twitchapon-anim

graphics.go (30854B)

---

 // Copyright 2018 The Ebiten Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 // +build darwin
 
 package metal
 
 import (
 	"fmt"
 	"strings"
 	"unsafe"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/affine"
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/ca"
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver/metal/mtl"
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
 	"github.com/hajimehoshi/ebiten/v2/internal/thread"
 )
 
 // #cgo CFLAGS: -x objective-c
 // #cgo !ios CFLAGS: -mmacosx-version-min=10.12
 // #cgo LDFLAGS: -framework Foundation
 //
 // #import <Foundation/Foundation.h>
 //
 // static void* allocAutoreleasePool() {
 //   return [[NSAutoreleasePool alloc] init];
 // }
 //
 // static void releaseAutoreleasePool(void* pool) {
 //   [(NSAutoreleasePool*)pool release];
 // }
 import "C"
 
 const source = `#include <metal_stdlib>
 
 #define FILTER_NEAREST {{.FilterNearest}}
 #define FILTER_LINEAR {{.FilterLinear}}
 #define FILTER_SCREEN {{.FilterScreen}}
 
 #define ADDRESS_CLAMP_TO_ZERO {{.AddressClampToZero}}
 #define ADDRESS_REPEAT {{.AddressRepeat}}
 #define ADDRESS_UNSAFE {{.AddressUnsafe}}
 
 using namespace metal;
 
 struct VertexIn {
   packed_float2 position;
   packed_float2 tex;
   packed_float4 color;
 };
 
 struct VertexOut {
   float4 position [[position]];
   float2 tex;
   float4 color;
 };
 
 vertex VertexOut VertexShader(
   uint vid [[vertex_id]],
   const device VertexIn* vertices [[buffer(0)]],
   constant float2& viewport_size [[buffer(1)]]
 ) {
   float4x4 projectionMatrix = float4x4(
     float4(2.0 / viewport_size.x, 0, 0, 0),
     float4(0, 2.0 / viewport_size.y, 0, 0),
     float4(0, 0, 1, 0),
     float4(-1, -1, 0, 1)
   );
 
   VertexIn in = vertices[vid];
   VertexOut out = {
     .position = projectionMatrix * float4(in.position, 0, 1),
     .tex = in.tex,
     .color = in.color,
   };
 
   return out;
 }
 
 float FloorMod(float x, float y) {
   if (x < 0.0) {
     return y - (-x - y * floor(-x/y));
   }
   return x - y * floor(x/y);
 }
 
 template<uint8_t address>
 float2 AdjustTexelByAddress(float2 p, float4 source_region);
 
 template<>
 inline float2 AdjustTexelByAddress<ADDRESS_CLAMP_TO_ZERO>(float2 p, float4 source_region) {
   return p;
 }
 
 template<>
 inline float2 AdjustTexelByAddress<ADDRESS_REPEAT>(float2 p, float4 source_region) {
   float2 o = float2(source_region[0], source_region[1]);
   float2 size = float2(source_region[2] - source_region[0], source_region[3] - source_region[1]);
   return float2(FloorMod((p.x - o.x), size.x) + o.x, FloorMod((p.y - o.y), size.y) + o.y);
 }
 
 template<uint8_t filter, uint8_t address>
 struct ColorFromTexel;
 
 constexpr sampler texture_sampler{filter::nearest};
 
 template<>
 struct ColorFromTexel<FILTER_NEAREST, ADDRESS_UNSAFE> {
   inline float4 Do(VertexOut v, texture2d<float> texture, constant float2& source_size, float scale, constant float4& source_region) {
     float2 p = v.tex;
     return texture.sample(texture_sampler, p);
   }
 };
 
 template<uint8_t address>
 struct ColorFromTexel<FILTER_NEAREST, address> {
   inline float4 Do(VertexOut v, texture2d<float> texture, constant float2& source_size, float scale, constant float4& source_region) {
     float2 p = AdjustTexelByAddress<address>(v.tex, source_region);
     if (source_region[0] <= p.x &&
         source_region[1] <= p.y &&
         p.x < source_region[2] &&
         p.y < source_region[3]) {
       return texture.sample(texture_sampler, p);
     }
     return 0.0;
   }
 };
 
 template<>
 struct ColorFromTexel<FILTER_LINEAR, ADDRESS_UNSAFE> {
   inline float4 Do(VertexOut v, texture2d<float> texture, constant float2& source_size, float scale, constant float4& source_region) {
     const float2 texel_size = 1 / source_size;
 
