[MetaballsKit] Do not compute a texture, just provide buffers for balls and parameter data

This commit is contained in:
Eryn Wells 2017-08-05 11:10:06 -07:00
parent 2441bd0b76
commit 8b4f2d8cc2

View file

@ -14,13 +14,13 @@ public enum MetaballsError: Error {
}
public struct Ball {
let radius: CGFloat
var position = CGPoint()
var velocity = CGVector()
let radius: Float
var position = Point()
var velocity = Vector()
internal var bounds: CGRect {
let diameter = radius * 2
return CGRect(x: position.x - radius, y: position.y - radius, width: diameter, height: diameter)
let diameter = CGFloat(radius * 2)
return CGRect(x: CGFloat(position.x - radius), y: CGFloat(position.y - radius), width: diameter, height: diameter)
}
internal mutating func update() {
@ -29,22 +29,35 @@ public struct Ball {
}
}
extension Ball: CustomStringConvertible {
public var description: String {
return "<Ball p:\(position), r:\(radius), v:\(velocity)>"
}
}
public class Field {
public var size: CGSize {
didSet {
if size != oldValue {
NSLog("Updating size of field: old:\(oldValue), new:\(size)")
let numberOfBallsBeforeFilter = balls.count
// Remove balls that fall outside the new bounds.
balls = balls.filter { bounds.contains($0.bounds) }
// Update Metal state as needed.
updateThreadgroupSizes(withFieldSize: size)
parametersBuffer = nil
sampleTexture = nil
// updateThreadgroupSizes(withFieldSize: size)
// parametersBuffer = nil
// sampleTexture = nil
if numberOfBallsBeforeFilter != balls.count {
ballBuffer = nil
}
do {
try updateBuffers()
} catch let e {
NSLog("Error updating size: \(e)")
return
}
}
}
}
@ -65,9 +78,9 @@ public class Field {
// Update position of ball.
ball.update()
if !selfBounds.contains(ball.position) {
if !selfBounds.contains(ball.position.CGPoint) {
// Degenerate case. If the ball finds itself outside the bounds of the field, plop it back in the center.
ball.position = CGPoint(x: selfBounds.midX, y: selfBounds.midY)
ball.position = Point(x: Float(selfBounds.midX), y: Float(selfBounds.midY))
} else {
// Do collision detection with walls.
let ballBounds = ball.bounds
@ -83,33 +96,33 @@ public class Field {
}
}
public func add(ballWithRadius radius: CGFloat) {
NSLog("Adding ball with r=\(radius); fieldSize=\(size)")
let insetBounds = bounds.insetBy(dx: radius, dy: radius)
public func add(ballWithRadius radius: Float) {
let insetBounds = bounds.insetBy(dx: CGFloat(radius), dy: CGFloat(radius))
// let x = CGFloat(UInt32(insetBounds.minX) + arc4random_uniform(UInt32(insetBounds.width)))
// let y = CGFloat(UInt32(insetBounds.minY) + arc4random_uniform(UInt32(insetBounds.height)))
let position = CGPoint(x: insetBounds.midX, y: insetBounds.midY)
let position = Point(x: Float(insetBounds.midX), y: Float(insetBounds.midY))
// TODO: Randomly generate velocity too.
let ball = Ball(radius: radius, position: position, velocity: CGVector())
let ball = Ball(radius: radius, position: position, velocity: Vector())
balls.append(ball)
NSLog("Added ball \(ball); fieldSize=\(size)")
}
// MARK: - Metal Configuration
private var device: MTLDevice?
private var sampleComputeState: MTLComputePipelineState?
private var parametersBuffer: MTLBuffer?
private var ballBuffer: MTLBuffer?
public private(set) var sampleTexture: MTLTexture?
// private var sampleComputeState: MTLComputePipelineState?
public private(set) var parametersBuffer: MTLBuffer?
public private(set) var ballBuffer: MTLBuffer?
