Merge pull request #852 from flashback-fx/master

easings.h refinement and example

examples/others/easings.h

@@ -0,0 +1,263 @@
+/*******************************************************************************************
+*
+*   raylib easings (header only file)
+*
+*   Useful easing functions for values animation
+*
+*   This header uses:
+*       #define EASINGS_STATIC_INLINE       // Inlines all functions code, so it runs faster.
+*                                           // This requires lots of memory on system.
+*   How to use:
+*   The four inputs t,b,c,d are defined as follows:
+*   t = current time (in any unit measure, but same unit as duration)
+*   b = starting value to interpolate
+*   c = the total change in value of b that needs to occur
+*   d = total time it should take to complete (duration)
+*
+*   Example:
+*
+*   int currentTime = 0;
+*   int duration = 100;
+*   float startPositionX = 0.0f;
+*   float finalPositionX = 30.0f;
+*   float currentPositionX = startPositionX;
+*
+*   while (currentPositionX < finalPositionX)
+*   {
+*       currentPositionX = EaseSineIn(currentTime, startPositionX, finalPositionX - startPositionX, duration);
+*       currentTime++;
+*   }
+*
+*   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
+
+#define EASINGS_STATIC_INLINE     // NOTE: By default, compile functions as static inline
+
+#if defined(EASINGS_STATIC_INLINE)
+    #define EASEDEF static inline
+#else
+    #define EASEDEF extern
+#endif
+
+#include <tgmath.h>       // Required for: sin(), cos(), sqrt(), pow()
+
+#ifndef PI
+    #define PI 3.14159265358979323846f //Required as PI is not always defined in math.h
+#endif
+
+#ifdef __cplusplus
+extern "C" {            // Prevents name mangling of functions
+#endif
+
+// Linear Easing functions
+EASEDEF float EaseLinearNone(float t, float b, float c, float d) { return (c*t/d + b); }
+EASEDEF float EaseLinearIn(float t, float b, float c, float d) { return (c*t/d + b); }
+EASEDEF float EaseLinearOut(float t, float b, float c, float d) { return (c*t/d + b); }
+EASEDEF float EaseLinearInOut(float t,float b, float c, float d) { return (c*t/d + b); }
+
+// Sine Easing functions
+EASEDEF float EaseSineIn(float t, float b, float c, float d) { return (-c*cos(t/d*(PI/2.0f)) + c + b); }
+EASEDEF float EaseSineOut(float t, float b, float c, float d) { return (c*sin(t/d*(PI/2.0f)) + b); }
+EASEDEF float EaseSineInOut(float t, float b, float c, float d) { return (-c/2.0f*(cos(PI*t/d) - 1.0f) + b); }
+
+// Circular Easing functions
+EASEDEF float EaseCircIn(float t, float b, float c, float d) { t /= d; return (-c*(sqrt(1.0f - t*t) - 1.0f) + b); }
+EASEDEF float EaseCircOut(float t, float b, float c, float d) { t = t/d - 1.0f; return (c*sqrt(1.0f - t*t) + b); }
+EASEDEF float EaseCircInOut(float t, float b, float c, float d)
+{
+    if ((t/=d/2.0f) < 1.0f) return (-c/2.0f*(sqrt(1.0f - t*t) - 1.0f) + b);
+    t -= 2.0f; return (c/2.0f*(sqrt(1.0f - t*t) + 1.0f) + b);
+}
+
+// Cubic Easing functions
+EASEDEF float EaseCubicIn(float t, float b, float c, float d) { t /= d; return (c*t*t*t + b); }
+EASEDEF float EaseCubicOut(float t, float b, float c, float d) { t = t/d - 1.0f; return (c*(t*t*t + 1.0f) + b); }
+EASEDEF float EaseCubicInOut(float t, float b, float c, float d)
+{
+    if ((t/=d/2.0f) < 1.0f) return (c/2.0f*t*t*t + b);
+    t -= 2.0f; return (c/2.0f*(t*t*t + 2.0f) + b);
+}
+
+// Quadratic Easing functions