     // Shift 1/512 [texel] to avoid the tie-breaking issue.
     // As all the vertex positions are aligned to 1/16 [pixel], this shiting should work in most cases.
     float2 p0 = v.tex - texel_size / 2.0 + (texel_size / 512.0);
     float2 p1 = v.tex + texel_size / 2.0 + (texel_size / 512.0);
 
     float4 c0 = texture.sample(texture_sampler, p0);
     float4 c1 = texture.sample(texture_sampler, float2(p1.x, p0.y));
     float4 c2 = texture.sample(texture_sampler, float2(p0.x, p1.y));
     float4 c3 = texture.sample(texture_sampler, p1);
 
     float2 rate = fract(p0 * source_size);
     return mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y);
   }
 };
 
 template<uint8_t address>
 struct ColorFromTexel<FILTER_LINEAR, address> {
   inline float4 Do(VertexOut v, texture2d<float> texture, constant float2& source_size, float scale, constant float4& source_region) {
     const float2 texel_size = 1 / source_size;
 
     // Shift 1/512 [texel] to avoid the tie-breaking issue.
     // As all the vertex positions are aligned to 1/16 [pixel], this shiting should work in most cases.
     float2 p0 = v.tex - texel_size / 2.0 + (texel_size / 512.0);
     float2 p1 = v.tex + texel_size / 2.0 + (texel_size / 512.0);
     p0 = AdjustTexelByAddress<address>(p0, source_region);
     p1 = AdjustTexelByAddress<address>(p1, source_region);
 
     float4 c0 = texture.sample(texture_sampler, p0);
     float4 c1 = texture.sample(texture_sampler, float2(p1.x, p0.y));
     float4 c2 = texture.sample(texture_sampler, float2(p0.x, p1.y));
     float4 c3 = texture.sample(texture_sampler, p1);
 
     if (p0.x < source_region[0]) {
       c0 = 0;
       c2 = 0;
     }
     if (p0.y < source_region[1]) {
       c0 = 0;
       c1 = 0;
     }
     if (source_region[2] <= p1.x) {
       c1 = 0;
       c3 = 0;
     }
     if (source_region[3] <= p1.y) {
       c2 = 0;
       c3 = 0;
     }
 
     float2 rate = fract(p0 * source_size);
     return mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y);
   }
 };
 
 template<uint8_t address>
 struct ColorFromTexel<FILTER_SCREEN, address> {
   inline float4 Do(VertexOut v, texture2d<float> texture, constant float2& source_size, float scale, constant float4& source_region) {
     const float2 texel_size = 1 / source_size;
 
     float2 p0 = v.tex - texel_size / 2.0 / scale + (texel_size / 512.0);
     float2 p1 = v.tex + texel_size / 2.0 / scale + (texel_size / 512.0);
 
     float4 c0 = texture.sample(texture_sampler, p0);
     float4 c1 = texture.sample(texture_sampler, float2(p1.x, p0.y));
     float4 c2 = texture.sample(texture_sampler, float2(p0.x, p1.y));
     float4 c3 = texture.sample(texture_sampler, p1);
 
     float2 rate_center = float2(1.0, 1.0) - texel_size / 2.0 / scale;
     float2 rate = clamp(((fract(p0 * source_size) - rate_center) * scale) + rate_center, 0.0, 1.0);
     return mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y);
   }
 };
 
 template<bool useColorM, uint8_t filter, uint8_t address>
 struct FragmentShaderImpl {
   inline float4 Do(
       VertexOut v,
       texture2d<float> texture,
       constant float2& source_size,
       constant float4x4& color_matrix_body,
       constant float4& color_matrix_translation,
       constant float& scale,
       constant float4& source_region) {
     float4 c = ColorFromTexel<filter, address>().Do(v, texture, source_size, scale, source_region);
     if (useColorM) {
       c.rgb /= c.a + (1.0 - sign(c.a));
       c = (color_matrix_body * c) + color_matrix_translation;
       c *= v.color;
       c.rgb *= c.a;
     } else {
       float4 s = v.color;
       c *= float4(s.r, s.g, s.b, 1.0) * s.a;
     }
     c = min(c, c.a);
     return c;
   }
 };
 
 template<bool useColorM, uint8_t address>
 struct FragmentShaderImpl<useColorM, FILTER_SCREEN, address> {
   inline float4 Do(
       VertexOut v,
       texture2d<float> texture,
       constant float2& source_size,
       constant float4x4& color_matrix_body,
       constant float4& color_matrix_translation,
       constant float& scale,
       constant float4& source_region) {
     return ColorFromTexel<FILTER_SCREEN, address>().Do(v, texture, source_size, scale, source_region);
   }
 };
 
 // Define Foo and FooCp macros to force macro replacement.
 // See "6.10.3.1 Argument substitution" in ISO/IEC 9899.
 
