// figuring out a decent line width is tricky. Want to be responsive to camera
// pos, so line doesn't get super-thick when zoomed in. So we want to measure
// screen-space radius. But off-screen vertices are a problem. So, only consider
// vertices within a level, pointing-forward view cone (can't be actual view cone
// because then line thickness changes as you turn head!).
//
// Also sub-sample verts for efficiency. Probably we don't need to do this
// every frame...but how to distribute?
//
// ***returns 0*** if we couldn't find any points in view cone
public static float EstimateStableCurveWidth(FScene scene,
Frame3f curveFrameS, DCurve3 curve, float fVisualAngleDeg)
{
// do computations in Scene coords..."safest"?
Vector3f camPos = scene.ActiveCamera.GetPosition();
Vector3f camForward = scene.ActiveCamera.Forward();
// use level-forward
camForward[1] = 0; camForward.Normalize();
camPos = scene.ToSceneP(camPos);
camForward = scene.ToSceneN(camForward);
const float ViewConeDotThresh = 0.707106f; // 45 degrees
int nSubSampleInc = Math.Max(2, curve.VertexCount / 10);
float rSum = 0; int iSum = 0;
for (int k = 0; k < curve.VertexCount; k += nSubSampleInc)
{
Vector3f vS = (Vector3f)curve.GetVertex(k);
vS = curveFrameS.FromFrameP(vS);
Vector3f dv = (vS - camPos).Normalized;
if (dv.Dot(camForward) < ViewConeDotThresh)
{
continue;
}
float r = VRUtil.GetVRRadiusForVisualAngle(vS, camPos, fVisualAngleDeg);
rSum += r; iSum++;
}
return((rSum == 0) ? 0 : scene.ToWorldDimension(rSum / (float)iSum));
}
/// <summary>
/// Estimates the 3D centroid of a DCurve
/// </summary>
/// <param name="curve">DCurve</param>
/// <returns>Vector3[]</returns>
public static Vector3d Center(this DCurve3 curve)
{
Vector3d center = Vector3d.Zero;
int len = curve.SegmentCount;
if (!curve.Closed)
{
len++;
}
for (int i = 0; i < len; i++)
{
center += curve.GetVertex(i);
}
center /= len;
return(center);
}
public override bool BeginCapture(ITransformable target, Ray3f worldRay, UIRayHit hit)
{
if (deformer == null)
{
deformer = new ArcLengthSoftTranslation()
{
Curve = curve.Curve, ArcRadius = 3.0f
};
}
DCurve3 c = curve.Curve;
int vi = (VertexIndex == LastIndex) ? c.VertexCount - 1 : 0;
deformer.Handle = c.GetVertex(vi);
deformer.UpdateROI(vi);
deformer.BeginDeformation();
targetW = target.GetLocalFrame(CoordSpace.WorldCoords);
return(true);
}
