godot/scene/animation/tween_interpolaters.cpp

/*************************************************************************/
/*  tween.cpp                                                            */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/
#include "tween.h"

const real_t pi = 3.1415926535898;

///////////////////////////////////////////////////////////////////////////
// linear
///////////////////////////////////////////////////////////////////////////
namespace linear {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return c * t / d + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		return c * t / d + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		return c * t / d + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return c * t / d + b;
	}
};
///////////////////////////////////////////////////////////////////////////
// sine
///////////////////////////////////////////////////////////////////////////
namespace sine {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return -c * cos(t / d * (pi / 2)) + c + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		return c * sin(t / d * (pi / 2)) + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		return -c / 2 * (cos(pi * t / d) - 1) + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// quint
///////////////////////////////////////////////////////////////////////////
namespace quint {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return c * pow(t / d, 5) + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		return c * (pow(t / d - 1, 5) + 1) + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		t = t / d * 2;
		if (t < 1) return c / 2 * pow(t, 5) + b;
		return c / 2 * (pow(t - 2, 5) + 2) + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// quart
///////////////////////////////////////////////////////////////////////////
namespace quart {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return c * pow(t / d, 4) + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		return -c * (pow(t / d - 1, 4) - 1) + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		t = t / d * 2;
		if (t < 1) return c / 2 * pow(t, 4) + b;
		return -c / 2 * (pow(t - 2, 4) - 2) + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// quad
///////////////////////////////////////////////////////////////////////////
namespace quad {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return c * pow(t / d, 2) + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		t = t / d;
		return -c * t * (t - 2) + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		t = t / d * 2;
		if (t < 1) return c / 2 * pow(t, 2) + b;
		return -c / 2 * ((t - 1) * (t - 3) - 1) + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// expo
///////////////////////////////////////////////////////////////////////////
namespace expo {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		if (t == 0) return b;
		return c * pow(2, 10 * (t / d - 1)) + b - c * 0.001;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		if (t == d) return b + c;
		return c * 1.001 * (-pow(2, -10 * t / d) + 1) + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		if (t == 0) return b;
		if (t == d) return b + c;
		t = t / d * 2;
		if (t < 1) return c / 2 * pow(2, 10 * (t - 1)) + b - c * 0.0005;
		return c / 2 * 1.0005 * (-pow(2, -10 * (t - 1)) + 2) + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// elastic
///////////////////////////////////////////////////////////////////////////
namespace elastic {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
        if (t == 0) return b;
		if ((t /= d) == 1) return b + c;
        float p = d * 0.3f;
        float a = c;
        float s = p / 4;
        float postFix = a * pow(2,10 * (t -= 1)); // this is a fix, again, with post-increment operators
        return -(postFix * sin((t * d - s) * (2 * pi) / p )) + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
        if (t == 0) return b;
		if ((t /= d) == 1) return b + c;
        float p = d * 0.3f;
        float a = c;
        float s = p / 4;
        return (a * pow(2, -10 * t) * sin((t * d - s) * (2 * pi) / p ) + c + b);
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
        if (t == 0) return b;
		if ((t /= d / 2) == 2) return b + c;
        float p = d * (0.3f * 1.5f);
        float a = c;
        float s = p / 4;

        if (t < 1) {
			float postFix = a * pow(2, 10 * (t -= 1)); // postIncrement is evil
            return -0.5f * (postFix * sin((t * d - s) * (2 * pi) / p)) + b;
        }
        float postFix = a * pow(2, -10 * (t -= 1)); // postIncrement is evil
        return postFix * sin((t * d - s) * (2 * pi) / p ) * 0.5f + c + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// cubic
///////////////////////////////////////////////////////////////////////////
namespace cubic {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return c * (t /= d) * t * t + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		return c * ((t = t / d - 1) * t * t + 1) + b;
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		if ((t /= d / 2) < 1) return c / 2 * t * t * t + b;
		return c / 2 * ((t -= 2) * t * t + 2) + b;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// circ
///////////////////////////////////////////////////////////////////////////
namespace circ {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return -c * (sqrt(1 - (t /= d) * t) - 1) + b; // TODO: ehrich: operation with t is undefined
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		return c * sqrt(1 - (t = t / d - 1) * t) + b; // TODO: ehrich: operation with t is undefined
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		if ((t /= d / 2) < 1) return -c / 2 * (sqrt(1 - t * t) - 1) + b;
		return c / 2 * (sqrt(1 - t * (t -= 2)) + 1) + b; // TODO: ehrich: operation with t is undefined
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// bounce
///////////////////////////////////////////////////////////////////////////
namespace bounce {
	static real_t out(real_t t, real_t b, real_t c, real_t d);