 #define FragmentShaderFunc(useColorM, filter, address) \
   FragmentShaderFuncCp(useColorM, filter, address)
 
 #define FragmentShaderFuncCp(useColorM, filter, address) \
   fragment float4 FragmentShader_##useColorM##_##filter##_##address( \
       VertexOut v [[stage_in]], \
       texture2d<float> texture [[texture(0)]], \
       constant float2& source_size [[buffer(2)]], \
       constant float4x4& color_matrix_body [[buffer(3)]], \
       constant float4& color_matrix_translation [[buffer(4)]], \
       constant float& scale [[buffer(5)]], \
       constant float4& source_region [[buffer(6)]]) { \
     return FragmentShaderImpl<useColorM, filter, address>().Do( \
         v, texture, source_size, color_matrix_body, color_matrix_translation, scale, source_region); \
   }
 
 FragmentShaderFunc(0, FILTER_NEAREST, ADDRESS_CLAMP_TO_ZERO)
 FragmentShaderFunc(0, FILTER_LINEAR, ADDRESS_CLAMP_TO_ZERO)
 FragmentShaderFunc(0, FILTER_NEAREST, ADDRESS_REPEAT)
 FragmentShaderFunc(0, FILTER_LINEAR, ADDRESS_REPEAT)
 FragmentShaderFunc(0, FILTER_NEAREST, ADDRESS_UNSAFE)
 FragmentShaderFunc(0, FILTER_LINEAR, ADDRESS_UNSAFE)
 FragmentShaderFunc(1, FILTER_NEAREST, ADDRESS_CLAMP_TO_ZERO)
 FragmentShaderFunc(1, FILTER_LINEAR, ADDRESS_CLAMP_TO_ZERO)
 FragmentShaderFunc(1, FILTER_NEAREST, ADDRESS_REPEAT)
 FragmentShaderFunc(1, FILTER_LINEAR, ADDRESS_REPEAT)
 FragmentShaderFunc(1, FILTER_NEAREST, ADDRESS_UNSAFE)
 FragmentShaderFunc(1, FILTER_LINEAR, ADDRESS_UNSAFE)
 
 FragmentShaderFunc(0, FILTER_SCREEN, ADDRESS_UNSAFE)
 
 #undef FragmentShaderFuncName
 `
 
 type rpsKey struct {
 	useColorM     bool
 	filter        driver.Filter
 	address       driver.Address
 	compositeMode driver.CompositeMode
 	screen        bool
 }
 
 type Graphics struct {
 	view view
 
 	screenRPS mtl.RenderPipelineState
 	rpss      map[rpsKey]mtl.RenderPipelineState
 	cq        mtl.CommandQueue
 	cb        mtl.CommandBuffer
 
 	screenDrawable ca.MetalDrawable
 
 	vb mtl.Buffer
 	ib mtl.Buffer
 
 	images      map[driver.ImageID]*Image
 	nextImageID driver.ImageID
 
 	shaders      map[driver.ShaderID]*Shader
 	nextShaderID driver.ShaderID
 
 	src *Image
 	dst *Image
 
 	transparent  bool
 	maxImageSize int
 	tmpTexture   mtl.Texture
 
 	t *thread.Thread
 
 	pool unsafe.Pointer
 }
 
 var theGraphics Graphics
 
 func Get() *Graphics {
 	return &theGraphics
 }
 
 func (g *Graphics) SetThread(thread *thread.Thread) {
 	g.t = thread
 }
 
 func (g *Graphics) Begin() {
 	g.t.Call(func() error {
 		// NSAutoreleasePool is required to release drawable correctly (#847).
 		// https://developer.apple.com/library/archive/documentation/3DDrawing/Conceptual/MTLBestPracticesGuide/Drawables.html
 		g.pool = C.allocAutoreleasePool()
 		return nil
 	})
 }
 
 func (g *Graphics) End() {
 	g.flushIfNeeded(false, true)
 	g.t.Call(func() error {
 		g.screenDrawable = ca.MetalDrawable{}
 		C.releaseAutoreleasePool(g.pool)
 		g.pool = nil
 		return nil
 	})
 }
 
 func (g *Graphics) SetWindow(window uintptr) {
 	g.t.Call(func() error {
 		// Note that [NSApp mainWindow] returns nil when the window is borderless.
 		// Then the window is needed to be given explicitly.
 		g.view.setWindow(window)
 		return nil
 	})
 }
 
 func (g *Graphics) SetUIView(uiview uintptr) {
 	// TODO: Should this be called on the main thread?
 	g.view.setUIView(uiview)
 }
 
 func (g *Graphics) SetVertices(vertices []float32, indices []uint16) {
 	g.t.Call(func() error {
 		if g.vb != (mtl.Buffer{}) {
 			g.vb.Release()
 		}
 		if g.ib != (mtl.Buffer{}) {
 			g.ib.Release()
 		}
 		g.vb = g.view.getMTLDevice().MakeBufferWithBytes(unsafe.Pointer(&vertices[0]), unsafe.Sizeof(vertices[0])*uintptr(len(vertices)), resourceStorageMode)
 		g.ib = g.view.getMTLDevice().MakeBufferWithBytes(unsafe.Pointer(&indices[0]), unsafe.Sizeof(indices[0])*uintptr(len(indices)), resourceStorageMode)
 		return nil
 	})
 }
 
