ImDrawList::PrimReserve() minor renaming of locals to make things clearer

imgui_draw.cpp

@@ -359,13 +359,13 @@ void ImDrawList::PrimReserve(int idx_count, int vtx_count)
     ImDrawCmd& draw_cmd = CmdBuffer.Data[CmdBuffer.Size-1];
     draw_cmd.ElemCount += idx_count;
 
-    int vtx_buffer_size = VtxBuffer.Size;
-    VtxBuffer.resize(vtx_buffer_size + vtx_count);
-    _VtxWritePtr = VtxBuffer.Data + vtx_buffer_size;
+    int vtx_buffer_old_size = VtxBuffer.Size;
+    VtxBuffer.resize(vtx_buffer_old_size + vtx_count);
+    _VtxWritePtr = VtxBuffer.Data + vtx_buffer_old_size;
 
-    int idx_buffer_size = IdxBuffer.Size;
-    IdxBuffer.resize(idx_buffer_size + idx_count);
-    _IdxWritePtr = IdxBuffer.Data + idx_buffer_size;
+    int idx_buffer_old_size = IdxBuffer.Size;
+    IdxBuffer.resize(idx_buffer_old_size + idx_count);
+    _IdxWritePtr = IdxBuffer.Data + idx_buffer_old_size;
 }
 
 // Fully unrolled with inline call to keep our debug builds decently fast.