88 lines
1.7 KiB
C++
88 lines
1.7 KiB
C++
#ifndef _EASING_H_
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#define _EASING_H_
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//see http://www.gizma.com/easing/ for more information
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class Easing
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{
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public:
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float start_value;
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float delta_value;
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float value;
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float duration;
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float time_acc;
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Easing(float val): start_value(val), delta_value(0), value(val), duration(0), time_acc(0)
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{
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}
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void reset()
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{
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value = start_value;
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time_acc = 0;
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}
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void finish()
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{
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value = start_value + delta_value;
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time_acc = 0; duration = 0;
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}
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virtual void update(float dt) = 0;
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void start(float targetValue, float _duration)
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{
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start_value = value;
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delta_value = targetValue - start_value;
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time_acc = 0;
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duration = _duration;
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}
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void translate(float delta_value)
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{
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start_value += delta_value;
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value += delta_value;
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}
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bool finished()
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{
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return time_acc >= duration;
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}
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};
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class InOutQuadEasing : public Easing
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{
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public:
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InOutQuadEasing(float val): Easing(val) {}
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void update(float dt)
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{
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if(duration > 0)
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{
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time_acc += dt;
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if(time_acc > duration)
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{
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time_acc = duration;
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value = start_value + delta_value;
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}
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else
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{
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float time_tmp = time_acc * 2 / duration;
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if (time_tmp < 1)
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{
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value = delta_value/2*time_tmp*time_tmp + start_value;
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}
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else
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{
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time_tmp -= 1;
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value = -delta_value/2 * (time_tmp*(time_tmp-2) - 1) + start_value;
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}
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}
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}
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}
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};
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#endif //_EASING_H_
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