[gfx] metal backend skeleton (#4223)

* add metal-cpp submodule

* add metal-cpp cmake target

* gfx metal backend skeleton

* add premake support

* add foundation framework

* add metal-cpp include to premake

* update vs project file

---------

Co-authored-by: Simon Kallweit <skallweit@nvidia.com>
Co-authored-by: Jay Kwak <82421531+jkwak-work@users.noreply.github.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/tools/gfx/metal/metal-framebuffer.cpp b/tools/gfx/metal/metal-framebuffer.cpp
new file mode 100644
index 000000000..c676f44eb
--- /dev/null
+++ b/tools/gfx/metal/metal-framebuffer.cpp
@@ -0,0 +1,75 @@
+// metal-framebuffer.cpp
+#include "metal-framebuffer.h"
+#include "metal-device.h"
+#include "metal-resource-views.h"
+#include "metal-helper-functions.h"
+
+namespace gfx
+{
+
+using namespace Slang;
+
+namespace metal
+{
+
+FramebufferLayoutImpl::~FramebufferLayoutImpl()
+{
+    //m_renderPass->release();
+}
+
+Result FramebufferLayoutImpl::init(DeviceImpl* renderer, const IFramebufferLayout::Desc& desc)
+{
+    // Metal doesn't have a notion of Framebuffers or FramebufferLayouts per se.
+    // We simply stash the desc and use it when creating the (convenience) Framebuffer
+    m_renderer = renderer;
+    m_desc = desc;
+    return SLANG_OK;
+}
+
+FramebufferImpl::~FramebufferImpl()
+{
+}
+
+Result FramebufferImpl::init(DeviceImpl* renderer, const IFramebuffer::Desc& desc)
+{
+    m_renderer = renderer;
+    m_layout = static_cast<FramebufferLayoutImpl*>(desc.layout);
+    m_width = m_height = 1;
+
+    TextureResourceViewImpl* dsv = static_cast<TextureResourceViewImpl*>(desc.depthStencilView);
+
+    // Get frame dimensions from attachments.
+    if (dsv)
+    {
+        // If we have a depth attachment, get frame size from there.
+        auto size = dsv->m_texture->getDesc()->size;
+        auto viewDesc = dsv->getViewDesc();
+        m_width = Math::Max(1u, uint32_t(size.width >> viewDesc->subresourceRange.mipLevel));
+        m_height = Math::Max(1u, uint32_t(size.height >> viewDesc->subresourceRange.mipLevel));
+    }
+    else if (desc.renderTargetCount > 0)
+    {
+        // If we don't have a depth attachment, then we must have at least
+        // one color attachment. Get frame dimension from there.
+        auto viewImpl = static_cast<TextureResourceViewImpl*>(desc.renderTargetViews[0]);
+        auto resourceDesc = viewImpl->m_texture->getDesc();
+        auto viewDesc = viewImpl->getViewDesc();
+        auto size = resourceDesc->size;
+        m_width = Math::Max(1u, uint32_t(size.width >> viewDesc->subresourceRange.mipLevel));
+        m_height = Math::Max(1u, uint32_t(size.height >> viewDesc->subresourceRange.mipLevel));
+    }
+
+    // Initialize depthstencil and render target views
+    depthStencilView = desc.depthStencilView;
+
+    renderTargetViews.setCount(desc.renderTargetCount);
+    for (int i = 0; i < desc.renderTargetCount; ++i)
+    {
+        renderTargetViews[i] = desc.renderTargetViews[i];
+    }
+
+    return SLANG_OK;
+}
+
+} // namespace metal
+} // namespace gfx