Added module: easings (header only)

src/easings.h

@@ -0,0 +1,219 @@
+/*******************************************************************************************
+*
+*   raylib Easings - Useful easing functions for values animation
+*
+*   A port of Robert Penner's easing equations to C (http://robertpenner.com/easing/)
+*
+*   Robert Penner License
+*   ---------------------------------------------------------------------------------
+*   Open source under the BSD License. 
+*
+*   Copyright (c) 2001 Robert Penner. All rights reserved.
+*
+*   Redistribution and use in source and binary forms, with or without modification, 
+*   are permitted provided that the following conditions are met:
+*
+*       - Redistributions of source code must retain the above copyright notice, 
+*         this list of conditions and the following disclaimer.
+*       - Redistributions in binary form must reproduce the above copyright notice, 
+*         this list of conditions and the following disclaimer in the documentation 
+*         and/or other materials provided with the distribution.
+*       - Neither the name of the author nor the names of contributors may be used 
+*         to endorse or promote products derived from this software without specific 
+*         prior written permission.
+*
+*   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+*   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+*   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+*   IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+*   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
+*   BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
+*   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
+*   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
+*   OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 
+*   OF THE POSSIBILITY OF SUCH DAMAGE.
+*   ---------------------------------------------------------------------------------
+*
+*   Copyright (c) 2015 Ramon Santamaria
+*
+*   This software is provided "as-is", without any express or implied warranty. In no event
+*   will the authors be held liable for any damages arising from the use of this software.
+*
+*   Permission is granted to anyone to use this software for any purpose, including commercial
+*   applications, and to alter it and redistribute it freely, subject to the following restrictions:
+*
+*     1. The origin of this software must not be misrepresented; you must not claim that you
+*     wrote the original software. If you use this software in a product, an acknowledgment
+*     in the product documentation would be appreciated but is not required.
+*
+*     2. Altered source versions must be plainly marked as such, and must not be misrepresented
+*     as being the original software.
+*
+*     3. This notice may not be removed or altered from any source distribution.
+*
+**********************************************************************************************/
+
+#ifndef EASINGS_H
+#define EASINGS_H
+
+#include <math.h>
+
+#ifdef __cplusplus
+extern "C" {            // Prevents name mangling of functions
+#endif
+
+// Linear Easing functions
+float EaseLinearNone(float t, float b, float c, float d) { return (c*t/d + b); }
+float EaseLinearIn(float t, float b, float c, float d) { return (c*t/d + b); }
+float EaseLinearOut(float t, float b, float c, float d) { return (c*t/d + b); }
+float EaseLinearInOut(float t,float b, float c, float d) { return (c*t/d + b); }
+
+// Sine Easing functions
+float EaseSineIn(float t, float b, float c, float d) { return (-c*cos(t/d*(PI/2)) + c + b); }
+float EaseSineOut(float t, float b, float c, float d) { return (c*sin(t/d*(PI/2)) + b); }
+float EaseSineInOut(float t, float b, float c, float d) { return (-c/2*(cos(PI*t/d) - 1) + b); }
+
+// Circular Easing functions
+float EaseCircIn(float t, float b, float c, float d) { return (-c*(sqrt(1 - (t/=d)*t) - 1) + b); }
+float EaseCircOut(float t, float b, float c, float d) { return (c*sqrt(1 - (t=t/d-1)*t) + b); }
+float EaseCircInOut(float t, float b, float c, float 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);
+}
+
+// Cubic Easing functions
+float EaseCubicIn(float t, float b, float c, float d) { return (c*(t/=d)*t*t + b); }
+float EaseCubicOut(float t, float b, float c, float d) { return (c*((t=t/d-1)*t*t + 1) + b); }
+float EaseCubicInOut(float t, float b, float c, float d) 
+{ 
+    if ((t/=d/2) < 1) return (c/2*t*t*t + b);
+    return (c/2*((t-=2)*t*t + 2) + b);    
+}
+
+// Quadratic Easing functions
+float EaseQuadIn(float t, float b, float c, float d) { return (c*(t/=d)*t + b); }
+float EaseQuadOut(float t, float b, float c, float d) { return (-c*(t/=d)*(t-2) + b); }
+float EaseQuadInOut(float t, float b, float c, float d) 
+{
+    if ((t/=d/2) < 1) return (((c/2)*(t*t)) + b);
+    return (-c/2*(((t-2)*(--t)) - 1) + b);
+}
+
+// Exponential Easing functions
+float EaseExpoIn(float t, float b, float c, float d) { return (t == 0) ? b : (c*pow(2, 10*(t/d - 1)) + b); }
+float EaseExpoOut(float t, float b, float c, float d) { return (t == d) ? (b + c) : (c*(-pow(2, -10*t/d) + 1) + b);    }
+float EaseExpoInOut(float t, float b, float c, float d) 
+{
+    if (t == 0) return b;
+    if (t == d) return (b + c);
+    if ((t/=d/2) < 1) return (c/2*pow(2, 10*(t - 1)) + b);
+    
+    return (c/2*(-pow(2, -10*--t) + 2) + b);
+}
+
+// Back Easing functions
+float EaseBackIn(float t, float b, float c, float d) 
+{
+    float s = 1.70158f;
+    float postFix = t/=d;
+    return (c*(postFix)*t*((s + 1)*t - s) + b);
+}
+
+float EaseBackOut(float t, float b, float c, float d)
+{    
+    float s = 1.70158f;
+    return (c*((t=t/d-1)*t*((s + 1)*t + s) + 1) + b);
+}
+
+float EaseBackInOut(float t, float b, float c, float d)
+{
+    float s = 1.70158f;
+    if ((t/=d/2) < 1) return (c/2*(t*t*(((s*=(1.525f)) + 1)*t - s)) + b);
+    
+    float postFix = t-=2;
+    return (c/2*((postFix)*t*(((s*=(1.525f)) + 1)*t + s) + 2) + b);
+}
+
+// Bounce Easing functions
+float EaseBounceIn(float t, float b, float c, float d) { return (c - EaseBounceOut(d-t, 0, c, d) + b); }
+float EaseBounceOut(float t, float b, float c, float 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 + 0.75f) + b);
+    } 
+    else if (t < (2.5/2.75)) 
+    {
+        float postFix = t-=(2.25f/2.75f);
+        return (c*(7.5625f*(postFix)*t + 0.9375f) + b);
+    } 
+    else 
+    {
+        float postFix = t-=(2.625f/2.75f);
+        return (c*(7.5625f*(postFix)*t + 0.984375f) + b);
+    }
+}
+
+float EaseBounceInOut(float t, float b, float c, float d) 
+{
+    if (t < d/2) return (EaseBounceIn(t*2, 0, c, d)*0.5f + b);
+    else return (EaseBounceOut(t*2-d, 0, c, d)*0.5f + c*0.5f + b);
+}
+
+// Elastic Easing functions
+float EaseElasticIn(float t, float b, float c, float 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));
+    
+    return (-(postFix*sin((t*d-s)*(2*PI)/p )) + b);
+}
+
+float EaseElasticOut(float t, float b, float c, float 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);    
+}
+
+float EaseElasticInOut(float t, float b, float c, float 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));
+        return -0.5f*(postFix*sin((t*d-s)*(2*PI)/p)) + b;
+    }
+    
+    float postFix = a*pow(2, -10*(t-=1));
+    
+    return (postFix*sin((t*d-s)*(2*PI)/p)*0.5f + c + b);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // EASINGS_H