 func (g *Graphics) flushIfNeeded(wait bool, present bool) {
 	g.t.Call(func() error {
 		if g.cb == (mtl.CommandBuffer{}) {
 			return nil
 		}
 
 		if present && g.screenDrawable != (ca.MetalDrawable{}) {
 			g.cb.PresentDrawable(g.screenDrawable)
 		}
 		g.cb.Commit()
 		if wait {
 			g.cb.WaitUntilCompleted()
 		}
 
 		g.cb = mtl.CommandBuffer{}
 
 		return nil
 	})
 }
 
 func (g *Graphics) checkSize(width, height int) {
 	if width < 1 {
 		panic(fmt.Sprintf("metal: width (%d) must be equal or more than %d", width, 1))
 	}
 	if height < 1 {
 		panic(fmt.Sprintf("metal: height (%d) must be equal or more than %d", height, 1))
 	}
 	m := g.MaxImageSize()
 	if width > m {
 		panic(fmt.Sprintf("metal: width (%d) must be less than or equal to %d", width, m))
 	}
 	if height > m {
 		panic(fmt.Sprintf("metal: height (%d) must be less than or equal to %d", height, m))
 	}
 }
 
 func (g *Graphics) genNextImageID() driver.ImageID {
 	id := g.nextImageID
 	g.nextImageID++
 	return id
 }
 
 func (g *Graphics) InvalidImageID() driver.ImageID {
 	return -1
 }
 
 func (g *Graphics) genNextShaderID() driver.ShaderID {
 	id := g.nextShaderID
 	g.nextShaderID++
 	return id
 }
 
 func (g *Graphics) NewImage(width, height int) (driver.Image, error) {
 	g.checkSize(width, height)
 	td := mtl.TextureDescriptor{
 		TextureType: mtl.TextureType2D,
 		PixelFormat: mtl.PixelFormatRGBA8UNorm,
 		Width:       graphics.InternalImageSize(width),
 		Height:      graphics.InternalImageSize(height),
 		StorageMode: storageMode,
 		Usage:       mtl.TextureUsageShaderRead | mtl.TextureUsageRenderTarget,
 	}
 	var t mtl.Texture
 	g.t.Call(func() error {
 		t = g.view.getMTLDevice().MakeTexture(td)
 		return nil
 	})
 	i := &Image{
 		id:       g.genNextImageID(),
 		graphics: g,
 		width:    width,
 		height:   height,
 		texture:  t,
 	}
 	g.addImage(i)
 	return i, nil
 }
 
 func (g *Graphics) NewScreenFramebufferImage(width, height int) (driver.Image, error) {
 	g.t.Call(func() error {
 		g.view.setDrawableSize(width, height)
 		return nil
 	})
 	i := &Image{
 		id:       g.genNextImageID(),
 		graphics: g,
 		width:    width,
 		height:   height,
 		screen:   true,
 	}
 	g.addImage(i)
 	return i, nil
 }
 
 func (g *Graphics) addImage(img *Image) {
 	if g.images == nil {
 		g.images = map[driver.ImageID]*Image{}
 	}
 	if _, ok := g.images[img.id]; ok {
 		panic(fmt.Sprintf("opengl: image ID %d was already registered", img.id))
 	}
 	g.images[img.id] = img
 }
 
 func (g *Graphics) removeImage(img *Image) {
 	delete(g.images, img.id)
 }
 
 func (g *Graphics) SetTransparent(transparent bool) {
 	g.transparent = transparent
 }
 
 func operationToBlendFactor(c driver.Operation) mtl.BlendFactor {
 	switch c {
 	case driver.Zero:
 		return mtl.BlendFactorZero
 	case driver.One:
 		return mtl.BlendFactorOne
 	case driver.SrcAlpha:
 		return mtl.BlendFactorSourceAlpha
 	case driver.DstAlpha:
 		return mtl.BlendFactorDestinationAlpha
 	case driver.OneMinusSrcAlpha:
 		return mtl.BlendFactorOneMinusSourceAlpha
 	case driver.OneMinusDstAlpha:
 		return mtl.BlendFactorOneMinusDestinationAlpha
 	case driver.DstColor:
 		return mtl.BlendFactorDestinationColor
 	default:
 		panic(fmt.Sprintf("metal: invalid operation: %d", c))
 	}
 }
 
 func (g *Graphics) Reset() error {
 	if err := g.t.Call(func() error {
 		if g.cq != (mtl.CommandQueue{}) {
 			g.cq.Release()
 			g.cq = mtl.CommandQueue{}
 		}
 
