Adds TexturedLine and animated EffectLine to sprites

examples/game/test_sprite_mesh.dart

+import 'dart:sky' as sky;
+
+import 'package:sky/services.dart';
+import 'package:sky/rendering.dart';
+import 'package:sky/theme/colors.dart' as colors;
+import 'package:sky/widgets.dart';
+import 'package:skysprites/skysprites.dart';
+
+AssetBundle _initBundle() {
+  if (rootBundle != null)
+    return rootBundle;
+  return new NetworkAssetBundle(Uri.base);
+}
+
+final AssetBundle _bundle = _initBundle();
+
+ImageMap _images;
+SpriteSheet _spriteSheet;
+TestApp _app;
+
+main() async {
+  _images = new ImageMap(_bundle);
+
+  await _images.load([
+    'assets/checker.png',
+    'assets/line_effects.png'
+  ]);
+
+  assert(_images["assets/checker.png"] != null);
+
+  _app = new TestApp();
+  runApp(_app);
+}
+
+class TestApp extends App {
+
+  TestApp() {
+    _testBed = new TestBed(_labelTexts[_selectedLine]);
+  }
+
+  TestBed _testBed;
+  int _selectedLine = 0;
+
+  List<String> _labelTexts = [
+    "Colored",
+    "Smoke",
+    "Electric"
+  ];
+
+  Widget build() {
+    ThemeData theme = new ThemeData(
+      brightness: ThemeBrightness.light,
+      primarySwatch: colors.Purple
+    );
+
+    return new Theme(
+      data: theme,
+      child: new Title(
+        title: 'Test drawAtlas',
+        child: _buildColumn()
+      )
+    );
+  }
+
+  Column _buildColumn() {
+    return new Column([
+      new Flexible(child: _buildSpriteWidget()),
+      _buildTabBar()
+    ]);
+  }
+
+  TabBar _buildTabBar() {
+    return new TabBar(
+      labels: _buildTabLabels(),
+      selectedIndex: _selectedLine,
+      onChanged: (int selectedLine) {
+        setState(() {
+          _selectedLine = selectedLine;
+        });
+      }
+    );
+  }
+
+  List<TabLabel> _buildTabLabels() {
+    List<TabLabel> labels = [];
+    for(String text in _labelTexts) {
+      labels.add(new TabLabel(text: text));
+    }
+    return labels;
+  }
+
+  SpriteWidget _buildSpriteWidget() {
+    _testBed.setupLine(_labelTexts[_selectedLine]);
+
+    return new SpriteWidget(
+      _testBed,
+      SpriteBoxTransformMode.letterbox
+    );
+  }
+}
+
+class TestBed extends NodeWithSize {
+  EffectLine _line;
+
+  TestBed(String lineType) : super(new Size(1024.0, 1024.0)) {
+    userInteractionEnabled = true;
+    setupLine(lineType);
+  }
+
+  void setupLine(String lineType) {
+    if (_line != null) {
+      _line.removeFromParent();
+    }
+
+    if (lineType == "Colored") {
+      // Create a line with no texture and a color sequence
+      _line = new EffectLine(
+        texture: null,
+        colorSequence: new ColorSequence.fromStartAndEndColor(new Color(0xffff0000), new Color(0xff0000ff)),
+        widthMode: EffectLineWidthMode.barrel,
+        minWidth: 20.0,
+        maxWidth: 50.0,
+        animationMode: EffectLineAnimationMode.scroll,
+        fadeAfterDelay: 1.0,
+        fadeDuration: 1.0
+      );
+    } else if (lineType == "Smoke") {
+      Texture baseTexture = new Texture(_images['assets/line_effects.png']);
+      Texture smokyLineTexture = baseTexture.textureFromRect(new Rect.fromLTRB(0.0, 0.0, 1024.0, 128.0));
+
+      _line = new EffectLine(
+        texture: smokyLineTexture,
+        textureLoopLength: 300.0,
+        colorSequence: new ColorSequence.fromStartAndEndColor(new Color(0xffffffff), new Color(0x00ffffff)),
+        widthMode: EffectLineWidthMode.barrel,
+        minWidth: 20.0,
+        maxWidth: 80.0,
+        animationMode: EffectLineAnimationMode.scroll
+      );
+    } else if (lineType == "Electric") {
+      Texture baseTexture = new Texture(_images['assets/line_effects.png']);
+      Texture electricLineTexture = baseTexture.textureFromRect(new Rect.fromLTRB(0.0, 384.0, 1024.0, 512.0));
+
+      _line = new EffectLine(
+        texture: electricLineTexture,
+        textureLoopLength: 300.0,
+        widthMode: EffectLineWidthMode.barrel,
+        minWidth: 20.0,
+        maxWidth: 100.0,
+        animationMode: EffectLineAnimationMode.random
+      );
+    }
+
+    addChild(_line);
+  }
+
+  bool handleEvent(SpriteBoxEvent event) {
+    if (event.type == "pointerdown") _line.points = [];
+
+    if (event.type == "pointerdown" || event.type == "pointermove") {
+      Point pos = convertPointToNodeSpace(event.boxPosition);
+      _line.addPoint(pos);
+    }
+    return true;
+  }
+}

