twitchapon-anim

mtl.go (36020B)

---

 // 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 mtl provides access to Apple's Metal API (https://developer.apple.com/documentation/metal).
 //
 // Package mtl requires macOS version 10.13 or newer.
 //
 // This package is in very early stages of development.
 // The API will change when opportunities for improvement are discovered; it is not yet frozen.
 // Less than 20% of the Metal API surface is implemented.
 // Current functionality is sufficient to render very basic geometry.
 package mtl
 
 import (
 	"errors"
 	"fmt"
 	"unsafe"
 )
 
 // #cgo !ios CFLAGS: -mmacosx-version-min=10.12
 // #cgo LDFLAGS: -framework Metal -framework CoreGraphics -framework Foundation
 //
 // #include <stdlib.h>
 // #include "mtl.h"
 // struct Library Go_Device_MakeLibrary(void * device, _GoString_ source) {
 //     return Device_MakeLibrary(device, _GoStringPtr(source), _GoStringLen(source));
 // }
 import "C"
 
 // FeatureSet defines a specific platform, hardware, and software configuration.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlfeatureset.
 type FeatureSet uint16
 
 // The device feature sets that define specific platform, hardware, and software configurations.
 const (
 	MacOSGPUFamily1V1          FeatureSet = 10000 // The GPU family 1, version 1 feature set for macOS.
 	MacOSGPUFamily1V2          FeatureSet = 10001 // The GPU family 1, version 2 feature set for macOS.
 	MacOSReadWriteTextureTier2 FeatureSet = 10002 // The read-write texture, tier 2 feature set for macOS.
 	MacOSGPUFamily1V3          FeatureSet = 10003 // The GPU family 1, version 3 feature set for macOS.
 	MacOSGPUFamily1V4          FeatureSet = 10004 // The GPU family 1, version 4 feature set for macOS.
 	MacOSGPUFamily2V1          FeatureSet = 10005 // The GPU family 2, version 1 feature set for macOS.
 )
 
 const (
 	FeatureSet_iOS_GPUFamily1_v1           FeatureSet = 0
 	FeatureSet_iOS_GPUFamily1_v2           FeatureSet = 2
 	FeatureSet_iOS_GPUFamily1_v3           FeatureSet = 5
 	FeatureSet_iOS_GPUFamily1_v4           FeatureSet = 8
 	FeatureSet_iOS_GPUFamily1_v5           FeatureSet = 12
 	FeatureSet_iOS_GPUFamily2_v1           FeatureSet = 1
 	FeatureSet_iOS_GPUFamily2_v2           FeatureSet = 3
 	FeatureSet_iOS_GPUFamily2_v3           FeatureSet = 6
 	FeatureSet_iOS_GPUFamily2_v4           FeatureSet = 9
 	FeatureSet_iOS_GPUFamily2_v5           FeatureSet = 13
 	FeatureSet_iOS_GPUFamily3_v1           FeatureSet = 4
 	FeatureSet_iOS_GPUFamily3_v2           FeatureSet = 7
 	FeatureSet_iOS_GPUFamily3_v3           FeatureSet = 10
 	FeatureSet_iOS_GPUFamily3_v4           FeatureSet = 14
 	FeatureSet_iOS_GPUFamily4_v1           FeatureSet = 11
 	FeatureSet_iOS_GPUFamily4_v2           FeatureSet = 15
 	FeatureSet_iOS_GPUFamily5_v1           FeatureSet = 16
 	FeatureSet_tvOS_GPUFamily1_v1          FeatureSet = 30000
 	FeatureSet_tvOS_GPUFamily1_v2          FeatureSet = 30001
 	FeatureSet_tvOS_GPUFamily1_v3          FeatureSet = 30002
 	FeatureSet_tvOS_GPUFamily1_v4          FeatureSet = 30004
 	FeatureSet_tvOS_GPUFamily2_v1          FeatureSet = 30003
 	FeatureSet_tvOS_GPUFamily2_v2          FeatureSet = 30005
 	FeatureSet_macOS_GPUFamily1_v1         FeatureSet = 10000
 	FeatureSet_macOS_GPUFamily1_v2         FeatureSet = 10001
 	FeatureSet_macOS_GPUFamily1_v3         FeatureSet = 10003
 	FeatureSet_macOS_GPUFamily1_v4         FeatureSet = 10004
 	FeatureSet_macOS_GPUFamily2_v1         FeatureSet = 10005
 	FeatureSet_macOS_ReadWriteTextureTier2 FeatureSet = 10002
 )
 
 // TextureType defines The dimension of each image, including whether multiple images are arranged into an array or
 // a cube.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexturetype
 type TextureType uint16
 
 const (
 	TextureType2D TextureType = 2
 )
 