// public private(set) var sampleTexture: MTLTexture?
private var threadgroupCount = MTLSize()
// private var threadgroupCount = MTLSize()
// TODO: It might be possible to (more dynamically) right-size this.
private var threadgroupSize = MTLSize(width: 16, height: 16, depth: 1)
// private var threadgroupSize = MTLSize(width: 16, height: 16, depth: 1)
/// Create the Metal buffer containing basic parameters of the simulation.
private func makeParametersBufferIfNeeded(withDevice device: MTLDevice) -> MTLBuffer? {
if parametersBuffer == nil {
parametersBuffer = device.makeBuffer(length: MemoryLayout<Int>.size * 3, options: [])
parametersBuffer = device.makeBuffer(length: MemoryLayout<Int>.stride * 3, options: [])
}
return parametersBuffer
}
@ -118,8 +131,8 @@ public class Field {
/// @param device The Metal device to use to create the buffer.
/// @return A new buffer containing metaball data.
private func makeBallBufferIfNeeded(withDevice device: MTLDevice) -> MTLBuffer? {
if ballBuffer == nil {
let sizeOfBall = MemoryLayout<Ball>.size
if ballBuffer == nil && balls.count > 0 {
let sizeOfBall = MemoryLayout<Float>.stride * 3 // A Ball in shader-land is a float3.
let length = balls.count * sizeOfBall
ballBuffer = device.makeBuffer(length: length, options: [])
}
@ -129,63 +142,59 @@ public class Field {
/// Create a Metal texture to hold sample values created by the sampling compute shader.
/// @param device The Metal device to use to create the texture.
/// @return A new texture.
private func makeSampleTextureIfNeeded(withDevice device: MTLDevice) -> MTLTexture? {
if sampleTexture == nil {
let desc = MTLTextureDescriptor()
desc.pixelFormat = .r16Float
desc.width = Int(size.width)
desc.height = Int(size.height)
desc.usage = [.shaderWrite, .shaderRead]
sampleTexture = device.makeTexture(descriptor: desc)
}
return sampleTexture
}
// private func makeSampleTextureIfNeeded(withDevice device: MTLDevice) -> MTLTexture? {
// if sampleTexture == nil {
// let desc = MTLTextureDescriptor()
// desc.pixelFormat = .r16Float
// desc.width = Int(size.width)
// desc.height = Int(size.height)
// desc.usage = [.shaderWrite, .shaderRead]
// sampleTexture = device.makeTexture(descriptor: desc)
// }
// return sampleTexture
// }
/// Update the threadgroup divisions based on the size of the field.
/// @param size The size of the field.
private func updateThreadgroupSizes(withFieldSize size: CGSize) {
let width = Int(size.width)
let height = Int(size.height)
threadgroupCount = MTLSize(width: width + threadgroupSize.width - 1, height: height + threadgroupSize.height - 1, depth: 1)
}
// private func updateThreadgroupSizes(withFieldSize size: CGSize) {
// let width = Int(size.width)
// let height = Int(size.height)
// threadgroupCount = MTLSize(width: width + threadgroupSize.width - 1, height: height + threadgroupSize.height - 1, depth: 1)
// }
/// Copy metaballs data into the parameters buffer.
private func updateParametersBuffer() {
guard let parameters = parametersBuffer,
let balls = ballBuffer
public func updateBuffers() throws {
guard let device = self.device else {
throw MetaballsError.metalError("Missing Metal device for update")
}
guard let parameters = makeParametersBufferIfNeeded(withDevice: device),
let balls = makeBallBufferIfNeeded(withDevice: device)
else {
return
throw MetaballsError.metalError("Couldn't create buffers")
}
var ptr = parameters.contents()
var width = Int(size.width)
ptr = writeValue(value: &width, to: ptr)
ptr = write(value: &width, to: ptr)
var height = Int(size.height)
ptr = writeValue(value: &height, to: ptr)
ptr = write(value: &height, to: ptr)
var numberOfBalls = self.balls.count
ptr = writeValue(value: &numberOfBalls, to: ptr)
ptr = write(value: &numberOfBalls, to: ptr)
ptr = balls.contents()
for ball in self.balls {
var radius = Float(ball.radius)
ptr = writeValue(value: &radius, to: ptr)
var posX = Float(ball.position.x)
ptr = writeValue(value: &posX, to: ptr)