packages/flutter_sprites/lib/color_secuence.dart

@@ -37,6 +37,8 @@ class ColorSequence {
   Color colorAtPosition(double pos) {
     assert(pos >= 0.0 && pos <= 1.0);
 
+    if (pos == 0.0) return colors[0];
+
     double lastStop = colorStops[0];
     Color lastColor = colors[0];
 

packages/flutter_sprites/lib/effect_line.dart

+part of skysprites;
+
+enum EffectLineWidthMode {
+  linear,
+  barrel,
+}
+
+enum EffectLineAnimationMode {
+  none,
+  scroll,
+  random,
+}
+
+class EffectLine extends Node {
+
+  EffectLine({
+    this.texture: null,
+    List<Point> points,
+    this.widthMode : EffectLineWidthMode.linear,
+    this.minWidth: 10.0,
+    this.maxWidth: 10.0,
+    this.animationMode: EffectLineAnimationMode.none,
+    this.scrollSpeed: 0.1,
+    this.fadeDuration: null,
+    this.fadeAfterDelay: null,
+    this.textureLoopLength: null,
+    this.simplify: true,
+    ColorSequence colorSequence
+  }) {
+    if (points == null) this.points = [];
+    else this.points = points;
+
+    _colorSequence = colorSequence;
+    if (_colorSequence == null)
+      _colorSequence = new ColorSequence.fromStartAndEndColor(
+        new Color(0xffffffff),
+        new Color(0xffffffff));
+
+    _painter = new TexturedLinePainter(points, _colors, _widths, texture);
+    _painter.textureLoopLength = textureLoopLength;
+  }
+
+  final Texture texture;
+
+  final EffectLineWidthMode widthMode;
+  final double minWidth;
+  final double maxWidth;
+
+  final EffectLineAnimationMode animationMode;
+  final double scrollSpeed;
+  ColorSequence _colorSequence;
+  ColorSequence get colorSequence => _colorSequence;
+
+  List<Point> _points;
+
+  List<Point> get points => _points;
+
+  set points(List<Point> points) {
+    _points = points;
+    _pointAges = [];
+    for (int i = 0; i < _points.length; i++) {
+      _pointAges.add(0.0);
+    }
+  }
+
+  List<double> _pointAges;
+  List<Color> _colors;
+  List<double> _widths;
+
+  final double fadeDuration;
+  final double fadeAfterDelay;
+
+  final double textureLoopLength;
+
+  final bool simplify;
+
+  TexturedLinePainter _painter;
+  double _offset = 0.0;
+
+  void update(double dt) {
+    // Update scrolling position
+    if (animationMode == EffectLineAnimationMode.scroll) {
+      _offset += dt * scrollSpeed;
+      _offset %= 1.0;
+    } else if (animationMode == EffectLineAnimationMode.random) {
+      _offset = randomDouble();
+    }
+
+    // Update age of line points, and remove if neccessary
+    if (fadeDuration != null && fadeAfterDelay != null) {
