skip SSAO texture read if SSAO is disabled

filament/src/PerViewUniforms.cpp

@@ -168,7 +168,7 @@ void PerViewUniforms::prepareSSAO(Handle<HwTexture> ssao,
     const float edgeDistance = 1.0f / options.bilateralThreshold;
     auto& s = mUniforms.edit();
     s.aoSamplingQualityAndEdgeDistance =
-            options.enabled && highQualitySampling ? edgeDistance : 0.0f;
+            options.enabled ? (highQualitySampling ? edgeDistance : 0.0f) : -1.0f;
     s.aoBentNormals = options.enabled && options.bentNormals ? 1.0f : 0.0f;
 }
 

libs/filabridge/include/private/filament/UibStructs.h

@@ -83,7 +83,7 @@ struct PerViewUib { // NOLINT(cppcoreguidelines-pro-type-member-init)
     float needsAlphaChannel;
 
     // AO
-    float aoSamplingQualityAndEdgeDistance;     // 0: bilinear, !0: bilateral edge distance
+    float aoSamplingQualityAndEdgeDistance;     // <0: no AO, 0: bilinear, !0: bilateral edge distance
     float aoBentNormals;                        // 0: no AO bent normal, >0.0 AO bent normals
     float aoReserved0;
     float aoReserved1;

shaders/src/ambient_occlusion.fs

@@ -25,6 +25,12 @@ struct SSAOInterpolationCache {
 
 float evaluateSSAO(inout SSAOInterpolationCache cache) {
 #if defined(BLEND_MODE_OPAQUE) || defined(BLEND_MODE_MASKED)
+
+    if (frameUniforms.aoSamplingQualityAndEdgeDistance < 0.0) {
+        // SSAO is disabled
+        return 1.0;
+    }
+
     // Upscale the SSAO buffer in real-time, in high quality mode we use a custom bilinear
     // filter. This adds about 2.0ms @ 250MHz on Pixel 4.