Add caps files for metal

Bug: skia:
Change-Id: I8e7488320d4237cf67d6ebeaad319d3de75b67e6
Reviewed-on: https://skia-review.googlesource.com/27741
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>

4 files changed, 492 insertions, 3 deletions

diff --git a/src/gpu/mtl/GrMtlCaps.h b/src/gpu/mtl/GrMtlCaps.h
new file mode 100644
index 0000000000..9590bb9e12
--- /dev/null
+++ b/src/gpu/mtl/GrMtlCaps.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrMtlCaps_DEFINED
+#define GrMtlCaps_DEFINED
+
+#include "GrCaps.h"
+
+#include "SkTDArray.h"
+
+#import <Metal/Metal.h>
+
+class GrShaderCaps;
+
+/**
+ * Stores some capabilities of a Mtl backend.
+ */
+class GrMtlCaps : public GrCaps {
+public:
+    GrMtlCaps(const GrContextOptions& contextOptions, id<MTLDevice> device,
+              MTLFeatureSet featureSet);
+
+    int getSampleCount(int requestedCount, GrPixelConfig config) const override;
+
+    bool isConfigTexturable(GrPixelConfig config) const override {
+        return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kTextureable_Flag);
+    }
+
+    bool isConfigRenderable(GrPixelConfig config, bool withMSAA) const override {
+        if (withMSAA) {
+            return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kRenderable_Flag) &&
+                   SkToBool(fConfigTable[config].fFlags & ConfigInfo::kMSAA_Flag);
+        } else {
+            return SkToBool(fConfigTable[config].fFlags & ConfigInfo::kRenderable_Flag);
+        }
+    }
+
+    bool canConfigBeImageStorage(GrPixelConfig) const override { return false; }
+
+#if 0
+    /**
+     * Returns both a supported and most prefered stencil format to use in draws.
+     */
+    const StencilFormat& preferedStencilFormat() const {
+        return fPreferedStencilFormat;
+    }
+#endif
+    bool initDescForDstCopy(const GrRenderTargetProxy* src, GrSurfaceDesc* desc,
+                            bool* rectsMustMatch, bool* disallowSubrect) const override {
+        return false;
+    }
+
+private:
+    void initFeatureSet(MTLFeatureSet featureSet);
+ 
+    void initGrCaps(const id<MTLDevice> device);
+    void initShaderCaps();
+    void initSampleCount();
+    void initConfigTable();
+
+    struct ConfigInfo {
+        ConfigInfo() : fFlags(0) {}
+
+        enum {
+            kTextureable_Flag = 0x1,
+            kRenderable_Flag  = 0x2, // Color attachment and blendable
+            kMSAA_Flag        = 0x4,
+            kResolve_Flag     = 0x8,
+        };
+        static const uint16_t kAllFlags = kTextureable_Flag | kRenderable_Flag |
+                                          kMSAA_Flag | kResolve_Flag;
+
+        uint16_t fFlags;
+    };
+    ConfigInfo fConfigTable[kGrPixelConfigCnt];
+
+    enum class Platform {
+        kMac,
+        kIOS
+    };
+    bool isMac() { return Platform::kMac == fPlatform; }
+    bool isIOS() { return Platform::kIOS == fPlatform; }
+
+    Platform fPlatform;
+    int fFamilyGroup;
+    int fVersion;
+
+    SkTDArray<int> fSampleCounts;
+
+    typedef GrCaps INHERITED;
+};
+
+#endif
diff --git a/src/gpu/mtl/GrMtlCaps.mm b/src/gpu/mtl/GrMtlCaps.mm
new file mode 100644
index 0000000000..29e28cff03
--- /dev/null
+++ b/src/gpu/mtl/GrMtlCaps.mm
@@ -0,0 +1,322 @@
+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrMtlCaps.h"
+
+#include "GrShaderCaps.h"
+
+GrMtlCaps::GrMtlCaps(const GrContextOptions& contextOptions, const id<MTLDevice> device,