+EASEDEF float EaseQuadIn(float t, float b, float c, float d) { t /= d; return (c*t*t + b); }
+EASEDEF float EaseQuadOut(float t, float b, float c, float d) { t /= d; return (-c*t*(t - 2.0f) + b); }
+EASEDEF float EaseQuadInOut(float t, float b, float c, float d)
+{
+    if ((t/=d/2) < 1) return (((c/2)*(t*t)) + b);
+	return (-c/2.0f*(((t - 1.0f)*(t - 3.0f)) - 1.0f) + b);
+}
+
+// Exponential Easing functions
+EASEDEF float EaseExpoIn(float t, float b, float c, float d) { return (t == 0.0f) ? b : (c*pow(2.0f, 10.0f*(t/d - 1.0f)) + b); }
+EASEDEF float EaseExpoOut(float t, float b, float c, float d) { return (t == d) ? (b + c) : (c*(-pow(2.0f, -10.0f*t/d) + 1.0f) + b);    }
+EASEDEF float EaseExpoInOut(float t, float b, float c, float d)
+{
+    if (t == 0.0f) return b;
+    if (t == d) return (b + c);
+    if ((t/=d/2.0f) < 1.0f) return (c/2.0f*pow(2.0f, 10.0f*(t - 1.0f)) + b);
+
+	return (c/2.0f*(-pow(2.0f, -10.0f*(t - 1.0f)) + 2.0f) + b);
+}
+
+// Back Easing functions
+EASEDEF float EaseBackIn(float t, float b, float c, float d)
+{
+    float s = 1.70158f;
+    float postFix = t/=d;
+    return (c*(postFix)*t*((s + 1.0f)*t - s) + b);
+}
+
+EASEDEF float EaseBackOut(float t, float b, float c, float d)
+{
+    float s = 1.70158f;
+    t = t/d - 1.0f;
+    return (c*(t*t*((s + 1.0f)*t + s) + 1.0f) + b);
+}
+
+EASEDEF float EaseBackInOut(float t, float b, float c, float d)
+{
+    float s = 1.70158f;
+    if ((t/=d/2.0f) < 1.0f)
+    {
+        s *= 1.525f;
+        return (c/2.0f*(t*t*((s + 1.0f)*t - s)) + b);
+    }
+
+    float postFix = t-=2.0f;
+    s *= 1.525f;
+    return (c/2.0f*((postFix)*t*((s + 1.0f)*t + s) + 2.0f) + b);
+}
+
+// Bounce Easing functions
+EASEDEF float EaseBounceOut(float t, float b, float c, float d)
+{
+    if ((t/=d) < (1.0f/2.75f))
+    {
+        return (c*(7.5625f*t*t) + b);
+    }
+    else if (t < (2.0f/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);
+    }
+}
+
+EASEDEF float EaseBounceIn(float t, float b, float c, float d) { return (c - EaseBounceOut(d - t, 0.0f, c, d) + b); }
+EASEDEF float EaseBounceInOut(float t, float b, float c, float d)
+{
+    if (t < d/2.0f) return (EaseBounceIn(t*2.0f, 0.0f, c, d)*0.5f + b);
+    else return (EaseBounceOut(t*2.0f - d, 0.0f, c, d)*0.5f + c*0.5f + b);
+}
+
+// Elastic Easing functions
+EASEDEF float EaseElasticIn(float t, float b, float c, float d)
+{
+    if (t == 0.0f) return b;
+    if ((t/=d) == 1.0f) return (b + c);
+
+    float p = d*0.3f;
+    float a = c;
+    float s = p/4.0f;
+    float postFix = a*pow(2.0f, 10.0f*(t-=1.0f));
+
+    return (-(postFix*sin((t*d-s)*(2.0f*PI)/p )) + b);
+}
+
+EASEDEF float EaseElasticOut(float t, float b, float c, float d)
+{
+    if (t == 0.0f) return b;
+    if ((t/=d) == 1.0f) return (b + c);
+
+    float p = d*0.3f;
+    float a = c;
+    float s = p/4.0f;
+
+    return (a*pow(2.0f,-10.0f*t)*sin((t*d-s)*(2.0f*PI)/p) + c + b);
+}
+
+EASEDEF float EaseElasticInOut(float t, float b, float c, float d)
+{
+    if (t == 0.0f) return b;
+    if ((t/=d/2.0f) == 2.0f) return (b + c);
+
+    float p = d*(0.3f*1.5f);
+    float a = c;
+    float s = p/4.0f;
+
+    if (t < 1.0f)
+    {
+        float postFix = a*pow(2.0f, 10.0f*(t-=1.0f));
+        return -0.5f*(postFix*sin((t*d-s)*(2.0f*PI)/p)) + b;
+    }
+
+    float postFix = a*pow(2.0f, -10.0f*(t-=1.0f));
+
+    return (postFix*sin((t*d-s)*(2.0f*PI)/p)*0.5f + c + b);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // EASINGS_H

