Vertex Format Reset Optimization (#1372)

Clear the current vertex format on begin instead of calling the default constructor to avoid reallocating its flags vector and speed up vertex format declaring.

ENIGMAsystem/SHELL/Graphics_Systems/General/GSvertex.cpp

@@ -41,7 +41,7 @@ std::unordered_map<size_t, int> vertexFormatCache;
 
 // current vertex format being specified
 // NOTE: this is not reset until the next vertex_format_begin
-// NOTE: this uses the stack until vertex_format_end to speed up creation
+// NOTE: this has static storage duration to avoid reallocation overhead (e.g, new is slow)
 enigma::VertexFormat currentVertexFormat;
 
 #define RESOURCE_EXISTS(id, container) return (id >= 0 && (unsigned)id < enigma::container.size() && enigma::container[id] != nullptr);
@@ -59,7 +59,10 @@ vector<IndexBuffer*> indexBuffers;
 namespace enigma_user {
 
 void vertex_format_begin() {
-  currentVertexFormat = enigma::VertexFormat();
+  // resetting the current vertex format this way is faster
+  // than simply calling the default constructor because we
+  // avoid reallocating the flags vector this way
+  currentVertexFormat.Clear();
 }
 
 unsigned vertex_format_get_hash() {

ENIGMAsystem/SHELL/Graphics_Systems/General/GSvertex_impl.h

@@ -55,6 +55,11 @@ struct VertexFormat {
 
   VertexFormat(): stride(0), stride_size(0), hash(0) {}
 
+  void Clear() {
+    hash = stride = stride_size = 0;
+    flags.clear();
+  }
+
   void AddAttribute(int type, int attribute) {
     using namespace enigma_user;