From 34f8b8524b5e2cb2202d48fc3e16e2fa6eb6c14e Mon Sep 17 00:00:00 2001
From: RaveYard <29225776+MrRaveYard@users.noreply.github.com>
Date: Wed, 30 Aug 2023 17:48:34 +0200
Subject: [PATCH] Add DumpLevelMesh ccmd

---
 src/rendering/hwrenderer/doom_levelmesh.cpp | 39 +++++++++++++++++++++
 src/rendering/hwrenderer/doom_levelmesh.h   |  2 ++
 2 files changed, 41 insertions(+)

diff --git a/src/rendering/hwrenderer/doom_levelmesh.cpp b/src/rendering/hwrenderer/doom_levelmesh.cpp
index 81c9e50f08..6ec534fa4b 100644
--- a/src/rendering/hwrenderer/doom_levelmesh.cpp
+++ b/src/rendering/hwrenderer/doom_levelmesh.cpp
@@ -5,6 +5,22 @@
 #include "texturemanager.h"
 #include "playsim/p_lnspec.h"
 
+#include "c_dispatch.h"
+#include "g_levellocals.h"
+
+CCMD(dumplevelmesh)
+{
+	if (level.levelMesh)
+	{
+		level.levelMesh->DumpMesh(FString("levelmesh.obj"));
+		Printf("Level mesh exported.");
+	}
+	else
+	{
+		Printf("No level mesh. Perhaps your level has no lightmap loaded?");
+	}
+}
+
 DoomLevelMesh::DoomLevelMesh(FLevelLocals &doomMap)
 {
 	for (unsigned int i = 0; i < doomMap.sides.Size(); i++)
@@ -418,3 +434,26 @@ bool DoomLevelMesh::IsDegenerate(const FVector3 &v0, const FVector3 &v1, const F
 	float crosslengthsqr = crossx * crossx + crossy * crossy + crossz * crossz;
 	return crosslengthsqr <= 1.e-6f;
 }
+
+void DoomLevelMesh::DumpMesh(const FString& filename) const
+{
+	auto f = fopen(filename.GetChars(), "w");
+
+	fprintf(f, "# DoomLevelMesh debug export\n");
+	fprintf(f, "# MeshVertices: %d, MeshElements: %d\n", MeshVertices.Size(), MeshElements.Size());
+
+	double scale = 1 / 100.0;
+
+	for (const auto& v : MeshVertices)
+	{
+		fprintf(f, "v %f %f %f\n", v.X * scale, v.Y * scale, v.Z * scale);
+	}
+
+	const auto s = MeshElements.Size();
+	for (auto i = 0; i + 2 < s; i += 3)
+	{
+		fprintf(f, "f %d %d %d\n", MeshElements[i] + 1, MeshElements[i + 1] + 1, MeshElements[i + 2] + 1);
+	}
+
+	fclose(f);
+}
diff --git a/src/rendering/hwrenderer/doom_levelmesh.h b/src/rendering/hwrenderer/doom_levelmesh.h
index 5c668eb7d2..bc8505d4fa 100644
--- a/src/rendering/hwrenderer/doom_levelmesh.h
+++ b/src/rendering/hwrenderer/doom_levelmesh.h
@@ -38,6 +38,8 @@ public:
 
 	TArray<Surface> Surfaces;
 
+	void DumpMesh(const FString& filename) const;
+
 private:
 	void CreateSubsectorSurfaces(FLevelLocals &doomMap);
 	void CreateCeilingSurface(FLevelLocals &doomMap, subsector_t *sub, sector_t *sector, int typeIndex, bool is3DFloor);