 // PixelFormat defines data formats that describe the organization
 // and characteristics of individual pixels in a texture.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlpixelformat.
 type PixelFormat uint16
 
 // The data formats that describe the organization and characteristics
 // of individual pixels in a texture.
 const (
 	PixelFormatRGBA8UNorm     PixelFormat = 70 // Ordinary format with four 8-bit normalized unsigned integer components in RGBA order.
 	PixelFormatRGBA8UNormSRGB PixelFormat = 71 // Ordinary format with four 8-bit normalized unsigned integer components in RGBA order with conversion between sRGB and linear space.
 	PixelFormatBGRA8UNorm     PixelFormat = 80 // Ordinary format with four 8-bit normalized unsigned integer components in BGRA order.
 	PixelFormatBGRA8UNormSRGB PixelFormat = 81 // Ordinary format with four 8-bit normalized unsigned integer components in BGRA order with conversion between sRGB and linear space.
 )
 
 // PrimitiveType defines geometric primitive types for drawing commands.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlprimitivetype.
 type PrimitiveType uint8
 
 // Geometric primitive types for drawing commands.
 const (
 	PrimitiveTypePoint         PrimitiveType = 0
 	PrimitiveTypeLine          PrimitiveType = 1
 	PrimitiveTypeLineStrip     PrimitiveType = 2
 	PrimitiveTypeTriangle      PrimitiveType = 3
 	PrimitiveTypeTriangleStrip PrimitiveType = 4
 )
 
 // LoadAction defines actions performed at the start of a rendering pass
 // for a render command encoder.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlloadaction.
 type LoadAction uint8
 
 // Actions performed at the start of a rendering pass for a render command encoder.
 const (
 	LoadActionDontCare LoadAction = 0
 	LoadActionLoad     LoadAction = 1
 	LoadActionClear    LoadAction = 2
 )
 
 // StoreAction defines actions performed at the end of a rendering pass
 // for a render command encoder.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlstoreaction.
 type StoreAction uint8
 
 // Actions performed at the end of a rendering pass for a render command encoder.
 const (
 	StoreActionDontCare                   StoreAction = 0
 	StoreActionStore                      StoreAction = 1
 	StoreActionMultisampleResolve         StoreAction = 2
 	StoreActionStoreAndMultisampleResolve StoreAction = 3
 	StoreActionUnknown                    StoreAction = 4
 	StoreActionCustomSampleDepthStore     StoreAction = 5
 )
 
 // StorageMode defines defines the memory location and access permissions of a resource.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlstoragemode.
 type StorageMode uint8
 
 const (
 	// StorageModeShared indicates that the resource is stored in system memory
 	// accessible to both the CPU and the GPU.
 	StorageModeShared StorageMode = 0
 
 	// StorageModeManaged indicates that the resource exists as a synchronized
 	// memory pair with one copy stored in system memory accessible to the CPU
 	// and another copy stored in video memory accessible to the GPU.
 	StorageModeManaged StorageMode = 1
 
 	// StorageModePrivate indicates that the resource is stored in memory
 	// only accessible to the GPU. In iOS and tvOS, the resource is stored in
 	// system memory. In macOS, the resource is stored in video memory.
 	StorageModePrivate StorageMode = 2
 
 	// StorageModeMemoryless indicates that the resource is stored in on-tile memory,
 	// without CPU or GPU memory backing. The contents of the on-tile memory are undefined
 	// and do not persist; the only way to populate the resource is to render into it.
 	// Memoryless resources are limited to temporary render targets (i.e., Textures configured
 	// with a TextureDescriptor and used with a RenderPassAttachmentDescriptor).
 	StorageModeMemoryless StorageMode = 3
 )
 
 // ResourceOptions defines optional arguments used to create
 // and influence behavior of buffer and texture objects.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlresourceoptions.
 type ResourceOptions uint16
 
 const (
 	// ResourceCPUCacheModeDefaultCache is the default CPU cache mode for the resource.
 	// Guarantees that read and write operations are executed in the expected order.
 	ResourceCPUCacheModeDefaultCache ResourceOptions = ResourceOptions(CPUCacheModeDefaultCache) << resourceCPUCacheModeShift
 
 	// ResourceCPUCacheModeWriteCombined is a write-combined CPU cache mode for the resource.
 	// Optimized for resources that the CPU will write into, but never read.
 	ResourceCPUCacheModeWriteCombined ResourceOptions = ResourceOptions(CPUCacheModeWriteCombined) << resourceCPUCacheModeShift
 
