Enable QRhi Metal backend on iOS

While we are at it, remove the Border and MirrorOnce wrap modes that have
not been supported on OpenGL, because they are unsupported with Metal+iOS
as well.

Task-number: QTBUG-78580
Change-Id: I0db94b9d3a6125b3bb5d7b1db5d02a42cd94d2c2
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 54 insertions, 10 deletions

diff --git a/src/gui/rhi/qrhimetal.mm b/src/gui/rhi/qrhimetal.mm
index 131b2da802..06e81465a2 100644
--- a/src/gui/rhi/qrhimetal.mm
+++ b/src/gui/rhi/qrhimetal.mm
@@ -41,6 +41,8 @@
 
 #ifdef Q_OS_MACOS
 #include <AppKit/AppKit.h>
+#else
+#include <UIKit/UIKit.h>
 #endif
 
 #include <Metal/Metal.h>
@@ -318,7 +320,13 @@ struct QMetalComputePipelineData
 
 struct QMetalSwapChainData
 {
+    // The iOS simulator's headers mark CAMetalLayer as iOS 13.0+ only.
+    // (for real device SDKs it is 8.0+)
+#ifdef TARGET_IPHONE_SIMULATOR
+    API_AVAILABLE(ios(13.0)) CAMetalLayer *layer = nullptr;
+#else
     CAMetalLayer *layer = nullptr;
+#endif
     id<CAMetalDrawable> curDrawable;
     dispatch_semaphore_t sem[QMTL_FRAMES_IN_FLIGHT];
     MTLRenderPassDescriptor *rp = nullptr;
@@ -1763,8 +1771,10 @@ void QRhiMetal::executeBufferHostWritesForCurrentFrame(QMetalBuffer *bufD)
         if (changeEnd == -1 || u.offset + u.data.size() > changeEnd)
             changeEnd = u.offset + u.data.size();
     }
+#ifdef Q_OS_MACOS
     if (changeBegin >= 0 && bufD->d->managed)
         [bufD->d->buf[idx] didModifyRange: NSMakeRange(NSUInteger(changeBegin), NSUInteger(changeEnd - changeBegin))];
+#endif
 
     bufD->d->pendingUpdates[idx].clear();
 }
@@ -1798,8 +1808,12 @@ void QRhiMetal::beginPass(QRhiCommandBuffer *cb,
             if (color0.needsDrawableForTex || color0.needsDrawableForResolveTex) {
                 Q_ASSERT(currentSwapChain);
                 QMetalSwapChain *swapChainD = QRHI_RES(QMetalSwapChain, currentSwapChain);
-                if (!swapChainD->d->curDrawable)
-                    swapChainD->d->curDrawable = [swapChainD->d->layer nextDrawable];
+                if (!swapChainD->d->curDrawable) {
+#ifdef TARGET_IPHONE_SIMULATOR
+                    if (@available(ios 13.0, *))
+#endif
+                        swapChainD->d->curDrawable = [swapChainD->d->layer nextDrawable];
+                }
                 if (!swapChainD->d->curDrawable) {
                     qWarning("No drawable");
                     return;
@@ -2170,12 +2184,13 @@ bool QMetalRenderBuffer::build()
     case DepthStencil:
 #ifdef Q_OS_MACOS
         desc.storageMode = MTLStorageModePrivate;
+        d->format = rhiD->d->dev.depth24Stencil8PixelFormatSupported
+                ? MTLPixelFormatDepth24Unorm_Stencil8 : MTLPixelFormatDepth32Float_Stencil8;
 #else
-        desc.storageMode = MTLResourceStorageModeMemoryless;
+        desc.storageMode = MTLStorageModeMemoryless;
         transientBacking = true;
+        d->format = MTLPixelFormatDepth32Float_Stencil8;
 #endif
-        d->format = rhiD->d->dev.depth24Stencil8PixelFormatSupported
-                ? MTLPixelFormatDepth24Unorm_Stencil8 : MTLPixelFormatDepth32Float_Stencil8;
         desc.pixelFormat = d->format;
         break;
     case Color:
@@ -2569,12 +2584,8 @@ static inline MTLSamplerAddressMode toMetalAddressMode(QRhiSampler::AddressMode
         return MTLSamplerAddressModeRepeat;
     case QRhiSampler::ClampToEdge:
         return MTLSamplerAddressModeClampToEdge;
-    case QRhiSampler::Border:
-        return MTLSamplerAddressModeClampToBorderColor;
     case QRhiSampler::Mirror:
         return MTLSamplerAddressModeMirrorRepeat;
-    case QRhiSampler::MirrorOnce:
-        return MTLSamplerAddressModeMirrorClampToEdge;
     default:
         Q_UNREACHABLE();
         return MTLSamplerAddressModeClampToEdge;
@@ -3311,7 +3322,11 @@ bool QMetalGraphicsPipeline::build()
         // validation blows up otherwise.
         MTLPixelFormat fmt = MTLPixelFormat(rpD->dsFormat);
         rpDesc.depthAttachmentPixelFormat = fmt;
+#ifdef Q_OS_MACOS
         if (fmt != MTLPixelFormatDepth16Unorm && fmt != MTLPixelFormatDepth32Float)
+#else
+        if (fmt != MTLPixelFormatDepth32Float)
+#endif
             rpDesc.stencilAttachmentPixelFormat = fmt;
     }
 