+      for (int i = _points.length - 1; i >= 0; i--) {
+        _pointAges[i] += dt;
+        if (_pointAges[i] > (fadeDuration + fadeAfterDelay)) {
+          _pointAges.removeAt(i);
+          _points.removeAt(i);
+        }
+      }
+    }
+  }
+
+  void paint(PaintingCanvas canvas) {
+    if (points.length < 2) return;
+
+    //_painter.textureLoopLength = textureLoopLength;
+
+    _painter.points = points;
+
+    // Calculate colors
+    List<double> stops = _painter.calculatedTextureStops;
+
+    List<Color> colors = [];
+    for (int i = 0; i < stops.length; i++) {
+      double stop = stops[i];
+      Color color = _colorSequence.colorAtPosition(stop);
+
+      if (fadeDuration != null && fadeAfterDelay != null) {
+        double age = _pointAges[i];
+        if (age > fadeAfterDelay) {
+          double fade = 1.0 - (age - fadeAfterDelay) / fadeDuration;
+          int alpha = (color.alpha * fade).toInt().clamp(0, 255);
+          color = new Color.fromARGB(alpha, color.red, color.green, color.blue);
+        }
+      }
+      colors.add(color);
+    }
+    _painter.colors = colors;
+
+    // Calculate widths
+    List<double> widths = [];
+    for (double stop in stops) {
+      if (widthMode == EffectLineWidthMode.linear) {
+        double width = minWidth + (maxWidth - minWidth) * stop;
+        widths.add(width);
+      } else if (widthMode == EffectLineWidthMode.barrel) {
+        double width = minWidth + math.sin(stop * math.PI) * (maxWidth - minWidth);
+        widths.add(width);
+      }
+    }
+    _painter.widths = widths;
+
+    _painter.textureStopOffset = _offset;
+
+    _painter.paint(canvas);
+  }
+
+  void addPoint(Point point) {
+    // Skip duplicate points
+    if (points.length > 0 && point.x == points[points.length - 1].x && point.y == points[points.length - 1].y)
+      return;
+
+    if (simplify) {
+
+    }
+
+    // Add point and point's age
+    _points.add(point);
+    _pointAges.add(0.0);
+  }
+}

packages/flutter_sprites/lib/skysprites.dart

@@ -21,9 +21,10 @@ import 'package:sky_services/media/media.mojom.dart';
 import 'package:vector_math/vector_math.dart';
 
 part 'action.dart';
-part 'constraint.dart';
 part 'action_spline.dart';
 part 'color_secuence.dart';
+part 'constraint.dart';
+part 'effect_line.dart';
 part 'image_map.dart';
 part 'label.dart';
 part 'layer.dart';
@@ -38,5 +39,6 @@ part 'spritesheet.dart';
 part 'sprite_box.dart';
 part 'sprite_widget.dart';
 part 'texture.dart';
+part 'textured_line.dart';
 part 'util.dart';
 part 'virtual_joystick.dart';

