From 137b144fe1ee5b90039cc5aca4b4a79a24d967fd Mon Sep 17 00:00:00 2001
From: RaveYard <29225776+MrRaveYard@users.noreply.github.com>
Date: Mon, 4 Sep 2023 12:35:36 +0200
Subject: [PATCH] Round sampledist to power of 2

---
 src/common/rendering/hwrenderer/data/hw_levelmesh.h |  2 +-
 src/rendering/hwrenderer/doom_levelmesh.cpp         | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/common/rendering/hwrenderer/data/hw_levelmesh.h b/src/common/rendering/hwrenderer/data/hw_levelmesh.h
index f294bcbbd..885c33f29 100644
--- a/src/common/rendering/hwrenderer/data/hw_levelmesh.h
+++ b/src/common/rendering/hwrenderer/data/hw_levelmesh.h
@@ -59,7 +59,7 @@ struct LevelMeshSurface
 	int sectorGroup = 0;
 
 	BBox bounds;
-	int sampleDimension = 0;
+	uint16_t sampleDimension = 0;
 
 	// Lightmap world coordinates for the texture
 	FVector3 worldOrigin = { 0.f, 0.f, 0.f };
diff --git a/src/rendering/hwrenderer/doom_levelmesh.cpp b/src/rendering/hwrenderer/doom_levelmesh.cpp
index 932a5f08a..f089e5c18 100644
--- a/src/rendering/hwrenderer/doom_levelmesh.cpp
+++ b/src/rendering/hwrenderer/doom_levelmesh.cpp
@@ -893,7 +893,17 @@ void DoomLevelMesh::BuildSurfaceParams(int lightMapTextureWidth, int lightMapTex
 	{
 		surface.sampleDimension = LightmapSampleDistance;
 	}
-	//surface->sampleDimension = Math::RoundPowerOfTwo(surface->sampleDimension);
+
+	{
+		// Round to nearest power of two
+		uint32_t n = uint16_t(surface.sampleDimension);
+		n |= n >> 1;
+		n |= n >> 2;
+		n |= n >> 4;
+		n |= n >> 8;
+		++n;
+		surface.sampleDimension = uint16_t(n) ? uint16_t(n) : uint16_t(0xFFFF);
+	}
 
 	// round off dimensions
 	for (int i = 0; i < 3; i++)