@@ -3528,6 +3543,10 @@ QMetalSwapChain::~QMetalSwapChain()
 
 void QMetalSwapChain::release()
 {
+#ifdef TARGET_IPHONE_SIMULATOR
+    if (@available(ios 13.0, *)) {
+#endif
+
     if (!d->layer)
         return;
 
@@ -3556,6 +3575,10 @@ void QMetalSwapChain::release()
     QRHI_PROF_F(releaseSwapChain(this));
 
     rhiD->unregisterResource(this);
+
+#ifdef TARGET_IPHONE_SIMULATOR
+    }
+#endif
 }
 
 QRhiCommandBuffer *QMetalSwapChain::currentFrameCommandBuffer()
@@ -3578,16 +3601,20 @@ QRhiRenderPassDescriptor *QMetalSwapChain::newCompatibleRenderPassDescriptor()
 {
     chooseFormats(); // ensure colorFormat and similar are filled out
 
-    QRHI_RES_RHI(QRhiMetal);
     QMetalRenderPassDescriptor *rpD = new QMetalRenderPassDescriptor(m_rhi);
     rpD->colorAttachmentCount = 1;
     rpD->hasDepthStencil = m_depthStencil != nullptr;
 
     rpD->colorFormat[0] = int(d->colorFormat);
 
+#ifdef Q_OS_MACOS
     // m_depthStencil may not be built yet so cannot rely on computed fields in it
+    QRHI_RES_RHI(QRhiMetal);
     rpD->dsFormat = rhiD->d->dev.depth24Stencil8PixelFormatSupported
             ? MTLPixelFormatDepth24Unorm_Stencil8 : MTLPixelFormatDepth32Float_Stencil8;
+#else
+    rpD->dsFormat = MTLPixelFormatDepth32Float_Stencil8;
+#endif
 
     return rpD;
 }
@@ -3603,6 +3630,10 @@ void QMetalSwapChain::chooseFormats()
 
 bool QMetalSwapChain::buildOrResize()
 {
+#ifdef TARGET_IPHONE_SIMULATOR
+    if (@available(ios 13.0, *)) {
+#endif
+
     Q_ASSERT(m_window);
 
     const bool needsRegistration = !window || window != m_window;
@@ -3622,7 +3653,11 @@ bool QMetalSwapChain::buildOrResize()
         return false;
     }
 
+#ifdef Q_OS_MACOS
     NSView *view = reinterpret_cast<NSView *>(window->winId());
+#else
+    UIView *view = reinterpret_cast<UIView *>(window->winId());
+#endif
     Q_ASSERT(view);
     d->layer = static_cast<CAMetalLayer *>(view.layer);
     Q_ASSERT(d->layer);
@@ -3726,6 +3761,15 @@ bool QMetalSwapChain::buildOrResize()
         rhiD->registerResource(this);
 
     return true;
+
+#ifdef TARGET_IPHONE_SIMULATOR
+    } else {
+        // Won't ever get here in a normal app because MTLDevice creation would
+        // fail too. Print a warning, just in case.
+        qWarning("No CAMetalLayer support in this version of the iOS Simulator");
+        return false;
+    }
+#endif
 }
 
 QT_END_NAMESPACE