7fdd9e1 · metal-metaballs

git.iko.soy/metal-metaballs

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Refactored shader and renderer to accept graph data.

7fdd9e1vinivendra11 years ago

PixelImage/Matrix.swift+10−4

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unifiedsplit

@@ -5,6 +5,12 @@ class Graph<T> {

5 var adjacencyMatrix: Matrix

6 var vertices: [T]

8+ var size: Int {

9+ get {

10+ return vertices.count

11+ }

12+ }

13+

8 init(vertices: [T]) {

14 init(vertices: [T]) {

9 let size = vertices.count

15 let size = vertices.count

@@ -24,20 +30,20 @@ class Graph<T> {

24}

30}

26struct Matrix: CustomStringConvertible {

32struct Matrix: CustomStringConvertible {

27− private var buffer: [CGFloat]

33+ var buffer: [Float]

29 let size: Int

35 let size: Int

31 init(size: Int) {

37 init(size: Int) {

32− buffer = [CGFloat](count: size * size, repeatedValue: 0.0)

38+ buffer = [Float](count: size * size, repeatedValue: 0.0)

33 self.size = size

39 self.size = size

34 }

40 }

36− func get(i: Int, j: Int) -> CGFloat {

42+ func get(i: Int, j: Int) -> Float {

37 return buffer[index(i, j)]

43 return buffer[index(i, j)]

38 }

44 }

40− mutating func set(i: Int, _ j: Int, value: CGFloat = 1.0) {

46+ mutating func set(i: Int, _ j: Int, value: Float = 1.0) {

41 buffer[index(i, j)] = value

47 buffer[index(i, j)] = value

42 }

48 }

PixelImage/MetalMetaballRenderer.swift+10−4

@@ -1,8 +1,6 @@

1import Metal

2import UIKit

4−var i = 0

5−

6class MetalMetaballRenderer {

4class MetalMetaballRenderer {

8 typealias TargetView = UIImageView

6 typealias TargetView = UIImageView

@@ -54,8 +52,6 @@ class MetalMetaballRenderer {

54 let timeout = dispatch_time(DISPATCH_TIME_NOW, 1000000000)

52 let timeout = dispatch_time(DISPATCH_TIME_NOW, 1000000000)

55 dispatch_semaphore_wait(semaphore, timeout)

53 dispatch_semaphore_wait(semaphore, timeout)

57− print("Update \(i++)!")

58−

59 state = .Ending

55 state = .Ending

61 dispatch_async(dispatch_get_global_queue(Int(QOS_CLASS_USER_INTERACTIVE.rawValue), 0)) { () -> Void in

57 dispatch_async(dispatch_get_global_queue(Int(QOS_CLASS_USER_INTERACTIVE.rawValue), 0)) { () -> Void in

@@ -108,6 +104,8 @@ class MetalMetaballRenderer {

108 commandEncoder.setTexture(computeContext.texture, atIndex: 0)

104 commandEncoder.setTexture(computeContext.texture, atIndex: 0)

109 let metaballInfoBuffer = metaballBuffer()

105 let metaballInfoBuffer = metaballBuffer()

110 commandEncoder.setBuffer(metaballInfoBuffer, offset: 0, atIndex: 0)

106 commandEncoder.setBuffer(metaballInfoBuffer, offset: 0, atIndex: 0)

107+ let edgesBuffer = metaballEdgesBuffer()

108+ commandEncoder.setBuffer(edgesBuffer, offset: 0, atIndex: 1)

111 commandEncoder.dispatchThreadgroups(threadGroups,

109 commandEncoder.dispatchThreadgroups(threadGroups,

112 threadsPerThreadgroup: threadGroupCounts)

110 threadsPerThreadgroup: threadGroupCounts)

113 commandEncoder.endEncoding()

111 commandEncoder.endEncoding()

@@ -163,6 +161,14 @@ class MetalMetaballRenderer {

163 return image

161 return image

164 }

162 }

165

163

164+ func metaballEdgesBuffer() -> MTLBuffer {

165+ let floats = dataSource.metaballGraph.adjacencyMatrix.buffer

166+

167+ let buffer = context.device.newBufferWithBytes(floats, length: floats.count * sizeof(Float), options: .StorageModeShared)

168+

169+ return buffer

170+ }

171+

166 func metaballBuffer() -> MTLBuffer {

172 func metaballBuffer() -> MTLBuffer {

167 // Create Float array for buffer

173 // Create Float array for buffer

168 // Exclude metaballs far from the view's bounds

174 // Exclude metaballs far from the view's bounds

PixelImage/ViewController.swift+7−1

@@ -20,10 +20,16 @@ class ViewController: UIViewController, MetaballDataSource {

20 let recognizer = UIPanGestureRecognizer(target: self, action: "handlePan:")

