[Rendering] Optimize frame allocator native address handling;

Author: LittleCodingFox

Engine/Staple.Core/Rendering/RenderSystem/Backend/Impls/SDLGPU/Commands/SDLGPURenderCommand.cs

@@ -142,7 +142,7 @@ pair.Value is not SDLGPUVertexBuffer v ||
         {
             var uniform = vertexUniformData[i];
 
-            var target = backend.frameAllocator.Get(uniform.position);
+            var target = backend.frameAllocator.pinAddress + uniform.position;
 
             SDL.PushGPUVertexUniformData(backend.commandBuffer, uniform.binding, target, (uint)uniform.size);
         }
@@ -151,7 +151,7 @@ pair.Value is not SDLGPUVertexBuffer v ||
         {
             var uniform = fragmentUniformData[i];
 
-            var target = backend.frameAllocator.Get(uniform.position);
+            var target = backend.frameAllocator.pinAddress + uniform.position;
 
             SDL.PushGPUFragmentUniformData(backend.commandBuffer, uniform.binding, target, (uint)uniform.size);
         }

Engine/Staple.Core/Rendering/RenderSystem/Backend/Impls/SDLGPU/Commands/SDLGPURenderTransientCommand.cs

@@ -155,7 +155,7 @@ pair.Value is not SDLGPUVertexBuffer v ||
         {
             var uniform = vertexUniformData[i];
 
-            var target = backend.frameAllocator.Get(uniform.position);
+            var target = backend.frameAllocator.pinAddress + uniform.position;
 
             SDL.PushGPUVertexUniformData(backend.commandBuffer, uniform.binding, target, (uint)uniform.size);
         }
@@ -164,7 +164,7 @@ pair.Value is not SDLGPUVertexBuffer v ||
         {
             var uniform = fragmentUniformData[i];
 
-            var target = backend.frameAllocator.Get(uniform.position);
+            var target = backend.frameAllocator.pinAddress + uniform.position;
 
             SDL.PushGPUFragmentUniformData(backend.commandBuffer, uniform.binding, target, (uint)uniform.size);
         }

Engine/Staple.Core/Rendering/RenderSystem/Backend/Impls/SDLGPU/Commands/SDLGPURenderTransientUIntCommand.cs

@@ -154,7 +154,7 @@ pair.Value is not SDLGPUVertexBuffer v ||
         {
             var uniform = vertexUniformData[i];
 
-            var target = backend.frameAllocator.Get(uniform.position);
+            var target = backend.frameAllocator.pinAddress + uniform.position;
 
             SDL.PushGPUVertexUniformData(backend.commandBuffer, uniform.binding, target, (uint)uniform.size);
         }
@@ -163,7 +163,7 @@ pair.Value is not SDLGPUVertexBuffer v ||
         {
             var uniform = fragmentUniformData[i];
 
-            var target = backend.frameAllocator.Get(uniform.position);
+            var target = backend.frameAllocator.pinAddress + uniform.position;
 
             SDL.PushGPUFragmentUniformData(backend.commandBuffer, uniform.binding, target, (uint)uniform.size);
         }

Engine/Staple.Core/Rendering/RenderSystem/Backend/Impls/SDLGPU/SDLGPURendererBackend.cs

@@ -401,6 +401,10 @@ internal class MemoryAllocator
     {
         public byte[] buffer = new byte[1024];
 
+        public GCHandle pinHandle;
+
+        public nint pinAddress;
+
         internal int position;
 
         public void Allocate(int size)
@@ -419,23 +423,30 @@ public void Allocate(int size)
                 newSize *= 2;
 
                 Array.Resize(ref buffer, newSize);
+
+                Repin();
             }
 
             position += size;
         }
 
-        public nint Get(int position)
+        private void Repin()
         {
-            unsafe
+            if (pinHandle.IsAllocated)
             {
-                fixed (void* target = buffer)
-                {
-                    byte* p = (byte*)target;
+                pinHandle.Free();
+            }
 
-                    p += position;
+            pinHandle = GCHandle.Alloc(buffer, GCHandleType.Pinned);
 
-                    return (nint)p;
-                }
+            pinAddress = pinHandle.AddrOfPinnedObject();
+        }
+
+        public void EnsurePin()
+        {
+            if(pinHandle.IsAllocated == false)
+            {
+                pinHandle = GCHandle.Alloc(buffer, GCHandleType.Pinned);
             }
         }
 
@@ -810,6 +821,8 @@ public void EndFrame()
 
         UpdateDepthTextureIfNeeded(false);
 
+        frameAllocator.EnsurePin();
+
         foreach (var pair in transientBuffers)
         {
             pair.Value.CreateBuffers();