From b3b2eb42c67e804a444036d7f8f1758158eb5e5b Mon Sep 17 00:00:00 2001
From: Jordon Moss <mossj32@gmail.com>
Date: Thu, 14 Jul 2016 12:35:30 -0300
Subject: [PATCH] Added SurfaceSkin MODELDEF property, allows overriding MD3
 per-surface skins.

---
 src/gl/models/gl_models.cpp     | 37 ++++++++++++++++++++++++++++++++-
 src/gl/models/gl_models.h       |  8 +++++++
 src/gl/models/gl_models_md3.cpp | 16 ++++++++++++--
 src/gl/scene/gl_scene.cpp       |  1 +
 4 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/src/gl/models/gl_models.cpp b/src/gl/models/gl_models.cpp
index 7f05ebb2e..3c2eb05c8 100644
--- a/src/gl/models/gl_models.cpp
+++ b/src/gl/models/gl_models.cpp
@@ -460,7 +460,7 @@ void gl_InitModels()
 {
 	int Lump, lastLump;
 	FString path;
-	int index;
+	int index, surface;
 	int i;
 
 	FSpriteModelFrame smf;
@@ -696,6 +696,39 @@ void gl_InitModels()
 							}
 						}
 					}
+					else if (sc.Compare("surfaceskin"))
+					{
+						sc.MustGetNumber();
+						index = sc.Number;
+						sc.MustGetNumber();
+						surface = sc.Number;
+
+						if (index<0 || index >= MAX_MODELS_PER_FRAME)
+						{
+							sc.ScriptError("Too many models in %s", smf.type->TypeName.GetChars());
+						}
+
+						if (surface<0 || index >= MD3_MAX_SURFACES)
+						{
+							sc.ScriptError("Invalid MD3 Surface %d in %s", MD3_MAX_SURFACES, smf.type->TypeName.GetChars());
+						}
+
+						sc.MustGetString();
+						FixPathSeperator(sc.String);
+						if (sc.Compare(""))
+						{
+							smf.surfaceskinIDs[index][surface] = FNullTextureID();
+						}
+						else
+						{
+							smf.surfaceskinIDs[index][surface] = LoadSkin("", sc.String);
+							if (!smf.surfaceskinIDs[index][surface].isValid())
+							{
+								Printf("Surface Skin '%s' not found in '%s'\n",
+									sc.String, smf.type->TypeName.GetChars());
+							}
+						}
+					}
 					else if (sc.Compare("frameindex") || sc.Compare("frame"))
 					{
 						bool isframe=!!sc.Compare("frame");
@@ -901,6 +934,8 @@ void gl_RenderFrameModels( const FSpriteModelFrame *smf,
 			mdl->BuildVertexBuffer();
 			gl_RenderState.SetVertexBuffer(mdl->mVBuf);
 
+			mdl->PushSpriteFrame(smf, i);
+
 			if ( smfNext && smf->modelframes[i] != smfNext->modelframes[i] )
 				mdl->RenderFrame(tex, smf->modelframes[i], smfNext->modelframes[i], inter, translation);
 			else
diff --git a/src/gl/models/gl_models.h b/src/gl/models/gl_models.h
index ab53bd7e4..a75e74305 100644
--- a/src/gl/models/gl_models.h
+++ b/src/gl/models/gl_models.h
@@ -16,9 +16,12 @@ enum { VX, VZ, VY };
 #define DMD_MAGIC			0x4D444D44
 #define MD3_MAGIC			0x33504449
 #define NUMVERTEXNORMALS	162
+#define MD3_MAX_SURFACES	32
 
 FTextureID LoadSkin(const char * path, const char * fn);
 
+// [JM] Necessary forward declaration
+typedef struct FSpriteModelFrame FSpriteModelFrame;
 
 class FModel
 {
@@ -42,6 +45,10 @@ public:
 	}
 	virtual float getAspectFactor() { return 1.f; }
 
+	const FSpriteModelFrame *curSpriteMDLFrame;
+	int curMDLIndex;
+	void PushSpriteFrame(const FSpriteModelFrame *smf, int index) { curSpriteMDLFrame = smf; curMDLIndex = index; };
+
 	FModelVertexBuffer *mVBuf;
 	FString mFileName;
 };
@@ -347,6 +354,7 @@ struct FSpriteModelFrame
 {
 	int modelIDs[MAX_MODELS_PER_FRAME];
 	FTextureID skinIDs[MAX_MODELS_PER_FRAME];
+	FTextureID surfaceskinIDs[MAX_MODELS_PER_FRAME][MD3_MAX_SURFACES];
 	int modelframes[MAX_MODELS_PER_FRAME];
 	float xscale, yscale, zscale;
 	// [BB] Added zoffset, rotation parameters and flags.
diff --git a/src/gl/models/gl_models_md3.cpp b/src/gl/models/gl_models_md3.cpp
index 267e85c91..b9c0a120a 100644
--- a/src/gl/models/gl_models_md3.cpp
+++ b/src/gl/models/gl_models_md3.cpp
@@ -319,6 +319,11 @@ void FMD3Model::AddSkins(BYTE *hitlist)
 {
 	for (int i = 0; i < numSurfaces; i++)
 	{
+		if (curSpriteMDLFrame->surfaceskinIDs[curMDLIndex][i].isValid())
+		{
+			hitlist[curSpriteMDLFrame->surfaceskinIDs[curMDLIndex][i].GetIndex()] |= FTexture::TEX_Flat;
+		}
+
 		MD3Surface * surf = &surfaces[i];
 		for (int j = 0; j < surf->numSkins; j++)
 		{
@@ -365,8 +370,15 @@ void FMD3Model::RenderFrame(FTexture * skin, int frameno, int frameno2, double i
 		FTexture *surfaceSkin = skin;
 		if (!surfaceSkin)
 		{
-			if (surf->numSkins==0 || !surf->skins[0].isValid()) return;
-			surfaceSkin = TexMan(surf->skins[0]);
+			if (curSpriteMDLFrame->surfaceskinIDs[curMDLIndex][i].isValid())
+			{
+				surfaceSkin = TexMan(curSpriteMDLFrame->surfaceskinIDs[curMDLIndex][i]);
+			}
+			else if(surf->numSkins > 0 && surf->skins[0].isValid())
+			{
+				surfaceSkin = TexMan(surf->skins[0]);
+			}
+
 			if (!surfaceSkin) return;
 		}
 
diff --git a/src/gl/scene/gl_scene.cpp b/src/gl/scene/gl_scene.cpp
index 6352ca0cd..619b94f84 100644
--- a/src/gl/scene/gl_scene.cpp
+++ b/src/gl/scene/gl_scene.cpp
@@ -1113,6 +1113,7 @@ void FGLInterface::Precache(BYTE *texhitlist, TMap<PClassActor*, bool> &actorhit
 					}
 					else if (smf->modelIDs[i] != -1)
 					{
+						Models[smf->modelIDs[i]]->PushSpriteFrame(smf, i);
 						Models[smf->modelIDs[i]]->AddSkins(texhitlist);
 					}
 					if (smf->modelIDs[i] != -1)