Fix: Cycles Metal graphics interop not working

It needs an MTLBuffer instead of a raw pointer.

intern/cycles/blender/display_driver.cpp

@@ -633,9 +633,10 @@ GraphicsInteropDevice BlenderDisplayDriver::graphics_interop_get_device()
       interop_device.type = GraphicsInteropDevice::VULKAN;
       break;
     case GPU_BACKEND_METAL:
+      interop_device.type = GraphicsInteropDevice::METAL;
+      break;
     case GPU_BACKEND_NONE:
     case GPU_BACKEND_ANY:
-      /* Metal not supported yet by Cycles. */
       interop_device.type = GraphicsInteropDevice::NONE;
       break;
   }
@@ -665,9 +666,10 @@ GraphicsInteropBuffer BlenderDisplayDriver::graphics_interop_get_buffer()
       interop_buffer.type = GraphicsInteropDevice::VULKAN;
       break;
     case GPU_BACKEND_METAL:
+      interop_buffer.type = GraphicsInteropDevice::METAL;
+      break;
     case GPU_BACKEND_NONE:
     case GPU_BACKEND_ANY:
-      /* Metal not supported yet by Cycles. */
       interop_buffer.type = GraphicsInteropDevice::NONE;
       break;
   }

intern/cycles/device/metal/graphics_interop.h

@@ -5,6 +5,8 @@
 #ifdef WITH_METAL
 
 #  include "device/graphics_interop.h"
+#  include "device/metal/device_impl.h"
+
 #  include "session/display_driver.h"
 
 CCL_NAMESPACE_BEGIN
@@ -34,7 +36,7 @@ class MetalDeviceGraphicsInterop : public DeviceGraphicsInterop {
   MetalDevice *device_ = nullptr;
 
   /* Native handle. */
-  void *buffer_ = nullptr;
+  MetalDevice::MetalMem mem_;
   size_t size_ = 0;
 
   /* The destination was requested to be cleared. */

intern/cycles/device/metal/graphics_interop.mm

@@ -22,18 +22,19 @@ void MetalDeviceGraphicsInterop::set_buffer(const GraphicsInteropBuffer &interop
   /* Trivial implementation due to unified memory. */
   if (interop_buffer.type == GraphicsInteropDevice::METAL) {
     need_clear_ |= interop_buffer.need_clear;
-    buffer_ = reinterpret_cast<void *>(interop_buffer.handle);
+    mem_.mtlBuffer = reinterpret_cast<id<MTLBuffer>>(interop_buffer.handle);
     size_ = interop_buffer.width * interop_buffer.height * sizeof(half4);
   }
 }
 
 device_ptr MetalDeviceGraphicsInterop::map()
 {
-  if (buffer_ && need_clear_) {
-    memset(buffer_, 0, size_);
+  if (mem_.mtlBuffer && need_clear_) {
+    memset([mem_.mtlBuffer contents], 0, size_);
+    need_clear_ = false;
   }
 
-  return device_ptr(buffer_);
+  return device_ptr(&mem_);
 }
 
 void MetalDeviceGraphicsInterop::unmap() {}

intern/cycles/session/display_driver.h

@@ -41,7 +41,7 @@ class GraphicsInteropBuffer {
    * - OpenGL: pixel buffer object ID.
    * - Vulkan on Windows: opaque handle for VkBuffer.
    * - Vulkan on Unix: opaque file descriptor for VkBuffer.
-   * - Metal: pixel buffer unified memory pointer. */
+   * - Metal: MTLBuffer with unified memory. */
   GraphicsInteropDevice::Type type = GraphicsInteropDevice::NONE;
   int64_t handle = 0;
 

source/blender/gpu/metal/mtl_texture.mm

@@ -2657,7 +2657,8 @@ GPUPixelBufferNativeHandle MTLPixelBuffer::get_native_handle()
   }
 
   /* Just get pointer to unified memory. No need to unmap. */
-  native_handle.handle = reinterpret_cast<int64_t>(map());
+  map();
+  native_handle.handle = reinterpret_cast<int64_t>(buffer_);
   native_handle.size = size_;
 
   return native_handle;