# UNDF: UNDF-2026-000000989
--- a/model_shared.c
+++ b/model_shared.c
@@ -4473,12 +4473,36 @@ void Mod_Mesh_Restart(model_t *mod)
 	mod->DrawAddWaterPlanes = NULL; // will be set if a texture needs it
 }

+// Hash table for Mod_Mesh_GetTexture to avoid O(T) linear scan per draw call.
+// Key: texture name + drawflag + texflags + materialflags, Value: texture index.
+#define MOD_MESH_TEX_HASHSIZE 256
+static unsigned Mod_Mesh_TexHashKey(const char *name, int drawflag, int texflags, int materialflags)
+{
+	unsigned hash = 0;
+	const unsigned char *p;
+	for (p = (const unsigned char *)name; *p; p++)
+		hash = hash * 31 + *p;
+	hash ^= (unsigned)drawflag * 2654435761u;
+	hash ^= (unsigned)texflags * 2246822519u;
+	hash ^= (unsigned)materialflags * 3266489917u;
+	return hash % MOD_MESH_TEX_HASHSIZE;
+}
+
 texture_t *Mod_Mesh_GetTexture(model_t *mod, const char *name, int defaultdrawflags, int defaulttexflags, int defaultmaterialflags)
 {
-	int i;
-	texture_t *t;
+	int i, hashkey;
+	texture_t *t, *oldtextures;
 	int drawflag = defaultdrawflags & DRAWFLAG_MASK;
-	for (i = 0, t = mod->data_textures; i < mod->num_textures; i++, t++)
+
+	// Use hash table for O(1) average lookup instead of O(T) linear scan.
+	// This function is called per draw call (every quad, character, image),
+	// so O(T) was a per-frame bottleneck scaling with texture count.
+	hashkey = Mod_Mesh_TexHashKey(name, drawflag, defaulttexflags, defaultmaterialflags);
+	for (i = mod->mesh_texture_hashtable[hashkey]; i >= 0; i = mod->mesh_texture_hashnext[i])
+	{
+		t = &mod->data_textures[i];
+		if (!strcmp(t->name, name) && t->mesh_drawflag == drawflag && t->mesh_defaulttexflags == defaulttexflags && t->mesh_defaultmaterialflags == defaultmaterialflags)
+			return t;
+	}
+
+	// Fallback: linear scan for textures not yet in hash table (should not happen)
+	for (i = 0, t = mod->data_textures; i < mod->num_textures; i++, t++)
 		if (!strcmp(t->name, name) && t->mesh_drawflag == drawflag && t->mesh_defaulttexflags == defaulttexflags && t->mesh_defaultmaterialflags == defaultmaterialflags)
 			return t;
 	if (mod->max_textures <= mod->num_textures)
--- a/model_shared.h
+++ b/model_shared.h
@@ -428,6 +428,10 @@ typedef struct model_s
 	int				max_textures; // preallocated for expansion (Mod_Mesh_GetTexture)
 	int				num_textures;
 	texture_t		*data_textures;
+	// Hash table for Mod_Mesh_GetTexture O(1) lookup.
+	// mesh_texture_hashtable[hashkey] = first texture index, -1 if empty.
+	int				mesh_texture_hashtable[256];
+	int				*mesh_texture_hashnext; // per-texture chain, -1 = end
 	int				num_surfaces;
 	int				max_surfaces; // preallocated for expansion (Mod_Mesh_AddSurface)
 	msurface_t		*data_surfaces;