packages/flutter_sprites/lib/textured_line.dart

+part of skysprites;
+
+class TexturedLine extends Node {
+  TexturedLine(List<Point> points, List<Color> colors, List<double> widths, [Texture texture, List<double> textureStops]) {
+    painter = new TexturedLinePainter(points, colors, widths, texture, textureStops);
+  }
+
+  TexturedLinePainter painter;
+
+  void paint(PaintingCanvas canvas) {
+    painter.paint(canvas);
+  }
+}
+
+class TexturedLinePainter {
+  TexturedLinePainter(this._points, this.colors, this.widths, [Texture texture, this.textureStops]) {
+    this.texture = texture;
+  }
+
+  List<Point> _points;
+
+  List<Point> get points => _points;
+
+  set points(List<Point> points) {
+    _points = points;
+    _calculatedTextureStops = null;
+  }
+
+  List<Color> colors;
+  List<double> widths;
+  Texture _texture;
+
+  Texture get texture => _texture;
+
+  set texture(Texture texture) {
+    _texture = texture;
+    if (texture == null) {
+      _cachedPaint = new Paint();
+    } else {
+      Matrix4 matrix = new Matrix4.identity();
+      ImageShader shader = new ImageShader(texture.image,
+        TileMode.repeated, TileMode.repeated, matrix.storage);
+
+      _cachedPaint = new Paint();
+      _cachedPaint.setShader(shader);
+    }
+  }
+
+  List<double> textureStops;
+
+  List<double> _calculatedTextureStops;
+
+  List<double> get calculatedTextureStops {
+    if (_calculatedTextureStops == null)
+      _calculateTextureStops();
+    return _calculatedTextureStops;
+  }
+
+  double _length;
+
+  double get length {
+    if (_calculatedTextureStops == null)
+      _calculateTextureStops();
+    return _length;
+  }
+
+  double textureStopOffset = 0.0;
+
+  double _textureLoopLength;
+
+  get textureLoopLength => textureLoopLength;
+
+  set textureLoopLength(double textureLoopLength) {
+    _textureLoopLength = textureLoopLength;
+    _calculatedTextureStops = null;
+  }
+
+  Paint _cachedPaint = new Paint();
+
+  void paint(PaintingCanvas canvas) {
+    // Check input values
+    assert(_points != null);
+    if (_points.length < 2) return;
+
+    assert(_points.length == colors.length);
+    assert(_points.length == widths.length);
+
+    // Calculate normals
+    List<Vector2> vectors = [];
+    for (Point pt in _points) {
+      vectors.add(new Vector2(pt.x, pt.y));
+    }
+    List<Vector2> miters = _computeMiterList(vectors, false);
+
+    List<Point> vertices = [];
+    List<int> indicies = [];
+    List<Color> verticeColors = [];
+    List<Point> textureCoordinates;
+    double textureTop;
+    double textureBottom;
+    List<double> stops;
+
+    // Add first point
+    Point lastPoint = _points[0];
+    Vector2 lastMiter = miters[0];
+
+    // Add vertices and colors
+    _addVerticesForPoint(vertices, lastPoint, lastMiter, widths[0]);
+    verticeColors.add(colors[0]);
+    verticeColors.add(colors[0]);
+
+    if (texture != null) {
+      assert(texture.rotated == false);
+
+      // Setup for calculating texture coordinates
+      textureTop = texture.frame.top;
+      textureBottom = texture.frame.bottom;
+      textureCoordinates = [];
+
+      // Use correct stops
+      if (textureStops != null) {
+        assert(_points.length == textureStops.length);
+        stops = textureStops;
+      } else {
+        if (_calculatedTextureStops == null) _calculateTextureStops();
+        stops = _calculatedTextureStops;
+      }
+
+      // Texture coordinate points
+      double xPos = _xPosForStop(stops[0]);
+      textureCoordinates.add(new Point(xPos, textureTop));
+      textureCoordinates.add(new Point(xPos, textureBottom));
+    }
+
+    // Add the rest of the points
+    for (int i = 1; i < _points.length; i++) {
+      // Add vertices
+      Point currentPoint = _points[i];
+      Vector2 currentMiter = miters[i];