 	// ResourceStorageModeShared indicates that the resource is stored in system memory
 	// accessible to both the CPU and the GPU.
 	ResourceStorageModeShared ResourceOptions = ResourceOptions(StorageModeShared) << resourceStorageModeShift
 
 	// ResourceStorageModeManaged indicates that the resource exists as a synchronized
 	// memory pair with one copy stored in system memory accessible to the CPU
 	// and another copy stored in video memory accessible to the GPU.
 	ResourceStorageModeManaged ResourceOptions = ResourceOptions(StorageModeManaged) << resourceStorageModeShift
 
 	// ResourceStorageModePrivate indicates that the resource is stored in memory
 	// only accessible to the GPU. In iOS and tvOS, the resource is stored
 	// in system memory. In macOS, the resource is stored in video memory.
 	ResourceStorageModePrivate ResourceOptions = ResourceOptions(StorageModePrivate) << resourceStorageModeShift
 
 	// ResourceStorageModeMemoryless indicates that the resource is stored in on-tile memory,
 	// without CPU or GPU memory backing. The contents of the on-tile memory are undefined
 	// and do not persist; the only way to populate the resource is to render into it.
 	// Memoryless resources are limited to temporary render targets (i.e., Textures configured
 	// with a TextureDescriptor and used with a RenderPassAttachmentDescriptor).
 	ResourceStorageModeMemoryless ResourceOptions = ResourceOptions(StorageModeMemoryless) << resourceStorageModeShift
 
 	// ResourceHazardTrackingModeUntracked indicates that the command encoder dependencies
 	// for this resource are tracked manually with Fence objects. This value is always set
 	// for resources sub-allocated from a Heap object and may optionally be specified for
 	// non-heap resources.
 	ResourceHazardTrackingModeUntracked ResourceOptions = 1 << resourceHazardTrackingModeShift
 )
 
 const (
 	resourceCPUCacheModeShift       = 0
 	resourceStorageModeShift        = 4
 	resourceHazardTrackingModeShift = 8
 )
 
 // CPUCacheMode is the CPU cache mode that defines the CPU mapping of a resource.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcpucachemode.
 type CPUCacheMode uint8
 
 const (
 	// CPUCacheModeDefaultCache is the default CPU cache mode for the resource.
 	// Guarantees that read and write operations are executed in the expected order.
 	CPUCacheModeDefaultCache CPUCacheMode = 0
 
 	// CPUCacheModeWriteCombined is a write-combined CPU cache mode for the resource.
 	// Optimized for resources that the CPU will write into, but never read.
 	CPUCacheModeWriteCombined CPUCacheMode = 1
 )
 
 // IndexType is the index type for an index buffer that references vertices of geometric primitives.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlstoragemode
 type IndexType uint8
 
 const (
 	// IndexTypeUInt16 is a 16-bit unsigned integer used as a primitive index.
 	IndexTypeUInt16 IndexType = 0
 
 	// IndexTypeUInt32 is a 32-bit unsigned integer used as a primitive index.
 	IndexTypeUInt32 IndexType = 1
 )
 
 type TextureUsage uint8
 
 const (
 	TextureUsageUnknown         TextureUsage = 0x0000
 	TextureUsageShaderRead      TextureUsage = 0x0001
 	TextureUsageShaderWrite     TextureUsage = 0x0002
 	TextureUsageRenderTarget    TextureUsage = 0x0004
 	TextureUsagePixelFormatView TextureUsage = 0x0008
 )
 
 type BlendFactor uint8
 
 const (
 	BlendFactorZero                     BlendFactor = 0
 	BlendFactorOne                      BlendFactor = 1
 	BlendFactorSourceColor              BlendFactor = 2
 	BlendFactorOneMinusSourceColor      BlendFactor = 3
 	BlendFactorSourceAlpha              BlendFactor = 4
 	BlendFactorOneMinusSourceAlpha      BlendFactor = 5
 	BlendFactorDestinationColor         BlendFactor = 6
 	BlendFactorOneMinusDestinationColor BlendFactor = 7
 	BlendFactorDestinationAlpha         BlendFactor = 8
 	BlendFactorOneMinusDestinationAlpha BlendFactor = 9
 	BlendFactorSourceAlphaSaturated     BlendFactor = 10
 	BlendFactorBlendColor               BlendFactor = 11
 	BlendFactorOneMinusBlendColor       BlendFactor = 12
 	BlendFactorBlendAlpha               BlendFactor = 13
 	BlendFactorOneMinusBlendAlpha       BlendFactor = 14
 	BlendFactorSource1Color             BlendFactor = 15
 	BlendFactorOneMinusSource1Color     BlendFactor = 16
 	BlendFactorSource1Alpha             BlendFactor = 17
 	BlendFactorOneMinusSource1Alpha     BlendFactor = 18
 )
 