 		// TODO: Release existing rpss
 		if g.rpss == nil {
 			g.rpss = map[rpsKey]mtl.RenderPipelineState{}
 		}
 
 		if err := g.view.reset(); err != nil {
 			return err
 		}
 		if g.transparent {
 			g.view.ml.SetOpaque(false)
 		}
 
 		replaces := map[string]string{
 			"{{.FilterNearest}}":      fmt.Sprintf("%d", driver.FilterNearest),
 			"{{.FilterLinear}}":       fmt.Sprintf("%d", driver.FilterLinear),
 			"{{.FilterScreen}}":       fmt.Sprintf("%d", driver.FilterScreen),
 			"{{.AddressClampToZero}}": fmt.Sprintf("%d", driver.AddressClampToZero),
 			"{{.AddressRepeat}}":      fmt.Sprintf("%d", driver.AddressRepeat),
 			"{{.AddressUnsafe}}":      fmt.Sprintf("%d", driver.AddressUnsafe),
 		}
 		src := source
 		for k, v := range replaces {
 			src = strings.Replace(src, k, v, -1)
 		}
 
 		lib, err := g.view.getMTLDevice().MakeLibrary(src, mtl.CompileOptions{})
 		if err != nil {
 			return err
 		}
 		vs, err := lib.MakeFunction("VertexShader")
 		if err != nil {
 			return err
 		}
 		fs, err := lib.MakeFunction(
 			fmt.Sprintf("FragmentShader_%d_%d_%d", 0, driver.FilterScreen, driver.AddressUnsafe))
 		if err != nil {
 			return err
 		}
 		rpld := mtl.RenderPipelineDescriptor{
 			VertexFunction:   vs,
 			FragmentFunction: fs,
 		}
 		rpld.ColorAttachments[0].PixelFormat = g.view.colorPixelFormat()
 		rpld.ColorAttachments[0].BlendingEnabled = true
 		rpld.ColorAttachments[0].DestinationAlphaBlendFactor = mtl.BlendFactorZero
 		rpld.ColorAttachments[0].DestinationRGBBlendFactor = mtl.BlendFactorZero
 		rpld.ColorAttachments[0].SourceAlphaBlendFactor = mtl.BlendFactorOne
 		rpld.ColorAttachments[0].SourceRGBBlendFactor = mtl.BlendFactorOne
 		rps, err := g.view.getMTLDevice().MakeRenderPipelineState(rpld)
 		if err != nil {
 			return err
 		}
 		g.screenRPS = rps
 
 		for _, screen := range []bool{false, true} {
 			for _, cm := range []bool{false, true} {
 				for _, a := range []driver.Address{
 					driver.AddressClampToZero,
 					driver.AddressRepeat,
 					driver.AddressUnsafe,
 				} {
 					for _, f := range []driver.Filter{
 						driver.FilterNearest,
 						driver.FilterLinear,
 					} {
 						for c := driver.CompositeModeSourceOver; c <= driver.CompositeModeMax; c++ {
 							cmi := 0
 							if cm {
 								cmi = 1
 							}
 							fs, err := lib.MakeFunction(fmt.Sprintf("FragmentShader_%d_%d_%d", cmi, f, a))
 							if err != nil {
 								return err
 							}
 							rpld := mtl.RenderPipelineDescriptor{
 								VertexFunction:   vs,
 								FragmentFunction: fs,
 							}
 
 							pix := mtl.PixelFormatRGBA8UNorm
 							if screen {
 								pix = g.view.colorPixelFormat()
 							}
 							rpld.ColorAttachments[0].PixelFormat = pix
 							rpld.ColorAttachments[0].BlendingEnabled = true
 
 							src, dst := c.Operations()
 							rpld.ColorAttachments[0].DestinationAlphaBlendFactor = operationToBlendFactor(dst)
 							rpld.ColorAttachments[0].DestinationRGBBlendFactor = operationToBlendFactor(dst)
 							rpld.ColorAttachments[0].SourceAlphaBlendFactor = operationToBlendFactor(src)
 							rpld.ColorAttachments[0].SourceRGBBlendFactor = operationToBlendFactor(src)
 							rps, err := g.view.getMTLDevice().MakeRenderPipelineState(rpld)
 							if err != nil {
 								return err
 							}
 							g.rpss[rpsKey{
 								screen:        screen,
 								useColorM:     cm,
 								filter:        f,
 								address:       a,
 								compositeMode: c,
 							}] = rps
 						}
 					}
 				}
 			}
 		}
 
 		g.cq = g.view.getMTLDevice().MakeCommandQueue()
 		return nil
 	}); err != nil {
 		return err
 	}
 
 	return nil
 }
 
 func (g *Graphics) draw(rps mtl.RenderPipelineState, dst *Image, srcs [graphics.ShaderImageNum]*Image, indexLen int, indexOffset int, uniforms []interface{}) error {
 	g.view.update()
 
 	rpd := mtl.RenderPassDescriptor{}
 	// Even though the destination pixels are not used, mtl.LoadActionDontCare might cause glitches
 	// (#1019). Always using mtl.LoadActionLoad is safe.
 	rpd.ColorAttachments[0].LoadAction = mtl.LoadActionLoad
 	rpd.ColorAttachments[0].StoreAction = mtl.StoreActionStore
 
 	var t mtl.Texture
 	if dst.screen {
 		if g.screenDrawable == (ca.MetalDrawable{}) {
 			drawable := g.view.drawable()
 			if drawable == (ca.MetalDrawable{}) {
 				return nil
 			}
 			g.screenDrawable = drawable
 		}
 		t = g.screenDrawable.Texture()
 	} else {
 		t = dst.texture
 	}
 	rpd.ColorAttachments[0].Texture = t
 	rpd.ColorAttachments[0].ClearColor = mtl.ClearColor{}
 
 	if g.cb == (mtl.CommandBuffer{}) {
 		g.cb = g.cq.MakeCommandBuffer()
 	}
 	rce := g.cb.MakeRenderCommandEncoder(rpd)
 	rce.SetRenderPipelineState(rps)
 