examples/others/easings_testbed.c

@@ -0,0 +1,354 @@
+/*******************************************************************************************
+*
+*   raylib [easings] example
+*
+*   This example has been created using raylib 2.5 (www.raylib.com)
+*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
+*
+*   Copyright (c) 2019 Juan Miguel López
+*
+********************************************************************************************/
+
+
+#include <raylib.h>
+#include "easings.h"
+
+
+// Application constants
+#define SCR_WIDTH 800
+#define SCR_HEIGHT 450
+#define BALL_RADIUS 16.0f
+#define BALL_COLOR MAROON
+#define PAD 80.0f
+#define START_X (0.0f + (BALL_RADIUS) + (PAD))
+#define END_X ((SCR_WIDTH) - ((BALL_RADIUS) + (PAD)))
+#define START_Y (0.0f + (BALL_RADIUS) + (PAD))
+#define END_Y ((SCR_HEIGHT) - ((BALL_RADIUS) + (PAD)))
+#define T_ADVANCE 1.0f
+#define D_DFT 300.0f
+#define TARGET_FPS 60
+#define BG_COLOR RAYWHITE
+#define TEXT_COLOR LIGHTGRAY
+#define FONT_SIZE 20
+#define D_STEP 20.0f
+#define D_STEP_FINE 2.0f
+#define D_MIN 1.0f
+#define D_MAX 10000.0f
+
+// Application control keys
+#define KEY_NEXT_EASE_X KEY_RIGHT
+#define KEY_PREV_EASE_X KEY_LEFT
+#define KEY_NEXT_EASE_Y KEY_DOWN
+#define KEY_PREV_EASE_Y KEY_UP
+#define KEY_INCR_D_STEP KEY_W
+#define KEY_DECR_D_STEP KEY_Q
+#define KEY_INCR_D_FINE KEY_S
+#define KEY_DECR_D_FINE KEY_A
+#define KEY_PLAY_PAUSE KEY_ENTER
+#define KEY_RESTART KEY_SPACE
+#define KEY_TOGGLE_UNBOUNDED_T KEY_T
+
+
+// Easing types
+enum EasingTypes {
+    EASE_LINEAR_NONE,
+    EASE_LINEAR_IN,
+    EASE_LINEAR_OUT,
+    EASE_LINEAR_IN_OUT,
+    EASE_SINE_IN,
+    EASE_SINE_OUT,
+    EASE_SINE_IN_OUT,
+    EASE_CIRC_IN,
+    EASE_CIRC_OUT,
+    EASE_CIRC_IN_OUT,
+    EASE_CUBIC_IN,
+    EASE_CUBIC_OUT,
+    EASE_CUBIC_IN_OUT,
+    EASE_QUAD_IN,
+    EASE_QUAD_OUT,
+    EASE_QUAD_IN_OUT,
+    EASE_EXPO_IN,
+    EASE_EXPO_OUT,
+    EASE_EXPO_IN_OUT,
+    EASE_BACK_IN,
+    EASE_BACK_OUT,
+    EASE_BACK_IN_OUT,
+    EASE_BOUNCE_OUT,
+    EASE_BOUNCE_IN,
+    EASE_BOUNCE_IN_OUT,
+    EASE_ELASTIC_IN,
+    EASE_ELASTIC_OUT,
+    EASE_ELASTIC_IN_OUT,
+    NUM_EASING_TYPES,
+    EASING_NONE = NUM_EASING_TYPES
+};
+
+
+static float NoEase(float t, float b, float c, float d);  // NoEase function declaration, function used when "no easing" is selected for any axis
+
+
+// Easing functions reference data
+static const struct {
+    const char *name;
+    float (*func)(float, float, float, float);
+} Easings[] = {
+    [EASE_LINEAR_NONE] = {
+        .name = "EaseLinearNone",
+        .func = EaseLinearNone,
+    },
+    [EASE_LINEAR_IN] = {
+        .name = "EaseLinearIn",
+        .func = EaseLinearIn,
+    },
+    [EASE_LINEAR_OUT] = {
+        .name = "EaseLinearOut",
+        .func = EaseLinearOut,
+    },
+    [EASE_LINEAR_IN_OUT] = {
+        .name = "EaseLinearInOut",
+        .func = EaseLinearInOut,
+    },
+    [EASE_SINE_IN] = {
+        .name = "EaseSineIn",
+        .func = EaseSineIn,
+    },
+    [EASE_SINE_OUT] = {
+        .name = "EaseSineOut",
+        .func = EaseSineOut,
+    },
+    [EASE_SINE_IN_OUT] = {
+        .name = "EaseSineInOut",
+        .func = EaseSineInOut,
+    },
+    [EASE_CIRC_IN] = {
+        .name = "EaseCircIn",
+        .func = EaseCircIn,
+    },
+    [EASE_CIRC_OUT] = {
+        .name = "EaseCircOut",