 // Resource represents a memory allocation for storing specialized data
 // that is accessible to the GPU.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlresource.
 type Resource interface {
 	// resource returns the underlying id<MTLResource> pointer.
 	resource() unsafe.Pointer
 }
 
 // RenderPipelineDescriptor configures new RenderPipelineState objects.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrenderpipelinedescriptor.
 type RenderPipelineDescriptor struct {
 	// VertexFunction is a programmable function that processes individual vertices in a rendering pass.
 	VertexFunction Function
 
 	// FragmentFunction is a programmable function that processes individual fragments in a rendering pass.
 	FragmentFunction Function
 
 	// ColorAttachments is an array of attachments that store color data.
 	ColorAttachments [1]RenderPipelineColorAttachmentDescriptor
 }
 
 // RenderPipelineColorAttachmentDescriptor describes a color render target that specifies
 // the color configuration and color operations associated with a render pipeline.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrenderpipelinecolorattachmentdescriptor.
 type RenderPipelineColorAttachmentDescriptor struct {
 	// PixelFormat is the pixel format of the color attachment's texture.
 	PixelFormat PixelFormat
 
 	BlendingEnabled bool
 
 	DestinationAlphaBlendFactor BlendFactor
 	DestinationRGBBlendFactor   BlendFactor
 	SourceAlphaBlendFactor      BlendFactor
 	SourceRGBBlendFactor        BlendFactor
 }
 
 // RenderPassDescriptor describes a group of render targets that serve as
 // the output destination for pixels generated by a render pass.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrenderpassdescriptor.
 type RenderPassDescriptor struct {
 	// ColorAttachments is array of state information for attachments that store color data.
 	ColorAttachments [1]RenderPassColorAttachmentDescriptor
 }
 
 // RenderPassColorAttachmentDescriptor describes a color render target that serves
 // as the output destination for color pixels generated by a render pass.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrenderpasscolorattachmentdescriptor.
 type RenderPassColorAttachmentDescriptor struct {
 	RenderPassAttachmentDescriptor
 	ClearColor ClearColor
 }
 
 // RenderPassAttachmentDescriptor describes a render target that serves
 // as the output destination for pixels generated by a render pass.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrenderpassattachmentdescriptor.
 type RenderPassAttachmentDescriptor struct {
 	LoadAction  LoadAction
 	StoreAction StoreAction
 	Texture     Texture
 }
 
 // ClearColor is an RGBA value used for a color pixel.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlclearcolor.
 type ClearColor struct {
 	Red, Green, Blue, Alpha float64
 }
 
 // TextureDescriptor configures new Texture objects.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexturedescriptor.
 type TextureDescriptor struct {
 	TextureType TextureType
 	PixelFormat PixelFormat
 	Width       int
 	Height      int
 	StorageMode StorageMode
 	Usage       TextureUsage
 }
 
 // Device is abstract representation of the GPU that
 // serves as the primary interface for a Metal app.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice.
 type Device struct {
 	device unsafe.Pointer
 
 	// Headless indicates whether a device is configured as headless.
 	Headless bool
 
 	// LowPower indicates whether a device is low-power.
 	LowPower bool
 
 	// Name is the name of the device.
 	Name string
 }
 
 // CreateSystemDefaultDevice returns the preferred system default Metal device.
 //
 // Reference: https://developer.apple.com/documentation/metal/1433401-mtlcreatesystemdefaultdevice.
 func CreateSystemDefaultDevice() (Device, error) {
 	d := C.CreateSystemDefaultDevice()
 	if d.Device == nil {
 		return Device{}, errors.New("Metal is not supported on this system")
 	}
 
 	return Device{
 		device:   d.Device,
 		Headless: d.Headless != 0,
 		LowPower: d.LowPower != 0,
 		Name:     C.GoString(d.Name),
 	}, nil
 }
 
 // Device returns the underlying id<MTLDevice> pointer.
 func (d Device) Device() unsafe.Pointer { return d.device }
 
 // SupportsFeatureSet reports whether device d supports feature set fs.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433418-supportsfeatureset.
 func (d Device) SupportsFeatureSet(fs FeatureSet) bool {
 	return C.Device_SupportsFeatureSet(d.device, C.uint16_t(fs)) != 0
 }
 
 // MakeCommandQueue creates a serial command submission queue.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433388-makecommandqueue.
 func (d Device) MakeCommandQueue() CommandQueue {
 	return CommandQueue{C.Device_MakeCommandQueue(d.device)}
 }
 