 	// In Metal, the NDC's Y direction (upward) and the framebuffer's Y direction (downward) don't
 	// match. Then, the Y direction must be inverted.
 	w, h := dst.internalSize()
 	rce.SetViewport(mtl.Viewport{
 		OriginX: 0,
 		OriginY: float64(h),
 		Width:   float64(w),
 		Height:  -float64(h),
 		ZNear:   -1,
 		ZFar:    1,
 	})
 	rce.SetVertexBuffer(g.vb, 0, 0)
 
 	for i, u := range uniforms {
 		switch u := u.(type) {
 		case float32:
 			rce.SetVertexBytes(unsafe.Pointer(&u), unsafe.Sizeof(u), i+1)
 			rce.SetFragmentBytes(unsafe.Pointer(&u), unsafe.Sizeof(u), i+1)
 		case []float32:
 			rce.SetVertexBytes(unsafe.Pointer(&u[0]), unsafe.Sizeof(u[0])*uintptr(len(u)), i+1)
 			rce.SetFragmentBytes(unsafe.Pointer(&u[0]), unsafe.Sizeof(u[0])*uintptr(len(u)), i+1)
 		default:
 			return fmt.Errorf("metal: unexpected uniform value: %[1]v (type: %[1]T)", u)
 		}
 	}
 
 	for i, src := range srcs {
 		if src != nil {
 			rce.SetFragmentTexture(src.texture, i)
 		} else {
 			rce.SetFragmentTexture(mtl.Texture{}, i)
 		}
 	}
 	rce.DrawIndexedPrimitives(mtl.PrimitiveTypeTriangle, indexLen, mtl.IndexTypeUInt16, g.ib, indexOffset*2)
 	rce.EndEncoding()
 	return nil
 }
 
 func (g *Graphics) Draw(dstID, srcID driver.ImageID, indexLen int, indexOffset int, mode driver.CompositeMode, colorM *affine.ColorM, filter driver.Filter, address driver.Address, sourceRegion driver.Region) error {
 	dst := g.images[dstID]
 	srcs := [graphics.ShaderImageNum]*Image{g.images[srcID]}
 
 	var rps mtl.RenderPipelineState
 	if dst.screen && filter == driver.FilterScreen {
 		rps = g.screenRPS
 	} else {
 		rps = g.rpss[rpsKey{
 			screen:        dst.screen,
 			useColorM:     colorM != nil,
 			filter:        filter,
 			address:       address,
 			compositeMode: mode,
 		}]
 	}
 
 	if err := g.t.Call(func() error {
 		w, h := dst.internalSize()
 		sourceSize := []float32{0, 0}
 		if filter != driver.FilterNearest {
 			w, h := srcs[0].internalSize()
 			sourceSize[0] = float32(w)
 			sourceSize[1] = float32(h)
 		}
 		esBody, esTranslate := colorM.UnsafeElements()
 		scale := float32(0)
 		if filter == driver.FilterScreen {
 			scale = float32(dst.width) / float32(srcs[0].width)
 		}
 		uniforms := []interface{}{
 			[]float32{float32(w), float32(h)},
 			sourceSize,
 			esBody,
 			esTranslate,
 			scale,
 			[]float32{
 				sourceRegion.X,
 				sourceRegion.Y,
 				sourceRegion.X + sourceRegion.Width,
 				sourceRegion.Y + sourceRegion.Height,
 			},
 		}
 		if err := g.draw(rps, dst, srcs, indexLen, indexOffset, uniforms); err != nil {
 			return err
 		}
 		return nil
 	}); err != nil {
 		return err
 	}
 	return nil
 }
 
 func (g *Graphics) SetVsyncEnabled(enabled bool) {
 	g.view.setDisplaySyncEnabled(enabled)
 }
 
 func (g *Graphics) FramebufferYDirection() driver.YDirection {
 	return driver.Downward
 }
 
