paint method

@override void paint(InfinityModelConfig config, InfinityModelController controller, PaintViewPort viewPort, Line3D model, Matrix4 matrix, int vertexIndex, Float32List zIndices, Int32List colors, Float32List vertices,)

Fills the buffer with the Model3D data.

Implementation

@override
void paint(
    InfinityModelConfig config,
    InfinityModelController controller,
    PaintViewPort viewPort,
    Line3D model,
    Matrix4 matrix,
    int vertexIndex,
    Float32List zIndices,
    Int32List colors,
    Float32List vertices) {
  _a.setFrom(model.a);
  _b.setFrom(model.b);
  matrix
    ..perspectiveTransform(_a)
    ..perspectiveTransform(_b);

  // z-index
  final z = (_a.z + _b.z) / 2.0 + 0.4;
  zIndices[vertexIndex ~/ 3 + 0] = z;
  zIndices[vertexIndex ~/ 3 + 1] = z;

  final pointIndex = vertexIndex * 2;

  if (viewPort.isLineVisible(_a, _b)) {
    // color
    final vertexColor = model.color?.value ?? config.defaultColorPoints.value;
    colors[vertexIndex + 0] = vertexColor;
    colors[vertexIndex + 1] = vertexColor;
    colors[vertexIndex + 2] = vertexColor;
    colors[vertexIndex + 3] = vertexColor;
    colors[vertexIndex + 4] = vertexColor;
    colors[vertexIndex + 5] = vertexColor;

    // vertex
    // d           c
    // o-----------o
    // |         x |
    // |     x     |
    // | x         |
    // o-----------o
    // a           b
    var dx = _b.x - _a.x;
    var dy = _b.y - _a.y;
    final lineLength = sqrt(dx * dx + dy * dy);
    if (lineLength != 0) {
      dx /= lineLength;
      dy /= lineLength;
    }
    final thick = model.width ?? config.defaultLineWidth;
    final px = 0.5 * thick * (-dy);
    final py = 0.5 * thick * dx;
    // a
    vertices[pointIndex + 00] = _a.x + px;
    vertices[pointIndex + 01] = _a.y + py;
    // b
    vertices[pointIndex + 02] = _b.x + px;
    vertices[pointIndex + 03] = _b.y + py;
    // c
    vertices[pointIndex + 04] = _b.x - px;
    vertices[pointIndex + 05] = _b.y - py;
    // d
    vertices[pointIndex + 06] = _a.x - px;
    vertices[pointIndex + 07] = _a.y - py;
    // a
    vertices[pointIndex + 08] = _a.x + px;
    vertices[pointIndex + 09] = _a.y + py;
    // c
    vertices[pointIndex + 10] = _b.x - px;
    vertices[pointIndex + 11] = _b.y - py;
  } else {
    vertices[pointIndex + 00] = 0;
    vertices[pointIndex + 01] = 0;
    vertices[pointIndex + 02] = 0;
    vertices[pointIndex + 03] = 0;
    vertices[pointIndex + 04] = 0;
    vertices[pointIndex + 05] = 0;
    vertices[pointIndex + 06] = 0;
    vertices[pointIndex + 07] = 0;
    vertices[pointIndex + 08] = 0;
    vertices[pointIndex + 09] = 0;
    vertices[pointIndex + 10] = 0;
    vertices[pointIndex + 11] = 0;
  }
}