 // MakeLibrary creates a new library that contains
 // the functions stored in the specified source string.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433431-makelibrary.
 func (d Device) MakeLibrary(source string, opt CompileOptions) (Library, error) {
 	l := C.Go_Device_MakeLibrary(d.device, source) // TODO: opt.
 	if l.Library == nil {
 		return Library{}, errors.New(C.GoString(l.Error))
 	}
 
 	return Library{l.Library}, nil
 }
 
 // MakeRenderPipelineState creates a render pipeline state object.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433369-makerenderpipelinestate.
 func (d Device) MakeRenderPipelineState(rpd RenderPipelineDescriptor) (RenderPipelineState, error) {
 	blendingEnabled := 0
 	if rpd.ColorAttachments[0].BlendingEnabled {
 		blendingEnabled = 1
 	}
 	c := &rpd.ColorAttachments[0]
 	descriptor := C.struct_RenderPipelineDescriptor{
 		VertexFunction:                              rpd.VertexFunction.function,
 		FragmentFunction:                            rpd.FragmentFunction.function,
 		ColorAttachment0PixelFormat:                 C.uint16_t(c.PixelFormat),
 		ColorAttachment0BlendingEnabled:             C.uint8_t(blendingEnabled),
 		ColorAttachment0DestinationAlphaBlendFactor: C.uint8_t(c.DestinationAlphaBlendFactor),
 		ColorAttachment0DestinationRGBBlendFactor:   C.uint8_t(c.DestinationRGBBlendFactor),
 		ColorAttachment0SourceAlphaBlendFactor:      C.uint8_t(c.SourceAlphaBlendFactor),
 		ColorAttachment0SourceRGBBlendFactor:        C.uint8_t(c.SourceRGBBlendFactor),
 	}
 	rps := C.Device_MakeRenderPipelineState(d.device, descriptor)
 	if rps.RenderPipelineState == nil {
 		return RenderPipelineState{}, errors.New(C.GoString(rps.Error))
 	}
 
 	return RenderPipelineState{rps.RenderPipelineState}, nil
 }
 
 // MakeBufferWithBytes allocates a new buffer of a given length
 // and initializes its contents by copying existing data into it.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433429-makebuffer.
 func (d Device) MakeBufferWithBytes(bytes unsafe.Pointer, length uintptr, opt ResourceOptions) Buffer {
 	return Buffer{C.Device_MakeBufferWithBytes(d.device, bytes, C.size_t(length), C.uint16_t(opt))}
 }
 
 // MakeBufferWithLength allocates a new zero-filled buffer of a given length.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433375-newbufferwithlength
 func (d Device) MakeBufferWithLength(length uintptr, opt ResourceOptions) Buffer {
 	return Buffer{C.Device_MakeBufferWithLength(d.device, C.size_t(length), C.uint16_t(opt))}
 }
 
 // MakeTexture creates a texture object with privately owned storage
 // that contains texture state.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldevice/1433425-maketexture.
 func (d Device) MakeTexture(td TextureDescriptor) Texture {
 	descriptor := C.struct_TextureDescriptor{
 		TextureType: C.uint16_t(td.TextureType),
 		PixelFormat: C.uint16_t(td.PixelFormat),
 		Width:       C.uint_t(td.Width),
 		Height:      C.uint_t(td.Height),
 		StorageMode: C.uint8_t(td.StorageMode),
 		Usage:       C.uint8_t(td.Usage),
 	}
 	return Texture{
 		texture: C.Device_MakeTexture(d.device, descriptor),
 	}
 }
 
 // CompileOptions specifies optional compilation settings for
 // the graphics or compute functions within a library.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcompileoptions.
 type CompileOptions struct {
 	// TODO.
 }
 
 // Drawable is a displayable resource that can be rendered or written to.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtldrawable.
 type Drawable interface {
 	// Drawable returns the underlying id<MTLDrawable> pointer.
 	Drawable() unsafe.Pointer
 }
 
 // CommandQueue is a queue that organizes the order
 // in which command buffers are executed by the GPU.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandqueue.
 type CommandQueue struct {
 	commandQueue unsafe.Pointer
 }
 
 func (c CommandQueue) Release() {
 	C.CommandQueue_Release(c.commandQueue)
 }
 
 // MakeCommandBuffer creates a command buffer.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandqueue/1508686-makecommandbuffer.
 func (cq CommandQueue) MakeCommandBuffer() CommandBuffer {
 	return CommandBuffer{C.CommandQueue_MakeCommandBuffer(cq.commandQueue)}
 }
 
 // CommandBuffer is a container that stores encoded commands
 // that are committed to and executed by the GPU.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandbuffer.
 type CommandBuffer struct {
 	commandBuffer unsafe.Pointer
 }
 
