From 7f562030be89be6fca9b09b3a403e14667e87806 Mon Sep 17 00:00:00 2001
From: bruvzg <7645683+bruvzg@users.noreply.github.com>
Date: Mon, 4 Jul 2022 09:46:38 +0300
Subject: [PATCH] Use custom key struct, instead of raw hashes for the Label3D
 cache to avoid potential hash collisions.

---
 scene/3d/label_3d.cpp | 21 +++++++--------------
 scene/3d/label_3d.h   | 25 ++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/scene/3d/label_3d.cpp b/scene/3d/label_3d.cpp
index 00c95063a99..8791c9b6e57 100644
--- a/scene/3d/label_3d.cpp
+++ b/scene/3d/label_3d.cpp
@@ -535,15 +535,8 @@ float Label3D::_generate_glyph_surfaces(const Ref<Font> &p_font, CharType p_char
 	gl_uv = p_font->get_char_tx_uv_rect(p_char, p_next, p_outline);
 	texs = p_font->get_char_texture_size(p_char, p_next, p_outline);
 
-	uint64_t mat_hash;
-	if (tex != RID()) {
-		mat_hash = hash_one_uint64(tex.get_id());
-	} else {
-		mat_hash = hash_one_uint64(0);
-	}
-	mat_hash = hash_djb2_one_64(p_priority, mat_hash);
-
-	if (!surfaces.has(mat_hash)) {
+	SurfaceKey key = SurfaceKey(tex.get_id(), p_priority);
+	if (!surfaces.has(key)) {
 		SurfaceData surf;
 		surf.material = RID_PRIME(VisualServer::get_singleton()->material_create());
 		// Set defaults for material, names need to match up those in SpatialMaterial
@@ -567,9 +560,9 @@ float Label3D::_generate_glyph_surfaces(const Ref<Font> &p_font, CharType p_char
 			surf.z_shift = p_priority;
 		}
 
-		surfaces[mat_hash] = surf;
+		surfaces[key] = surf;
 	}
-	SurfaceData &s = surfaces[mat_hash];
+	SurfaceData &s = surfaces[key];
 
 	s.mesh_vertices.resize((s.offset + 1) * 4);
 	s.mesh_normals.resize((s.offset + 1) * 4);
@@ -624,7 +617,7 @@ void Label3D::_shape() {
 
 	// Clear materials.
 	{
-		const uint64_t *k = nullptr;
+		const SurfaceKey *k = nullptr;
 		while ((k = surfaces.next(k))) {
 			VS::get_singleton()->free(surfaces[*k].material);
 		}
@@ -754,7 +747,7 @@ void Label3D::_shape() {
 		line++;
 	}
 
-	const uint64_t *k = nullptr;
+	const SurfaceKey *k = nullptr;
 	int idx = 0;
 	while ((k = surfaces.next(k))) {
 		const SurfaceData &surf = surfaces[*k];
@@ -1063,7 +1056,7 @@ Label3D::~Label3D() {
 	}
 
 	VS::get_singleton()->free(mesh);
-	const uint64_t *k = nullptr;
+	const SurfaceKey *k = nullptr;
 	while ((k = surfaces.next(k))) {
 		VS::get_singleton()->free(surfaces[*k].material);
 	}
diff --git a/scene/3d/label_3d.h b/scene/3d/label_3d.h
index ab578a257d0..6bf08a54382 100644
--- a/scene/3d/label_3d.h
+++ b/scene/3d/label_3d.h
@@ -78,6 +78,7 @@ private:
 
 	mutable Ref<TriangleMesh> triangle_mesh;
 	RID mesh;
+
 	struct SurfaceData {
 		PoolVector3Array mesh_vertices;
 		PoolVector3Array mesh_normals;
@@ -89,7 +90,29 @@ private:
 		float z_shift = 0.0;
 		RID material;
 	};
-	HashMap<uint64_t, SurfaceData> surfaces;
+
+	struct SurfaceKey {
+		uint64_t texture_id;
+		int32_t priority;
+
+		bool operator==(const SurfaceKey &p_b) const {
+			return (texture_id == p_b.texture_id) && (priority == p_b.priority);
+		}
+
+		SurfaceKey(uint64_t p_texture_id, int p_priority) {
+			texture_id = p_texture_id;
+			priority = p_priority;
+		}
+	};
+
+	struct SurfaceKeyHasher {
+		_FORCE_INLINE_ static uint32_t hash(const SurfaceKey &p_a) {
+			uint32_t hash = hash_djb2_one_32(p_a.texture_id);
+			return hash_djb2_one_32(p_a.priority, hash);
+		}
+	};
+
+	HashMap<SurfaceKey, SurfaceData, SurfaceKeyHasher> surfaces;
 
 	struct WordCache {
 		enum {