 func (g *Graphics) NeedsRestoring() bool {
 	return false
 }
 
 func (g *Graphics) IsGL() bool {
 	return false
 }
 
 func (g *Graphics) HasHighPrecisionFloat() bool {
 	return true
 }
 
 func (g *Graphics) MaxImageSize() int {
 	m := 0
 	g.t.Call(func() error {
 		if g.maxImageSize == 0 {
 			g.maxImageSize = 4096
 			// https://developer.apple.com/metal/Metal-Feature-Set-Tables.pdf
 			switch {
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily5_v1):
 				g.maxImageSize = 16384
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily4_v1):
 				g.maxImageSize = 16384
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily3_v1):
 				g.maxImageSize = 16384
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily2_v2):
 				g.maxImageSize = 8192
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily2_v1):
 				g.maxImageSize = 4096
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily1_v2):
 				g.maxImageSize = 8192
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_iOS_GPUFamily1_v1):
 				g.maxImageSize = 4096
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_tvOS_GPUFamily2_v1):
 				g.maxImageSize = 16384
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_tvOS_GPUFamily1_v1):
 				g.maxImageSize = 8192
 			case g.view.getMTLDevice().SupportsFeatureSet(mtl.FeatureSet_macOS_GPUFamily1_v1):
 				g.maxImageSize = 16384
 			default:
 				panic("metal: there is no supported feature set")
 			}
 		}
 		m = g.maxImageSize
 		return nil
 	})
 	return m
 }
 
 func (g *Graphics) NewShader(program *shaderir.Program) (driver.Shader, error) {
 	var s *Shader
 	if err := g.t.Call(func() error {
 		var err error
 		s, err = newShader(g.view.getMTLDevice(), g.genNextShaderID(), program)
 		if err != nil {
 			return err
 		}
 		return nil
 	}); err != nil {
 		return nil, err
 	}
 	g.addShader(s)
 	return s, nil
 }
 
 func (g *Graphics) addShader(shader *Shader) {
 	if g.shaders == nil {
 		g.shaders = map[driver.ShaderID]*Shader{}
 	}
 	if _, ok := g.shaders[shader.id]; ok {
 		panic(fmt.Sprintf("metal: shader ID %d was already registered", shader.id))
 	}
 	g.shaders[shader.id] = shader
 }
 
 func (g *Graphics) removeShader(shader *Shader) {
 	delete(g.shaders, shader.id)
 }
 
 type Image struct {
 	id       driver.ImageID
 	graphics *Graphics
 	width    int
 	height   int
 	screen   bool
 	texture  mtl.Texture
 }
 
 func (i *Image) ID() driver.ImageID {
 	return i.id
 }
 
 func (i *Image) internalSize() (int, int) {
 	if i.screen {
 		return i.width, i.height
 	}
 	return graphics.InternalImageSize(i.width), graphics.InternalImageSize(i.height)
 }
 
 func (i *Image) Dispose() {
 	i.graphics.t.Call(func() error {
 		if i.texture != (mtl.Texture{}) {
 			i.texture.Release()
 			i.texture = mtl.Texture{}
 		}
 		return nil
 	})
 	i.graphics.removeImage(i)
 }
 
 func (i *Image) IsInvalidated() bool {
 	// TODO: Does Metal cause context lost?
 	// https://developer.apple.com/documentation/metal/mtlresource/1515898-setpurgeablestate
 	// https://developer.apple.com/documentation/metal/mtldevicenotificationhandler
 	return false
 }
 
 func (i *Image) syncTexture() {
 	// Calling SynchronizeTexture is ignored on iOS (see mtl.m), but it looks like committing BliCommandEncoder
 	// is necessary (#1337).
 	i.graphics.t.Call(func() error {
 		if i.graphics.cb != (mtl.CommandBuffer{}) {
 			panic("metal: command buffer must be empty at syncTexture: flushIfNeeded is not called yet?")
 		}
 
 		cb := i.graphics.cq.MakeCommandBuffer()
 		bce := cb.MakeBlitCommandEncoder()
 		bce.SynchronizeTexture(i.texture, 0, 0)
 		bce.EndEncoding()
 		cb.Commit()
 		cb.WaitUntilCompleted()
 		return nil
 	})
 }
 
 func (i *Image) Pixels() ([]byte, error) {
 	i.graphics.flushIfNeeded(true, false)
 	i.syncTexture()
 
 	b := make([]byte, 4*i.width*i.height)
 	i.graphics.t.Call(func() error {
 		i.texture.GetBytes(&b[0], uintptr(4*i.width), mtl.Region{
 			Size: mtl.Size{Width: i.width, Height: i.height, Depth: 1},
 		}, 0)
 		return nil
 	})
 	return b, nil
 }
 
 func (i *Image) ReplacePixels(args []*driver.ReplacePixelsArgs) {
 	g := i.graphics
 	g.flushIfNeeded(true, false)
 
 	// If the memory is shared (e.g., iOS), texture data doen't have to be synced. Send the data directly.
 	if storageMode == mtl.StorageModeShared {
 		g.t.Call(func() error {
 			for _, a := range args {
 				i.texture.ReplaceRegion(mtl.Region{
 					Origin: mtl.Origin{X: a.X, Y: a.Y, Z: 0},
 					Size:   mtl.Size{Width: a.Width, Height: a.Height, Depth: 1},
 				}, 0, unsafe.Pointer(&a.Pixels[0]), 4*a.Width)
 			}
 			return nil
 		})
 		return
 	}
 
