From ea82291c90c9dbdb15e175f4b36f69d01348228c Mon Sep 17 00:00:00 2001
From: DaveH355 <101005658+DaveH355@users.noreply.github.com>
Date: Mon, 2 Oct 2023 15:25:54 +0800
Subject: [PATCH] Optimize m3d mesh creation

---
 src/rmodels.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/rmodels.c b/src/rmodels.c
index f9ceec13..2e836b33 100644
--- a/src/rmodels.c
+++ b/src/rmodels.c
@@ -5567,6 +5567,15 @@ static Model LoadVOX(const char *fileName)
 unsigned char *m3d_loaderhook(char *fn, unsigned int *len) { return LoadFileData((const char *)fn, (int *)len); }
 void m3d_freehook(void *data) { UnloadFileData((unsigned char *)data); }
 
+// Comparison function for qsort
+static int m3d_compare_faces(const void *a, const void *b)
+{
+  m3df_t *fa = (m3df_t *)a;
+  m3df_t *fb = (m3df_t *)b;
+
+  return (fa->materialid - fb->materialid);
+}
+
 // Load M3D mesh data
 static Model LoadM3D(const char *fileName)
 {
@@ -5614,6 +5623,9 @@ static Model LoadM3D(const char *fileName)
         // We always need a default material, so we add +1
         model.materialCount++;
 
+        // Sort faces by material.
+        qsort(m3d->face, m3d->numface, sizeof(m3df_t), m3d_compare_faces);
+
         model.meshes = (Mesh *)RL_CALLOC(model.meshCount, sizeof(Mesh));
         model.meshMaterial = (int *)RL_CALLOC(model.meshCount, sizeof(int));
         model.materials = (Material *)RL_CALLOC(model.materialCount + 1, sizeof(Material));