+        .func = EaseCircOut,
+    },
+    [EASE_CIRC_IN_OUT] = {
+        .name = "EaseCircInOut",
+        .func = EaseCircInOut,
+    },
+    [EASE_CUBIC_IN] = {
+        .name = "EaseCubicIn",
+        .func = EaseCubicIn,
+    },
+    [EASE_CUBIC_OUT] = {
+        .name = "EaseCubicOut",
+        .func = EaseCubicOut,
+    },
+    [EASE_CUBIC_IN_OUT] = {
+        .name = "EaseCubicInOut",
+        .func = EaseCubicInOut,
+    },
+    [EASE_QUAD_IN] = {
+        .name = "EaseQuadIn",
+        .func = EaseQuadIn,
+    },
+    [EASE_QUAD_OUT] = {
+        .name = "EaseQuadOut",
+        .func = EaseQuadOut,
+    },
+    [EASE_QUAD_IN_OUT] = {
+        .name = "EaseQuadInOut",
+        .func = EaseQuadInOut,
+    },
+    [EASE_EXPO_IN] = {
+        .name = "EaseExpoIn",
+        .func = EaseExpoIn,
+    },
+    [EASE_EXPO_OUT] = {
+        .name = "EaseExpoOut",
+        .func = EaseExpoOut,
+    },
+    [EASE_EXPO_IN_OUT] = {
+        .name = "EaseExpoInOut",
+        .func = EaseExpoInOut,
+    },
+    [EASE_BACK_IN] = {
+        .name = "EaseBackIn",
+        .func = EaseBackIn,
+    },
+    [EASE_BACK_OUT] = {
+        .name = "EaseBackOut",
+        .func = EaseBackOut,
+    },
+    [EASE_BACK_IN_OUT] = {
+        .name = "EaseBackInOut",
+        .func = EaseBackInOut,
+    },
+    [EASE_BOUNCE_OUT] = {
+        .name = "EaseBounceOut",
+        .func = EaseBounceOut,
+    },
+    [EASE_BOUNCE_IN] = {
+        .name = "EaseBounceIn",
+        .func = EaseBounceIn,
+    },
+    [EASE_BOUNCE_IN_OUT] = {
+        .name = "EaseBounceInOut",
+        .func = EaseBounceInOut,
+    },
+    [EASE_ELASTIC_IN] = {
+        .name = "EaseElasticIn",
+        .func = EaseElasticIn,
+    },
+    [EASE_ELASTIC_OUT] = {
+        .name = "EaseElasticOut",
+        .func = EaseElasticOut,
+    },
+    [EASE_ELASTIC_IN_OUT] = {
+        .name = "EaseElasticInOut",
+        .func = EaseElasticInOut,
+    },
+    [EASING_NONE] = {
+        .name = "None",
+        .func = NoEase,
+    },
+};
+
+
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    Vector2 ballPos = { .x = START_X, .y = START_Y };
+    float t = 0.0f;        // Current time (in any unit measure, but same unit as duration)
+    float d = D_DFT;       // Total time it should take to complete (duration)
+    bool paused = true;
+    bool boundedT = true;  // If true, t will stop when d >= td, otherwise t will keep adding td to its value every loop
+
+    enum EasingTypes easingX = EASING_NONE;  // Easing selected for x axis
+    enum EasingTypes easingY = EASING_NONE;  // Easing selected for y axis
+
+    InitWindow(SCR_WIDTH, SCR_HEIGHT, "raylib [easings] example");
+    SetTargetFPS(TARGET_FPS);
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        if (IsKeyPressed(KEY_TOGGLE_UNBOUNDED_T))
+            boundedT = 1 - boundedT;
+
+        // Choose easing for the X axis
+        if (IsKeyPressed(KEY_NEXT_EASE_X))
+        {
+            ++easingX;
+
+            if (easingX > EASING_NONE)
+                easingX = 0;
+        }
+        else if (IsKeyPressed(KEY_PREV_EASE_X))
+        {
+            if (easingX == 0)
+                easingX = EASING_NONE;
+            else
+                --easingX;
+        }
+
+        // Choose easing for the Y axis
+        if (IsKeyPressed(KEY_NEXT_EASE_Y))
+        {
+            ++easingY;
+
+            if (easingY > EASING_NONE)
+                easingY = 0;
