public SpriteBatchBufferGenerator(int sourceSurfaceWidth, int sourceSurfaceHeight, int targetSurfaceWidth, int targetSurfaceHeight)
{
vertexBufferGenerator = new BufferGenerator();
indexBufferGenerator = new BufferGenerator();
SourceSurfaceWidth = sourceSurfaceWidth;
SourceSurfaceHeight = sourceSurfaceHeight;
TargetSurfaceWidth = targetSurfaceWidth;
TargetSurfaceHeight = targetSurfaceHeight;
}
public static VectorMesh TriangulateShape(Shape shape)
{
P2T.CreateContext(TriangulationAlgorithm.DTSweep);
var vertexBufferGenerator = new BufferGenerator();
var indexBufferGenerator = new BufferGenerator();
int indexCount = 0;
foreach(var path in shape.Paths)
{
AddPathToBuffers(path, vertexBufferGenerator, indexBufferGenerator, ref indexCount);
}
var vertexBuffer = BufferFactory.Allocate(BufferTarget.ArrayBuffer, BufferUsageHint.StaticDraw, vertexBufferGenerator.GetBuffer());
var indexBuffer = BufferFactory.Allocate(BufferTarget.ElementArrayBuffer, BufferUsageHint.StaticDraw, indexBufferGenerator.GetBuffer());
return new VectorMesh(vertexBuffer, indexBuffer, indexCount);
}
private static void AddPathToBuffers(Path path, BufferGenerator vertexBufferGenerator, BufferGenerator indexBufferGenerator, ref int indexCount)
{
List<PolygonPoint> points = new List<PolygonPoint>();
float r;
float g;
float b;
if (path.CompositMode == CompositMode.Subtract)
{
r = 1f;
g = 0f;
b = 0f;
}
else
{
r = 1f;
g = 1f;
b = 1f;
}
foreach (var segment in path.Segments)
{
if (segment is QuadraticCurveSegment)
{
var quadraticCurveSegment = segment as QuadraticCurveSegment;
AddQuadraticCurveSegment(quadraticCurveSegment, points, vertexBufferGenerator, indexBufferGenerator, ref indexCount, r, g, b);
}
else if(segment is LineSegment)
{
var lineSegment = segment as LineSegment;
points.Add(new PolygonPoint(lineSegment.End.X, lineSegment.End.Y));
var ext = 0.01;
var normal = path.CompositMode == CompositMode.Subtract ? lineSegment.RightNormal : lineSegment.LeftNormal;
var p1 = (normal * ext) + lineSegment.Start;
var p2 = (normal * ext) + lineSegment.End;
AddVertex(vertexBufferGenerator, (float)lineSegment.Start.X, (float)lineSegment.Start.Y, 0f, 1f, r, g, b, 1f);
AddVertex(vertexBufferGenerator, (float)lineSegment.End.X, (float)lineSegment.End.Y, 0f, 1f, r, g, b, 1f);
AddVertex(vertexBufferGenerator, (float)p1.X, (float)p1.Y, 1f, 1f, r, g, b, 1f);
indexBufferGenerator.WriteUInt((uint)indexCount++, (uint)indexCount++, (uint)indexCount++);
AddVertex(vertexBufferGenerator, (float)lineSegment.Start.X, (float)lineSegment.Start.Y, 0f, 1f, r, g, b, 1f);
AddVertex(vertexBufferGenerator, (float)p1.X, (float)p1.Y, 0f, 0f, r, g, b, 1f);
AddVertex(vertexBufferGenerator, (float)p2.X, (float)p2.Y, 1f, 1f, r, g, b, 1f);
indexBufferGenerator.WriteUInt((uint)indexCount++, (uint)indexCount++, (uint)indexCount++);
}
else
{
throw new NotImplementedException();
}
}
Polygon polygon;
try
{
polygon = new Polygon(points);
P2T.Triangulate(polygon);
}
catch(Exception e)
{
System.Diagnostics.Debug.WriteLine(e.Message);
return;
}
foreach (var triangle in polygon.Triangles)
{
AddVertex(vertexBufferGenerator, (float)triangle.Points[0].X, (float)triangle.Points[0].Y, 0f, 1f, r, g, b, 1f);
AddVertex(vertexBufferGenerator, (float)triangle.Points[1].X, (float)triangle.Points[1].Y, 0f, 1f, r, g, b, 1f);
AddVertex(vertexBufferGenerator, (float)triangle.Points[2].X, (float)triangle.Points[2].Y, 0f, 1f, r, g, b, 1f);
indexBufferGenerator.WriteUInt((uint)indexCount++, (uint)indexCount++, (uint)indexCount++);
}
}
private static void AddVertex(BufferGenerator vertexBufferGenerator, float x, float y, float u, float v, float r, float g, float b, float sign)
{
vertexBufferGenerator.WriteFloat(x, y, u, v, r, g, b, sign);
}
private static void AddQuadraticCurveSegment(QuadraticCurveSegment quadraticCurveSegment, List<PolygonPoint> points, BufferGenerator vertexBufferGenerator, BufferGenerator indexBufferGenerator, ref int indexCount, float r, float g, float b, int subDiffs = 0)
{
if(subDiffs < 2)
{
var splits = quadraticCurveSegment.Split(0.5);
AddQuadraticCurveSegment(splits[0], points, vertexBufferGenerator, indexBufferGenerator, ref indexCount, r, g, b, subDiffs + 1);
AddQuadraticCurveSegment(splits[1], points, vertexBufferGenerator, indexBufferGenerator, ref indexCount, r, g, b, subDiffs + 1);
return;
}
float sign;
quadraticCurveSegment.Split(0.5);
if (quadraticCurveSegment.Convex)
{
sign = 1f;
points.Add(new PolygonPoint(quadraticCurveSegment.End.X, quadraticCurveSegment.End.Y));
}
else
{
sign = -1f;
points.Add(new PolygonPoint(quadraticCurveSegment.ControlPoint.X, quadraticCurveSegment.ControlPoint.Y));
points.Add(new PolygonPoint(quadraticCurveSegment.End.X, quadraticCurveSegment.End.Y));
}
AddVertex(vertexBufferGenerator, (float)quadraticCurveSegment.Start.X, (float)quadraticCurveSegment.Start.Y, 0f, 0f, r, g, b, sign);
AddVertex(vertexBufferGenerator, (float)quadraticCurveSegment.End.X, (float)quadraticCurveSegment.End.Y, 1f, 1f, r, g, b, sign);
AddVertex(vertexBufferGenerator, (float)quadraticCurveSegment.ControlPoint.X, (float)quadraticCurveSegment.ControlPoint.Y, 0.5f, 0f, r, g, b, sign);
indexBufferGenerator.WriteUInt((uint)indexCount++, (uint)indexCount++, (uint)indexCount++);
}