 	// If the memory is managed (e.g., macOS), texture data cannot be sent to the destination directly because
 	// this requires synchronizing data between CPU and GPU. As synchronizing is inefficient, let's send the
 	// data to a temporary texture once, and then copy it in GPU.
 	g.t.Call(func() error {
 		w, h := i.texture.Width(), i.texture.Height()
 		if g.tmpTexture == (mtl.Texture{}) || w > g.tmpTexture.Width() || h > g.tmpTexture.Height() {
 			if g.tmpTexture != (mtl.Texture{}) {
 				g.tmpTexture.Release()
 			}
 			td := mtl.TextureDescriptor{
 				TextureType: mtl.TextureType2D,
 				PixelFormat: mtl.PixelFormatRGBA8UNorm,
 				Width:       w,
 				Height:      h,
 				StorageMode: storageMode,
 				Usage:       mtl.TextureUsageShaderRead | mtl.TextureUsageRenderTarget,
 			}
 			g.tmpTexture = g.view.getMTLDevice().MakeTexture(td)
 		}
 
 		for _, a := range args {
 			g.tmpTexture.ReplaceRegion(mtl.Region{
 				Origin: mtl.Origin{X: a.X, Y: a.Y, Z: 0},
 				Size:   mtl.Size{Width: a.Width, Height: a.Height, Depth: 1},
 			}, 0, unsafe.Pointer(&a.Pixels[0]), 4*a.Width)
 		}
 
 		if g.cb == (mtl.CommandBuffer{}) {
 			g.cb = i.graphics.cq.MakeCommandBuffer()
 		}
 		bce := g.cb.MakeBlitCommandEncoder()
 		for _, a := range args {
 			o := mtl.Origin{X: a.X, Y: a.Y, Z: 0}
 			s := mtl.Size{Width: a.Width, Height: a.Height, Depth: 1}
 			bce.CopyFromTexture(g.tmpTexture, 0, 0, o, s, i.texture, 0, 0, o)
 		}
 		bce.EndEncoding()
 
 		return nil
 	})
 }
 
 func (g *Graphics) DrawShader(dstID driver.ImageID, srcIDs [graphics.ShaderImageNum]driver.ImageID, offsets [graphics.ShaderImageNum - 1][2]float32, shader driver.ShaderID, indexLen int, indexOffset int, sourceRegion driver.Region, mode driver.CompositeMode, uniforms []interface{}) error {
 	dst := g.images[dstID]
 	var srcs [graphics.ShaderImageNum]*Image
 	for i, srcID := range srcIDs {
 		srcs[i] = g.images[srcID]
 	}
 
 	if err := g.t.Call(func() error {
 		rps, err := g.shaders[shader].RenderPipelineState(g.view.getMTLDevice(), mode)
 		if err != nil {
 			return err
 		}
 
 		us := make([]interface{}, graphics.PreservedUniformVariablesNum+len(uniforms))
 
 		// Set the destination texture size.
 		dw, dh := dst.internalSize()
 		us[graphics.DestinationTextureSizeUniformVariableIndex] = []float32{float32(dw), float32(dh)}
 
 		// Set the source texture sizes.
 		usizes := make([]float32, 2*len(srcs))
 		for i, src := range srcs {
 			if src != nil {
 				w, h := src.internalSize()
 				usizes[2*i] = float32(w)
 				usizes[2*i+1] = float32(h)
 			}
 		}
 		us[graphics.TextureSizesUniformVariableIndex] = usizes
 
 		// Set the source offsets.
 		uoffsets := make([]float32, 2*len(offsets))
 		for i, offset := range offsets {
 			uoffsets[2*i] = offset[0]
 			uoffsets[2*i+1] = offset[1]
 		}
 		us[graphics.TextureSourceOffsetsUniformVariableIndex] = uoffsets
 
 		// Set the source region's origin of texture0.
 		uorigin := []float32{float32(sourceRegion.X), float32(sourceRegion.Y)}
 		us[graphics.TextureSourceRegionOriginUniformVariableIndex] = uorigin
 
 		// Set the source region's size of texture0.
 		ussize := []float32{float32(sourceRegion.Width), float32(sourceRegion.Height)}
 		us[graphics.TextureSourceRegionSizeUniformVariableIndex] = ussize
 
 		// Set the additional uniform variables.
 		for i, v := range uniforms {
 			const offset = graphics.PreservedUniformVariablesNum
 			us[offset+i] = v
 		}
 
 		if err := g.draw(rps, dst, srcs, indexLen, indexOffset, us); err != nil {
 			return err
 		}
 		return nil
 	}); err != nil {
 		return err
 	}
 	return nil
 }