better renderer defaults (occlusian radius, cmaera dist clipping)

src/mol-canvas3d/canvas3d.ts

@@ -188,10 +188,11 @@ namespace Canvas3D {
             let fogFar = cDist + (bRadius * fogFarFactor)
 
             if (camera.state.mode === 'perspective') {
-                near = Math.max(1, p.cameraClipDistance, near)
-                far = Math.max(1, far)
-                fogNear = Math.max(1, fogNear)
-                fogFar = Math.max(1, fogFar)
+                // set at least to 5 to avoid slow sphere impostor rendering
+                near = Math.max(5, p.cameraClipDistance, near)
+                far = Math.max(5, far)
+                fogNear = Math.max(5, fogNear)
+                fogFar = Math.max(5, fogFar)
             } else if (camera.state.mode === 'orthographic') {
                 if (p.cameraClipDistance > 0) {
                     near = Math.max(p.cameraClipDistance, near)

src/mol-canvas3d/passes/postprocessing.ts

@@ -51,7 +51,7 @@ export const PostprocessingParams = {
     occlusionEnable: PD.Boolean(false),
     occlusionKernelSize: PD.Numeric(4, { min: 1, max: 32, step: 1 }),
     occlusionBias: PD.Numeric(0.5, { min: 0, max: 1, step: 0.01 }),
-    occlusionRadius: PD.Numeric(64, { min: 0, max: 256, step: 1 }),
+    occlusionRadius: PD.Numeric(32, { min: 0, max: 256, step: 1 }),
 
     outlineEnable: PD.Boolean(false),
     outlineScale: PD.Numeric(1, { min: 0, max: 10, step: 1 }),