Justin Marshall
54 lines
1.0 KiB
C++
54 lines
1.0 KiB
C++
#include "decay.h"
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#include <cmath>
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idParametricDecay::idParametricDecay()
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: delta(0.0f)
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, linear(0.0f)
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, t0(0.0f)
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, tdelta(0.0f)
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, lambda(0.0f) {
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}
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void idParametricDecay::Init(
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const float newDelta,
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const float newLinear,
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const float newT0,
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const float newTDelta,
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const float newLambda
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) {
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delta = newDelta;
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linear = newLinear;
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t0 = newT0;
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tdelta = newTDelta;
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lambda = newLambda;
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}
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void idParametricDecay::SetTZero(const float newT0) {
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t0 = newT0;
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}
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void idParametricDecay::SetDelta(const float newDelta) {
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delta = newDelta;
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}
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float idParametricDecay::Evaluate(const float t) const {
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if (t < t0) {
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return delta;
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}
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const float elapsed = t - t0;
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if (elapsed > tdelta) {
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return 0.0f;
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}
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const float normalizedTime = elapsed / tdelta;
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const float exponential = std::pow(
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0.5f,
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elapsed / (lambda * tdelta)
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);
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return ((1.0f - linear) * exponential
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+ (1.0f - normalizedTime) * linear) * delta;
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}
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