rhi: Add rhi::recreate_buffer_to_size

Simple utility to retain or recreate a buffer to a desired size.

src/rhi/rhi.cpp

@@ -83,3 +83,28 @@ const ProgramRequirements& rhi::program_requirements_for_program(PipelineProgram
 		std::terminate();
 	}
 }
+
+bool rhi::recreate_buffer_to_size(Rhi& rhi, Handle<Buffer>& buffer, const BufferDesc& desc)
+{
+	bool recreate = false;
+	if (buffer == kNullHandle)
+	{
+		recreate = true;
+	}
+	else
+	{
+		std::size_t existing_size = rhi.get_buffer_size(buffer);
+		if (existing_size < desc.size)
+		{
+			rhi.destroy_buffer(buffer);
+			recreate = true;
+		}
+	}
+
+	if (recreate)
+	{
+		buffer = rhi.create_buffer(desc);
+	}
+
+	return recreate;
+}

src/rhi/rhi.hpp

@@ -654,6 +654,17 @@ struct Rhi
 	virtual void finish() = 0;
 };
 
+// Utility functions
+
+/// @brief If the buffer for the given handle is too small or does not exist, creates a new buffer with the given
+/// parameters.
+/// @param buffer the existing valid buffer handle or kNullHandle, replaced if recreated
+/// @param type
+/// @param usage
+/// @param size the target size of the new buffer
+/// @return true if the buffer was recreated, false otherwise
+bool recreate_buffer_to_size(Rhi& rhi, Handle<Buffer>& buffer, const BufferDesc& desc);
+
 } // namespace srb2::rhi
 
 #endif // __SRB2_RHI_RHI_HPP__