+                     MTLFeatureSet featureSet)
+        : INHERITED(contextOptions) {
+    fShaderCaps.reset(new GrShaderCaps(contextOptions));
+
+    this->initFeatureSet(featureSet);
+    this->initGrCaps(device);
+    this->initShaderCaps();
+    this->initConfigTable();
+
+    this->applyOptionsOverrides(contextOptions);
+    fShaderCaps->applyOptionsOverrides(contextOptions);
+}
+
+void GrMtlCaps::initFeatureSet(MTLFeatureSet featureSet) {
+    // Mac OSX
+#ifdef SK_BUILD_FOR_MAC
+    if (MTLFeatureSet_OSX_GPUFamily1_v2 == featureSet) {
+        fPlatform = Platform::kMac;
+        fFamilyGroup = 1;
+        fVersion = 2;
+        return;
+    }
+    if (MTLFeatureSet_OSX_GPUFamily1_v1 == featureSet) {
+        fPlatform = Platform::kMac;
+        fFamilyGroup = 1;
+        fVersion = 1;
+        return;
+    }
+#endif
+
+    // iOS Family group 3
+#ifdef SK_BUILD_FOR_IOS
+    if (MTLFeatureSet_iOS_GPUFamily3_v2 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 3;
+        fVersion = 2;
+        return;
+    }
+    if (MTLFeatureSet_iOS_GPUFamily3_v1 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 3;
+        fVersion = 1;
+        return;
+    }
+
+    // iOS Family group 2
+    if (MTLFeatureSet_iOS_GPUFamily2_v3 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 2;
+        fVersion = 3;
+        return;
+    }
+    if (MTLFeatureSet_iOS_GPUFamily2_v2 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 2;
+        fVersion = 2;
+        return;
+    }
+    if (MTLFeatureSet_iOS_GPUFamily2_v1 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 2;
+        fVersion = 1;
+        return;
+    }
+
+    // iOS Family group 1
+    if (MTLFeatureSet_iOS_GPUFamily1_v3 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 1;
+        fVersion = 3;
+        return;
+    }
+    if (MTLFeatureSet_iOS_GPUFamily1_v2 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 1;
+        fVersion = 2;
+        return;
+    }
+    if (MTLFeatureSet_iOS_GPUFamily1_v1 == featureSet) {
+        fPlatform = Platform::kIOS;
+        fFamilyGroup = 1;
+        fVersion = 1;
+        return;
+    }
+#endif
+    // No supported feature sets were found
+    SkFAIL("Requested an unsupported feature set");
+}
+
+void GrMtlCaps::initGrCaps(const id<MTLDevice> device) {
+    // Max vertex attribs is the same on all devices
+    fMaxVertexAttributes = 31;
+
+    // RenderTarget and Texture size
+    if (this->isMac()) {
+        fMaxRenderTargetSize = 16384;
+    } else {
+        if (3 == fFamilyGroup) {
+            fMaxRenderTargetSize = 16384;
+        } else {
+            // Family group 1 and 2 support 8192 for version 2 and above, 4096 for v1
+            if (1 == fVersion) {
+                fMaxRenderTargetSize = 4096;
+            } else {
+                fMaxRenderTargetSize = 8192;
+            }
+        }
+    }
+    fMaxTextureSize = fMaxRenderTargetSize;
+
+    // Init sample counts. All devices support 1 (i.e. 0 in skia).
+    fSampleCounts.push(0);
+    for (auto sampleCnt : {2, 4, 8}) {
+        if ([device supportsTextureSampleCount:sampleCnt]) {
+            fSampleCounts.push(sampleCnt);
+        }
+    }
+
+    // Starting with the assumption that there isn't a reason to not map small buffers.
+    fBufferMapThreshold = 0;
+
+    // Buffers are always fully mapped.
+    fMapBufferFlags = kCanMap_MapFlag;
+