var posY = Float(ball.position.y)
ptr = writeValue(value: &posY, to: ptr)
var dx = Float(ball.velocity.dx)
ptr = writeValue(value: &dx, to: ptr)
var dy = Float(ball.velocity.dy)
ptr = writeValue(value: &dy, to: ptr)
for var ball in self.balls {
ptr = write(value: &ball.position.x, to: ptr)
ptr = write(value: &ball.position.y, to: ptr)
var r = ball.radius
ptr = write(value: &r, to: ptr)
}
}
private func writeValue<T>(value: inout T, to ptr: UnsafeMutableRawPointer) -> UnsafeMutableRawPointer {
let sizeOfType = MemoryLayout<T>.size
private func write<T>(value: inout T, to ptr: UnsafeMutableRawPointer) -> UnsafeMutableRawPointer {
let sizeOfType = MemoryLayout<T>.stride
ptr.copyBytes(from: &value, count: sizeOfType)
return ptr.advanced(by: sizeOfType)
}
@ -194,39 +203,42 @@ public class Field {
guard self.device == nil else {
return
}
NSLog("Setting up Metal")
self.device = device
sampleComputeState = try computePipelineStateForSamplingKernel(withDevice: device)
// sampleComputeState = try computePipelineStateForSamplingKernel(withDevice: device)
parametersBuffer = makeParametersBufferIfNeeded(withDevice: device)
ballBuffer = makeBallBufferIfNeeded(withDevice: device)
}
public func computePipelineStateForSamplingKernel(withDevice device: MTLDevice) throws -> MTLComputePipelineState? {
let bundle = Bundle(for: type(of: self))
let library = try device.makeDefaultLibrary(bundle: bundle)
guard let samplingKernel = library.makeFunction(name: "sampleFieldKernel") else {
throw MetaballsError.metalError("Unable to create sampling kernel function")
}
let state = try device.makeComputePipelineState(function: samplingKernel)
return state
}
// public func computePipelineStateForSamplingKernel(withDevice device: MTLDevice) throws -> MTLComputePipelineState? {
// let bundle = Bundle(for: type(of: self))
// let library = try device.makeDefaultLibrary(bundle: bundle)
// guard let samplingKernel = library.makeFunction(name: "sampleFieldKernel") else {
// throw MetaballsError.metalError("Unable to create sampling kernel function")
// }
// let state = try device.makeComputePipelineState(function: samplingKernel)
// return state
// }
public func computeEncoderForSamplingKernel(withDevice device: MTLDevice, commandBuffer buffer: MTLCommandBuffer) throws -> MTLComputeCommandEncoder {
guard let parametersBuffer = makeParametersBufferIfNeeded(withDevice: device),
let ballBuffer = makeBallBufferIfNeeded(withDevice: device),
let sampleTexture = makeSampleTextureIfNeeded(withDevice: device),
let state = sampleComputeState
else {
throw MetaballsError.metalError("Missing Metal buffers or compute state")
}
let encoder = buffer.makeComputeCommandEncoder()
encoder.setComputePipelineState(state)
encoder.setBuffer(parametersBuffer, offset: 0, at: 0)
encoder.setBuffer(ballBuffer, offset: 0, at: 1)
encoder.setTexture(sampleTexture, at: 0)
encoder.dispatchThreadgroups(threadgroupCount, threadsPerThreadgroup: threadgroupSize)
encoder.endEncoding()
updateParametersBuffer()
return encoder
}
// public func computeEncoderForSamplingKernel(withDevice device: MTLDevice, commandBuffer buffer: MTLCommandBuffer) throws -> MTLComputeCommandEncoder {
// guard let parametersBuffer = makeParametersBufferIfNeeded(withDevice: device),
// let ballBuffer = makeBallBufferIfNeeded(withDevice: device),
// let sampleTexture = makeSampleTextureIfNeeded(withDevice: device),
// let state = sampleComputeState
// else {
// throw MetaballsError.metalError("Missing Metal buffers or compute state")
// }
//
// let encoder = buffer.makeComputeCommandEncoder()
// encoder.setComputePipelineState(state)
// encoder.setBuffer(parametersBuffer, offset: 0, at: 0)
// encoder.setBuffer(ballBuffer, offset: 0, at: 1)
// encoder.setTexture(sampleTexture, at: 0)
// encoder.dispatchThreadgroups(threadgroupCount, threadsPerThreadgroup: threadgroupSize)
// encoder.endEncoding()
//
// updateParametersBuffer()
//
// return encoder
// }
}