diff --git a/engine/gfx/metal/include/gfx_metal.hpp b/engine/gfx/metal/include/gfx_metal.hpp
index 0094c87..143a268 100755
--- a/engine/gfx/metal/include/gfx_metal.hpp
+++ b/engine/gfx/metal/include/gfx_metal.hpp
@@ -44,7 +44,7 @@ public:
     GFXPipeline* create_graphics_pipeline(const GFXGraphicsPipelineCreateInfo& info) override;
     GFXPipeline* create_compute_pipeline(const GFXComputePipelineCreateInfo& info) override;
 
-    GFXCommandBuffer* acquire_command_buffer() override;
+    GFXCommandBuffer* acquire_command_buffer(bool for_presentation_use = false) override;
     
     void submit(GFXCommandBuffer* command_buffer, const int window = -1) override;
         
diff --git a/engine/gfx/metal/src/gfx_metal.mm b/engine/gfx/metal/src/gfx_metal.mm
index f69a2b9..a2cb765 100755
--- a/engine/gfx/metal/src/gfx_metal.mm
+++ b/engine/gfx/metal/src/gfx_metal.mm
@@ -220,9 +220,8 @@ void GFXMetal::copy_buffer(GFXBuffer* buffer, void* data, const GFXSize offset,
 
     const unsigned char * src = reinterpret_cast<const unsigned char*>(data);
     unsigned char * dest = reinterpret_cast<unsigned char *>(metalBuffer->get(currentFrameIndex).contents);
-    memcpy(dest + offset, src, size);
-
-    //[metalBuffer->handle didModifyRange:NSMakeRange(offset, size)];
+    if(dest != nullptr)
+        memcpy(dest + offset, src, size);
 }
 
 void* GFXMetal::get_buffer_contents(GFXBuffer* buffer) {
@@ -699,7 +698,7 @@ GFXPipeline* GFXMetal::create_compute_pipeline(const GFXComputePipelineCreateInf
     return pipeline;
 }
 
-GFXCommandBuffer* GFXMetal::acquire_command_buffer() {
+GFXCommandBuffer* GFXMetal::acquire_command_buffer(bool for_presentation_use) {
     GFXCommandBuffer* cmdbuf = nullptr;
     while(cmdbuf == nullptr) {
         for(const auto [i, buffer_status] : utility::enumerate(free_command_buffers)) {