+      _addVerticesForPoint(vertices, currentPoint, currentMiter, widths[i]);
+
+      // Add references to the triangles
+      int lastIndex0 = (i - 1) * 2;
+      int lastIndex1 = (i - 1) * 2 + 1;
+      int currentIndex0 = i * 2;
+      int currentIndex1 = i * 2 + 1;
+      indicies.addAll([lastIndex0, lastIndex1, currentIndex0]);
+      indicies.addAll([lastIndex1, currentIndex1, currentIndex0]);
+
+      // Add colors
+      verticeColors.add(colors[i]);
+      verticeColors.add(colors[i]);
+
+      if (texture != null) {
+        // Texture coordinate points
+        double xPos = _xPosForStop(stops[i]);
+        textureCoordinates.add(new Point(xPos, textureTop));
+        textureCoordinates.add(new Point(xPos, textureBottom));
+      }
+
+      // Update last values
+      lastPoint = currentPoint;
+      lastMiter = currentMiter;
+    }
+
+    canvas.drawVertices(VertexMode.triangles, vertices, textureCoordinates, verticeColors, TransferMode.modulate, indicies, _cachedPaint);
+  }
+
+  double _xPosForStop(double stop) {
+    if (_textureLoopLength == null) {
+      return texture.frame.left + texture.frame.width * (stop - textureStopOffset);
+    } else {
+      return texture.frame.left + texture.frame.width * (stop - textureStopOffset * (_textureLoopLength / length)) * (length / _textureLoopLength);
+    }
+  }
+
+  void _addVerticesForPoint(List<Point> vertices, Point point, Vector2 miter, double width) {
+    double halfWidth = width / 2.0;
+
+    Offset offset0 = new Offset(miter[0] * halfWidth, miter[1] * halfWidth);
+    Offset offset1 = new Offset(-miter[0] * halfWidth, -miter[1] * halfWidth);
+
+    vertices.add(point + offset0);
+    vertices.add(point + offset1);
+  }
+
+  void _calculateTextureStops() {
+    List<double> stops = [];
+    double length = 0.0;
+
+    // Add first stop
+    stops.add(0.0);
+
+    // Calculate distance to each point from the first point along the line
+    for (int i = 1; i < _points.length; i++) {
+      Point lastPoint = _points[i - 1];
+      Point currentPoint = _points[i];
+
+      double dist = GameMath.pointQuickDist(lastPoint, currentPoint);
+      length += dist;
+      stops.add(length);
+    }
+
+    // Normalize the values in the range [0.0, 1.0]
+    for (int i = 1; i < points.length; i++) {
+      stops[i] = stops[i] / length;
+      new Point(512.0, 512.0);
+    }
+
+    _calculatedTextureStops = stops;
+    _length = length;
+  }
+}
+
+Vector2 _computeMiter(Vector2 lineA, Vector2 lineB) {
+  Vector2 miter = new Vector2(- (lineA[1] + lineB[1]), lineA[0] + lineB[0]);
+  miter.normalize();
+
+  double miterLength = 1.0 / dot2(miter, new Vector2(-lineA[1], lineA[0]));
+  miter = miter.scale(miterLength);
+
+  return miter;
+}
+
+Vector2 _vectorNormal(Vector2 v) {
+  return new Vector2(-v[1], v[0]);
+}
+
+Vector2 _vectorDirection(Vector2 a, Vector2 b) {
+  Vector2 result = a - b;
+  return result.normalize();
+}
+
+List<Vector2> _computeMiterList(List<Vector2> points, bool closed) {
+  List<Vector2> out = [];
+  Vector2 curNormal = null;
+
+  if (closed) {
+    points = new List<Vector2>.from(points);
+    points.add(points[0]);
+  }
+
+  int total = points.length;
+  for (int i = 1; i < total; i++) {
+    Vector2 last = points[i - 1];
+    Vector2 cur = points[i];
+    Vector2 next = (i < total - 1) ? points[i + 1] : null;
+
+    Vector2 lineA = _vectorDirection(cur, last);
+    if (curNormal == null) {
+      curNormal = _vectorNormal(lineA);
+    }
+
+    if (i == 1) {
+      out.add(curNormal);
+    }
+
+    if (next == null) {
+      curNormal = _vectorNormal(lineA);
+      out.add(curNormal);
+    } else {
+      Vector2 lineB = _vectorDirection(next, cur);
+      Vector2 miter = _computeMiter(lineA, lineB);
+      out.add(miter);
+    }
+  }
+
+  return out;
+}