(1, { min: 0, max: 5, step: 0.1 }, BaseGeometry.ShadingCategory),
     };

src/mol-geo/geometry/spheres/spheres.ts

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2019-2020 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ * Copyright (c) 2019-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  */
@@ -129,6 +129,7 @@ export namespace Spheres {
         doubleSided: PD.Boolean(false, BaseGeometry.CustomQualityParamInfo),
         ignoreLight: PD.Boolean(false, BaseGeometry.ShadingCategory),
         xrayShaded: PD.Boolean(false, BaseGeometry.ShadingCategory),
+        allowTransparentBackfaces: PD.Boolean(false, BaseGeometry.ShadingCategory),
         bumpFrequency: PD.Numeric(0, { min: 0, max: 10, step: 0.1 }, BaseGeometry.ShadingCategory),
         bumpAmplitude: PD.Numeric(1, { min: 0, max: 5, step: 0.1 }, BaseGeometry.ShadingCategory),
     };

src/mol-geo/geometry/texture-mesh/texture-mesh.ts

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2019-2021 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ * Copyright (c) 2019-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  */
@@ -113,6 +113,7 @@ export namespace TextureMesh {
         flatShaded: PD.Boolean(false, BaseGeometry.ShadingCategory),
         ignoreLight: PD.Boolean(false, BaseGeometry.ShadingCategory),
         xrayShaded: PD.Boolean(false, BaseGeometry.ShadingCategory),
+        allowTransparentBackfaces: PD.Boolean(false, BaseGeometry.ShadingCategory),
         bumpFrequency: PD.Numeric(0, { min: 0, max: 10, step: 0.1 }, BaseGeometry.ShadingCategory),
         bumpAmplitude: PD.Numeric(1, { min: 0, max: 5, step: 0.1 }, BaseGeometry.ShadingCategory),
     };

src/mol-gl/shader/chunks/wboit-write.glsl.ts

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2019-2020 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ * Copyright (c) 2019-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  * @author Áron Samuel Kovács <aron.kovacs@mail.muni.cz>
@@ -13,7 +13,7 @@ export const wboit_write = `
         }
     } else if (uRenderWboit) {
         // the 'fragmentDepth > 0.99' check is to handle precision issues with packed depth
-        if (preFogAlpha != 1.0 && !interior && (fragmentDepth < getDepth(gl_FragCoord.xy / uDrawingBufferSize) || fragmentDepth > 0.99)) {
+        if (preFogAlpha != 1.0 && (!interior || uDoubleSided) && (fragmentDepth < getDepth(gl_FragCoord.xy / uDrawingBufferSize) || fragmentDepth > 0.99)) {
             float alpha = gl_FragColor.a;
             float wboitWeight = alpha * clamp(pow(1.0 - fragmentDepth, 2.0), 0.01, 1.0);
             gl_FragColor = vec4(gl_FragColor.rgb * alpha * wboitWeight, alpha);

src/mol-repr/util.ts

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2018-2021 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ * Copyright (c) 2018-2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  */
@@ -57,6 +57,7 @@ export interface QualityProps {
     doubleSided: boolean
     xrayShaded: boolean
     alpha: number
+    allowTransparentBackfaces: boolean
 }
 
 export const DefaultQualityThresholds = {
@@ -192,7 +193,7 @@ export function getQualityProps(props: Partial<QualityProps>, data?: any) {
     resolution = Math.max(resolution, volume / 500_000_000);
     resolution = Math.min(resolution, 20);
 
-    if ((props.alpha !== undefined && props.alpha < 1) || !!props.xrayShaded) {
+    if (!props.allowTransparentBackfaces && ((props.alpha !== undefined && props.alpha < 1) || !!props.xrayShaded)) {
         doubleSided = false;
     }