From 33949281128a39663ac975de4685c2807cb5ac1c Mon Sep 17 00:00:00 2001
From: JoseEmilio-ARM <33630720+JoseEmilio-ARM@users.noreply.github.com>
Date: Thu, 7 Apr 2022 15:35:38 +0100
Subject: [PATCH] Update scene.frag

Ray Query example: shader optimization

Calling rayQueryProceedEXT in a loop can prevent certain shader optimizations. By setting the TerminateOnFirstHit and SkipAABB flags, there is no scenario where rayQueryProceedEXT will return true, hence the loop can be removed.

This way the implementation has a guarantee that the traversal can be completed without returning control to the shader, which improves performance.
---
 data/shaders/glsl/rayquery/scene.frag | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/data/shaders/glsl/rayquery/scene.frag b/data/shaders/glsl/rayquery/scene.frag
index edbd3617..059fc4d3 100644
--- a/data/shaders/glsl/rayquery/scene.frag
+++ b/data/shaders/glsl/rayquery/scene.frag
@@ -25,10 +25,10 @@ void main()
 	outFragColor = vec4(diffuse, 1.0);
 
 	rayQueryEXT rayQuery;
-	rayQueryInitializeEXT(rayQuery, topLevelAS, gl_RayFlagsTerminateOnFirstHitEXT, 0xFF, inWorldPos, 0.01, L, 1000.0);
+	rayQueryInitializeEXT(rayQuery, topLevelAS, gl_RayFlagsTerminateOnFirstHitEXT | gl_RayFlagsSkipAABBEXT, 0xFF, inWorldPos, 0.01, L, 1000.0);
 
-	// Start the ray traversal, rayQueryProceedEXT returns false if the traversal is complete
-	while (rayQueryProceedEXT(rayQuery)) { }
+	// Traverse the acceleration structure and store information about the first intersection (if any)
+	rayQueryProceedEXT(rayQuery);
 
 	// If the intersection has hit a triangle, the fragment is shadowed
 	if (rayQueryGetIntersectionTypeEXT(rayQuery, true) == gl_RayQueryCommittedIntersectionTriangleEXT ) {