private void OnEnable()
{
_diffusionTexture = PaintUtils.GenerateDiffusionTexture();
}
private void DrawStroke(RenderTexture targetTexture, PaintParameters current, float textureScale = 1f)
{
var previous = _lastParameters.Count > 0 ? _lastParameters[0] : current;
var last = _lastParameters.Count > 1 ? _lastParameters[1] : previous;
bool hasMoved = _lastParameters.Count > 0;
var actualSpeed = Vector2.Distance(current.Position, previous.Position) / (Time.deltaTime * 1000f);
// Smooth speed:
current.Speed = Mathf.Lerp(previous.Speed, actualSpeed, 0.2f);
var brushSize = current.BrushSize;
float angle = Angle;
float roundness = Roundness;
if (BrushTexture != null)
{
BrushMaterial.EnableKeyword("USE_TEXTURE");
}
else
{
BrushMaterial.DisableKeyword("USE_TEXTURE");
}
BrushMaterial.SetFloat("_Hardness", BrushHardness);
var brushTexture = BrushTexture != null ? BrushTexture : Texture2D.whiteTexture;
var positionOffset = Vector2.zero;
if (current.IsPen)
{
var tilt = current.Tilt;
//var azimuth = Mathf.Atan2(tilt.y, tilt.x);
var length = Mathf.Clamp01(tilt.magnitude);
var altitude = Mathf.Atan2(1f - length, length);
//angle = azimuth * Mathf.Rad2Deg;
var brushAngle = 1f - altitude / (Mathf.PI * 0.5f);
// scale brush none linearly:
roundness = 1f + Mathf.Pow(brushAngle, 4f) * MaxBrushScaleFromTilt;
positionOffset = new Vector2(tilt.x, -tilt.y) * brushSize * 0.4f;
}
var startPosition = previous.Position;
var endPosition = current.Position;
var startPressure = previous.Pressure;
var endPressure = current.Pressure;
var distance = Vector2.Distance(endPosition, startPosition);
var absoluteBrushDistance = Mathf.Max(1f, brushSize * BrushSpacing);
if (hasMoved && distance < absoluteBrushDistance)
{
return;
}
var tangent = (startPosition - last.Position).normalized;
var normal = new Vector2(tangent.y, -tangent.x);
var control = startPosition + tangent * (distance * 0.3f);
RenderTexture.active = targetTexture;
GL.PushMatrix();
GL.LoadPixelMatrix(0, targetTexture.width, 0, targetTexture.height);
Vector2 pos = endPosition;
foreach (float t in PaintUtils.DrawLine(startPosition, endPosition, absoluteBrushDistance))
{
if (hasMoved && t == 0f)
{
continue;
}
pos = QuadraticInterpolation
? PaintUtils.PointOnQuadraticCurve(startPosition, control, endPosition, t)
: Vector2.LerpUnclamped(startPosition, endPosition, t);
var pressure = Mathf.Lerp(startPressure, endPressure, t);
var speed = Mathf.Lerp(previous.Speed, current.Speed, t);
var modifiedBrushSize = brushSize
* Mathf.Lerp(1f, pressure, PenPressureInfluence)
* (1f + Random.Range(-1f, 1f) * SizeJitter)
* Mathf.Lerp(1f, 1f / (1f + speed), StrokeSpeedInfluence);
angle = Angle + Mathf.Lerp(0f, Random.Range(-180f, 180f), AngleJitter);
var localBrushRotation = Quaternion.Euler(0, 0, -angle);
roundness = Mathf.Clamp01(Roundness + Random.Range(-1f, 1f) * RoundnessJitter);
var offset = normal * (Random.Range(-1f, 1f) * modifiedBrushSize * Scatter) + positionOffset;
var posOnTexture = (pos + offset) * textureScale;
var sizeOnTexture = modifiedBrushSize * textureScale;
var matrix = Matrix4x4.TRS(posOnTexture, localBrushRotation,
new Vector3(roundness, 1f, 1f)) * Matrix4x4.TRS(-posOnTexture, Quaternion.identity, Vector3.one);
GL.MultMatrix(matrix);
var color = UseOwnColor ? Color : current.Color;
color.a = Mathf.Clamp01(Flow + Random.Range(-1f, 1f) * FlowJitter);
BrushMaterial.color = color;
var rect = new Rect(
posOnTexture.x - 0.5f * sizeOnTexture,
posOnTexture.y - 0.5f * sizeOnTexture,
sizeOnTexture, sizeOnTexture);
Graphics.DrawTexture(rect, brushTexture, BrushMaterial);
}
if (_lastParameters.Count > 1)
{
_lastParameters.RemoveAt(1);
}
current.Position = pos;
_lastParameters.Insert(0, current);
GL.PopMatrix();
RenderTexture.active = null;
}