adding device selection, buffer creation and pipeline creation to Metal backend

Sources/Backends/Metal/MetalBuffer.m

@@ -0,0 +1,73 @@
+// Copyright (C) 2025 kanel
+// This file is part of "Pulse"
+// For conditions of distribution and use, see copyright notice in LICENSE
+
+#include <string.h>
+
+#include <Pulse.h>
+#include "../../PulseInternal.h"
+#include "Metal.h"
+#include "MetalBuffer.h"
+#include "MetalDevice.h"
+#include "MetalCommandList.h"
+
+PulseBuffer MetalCreateBuffer(PulseDevice device, const PulseBufferCreateInfo* create_infos)
+{
+	@autoreleasepool
+	{
+		MetalDevice* metal_device = (MetalDevice*)METAL_RETRIEVE_DRIVER_DATA_AS(device, MetalDevice*);
+
+		PulseBuffer buffer = (PulseBuffer)calloc(1, sizeof(PulseBufferHandler));
+		PULSE_CHECK_ALLOCATION_RETVAL(buffer, PULSE_NULL_HANDLE);
+
+		MetalBuffer* metal_buffer = (MetalBuffer*)calloc(1, sizeof(MetalBuffer));
+		PULSE_CHECK_ALLOCATION_RETVAL(metal_buffer, PULSE_NULL_HANDLE);
+
+		uint32_t size = PULSE_ALIGN_UP(create_infos->size, 4);
+
+		buffer->device = device;
+		buffer->driver_data = metal_buffer;
+		buffer->size = size;
+		buffer->usage = create_infos->usage;
+
+		MTLResourceOptions options;
+		if((create_infos->usage & (PULSE_BUFFER_USAGE_TRANSFER_UPLOAD | PULSE_BUFFER_USAGE_TRANSFER_DOWNLOAD)) == 0) // Is storage only
+			options = MTLResourceStorageModePrivate;
+		else if((create_infos->usage & PULSE_BUFFER_USAGE_TRANSFER_DOWNLOAD) == 0)
+			options = MTLResourceCPUCacheModeWriteCombined;
+		else
+			options = MTLResourceCPUCacheModeDefaultCache;
+
+		metal_buffer->buffer = [metal_device->device newBufferWithLength:size options:options];
+		CHECK_METAL_RETVAL(device->backend, metal_buffer->buffer, PULSE_ERROR_INITIALIZATION_FAILED, PULSE_NULL_HANDLE);
+
+		return buffer;
+	}
+}
+
+bool MetalMapBuffer(PulseBuffer buffer, PulseMapMode mode, void** data)
+{
+	return true;
+}
+
+void MetalUnmapBuffer(PulseBuffer buffer)
+{
+}
+
+bool MetalCopyBufferToBuffer(PulseCommandList cmd, const PulseBufferRegion* src, const PulseBufferRegion* dst)
+{
+	return true;
+}
+
+bool MetalCopyBufferToImage(PulseCommandList cmd, const PulseBufferRegion* src, const PulseImageRegion* dst)
+{
+	return true;
+}
+
+void MetalDestroyBuffer(PulseDevice device, PulseBuffer buffer)
+{
+	MetalBuffer* metal_buffer = METAL_RETRIEVE_DRIVER_DATA_AS(buffer, MetalBuffer*);
+	metal_buffer->buffer = nil;
+	free(metal_buffer);
+	free(buffer);
+}