fix black artifacts

- on specular highlights with transparent background

CHANGELOG.md

@@ -9,6 +9,7 @@ Note that since we don't clearly distinguish between a public and private interf
 - Optimize BinaryCIF integer packing encoder
 - Fix Dual depth peeling when post-processing is off or when rendering direct-volumes
 - Add `cameraClipping.minNear` parameter
+- Fix black artifacts on specular highlights with transparent background
 
 ## [v3.18.0] - 2022-09-17
 

src/mol-canvas3d/passes/smaa.ts

@@ -74,6 +74,7 @@ export class SmaaPass {
         state.viewport(x, y, width, height);
         state.scissor(x, y, width, height);
 
+        state.colorMask(true, true, true, true);
         state.clearColor(0, 0, 0, 1);
         gl.clear(gl.COLOR_BUFFER_BIT);
 

src/mol-gl/shader/chunks/apply-light-color.glsl.ts

@@ -57,6 +57,7 @@ export const apply_light_color = `
     RE_IndirectSpecular_Physical(radiance, iblIrradiance, clearcoatRadiance, geometry, physicalMaterial, reflectedLight);
 
     vec3 outgoingLight = reflectedLight.directDiffuse + reflectedLight.indirectDiffuse + reflectedLight.directSpecular + reflectedLight.indirectSpecular;
+    outgoingLight = clamp(outgoingLight, 0.0, 1.0); // prevents black artifacts on specular highlight with transparent background
 
     gl_FragColor = vec4(outgoingLight, color.a);
 #endif