protected override void Dispose(bool isDisposing)
{
base.Dispose(isDisposing);
halfCircleBatch.Dispose();
quadBatch.Dispose();
}
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
vertexBatch.Dispose();
}
}
protected override void Dispose(bool isDisposing)
{
base.Dispose(isDisposing);
quadBatch?.Dispose();
triangleBatch?.Dispose();
}
protected override void Dispose(bool isDisposing)
{
base.Dispose(isDisposing);
// Children disposed via their source drawables
Children = null;
quadBatch?.Dispose();
triangleBatch?.Dispose();
}
private void updateVertexBuffer()
{
const float start_angle = 0;
float dir = Math.Sign(angle);
float radius = Math.Max(drawSize.X, drawSize.Y);
// The amount of points are selected such that discrete curvature is smaller than the provided tolerance.
// The exact angle required to meet the tolerance is: 2 * Math.Acos(1 - TOLERANCE / r)
// The special case is for extremely small circles where the radius is smaller than the tolerance.
int amountPoints = 2 * radius <= arc_tolerance ? 2 : Math.Max(2, (int)Math.Ceiling(Math.PI / Math.Acos(1 - arc_tolerance / radius)));
if (halfCircleBatch == null || halfCircleBatch.Size < amountPoints * 2)
{
halfCircleBatch?.Dispose();
// Amount of points is multiplied by 2 to account for each part requiring two vertices.
halfCircleBatch = new LinearBatch <TexturedVertex2D>(amountPoints * 2, 1, PrimitiveType.TriangleStrip);
}
Matrix3 transformationMatrix = DrawInfo.Matrix;
MatrixExtensions.ScaleFromLeft(ref transformationMatrix, drawSize);
Vector2 current = origin + pointOnCircle(start_angle) * 0.5f;
Color4 currentColour = colourAt(current);
current = Vector2Extensions.Transform(current, transformationMatrix);
Vector2 screenOrigin = Vector2Extensions.Transform(origin, transformationMatrix);
Color4 originColour = colourAt(origin);
// Offset by 0.5 pixels inwards to ensure we never sample texels outside the bounds
RectangleF texRect = texture.GetTextureRect(new RectangleF(0.5f, 0.5f, texture.Width - 1, texture.Height - 1));
float prevOffset = dir >= 0 ? 0 : 1;
// First center point
halfCircleBatch.Add(new TexturedVertex2D
{
Position = Vector2.Lerp(current, screenOrigin, innerRadius),
TexturePosition = new Vector2(dir >= 0 ? texRect.Left : texRect.Right, texRect.Top),
Colour = originColour
});
// First outer point.
halfCircleBatch.Add(new TexturedVertex2D
{
Position = new Vector2(current.X, current.Y),
TexturePosition = new Vector2(dir >= 0 ? texRect.Left : texRect.Right, texRect.Bottom),
Colour = currentColour
});
for (int i = 1; i < amountPoints; i++)
{
float fract = (float)i / (amountPoints - 1);
// Clamps the angle so we don't overshoot.
// dir is used so negative angles result in negative angularOffset.
float angularOffset = Math.Min(fract * two_pi, dir * angle);
float normalisedOffset = angularOffset / two_pi;
if (dir < 0)
{
normalisedOffset += 1.0f;
}
// Update `current`
current = origin + pointOnCircle(start_angle + angularOffset) * 0.5f;
currentColour = colourAt(current);
current = Vector2Extensions.Transform(current, transformationMatrix);
// current center point
halfCircleBatch.Add(new TexturedVertex2D
{
Position = Vector2.Lerp(current, screenOrigin, innerRadius),
TexturePosition = new Vector2(texRect.Left + (normalisedOffset + prevOffset) / 2 * texRect.Width, texRect.Top),
Colour = originColour
});
// current outer point
halfCircleBatch.Add(new TexturedVertex2D
{
Position = new Vector2(current.X, current.Y),
TexturePosition = new Vector2(texRect.Left + normalisedOffset * texRect.Width, texRect.Bottom),
Colour = currentColour
});
prevOffset = normalisedOffset;
}
}