 // PresentDrawable registers a drawable presentation to occur as soon as possible.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandbuffer/1443029-presentdrawable.
 func (cb CommandBuffer) PresentDrawable(d Drawable) {
 	C.CommandBuffer_PresentDrawable(cb.commandBuffer, d.Drawable())
 }
 
 // Commit commits this command buffer for execution as soon as possible.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandbuffer/1443003-commit.
 func (cb CommandBuffer) Commit() {
 	C.CommandBuffer_Commit(cb.commandBuffer)
 }
 
 // WaitUntilCompleted waits for the execution of this command buffer to complete.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandbuffer/1443039-waituntilcompleted.
 func (cb CommandBuffer) WaitUntilCompleted() {
 	C.CommandBuffer_WaitUntilCompleted(cb.commandBuffer)
 }
 
 // MakeRenderCommandEncoder creates an encoder object that can
 // encode graphics rendering commands into this command buffer.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandbuffer/1442999-makerendercommandencoder.
 func (cb CommandBuffer) MakeRenderCommandEncoder(rpd RenderPassDescriptor) RenderCommandEncoder {
 	descriptor := C.struct_RenderPassDescriptor{
 		ColorAttachment0LoadAction:  C.uint8_t(rpd.ColorAttachments[0].LoadAction),
 		ColorAttachment0StoreAction: C.uint8_t(rpd.ColorAttachments[0].StoreAction),
 		ColorAttachment0ClearColor: C.struct_ClearColor{
 			Red:   C.double(rpd.ColorAttachments[0].ClearColor.Red),
 			Green: C.double(rpd.ColorAttachments[0].ClearColor.Green),
 			Blue:  C.double(rpd.ColorAttachments[0].ClearColor.Blue),
 			Alpha: C.double(rpd.ColorAttachments[0].ClearColor.Alpha),
 		},
 		ColorAttachment0Texture: rpd.ColorAttachments[0].Texture.texture,
 	}
 	return RenderCommandEncoder{CommandEncoder{C.CommandBuffer_MakeRenderCommandEncoder(cb.commandBuffer, descriptor)}}
 }
 
 // MakeBlitCommandEncoder creates an encoder object that can encode
 // memory operation (blit) commands into this command buffer.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandbuffer/1443001-makeblitcommandencoder.
 func (cb CommandBuffer) MakeBlitCommandEncoder() BlitCommandEncoder {
 	return BlitCommandEncoder{CommandEncoder{C.CommandBuffer_MakeBlitCommandEncoder(cb.commandBuffer)}}
 }
 
 // CommandEncoder is an encoder that writes sequential GPU commands
 // into a command buffer.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandencoder.
 type CommandEncoder struct {
 	commandEncoder unsafe.Pointer
 }
 
 // EndEncoding declares that all command generation from this encoder is completed.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlcommandencoder/1458038-endencoding.
 func (ce CommandEncoder) EndEncoding() {
 	C.CommandEncoder_EndEncoding(ce.commandEncoder)
 }
 
 // RenderCommandEncoder is an encoder that specifies graphics-rendering commands
 // and executes graphics functions.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder.
 type RenderCommandEncoder struct {
 	CommandEncoder
 }
 
 func (rce RenderCommandEncoder) Release() {
 	C.RenderCommandEncoder_Release(rce.commandEncoder)
 }
 
 // SetRenderPipelineState sets the current render pipeline state object.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1515811-setrenderpipelinestate.
 func (rce RenderCommandEncoder) SetRenderPipelineState(rps RenderPipelineState) {
 	C.RenderCommandEncoder_SetRenderPipelineState(rce.commandEncoder, rps.renderPipelineState)
 }
 
 func (rce RenderCommandEncoder) SetViewport(viewport Viewport) {
 	C.RenderCommandEncoder_SetViewport(rce.commandEncoder, viewport.c())
 }
 
 // SetVertexBuffer sets a buffer for the vertex shader function at an index
 // in the buffer argument table with an offset that specifies the start of the data.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1515829-setvertexbuffer.
 func (rce RenderCommandEncoder) SetVertexBuffer(buf Buffer, offset, index int) {
 	C.RenderCommandEncoder_SetVertexBuffer(rce.commandEncoder, buf.buffer, C.uint_t(offset), C.uint_t(index))
 }
 
 // SetVertexBytes sets a block of data for the vertex function.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1515846-setvertexbytes.
 func (rce RenderCommandEncoder) SetVertexBytes(bytes unsafe.Pointer, length uintptr, index int) {
 	C.RenderCommandEncoder_SetVertexBytes(rce.commandEncoder, bytes, C.size_t(length), C.uint_t(index))
 }
 
 func (rce RenderCommandEncoder) SetFragmentBytes(bytes unsafe.Pointer, length uintptr, index int) {
 	C.RenderCommandEncoder_SetFragmentBytes(rce.commandEncoder, bytes, C.size_t(length), C.uint_t(index))
 }
 
