[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, 85 insertions, 0 deletions

diff --git a/tools/gfx/metal/metal-render-pass.cpp b/tools/gfx/metal/metal-render-pass.cpp
new file mode 100644
index 000000000..b7016ebc2
--- /dev/null
+++ b/tools/gfx/metal/metal-render-pass.cpp
@@ -0,0 +1,85 @@
+// metal-render-pass.cpp
+#include "metal-render-pass.h"
+
+//#include "metal-helper-functions.h"
+
+namespace gfx
+{
+
+using namespace Slang;
+
+namespace metal
+{
+
+IRenderPassLayout* RenderPassLayoutImpl::getInterface(const Guid& guid)
+{
+    if (guid == GfxGUID::IID_ISlangUnknown || guid == GfxGUID::IID_IRenderPassLayout)
+        return static_cast<IRenderPassLayout*>(this);
+    return nullptr;
+}
+
+RenderPassLayoutImpl::~RenderPassLayoutImpl()
+{
+}
+
+static inline MTL::LoadAction translateLoadOp(IRenderPassLayout::TargetLoadOp loadOp)
+{
+    switch (loadOp)
+    {
+    case IRenderPassLayout::TargetLoadOp::Clear:
+        return MTL::LoadAction::LoadActionClear;
+    case IRenderPassLayout::TargetLoadOp::Load:
+        return MTL::LoadAction::LoadActionLoad;
+    case IRenderPassLayout::TargetLoadOp::DontCare:
+    default:
+        return MTL::LoadAction::LoadActionDontCare;
+    }
+}
+
+static inline MTL::StoreAction translateStoreOp(IRenderPassLayout::TargetStoreOp storeOp)
+{
+    switch (storeOp)
+    {
+    case IRenderPassLayout::TargetStoreOp::Store:
+        return MTL::StoreAction::StoreActionStore;
+    case IRenderPassLayout::TargetStoreOp::DontCare:
+    default:
+        return MTL::StoreAction::StoreActionDontCare;
+    }
+}
+
+Result RenderPassLayoutImpl::init(DeviceImpl* renderer, const IRenderPassLayout::Desc& desc)
+{
+    m_renderer = renderer;
+
+    FramebufferLayoutImpl* framebufferLayout = static_cast<FramebufferLayoutImpl*>(desc.framebufferLayout);
+    assert(framebufferLayout);
+
+    // Initialize render pass descriptor, filling in attachment metadata, but leaving texture data unbound.
+    m_renderPassDesc = MTL::RenderPassDescriptor::alloc()->init();
+    m_renderPassDesc->setRenderTargetArrayLength(desc.renderTargetCount);
+
+    MTL::RenderPassColorAttachmentDescriptorArray* colorAttachments = m_renderPassDesc->colorAttachments();
+    for (GfxIndex i = 0; i < desc.renderTargetCount; ++i)
+    {
+        MTL::RenderPassColorAttachmentDescriptor* colorAttach = MTL::RenderPassColorAttachmentDescriptor::alloc()->init();
+        colorAttach->setLoadAction(translateLoadOp(desc.renderTargetAccess[i].loadOp));
+        colorAttach->setStoreAction(translateStoreOp(desc.renderTargetAccess[i].storeOp));
+        // We set the texture when the render pass is executed, using the associated framebuffer.
+        colorAttach->setTexture(nullptr);
+        colorAttachments->setObject(colorAttach, i);
+    }
+    m_renderPassDesc->depthAttachment()->setLoadAction(translateLoadOp(desc.depthStencilAccess->loadOp));
+    m_renderPassDesc->depthAttachment()->setStoreAction(translateStoreOp(desc.depthStencilAccess->storeOp));
+    // We set the depth texture when the render pass is executed, using the associated framebuffer.
+    m_renderPassDesc->depthAttachment()->setTexture(nullptr);
+    //m_renderPassDesc->depthAttachment()->setClearDepth(1000000.);
+    m_renderPassDesc->stencilAttachment()->setLoadAction(translateLoadOp(desc.depthStencilAccess->loadOp));
+    m_renderPassDesc->stencilAttachment()->setStoreAction(translateStoreOp(desc.depthStencilAccess->storeOp));
+    // We set the stencil texture when the render pass is executed, using the associated framebuffer.
+    m_renderPassDesc->stencilAttachment()->setTexture(nullptr);
+    return SLANG_OK;
+}
+
+} // namespace metal
+} // namespace gfx