21 view.addGestureRecognizer(recognizer)

23− let metaballs = [CGPoint(x: 70, y: 70), CGPoint(x: 270, y: 470), CGPoint(x: 270, y: 70), CGPoint(x: 70, y: 470)].map {

23+ let metaballs = [CGPoint(x: 70, y: 70), CGPoint(x: 270, y: 70), CGPoint(x: 270, y: 470), CGPoint(x: 70, y: 470)].map {

24 Metaball(position: $0)

25 }

26 metaballGraph = Graph(vertices: metaballs)

27+ metaballGraph.addEdge(0, 1)

28+ metaballGraph.addEdge(0, 3)

29+ metaballGraph.addEdge(1, 2)

30+ metaballGraph.addEdge(2, 3)

31+ metaballGraph.removeEdge(2, 3)

32+ print(metaballGraph.adjacencyMatrix)

28 let border = 20

34 let border = 20

29 let metaballViewFrame = CGRect(x: border/2, y: border/2, width: width, height: height)

35 let metaballViewFrame = CGRect(x: border/2, y: border/2, width: width, height: height)

PixelImage/shaders.metal+21−15

@@ -5,40 +5,46 @@ using namespace metal;

6kernel void

7 drawMetaballs(texture2d<float, access::write> outTexture[[texture(0)]],

8+ constant float *edgesBuffer[[buffer(1)]],

8− constant float *metaballBuffer [[buffer(0)]],

9+ constant float *metaballBuffer[[buffer(0)]],

9 uint2 gid[[thread_position_in_grid]]) {

10 uint2 gid[[thread_position_in_grid]]) {

11− char numberOfMetaballs = metaballBuffer[0];

12+ uint numberOfMetaballs = metaballBuffer[0];

12− char metaballArraySize = numberOfMetaballs * 2 + 1;

13+ uint metaballArraySize = numberOfMetaballs * 2 + 1;

14 float sum = 0;

15 float sum = 0;

16− for (char i = 1; i < metaballArraySize; i += 2) {

17+ uint i, j, x, y;

17− for (char j = i + 2; j < metaballArraySize; j += 2) {

18− float2 metaball1 = float2(metaballBuffer[i],

19− metaballBuffer[i + 1]);

19+ for (i = 1, x = 0; i < metaballArraySize; i += 2, x += 1) {

20+ for (j = i + 2, y = x + 1; j < metaballArraySize; j += 2, y += 1) {

21+ float2 metaball1 = float2(metaballBuffer[i], metaballBuffer[i + 1]);

22+

21− float2 metaball2 = float2(metaballBuffer[j],

23+ float2 metaball2 = float2(metaballBuffer[j], metaballBuffer[j + 1]);

22− metaballBuffer[j + 1]);

24 float2 metaball1Vector

25 float2 metaball1Vector

25 = float2(metaball1.x - gid.x, metaball1.y - gid.y);

26 = float2(metaball1.x - gid.x, metaball1.y - gid.y);

26 float2 metaball2Vector

27 float2 metaball2Vector

27 = float2(metaball2.x - gid.x, metaball2.y - gid.y);

28 = float2(metaball2.x - gid.x, metaball2.y - gid.y);

30+ float value1 = 2048 / (dot(metaball1Vector, metaball1Vector) + 1);

31+ float value2 = 2048 / (dot(metaball2Vector, metaball2Vector) + 1);

32+

33+ float v = value1 + value2;

34+

35+ float weightedValue = 0.5 * v;

36+

37+ char edgeIndex = y * numberOfMetaballs + x;

38+ float edgeWeight = edgesBuffer[edgeIndex];

29 float2 direction1 = normalize(metaball1Vector);

39 float2 direction1 = normalize(metaball1Vector);

30 float2 direction2 = normalize(metaball2Vector);

40 float2 direction2 = normalize(metaball2Vector);

32 float cosine = dot(direction1, direction2);

42 float cosine = dot(direction1, direction2);

34− float value1 = 2048 / (dot(metaball1Vector, metaball1Vector) + 1);

35− float value2 = 2048 / (dot(metaball2Vector, metaball2Vector) + 1);

36−

37− float v = value1 + value2;

38 float link = pow(((1 - cosine) * 0.5), 100);

44 float link = pow(((1 - cosine) * 0.5), 100);

40− float weightedLink = 0.6 * link;

46+ float weightedLink = 0.6 * link * edgeWeight;

41− float weightedValue = 0.5 * v;

47+

43 sum += mix(0.0, 1.0, step(0.5, weightedValue + weightedLink));

49 sum += mix(0.0, 1.0, step(0.5, weightedValue + weightedLink));

44 }

50 }