+    fOversizedStencilSupport = true;
+
+    // Looks like there is a field called rasterSampleCount labeled as beta in the Metal docs. This
+    // may be what we eventually need here, but it has no description.
+    fSampleShadingSupport = false;
+
+    fSRGBSupport = true;   // always available in Metal
+    fSRGBWriteControl = false;
+    fMipMapSupport = true;   // always available in Metal
+    fNPOTTextureTileSupport = true;  // always available in Metal
+    fDiscardRenderTargetSupport = true;
+
+    fReuseScratchTextures = true; // Assuming this okay
+
+    fTextureBarrierSupport = false; // Need to figure out if we can do this
+
+    fSampleLocationsSupport = false;
+    fMultisampleDisableSupport = false;
+
+    if (this->isMac() || 3 == fFamilyGroup) {
+        fInstanceAttribSupport = true;
+    }
+
+    fUsesMixedSamples = false;
+    fGpuTracingSupport = false;
+
+    fUseDrawInsteadOfClear = false;
+    fFenceSyncSupport = true;   // always available in Metal
+    fCrossContextTextureSupport = false;
+
+    fMaxColorSampleCount = 4; // minimum required by spec
+    fMaxStencilSampleCount = 4; // minimum required by spec
+}
+
+int GrMtlCaps::getSampleCount(int requestedCount, GrPixelConfig config) const {
+    int count = fSampleCounts.count();
+    SkASSERT(count > 0); // We always add 0 as a valid sample count
+    if (!this->isConfigRenderable(config, true)) {
+        return 0;
+    }
+
+    for (int i = 0; i < count; ++i) {
+        if (fSampleCounts[i] >= requestedCount) {
+            return fSampleCounts[i];
+        }
+    }
+    return fSampleCounts[count-1];
+}
+
+void GrMtlCaps::initShaderCaps() {
+    GrShaderCaps* shaderCaps = fShaderCaps.get();
+
+    // fConfigOutputSwizzle will default to RGBA so we only need to set it for alpha only config.
+    for (int i = 0; i < kGrPixelConfigCnt; ++i) {
+        GrPixelConfig config = static_cast<GrPixelConfig>(i);
+        if (GrPixelConfigIsAlphaOnly(config)) {
+            shaderCaps->fConfigTextureSwizzle[i] = GrSwizzle::RRRR();
+            shaderCaps->fConfigOutputSwizzle[i] = GrSwizzle::AAAA();
+        } else {
+            if (kGray_8_GrPixelConfig == config) {
+                shaderCaps->fConfigTextureSwizzle[i] = GrSwizzle::RRRA();
+            } else {
+                shaderCaps->fConfigTextureSwizzle[i] = GrSwizzle::RGBA();
+            }
+        }
+    }
+
+    // Setting this true with the assumption that this cap will eventually mean we support varying
+    // percisions and not just via modifiers.
+    shaderCaps->fUsesPrecisionModifiers = true;
+    shaderCaps->fFlatInterpolationSupport = true;
+
+    shaderCaps->fShaderDerivativeSupport = true;
+    shaderCaps->fGeometryShaderSupport = false;
+
+    if ((this->isMac() && fVersion >= 2) ||
+        (this->isIOS() && ((1 == fFamilyGroup && 4 == fVersion) ||
+                           (2 == fFamilyGroup && 4 == fVersion) ||
+                           (3 == fFamilyGroup && 3 == fVersion)))) {
+        shaderCaps->fDualSourceBlendingSupport = true;
+    }
+
+    if (this->isIOS()) {
+        shaderCaps->fFBFetchSupport = true;
+        shaderCaps->fFBFetchNeedsCustomOutput = true; // ??
+        shaderCaps->fFBFetchColorName = ""; // Somehow add [[color(0)]] to arguments to frag shader
+    }
+    shaderCaps->fDstReadInShaderSupport = shaderCaps->fFBFetchSupport;
+
+    shaderCaps->fIntegerSupport = true;