 // SetFragmentTexture sets a texture for the fragment function at an index in the texture argument table.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1515390-setfragmenttexture
 func (rce RenderCommandEncoder) SetFragmentTexture(texture Texture, index int) {
 	C.RenderCommandEncoder_SetFragmentTexture(rce.commandEncoder, texture.texture, C.uint_t(index))
 }
 
 func (rce RenderCommandEncoder) SetBlendColor(red, green, blue, alpha float32) {
 	C.RenderCommandEncoder_SetBlendColor(rce.commandEncoder, C.float(red), C.float(green), C.float(blue), C.float(alpha))
 }
 
 // DrawPrimitives renders one instance of primitives using vertex data
 // in contiguous array elements.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1516326-drawprimitives.
 func (rce RenderCommandEncoder) DrawPrimitives(typ PrimitiveType, vertexStart, vertexCount int) {
 	C.RenderCommandEncoder_DrawPrimitives(rce.commandEncoder, C.uint8_t(typ), C.uint_t(vertexStart), C.uint_t(vertexCount))
 }
 
 // DrawIndexedPrimitives encodes a command to render one instance of primitives using an index list specified in a buffer.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1515542-drawindexedprimitives
 func (rce RenderCommandEncoder) DrawIndexedPrimitives(typ PrimitiveType, indexCount int, indexType IndexType, indexBuffer Buffer, indexBufferOffset int) {
 	C.RenderCommandEncoder_DrawIndexedPrimitives(rce.commandEncoder, C.uint8_t(typ), C.uint_t(indexCount), C.uint8_t(indexType), indexBuffer.buffer, C.uint_t(indexBufferOffset))
 }
 
 // BlitCommandEncoder is an encoder that specifies resource copy
 // and resource synchronization commands.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlblitcommandencoder.
 type BlitCommandEncoder struct {
 	CommandEncoder
 }
 
 // Synchronize flushes any copy of the specified resource from its corresponding
 // Device caches and, if needed, invalidates any CPU caches.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlblitcommandencoder/1400775-synchronize.
 func (bce BlitCommandEncoder) Synchronize(resource Resource) {
 	C.BlitCommandEncoder_Synchronize(bce.commandEncoder, resource.resource())
 }
 
 func (bce BlitCommandEncoder) SynchronizeTexture(texture Texture, slice int, level int) {
 	C.BlitCommandEncoder_SynchronizeTexture(bce.commandEncoder, texture.texture, C.uint_t(slice), C.uint_t(level))
 }
 
 func (bce BlitCommandEncoder) CopyFromTexture(sourceTexture Texture, sourceSlice int, sourceLevel int, sourceOrigin Origin, sourceSize Size, destinationTexture Texture, destinationSlice int, destinationLevel int, destinationOrigin Origin) {
 	C.BlitCommandEncoder_CopyFromTexture(bce.commandEncoder, sourceTexture.texture, C.uint_t(sourceSlice), C.uint_t(sourceLevel), sourceOrigin.c(), sourceSize.c(), destinationTexture.texture, C.uint_t(destinationSlice), C.uint_t(destinationLevel), destinationOrigin.c())
 }
 
 // Library is a collection of compiled graphics or compute functions.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtllibrary.
 type Library struct {
 	library unsafe.Pointer
 }
 
 // MakeFunction returns a pre-compiled, non-specialized function.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtllibrary/1515524-makefunction.
 func (l Library) MakeFunction(name string) (Function, error) {
 	f := C.Library_MakeFunction(l.library, C.CString(name))
 	if f == nil {
 		return Function{}, fmt.Errorf("function %q not found", name)
 	}
 
 	return Function{f}, nil
 }
 
 // Texture is a memory allocation for storing formatted
 // image data that is accessible to the GPU.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexture.
 type Texture struct {
 	texture unsafe.Pointer
 }
 
 // NewTexture returns a Texture that wraps an existing id<MTLTexture> pointer.
 func NewTexture(texture unsafe.Pointer) Texture {
 	return Texture{texture: texture}
 }
 
 // resource implements the Resource interface.
 func (t Texture) resource() unsafe.Pointer { return t.texture }
 
 func (t Texture) Release() {
 	C.Texture_Release(t.texture)
 }
 
 // GetBytes copies a block of pixels from the storage allocation of texture
 // slice zero into system memory at a specified address.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexture/1515751-getbytes.
 func (t Texture) GetBytes(pixelBytes *byte, bytesPerRow uintptr, region Region, level int) {
 	r := region.c()
 	C.Texture_GetBytes(t.texture, unsafe.Pointer(pixelBytes), C.size_t(bytesPerRow), r, C.uint_t(level))
 }
 