	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
		return c - out(d - t, 0, c, d) + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
		if ((t /= d) < (1 / 2.75f)) {
			return c*(7.5625f*t*t) + b;
		} else if (t < (2/2.75f)) {
			float postFix = t-=(1.5f/2.75f);
			return c*(7.5625f*(postFix)*t + .75f) + b;
		} else if (t < (2.5/2.75)) {
			float postFix = t-=(2.25f/2.75f);
			return c*(7.5625f*(postFix)*t + .9375f) + b;
		} else {
			float postFix = t-=(2.625f/2.75f);
			return c*(7.5625f*(postFix)*t + .984375f) + b;
		}
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? in(t * 2, b, c / 2, d)
			: out((t * 2) - d, b + c / 2, c / 2, d)
		;
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};
///////////////////////////////////////////////////////////////////////////
// back
///////////////////////////////////////////////////////////////////////////
namespace back {
	static real_t in(real_t t, real_t b, real_t c, real_t d)
	{
        float s = 1.70158f;
        float postFix = t /= d;
        return c * (postFix) * t * ((s + 1) * t - s) + b;
	}

	static real_t out(real_t t, real_t b, real_t c, real_t d)
	{
        float s = 1.70158f;
        return c * ((t = t / d- 1) * t * ((s + 1) * t + s) + 1) + b; // TODO: ehrich: operation with t is undefined
	}

	static real_t in_out(real_t t, real_t b, real_t c, real_t d)
	{
		float s = 1.70158f;
		if ((t /= d / 2) < 1) return c / 2 * (t * t * (((s *= (1.525f)) + 1) * t - s)) + b; // TODO: ehrich: operation with s is undefined
		float postFix = t -= 2;
		return c / 2 * ((postFix) * t * (((s *= (1.525f)) + 1) * t + s) + 2) + b; // TODO: ehrich: operation with s is undefined
	}

	static real_t out_in(real_t t, real_t b, real_t c, real_t d)
	{
		return (t < d / 2)
			? out(t * 2, b, c / 2, d)
			: in((t * 2) - d, b + c / 2, c / 2, d)
		;
	}
};

Tween::interpolater Tween::interpolaters[Tween::TRANS_COUNT][Tween::EASE_COUNT] = {
	{ &linear::in, &linear::out, &linear::in_out, &linear::out_in },
	{ &sine::in, &sine::out, &sine::in_out, &sine::out_in },
	{ &quint::in, &quint::out, &quint::in_out, &quint::out_in },
	{ &quart::in, &quart::out, &quart::in_out, &quart::out_in },
	{ &quad::in, &quad::out, &quad::in_out, &quad::out_in },
	{ &expo::in, &expo::out, &expo::in_out, &expo::out_in },
	{ &elastic::in, &elastic::out, &elastic::in_out, &elastic::out_in },
	{ &cubic::in, &cubic::out, &cubic::in_out, &cubic::out_in },
	{ &circ::in, &circ::out, &circ::in_out, &circ::out_in },
	{ &bounce::in, &bounce::out, &bounce::in_out, &bounce::out_in },
	{ &back::in, &back::out, &back::in_out, &back::out_in },
};

real_t Tween::_run_equation(TransitionType p_trans_type, EaseType p_ease_type, real_t t, real_t b, real_t c, real_t d) {

	interpolater cb = interpolaters[p_trans_type][p_ease_type];
	ERR_FAIL_COND_V(cb == NULL, b);
	return cb(t, b, c, d);
}