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Simplify electric arc spline function

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Sezz 2023-01-21 01:30:43 +11:00
parent e6885c345e
commit eb83b13e78
2 changed files with 32 additions and 17 deletions
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45
TombEngine/Game/effects/lightning.cpp
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@ -236,15 +236,12 @@ namespace TEN::Effects::Lightning
{
for (int i = (arc.segments * 3) - 2; i > 0; i--)
{
auto spline = Vector3(
ElectricArcSpline(alpha, &posArray[0].x, posArray.size()),
ElectricArcSpline(alpha, &posArray[0].y, posArray.size()),
ElectricArcSpline(alpha, &posArray[0].z, posArray.size()));
auto spline = ElectricArcSpline(alpha, &posArray[0], posArray.size());
auto sphere = BoundingSphere(Vector3::Zero, 8.0f);
auto offset = Random::GeneratePointInSphere(sphere);
bufferArray[bufferIndex] = spline + offset;
alpha += interpStep;
bufferIndex++;
}
@ -284,25 +281,43 @@ namespace TEN::Effects::Lightning
// 4-point Catmull-Rom spline interpolation.
// NOTE: Alpha is in the range [0, 65536] rather than [0, 1].
// BIG TODO: Make a family of curve classes with Bezier, B-Spline, Catmull-Rom.
int ElectricArcSpline(int alpha, float* knots, int numKnots)
Vector3 ElectricArcSpline(int alpha, Vector3* knots, int numKnots)
{
alpha *= numKnots - 3;
int span = alpha >> 16;
int span = alpha / pow(2, 16);
if (span >= (numKnots - 3))
span = numKnots - 4;
alpha -= 65536 * span;
float* k = &knots[3 * span];
auto* knot = &knots[span];
int c1 = k[3] + (k[3] / 2) - (k[6] / 2) - k[6] + (k[9] / 2) + ((-k[0] - 1) / 2);
int ret = (long long)c1 * alpha >> 16;
int c2 = ret + 2 * k[6] - 2 * k[3] - (k[3] / 2) - (k[9] / 2) + k[0];
ret = (long long)c2 * alpha >> 16;
int c3 = ret + (k[6] / 2) + ((-k[0] - 1) / 2);
ret = (long long)c3 * alpha >> 16;
auto point1 = knot[1] + (knot[1] / 2) - (knot[2] / 2) - knot[2] + (knot[3] / 2) + ((-knot[0] - Vector3::One) / 2);
auto ret = (point1 * alpha) / pow(2, 16);
auto point2 = ret + Vector3(2.0f) * knot[2] - 2 * knot[1] - (knot[1] / 2) - (knot[3] / 2) + knot[0];
ret = (point2 * alpha) / pow(2, 16);
auto point3 = ret + (knot[2] / 2) + ((-knot[0] - Vector3::One) / 2);
ret = (point3 * alpha) / pow(2, 16);
return (ret + k[3]);
return (ret + knot[1]);
}
// More standard version. Maybe use this later.
Vector3 CatmullRomSpline(float alpha, const std::array<Vector3, 4>& knots)
{
auto knot0 = knots[0];
auto knot1 = knots[1];
auto knot2 = knots[2];
auto knot3 = knots[3];
auto point1 = knot1 + ((knot2 - knot0) * (1 / 6.0f));
auto point2 = knot2;
auto point3 = knot2 + ((knot3 - knot1) * (-1 / 6.0f));
auto point4 = knot3;
return (((point2 * 2) + (point3 - point1) * alpha) +
(((point1 * 2) - (point2 * 5) + (point3 * 4) - point4) * SQUARE(alpha)) +
(((point1 * -1) + (point2 * 3) - (point3 * 3) + point4) * CUBE(alpha)));
}
}

4
TombEngine/Game/effects/lightning.h
View file

@ -60,7 +60,7 @@ namespace TEN::Effects::Lightning
short Rotation = 0;
short Coil = 0;
int r, g, b;
int r, g, b; // TODO: Replace usage with Color.
};
extern std::vector<ElectricArc> ElectricArcs;
@ -77,5 +77,5 @@ namespace TEN::Effects::Lightning
void UpdateHelicalLasers();
void CalculateElectricArcSpline(std::array<Vector3, 6>& posArray, std::array<Vector3, 1024>& bufferArray, const ElectricArc& arc);
int ElectricArcSpline(int alpha, float* knots, int numKnots);
Vector3 ElectricArcSpline(int alpha, Vector3* knots, int numKnots);
}