+    shaderCaps->fTexelBufferSupport = false;
+    shaderCaps->fTexelFetchSupport = false;
+    shaderCaps->fVertexIDSupport = false;
+    shaderCaps->fImageLoadStoreSupport = false;
+    shaderCaps->fShaderPrecisionVaries = false; // ???
+
+    // Metal uses IEEE float and half floats so using those values here.
+    for (int s = 0; s < kGrShaderTypeCount; ++s) {
+        auto& highp = shaderCaps->fFloatPrecisions[s][kHigh_GrSLPrecision];
+        highp.fLogRangeLow = highp.fLogRangeHigh = 127;
+        highp.fBits = 23;
+
+        auto& mediump = shaderCaps->fFloatPrecisions[s][kMedium_GrSLPrecision];
+        mediump.fLogRangeLow = mediump.fLogRangeHigh = 15;
+        mediump.fBits = 10;
+
+        shaderCaps->fFloatPrecisions[s][kLow_GrSLPrecision] = mediump;
+    }
+    shaderCaps->initSamplerPrecisionTable();
+
+    shaderCaps->fMaxVertexSamplers =
+    shaderCaps->fMaxFragmentSamplers = 16;
+    // For now just cap at the per stage max. If we hit this limit we can come back to adjust this
+    shaderCaps->fMaxCombinedSamplers = shaderCaps->fMaxVertexSamplers;
+}
+
+void GrMtlCaps::initConfigTable() {
+    ConfigInfo* info;
+    // Alpha_8 uses R8Unorm
+    info = &fConfigTable[kAlpha_8_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // Gray_8 uses R8Unorm
+    info = &fConfigTable[kGray_8_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // RGB_565 uses B5G6R5Unorm, even though written opposite this format packs how we want
+    info = &fConfigTable[kRGB_565_GrPixelConfig];
+    if (this->isMac()) {
+        info->fFlags = 0;
+    } else {
+        info->fFlags = ConfigInfo::kAllFlags;
+    }
+
+    // RGBA_4444 uses ABGR4Unorm
+    info = &fConfigTable[kRGBA_4444_GrPixelConfig];
+    if (this->isMac()) {
+        info->fFlags = 0;
+    } else {
+        info->fFlags = ConfigInfo::kAllFlags;
+    }
+
+    // RGBA_8888 uses RGBA8Unorm
+    info = &fConfigTable[kRGBA_8888_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // BGRA_8888 uses BGRA8Unorm
+    info = &fConfigTable[kBGRA_8888_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // SRGBA_8888 uses RGBA8Unorm_sRGB
+    info = &fConfigTable[kSRGBA_8888_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // SBGRA_8888 uses BGRA8Unorm_sRGB
+    info = &fConfigTable[kSBGRA_8888_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // RGBA_8888_sint uses RGBA8Sint
+    info = &fConfigTable[kRGBA_8888_sint_GrPixelConfig];
+    info->fFlags = ConfigInfo::kMSAA_Flag;
+
+    // RGBA_float uses RGBA32Float
+    info = &fConfigTable[kRGBA_float_GrPixelConfig];
+    if (this->isMac()) {
+        info->fFlags = ConfigInfo::kAllFlags;
+    } else {
+        info->fFlags = 0;
+    }
+
+    // RG_float uses RG32Float
+    info = &fConfigTable[kRG_float_GrPixelConfig];
+    if (this->isMac()) {
+        info->fFlags = ConfigInfo::kAllFlags;
+    } else {
+        info->fFlags = ConfigInfo::kRenderable_Flag;
+    }
+
+    // Alpha_half uses R16Float
+    info = &fConfigTable[kAlpha_half_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+
+    // RGBA_half uses RGBA16Float
+    info = &fConfigTable[kRGBA_half_GrPixelConfig];
+    info->fFlags = ConfigInfo::kAllFlags;
+}
diff --git a/src/gpu/mtl/GrMtlGpu.h b/src/gpu/mtl/GrMtlGpu.h
index f150e3034a..53c214943f 100644
--- a/src/gpu/mtl/GrMtlGpu.h
+++ b/src/gpu/mtl/GrMtlGpu.h
@@ -13,6 +13,8 @@
 #include "GrSemaphore.h"
 #include "GrTexture.h"
 