 // ReplaceRegion copies a block of pixels from the caller's pointer into the storage allocation for slice 0 of a texture.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexture/1515464-replaceregion
 func (t Texture) ReplaceRegion(region Region, level int, pixelBytes unsafe.Pointer, bytesPerRow int) {
 	r := region.c()
 	C.Texture_ReplaceRegion(t.texture, r, C.uint_t(level), pixelBytes, C.uint_t(bytesPerRow))
 }
 
 // Width is the width of the texture image for the base level mipmap, in pixels.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexture/1515339-width
 func (t Texture) Width() int {
 	return int(C.Texture_Width(t.texture))
 }
 
 // Height is the height of the texture image for the base level mipmap, in pixels.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtltexture/1515938-height
 func (t Texture) Height() int {
 	return int(C.Texture_Height(t.texture))
 }
 
 // Buffer is a memory allocation for storing unformatted data
 // that is accessible to the GPU.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlbuffer.
 type Buffer struct {
 	buffer unsafe.Pointer
 }
 
 func (b Buffer) CopyToContents(data unsafe.Pointer, lengthInBytes uintptr) {
 	C.Buffer_CopyToContents(b.buffer, data, C.size_t(lengthInBytes))
 }
 
 func (b Buffer) Retain() {
 	C.Buffer_Retain(b.buffer)
 }
 
 func (b Buffer) Release() {
 	C.Buffer_Release(b.buffer)
 }
 
 func (b Buffer) Native() unsafe.Pointer {
 	return b.buffer
 }
 
 // Function represents a programmable graphics or compute function executed by the GPU.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlfunction.
 type Function struct {
 	function unsafe.Pointer
 }
 
 func (f Function) Release() {
 	C.Function_Release(f.function)
 }
 
 // RenderPipelineState contains the graphics functions
 // and configuration state used in a render pass.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlrenderpipelinestate.
 type RenderPipelineState struct {
 	renderPipelineState unsafe.Pointer
 }
 
 func (r RenderPipelineState) Release() {
 	C.RenderPipelineState_Release(r.renderPipelineState)
 }
 
 // Region is a rectangular block of pixels in an image or texture,
 // defined by its upper-left corner and its size.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlregion.
 type Region struct {
 	Origin Origin // The location of the upper-left corner of the block.
 	Size   Size   // The size of the block.
 }
 
 func (r *Region) c() C.struct_Region {
 	return C.struct_Region{
 		Origin: r.Origin.c(),
 		Size:   r.Size.c(),
 	}
 }
 
 // Origin represents the location of a pixel in an image or texture relative
 // to the upper-left corner, whose coordinates are (0, 0).
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlorigin.
 type Origin struct{ X, Y, Z int }
 
 func (o *Origin) c() C.struct_Origin {
 	return C.struct_Origin{
 		X: C.uint_t(o.X),
 		Y: C.uint_t(o.Y),
 		Z: C.uint_t(o.Z),
 	}
 }
 
 // Size represents the set of dimensions that declare the size of an object,
 // such as an image, texture, threadgroup, or grid.
 //
 // Reference: https://developer.apple.com/documentation/metal/mtlsize.
 type Size struct{ Width, Height, Depth int }
 
 func (s *Size) c() C.struct_Size {
 	return C.struct_Size{
 		Width:  C.uint_t(s.Width),
 		Height: C.uint_t(s.Height),
 		Depth:  C.uint_t(s.Depth),
 	}
 }
 
 // RegionMake2D returns a 2D, rectangular region for image or texture data.
 //
 // Reference: https://developer.apple.com/documentation/metal/1515675-mtlregionmake2d.
 func RegionMake2D(x, y, width, height int) Region {
 	return Region{
 		Origin: Origin{x, y, 0},
 		Size:   Size{width, height, 1},
 	}
 }
 
 type Viewport struct {
 	OriginX float64
 	OriginY float64
 	Width   float64
 	Height  float64
 	ZNear   float64
 	ZFar    float64
 }
 
 func (v *Viewport) c() C.struct_Viewport {
 	return C.struct_Viewport{
 		OriginX: C.double(v.OriginX),
 		OriginY: C.double(v.OriginY),
 		Width:   C.double(v.Width),
 		Height:  C.double(v.Height),
 		ZNear:   C.double(v.ZNear),
 		ZFar:    C.double(v.ZFar),
 	}
 }