From 1efd00227d3c38458d44193c4aa554f70a3b9c55 Mon Sep 17 00:00:00 2001
From: degasus <wickmarkus@web.de>
Date: Sun, 21 Dec 2014 14:29:44 +0100
Subject: [PATCH] VertexLoader: Skip vertices with position index = -1

---
 Source/Core/VideoCommon/VertexLoader.cpp      | 20 ++++++++++++++++++-
 Source/Core/VideoCommon/VertexLoader.h        |  2 ++
 .../VideoCommon/VertexLoader_Position.cpp     |  2 ++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Source/Core/VideoCommon/VertexLoader.cpp b/Source/Core/VideoCommon/VertexLoader.cpp
index 61303ab6f7..e2a2073ccf 100644
--- a/Source/Core/VideoCommon/VertexLoader.cpp
+++ b/Source/Core/VideoCommon/VertexLoader.cpp
@@ -92,6 +92,17 @@ static void LOADERDECL TexMtx_Write_Float4(VertexLoader* loader)
 #endif
 }
 
+static void LOADERDECL SkipVertex(VertexLoader* loader)
+{
+	if (loader->m_vertexSkip)
+	{
+		// reset the output buffer
+		g_vertex_manager_write_ptr -= loader->m_native_vtx_decl.stride;
+
+		loader->m_skippedVertices++;
+	}
+}
+
 VertexLoader::VertexLoader(const TVtxDesc &vtx_desc, const VAT &vtx_attr)
 : VertexLoaderBase(vtx_desc, vtx_attr)
 {
@@ -393,6 +404,12 @@ void VertexLoader::CompileVertexTranslator()
 		nat_offset += 4;
 	}
 
+	// indexed position formats may skip a the vertex
+	if (m_VtxDesc.Position & 2)
+	{
+		WriteCall(SkipVertex);
+	}
+
 	m_native_components = components;
 	m_native_vtx_decl.stride = nat_offset;
 
@@ -440,6 +457,7 @@ int VertexLoader::RunVertices(int primitive, int count, DataReader src, DataRead
 	src.WritePointer(&g_video_buffer_read_ptr);
 
 	m_numLoadedVertices += count;
+	m_skippedVertices = 0;
 
 	// Prepare bounding box
 	if (!g_ActiveConfig.backend_info.bSupportsBBox)
@@ -462,5 +480,5 @@ int VertexLoader::RunVertices(int primitive, int count, DataReader src, DataRead
 	}
 #endif
 
-	return count;
+	return count - m_skippedVertices;
 }
diff --git a/Source/Core/VideoCommon/VertexLoader.h b/Source/Core/VideoCommon/VertexLoader.h
index 2b61e683bc..4c883a3242 100644
--- a/Source/Core/VideoCommon/VertexLoader.h
+++ b/Source/Core/VideoCommon/VertexLoader.h
@@ -73,6 +73,8 @@ public:
 	u8 m_curtexmtx[8];
 	int m_texmtxwrite;
 	int m_texmtxread;
+	bool m_vertexSkip;
+	int m_skippedVertices;
 
 private:
 #ifndef USE_VERTEX_LOADER_JIT
diff --git a/Source/Core/VideoCommon/VertexLoader_Position.cpp b/Source/Core/VideoCommon/VertexLoader_Position.cpp
index c0fac7ef93..419c041b5b 100644
--- a/Source/Core/VideoCommon/VertexLoader_Position.cpp
+++ b/Source/Core/VideoCommon/VertexLoader_Position.cpp
@@ -93,6 +93,7 @@ void LOADERDECL Pos_ReadIndex(VertexLoader* loader)
 	static_assert(N <= 3, "N > 3 is not sane!");
 
 	auto const index = DataRead<I>();
+	loader->m_vertexSkip = index == std::numeric_limits<I>::max();
 	auto const data = reinterpret_cast<const T*>(cached_arraybases[ARRAY_POSITION] + (index * g_main_cp_state.array_strides[ARRAY_POSITION]));
 	auto const scale = loader->m_posScale[0];
 	DataReader dst(g_vertex_manager_write_ptr, nullptr);
@@ -119,6 +120,7 @@ void LOADERDECL Pos_ReadIndex_SSSE3(VertexLoader* loader)
 {
 	static_assert(std::is_unsigned<I>::value, "Only unsigned I is sane!");
 	auto const index = DataRead<I>();
+	loader->m_vertexSkip = index == std::numeric_limits<I>::max();
 	const T* pData = (const T*)(cached_arraybases[ARRAY_POSITION] + (index * g_main_cp_state.array_strides[ARRAY_POSITION]));
 	Vertex_Read_SSSE3<T, three, true>(pData, *(__m128*)loader->m_posScale);
 	LOG_VTX();