+#include "GrMtlCaps.h"
+
 #import <Metal/Metal.h>
 
 class GrSemaphore;
@@ -24,6 +26,8 @@ public:
                          id<MTLDevice> device, id<MTLCommandQueue> queue);
 
     ~GrMtlGpu() override {}
+ 
+    const GrMtlCaps& mtlCaps() const { return *fMtlCaps.get(); }
 
     bool onGetReadPixelsInfo(GrSurface* srcSurface, int readWidth, int readHeight, size_t rowBytes,
                              GrPixelConfig readConfig, DrawPreference*,
@@ -61,7 +65,7 @@ public:
 
 private:
     GrMtlGpu(GrContext* context, const GrContextOptions& options,
-             id<MTLDevice> device, id<MTLCommandQueue> queue);
+             id<MTLDevice> device, id<MTLCommandQueue> queue, MTLFeatureSet featureSet);
 
     void onResetContext(uint32_t resetBits) override {}
 
@@ -141,6 +145,8 @@ private:
     bool isTestingOnlyBackendTexture(GrBackendObject ) const override { return false; }
     void deleteTestingOnlyBackendTexture(GrBackendObject, bool abandonTexture) override {}
 
+    sk_sp<GrMtlCaps> fMtlCaps;
+
     id<MTLDevice> fDevice;
     id<MTLCommandQueue> fQueue;
 
diff --git a/src/gpu/mtl/GrMtlGpu.mm b/src/gpu/mtl/GrMtlGpu.mm
index 986bb8a6f7..7a9a673d69 100644
--- a/src/gpu/mtl/GrMtlGpu.mm
+++ b/src/gpu/mtl/GrMtlGpu.mm
@@ -11,19 +11,83 @@
 #error This file must be compiled with Arc. Use -fobjc-arc flag
 #endif
 
+static bool get_feature_set(id<MTLDevice> device, MTLFeatureSet* featureSet) {
+    // Mac OSX
+#ifdef SK_BUILD_FOR_MAC
+    if ([device supportsFeatureSet:MTLFeatureSet_OSX_GPUFamily1_v2]) {
+        *featureSet = MTLFeatureSet_OSX_GPUFamily1_v2;
+        return true;
+    }
+    if ([device supportsFeatureSet:MTLFeatureSet_OSX_GPUFamily1_v1]) {
+        *featureSet = MTLFeatureSet_OSX_GPUFamily1_v1;
+        return true;
+    }
+#endif
+
+    // iOS Family group 3
+#ifdef SK_BUILD_FOR_IOS
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily3_v2]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily3_v2;
+        return true;
+    }
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily3_v1]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily3_v1;
+        return true;
+    }
+
+    // iOS Family group 2
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily2_v3]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily2_v3;
+        return true;
+    }
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily2_v2]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily2_v2;
+        return true;
+    }
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily2_v1]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily2_v1;
+        return true;
+    }
+
+    // iOS Family group 1
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily1_v3]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily1_v3;
+        return true;
+    }
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily1_v2]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily1_v2;
+        return true;
+    }
+    if ([device supportsFeatureSet:MTLFeatureSet_iOS_GPUFamily1_v1]) {
+        *featureSet = MTLFeatureSet_iOS_GPUFamily1_v1;
+        return true;
+    }
+#endif
+    // No supported feature sets were found
+    return false;
+}
+
 GrGpu* GrMtlGpu::Create(GrContext* context, const GrContextOptions& options,
                         id<MTLDevice> device, id<MTLCommandQueue> queue) {
     if (!device || !queue) {
         return nullptr;
     }
-    return new GrMtlGpu(context, options, device, queue);
+    MTLFeatureSet featureSet;
+    if (!get_feature_set(device, &featureSet)) {
+        return nullptr;
+    }
+    return new GrMtlGpu(context, options, device, queue, featureSet);
 }
 
 GrMtlGpu::GrMtlGpu(GrContext* context, const GrContextOptions& options,
-                   id<MTLDevice> device, id<MTLCommandQueue> queue)
+                   id<MTLDevice> device, id<MTLCommandQueue> queue, MTLFeatureSet featureSet)
         : INHERITED(context)
         , fDevice(device)
         , fQueue(queue) {
+
+    fMtlCaps.reset(new GrMtlCaps(options, fDevice, featureSet));
+    fCaps = fMtlCaps;
+
     MTLTextureDescriptor* txDesc = [[MTLTextureDescriptor alloc] init];
     txDesc.textureType = MTLTextureType3D;
     txDesc.height = 64;