From 02941624f918d2fcc66f02098eadf77b2696756a Mon Sep 17 00:00:00 2001
From: Robert Beckebans <robert.beckebans@gmail.com>
Date: Mon, 26 Sep 2022 00:31:47 +0200
Subject: [PATCH] Repaired glTF2 animations for the Y-Up case

---
 neo/renderer/Model_gltf.cpp | 37 ++++++++++++++++++++-----------------
 neo/renderer/Model_gltf.h   |  2 +-
 2 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/neo/renderer/Model_gltf.cpp b/neo/renderer/Model_gltf.cpp
index 3f42932d..3ce2fd21 100644
--- a/neo/renderer/Model_gltf.cpp
+++ b/neo/renderer/Model_gltf.cpp
@@ -48,9 +48,8 @@ idCVar gltf_AnimSampleRate( "gltf_AnimSampleRate", "24", CVAR_SYSTEM | CVAR_INTE
 static const byte GLMB_VERSION = 101;
 static const unsigned int GLMB_MAGIC = ( 'M' << 24 ) | ( 'L' << 16 ) | ( 'G' << 8 ) | GLMB_VERSION;
 static const char* GLTF_SnapshotName = "_GLTF_Snapshot_";
-static const idAngles blenderToDoomAngels = idAngles( 0.0f, 0.0f, 90 );
-//static const idMat4 blenderToDoomTransform( blenderToDoomAngels.ToMat3(), vec3_origin );
-static const idMat4 blenderToDoomTransform = mat4_identity;
+static const idMat4 blenderToDoomTransform( idAngles( 0.0f, 0.0f, 90 ).ToMat3(), vec3_origin );
+//static const idMat4 blenderToDoomTransform = mat4_identity;
 static idRenderModelGLTF* lastMeshFromFile = nullptr;
 
 bool idRenderModelStatic::ConvertGltfMeshToModelsurfaces( const gltfMesh* mesh )
@@ -58,34 +57,34 @@ bool idRenderModelStatic::ConvertGltfMeshToModelsurfaces( const gltfMesh* mesh )
 	return false;
 }
 
-void idRenderModelGLTF::ProcessNode( gltfNode* modelNode, idMat4 trans, gltfData* data )
+void idRenderModelGLTF::ProcessNode_r( gltfNode* modelNode, idMat4 parentTransform, gltfData* data )
 {
 	auto& meshList = data->MeshList();
 	auto& nodeList = data->NodeList();
 
 	gltfData::ResolveNodeMatrix( modelNode );
 
-	idMat4 curTrans = trans * modelNode->matrix;
+	idMat4 nodeToWorldTransform = parentTransform * modelNode->matrix;
 
 	if( modelNode->mesh >= 0 )
 	{
 		gltfMesh* targetMesh = meshList[modelNode->mesh];
 
-		idMat4 newTrans;
+		idMat4 animTransform;
 
 		if( !animIds.Num() )
 		{
-			newTrans = curTrans;
+			animTransform = nodeToWorldTransform;
 		}
 		else
 		{
-			newTrans =  mat4_identity;
+			animTransform = mat4_identity;
 		}
 
 		for( auto prim : targetMesh->primitives )
 		{
 			//ConvertFromMeshGltf should only be used for the map, ConvertGltfMeshToModelsurfaces should be used.
-			auto* mesh = MapPolygonMesh::ConvertFromMeshGltf( prim, data, newTrans );
+			auto* mesh = MapPolygonMesh::ConvertFromMeshGltf( prim, data, animTransform * blenderToDoomTransform );
 			modelSurface_t	surf;
 
 			gltfMaterial* mat = NULL;
@@ -138,7 +137,7 @@ void idRenderModelGLTF::ProcessNode( gltfNode* modelNode, idMat4 trans, gltfData
 
 	for( auto& child : modelNode->children )
 	{
-		ProcessNode( nodeList[child], curTrans, data );
+		ProcessNode_r( nodeList[child], nodeToWorldTransform, data );
 	}
 }
 
@@ -243,7 +242,7 @@ void idRenderModelGLTF::InitFromFile( const char* fileName )
 	hasAnimations = totalAnims > 0;
 	model_state = hasAnimations ? DM_CACHED : DM_STATIC;
 
-	ProcessNode( root, mat4_identity, data );
+	ProcessNode_r( root, mat4_identity, data );
 
 	if( surfaces.Num() <= 0 )
 	{
@@ -538,7 +537,7 @@ idList<idJointQuat> GetPose( idList<gltfNode>& bones, idJointMat* poseMat )
 		}
 
 		idJointQuat& pose = ret[i];
-		pose.q = ( trans.ToMat3().Transpose().ToQuat() );
+		pose.q = ( trans.ToMat3().ToQuat() );
 		pose.t = idVec3( trans[0][3], trans[1][3], trans[2][3] );
 		pose.w = pose.q.CalcW();
 	}
@@ -830,11 +829,15 @@ idFile_Memory* idRenderModelGLTF::GetAnimBin( idStr animName ,  const ID_TIME_T
 			{
 				if( node->parent == nullptr )
 				{
-					q = blenderToDoomAngels.ToQuat() * animBones[i][b].rotation;
-					if( animBones[i].Num() == 1 )
-					{
-						q = -animBones[i][b].rotation;
-					}
+					//q = blenderToDoomAngels.ToQuat() * animBones[i][b].rotation;
+
+					q = blenderToDoomTransform.ToMat3().ToQuat() * animBones[i][b].rotation;
+
+					//if( animBones[i].Num() == 1 )
+					//{
+					// this is not hit
+					//	q = -animBones[i][b].rotation;
+					//}
 				}
 				else
 				{
diff --git a/neo/renderer/Model_gltf.h b/neo/renderer/Model_gltf.h
index a8f2023c..c8a5bf32 100644
--- a/neo/renderer/Model_gltf.h
+++ b/neo/renderer/Model_gltf.h
@@ -57,7 +57,7 @@ public:
 	static idFile_Memory* GetAnimBin( idStr animName, const ID_TIME_T sourceTimeStamp );
 	int rootID;
 private:
-	void ProcessNode( gltfNode* modelNode, idMat4 trans, gltfData* data );
+	void ProcessNode_r( gltfNode* modelNode, idMat4 trans, gltfData* data );
 	void UpdateSurface( const struct renderEntity_s* ent, const idJointMat* entJoints, const idJointMat* entJointsInverted, modelSurface_t* surf, const modelSurface_t& sourceSurf );
 	void UpdateMd5Joints();