+        }
+        else if (IsKeyPressed(KEY_PREV_EASE_Y))
+        {
+            if (easingY == 0)
+                easingY = EASING_NONE;
+            else
+                --easingY;
+        }
+
+        // Change d (duration) value
+        if (IsKeyPressed(KEY_INCR_D_STEP) && d < D_MAX - D_STEP)
+            d += D_STEP;
+        else if (IsKeyPressed(KEY_DECR_D_STEP) && d > D_MIN + D_STEP)
+            d -= D_STEP;
+
+        if (IsKeyDown(KEY_INCR_D_FINE) && d < D_MAX - D_STEP_FINE)
+            d += D_STEP_FINE;
+        else if (IsKeyDown(KEY_DECR_D_FINE) && d > D_MIN + D_STEP_FINE)
+            d -= D_STEP_FINE;
+
+        // Play, pause and restart controls
+        if (IsKeyPressed(KEY_RESTART) ||
+            IsKeyPressed(KEY_NEXT_EASE_X) || IsKeyPressed(KEY_PREV_EASE_X) ||
+            IsKeyPressed(KEY_NEXT_EASE_Y) || IsKeyPressed(KEY_PREV_EASE_Y) ||
+            IsKeyPressed(KEY_INCR_D_STEP) || IsKeyPressed(KEY_DECR_D_STEP) ||
+            IsKeyPressed(KEY_TOGGLE_UNBOUNDED_T) ||
+            IsKeyDown(KEY_INCR_D_FINE)  || IsKeyDown(KEY_DECR_D_FINE) ||
+            (IsKeyPressed(KEY_PLAY_PAUSE) && boundedT == true && t >= d))
+        {
+            t = 0.0f;
+            ballPos.x = START_X;
+            ballPos.y = START_Y;
+            paused = true;
+        }
+
+        if (IsKeyPressed(KEY_PLAY_PAUSE))
+            paused = 1 - paused;
+
+        // Movement computation
+        if ((paused == false) &&
+            ((boundedT == true && t < d) || boundedT == false))
+        {
+            ballPos.x = Easings[easingX].func(t, START_X, END_X - START_X, d);
+            ballPos.y = Easings[easingY].func(t, START_Y, END_Y - START_Y, d);
+            t += T_ADVANCE;
+        }
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(BG_COLOR);
+
+            // Draw information text
+            int line = 0;
+
+            DrawText(TextFormat("Easing x: %s", Easings[easingX].name), 0, FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+            DrawText(TextFormat("Easing y: %s", Easings[easingY].name), 0, FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+            DrawText(TextFormat("t (%c) = %.2f d = %.2f", (boundedT == true)? 'b' : 'u', t, d),
+                     0, FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+
+            // Draw instructions text
+            line = 1;
+            DrawText("Use ENTER to play or pause movement, use SPACE to restart", 0, SCR_HEIGHT - FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+            DrawText("Use D and W or A and S keys to change duration", 0, SCR_HEIGHT - FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+            DrawText("Use LEFT or RIGHT keys to choose easing for the x axis", 0, SCR_HEIGHT - FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+            DrawText("Use UP or DOWN keys to choose easing for the y axis", 0, SCR_HEIGHT - FONT_SIZE * (line++), FONT_SIZE, TEXT_COLOR);
+
+            // Draw ball
+            DrawCircleV(ballPos, BALL_RADIUS, BALL_COLOR);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}
+
+
+// NoEase function, used when "no easing" is selected for any axis. It just ignores all parameters besides b.
+static float NoEase(float t, float b, float c, float d)
+{
+    float burn = t + b + c + d;  // Hack to avoid compiler warning (about unused variables)
+    d += burn;
+
+    return b;
+}

src/easings.h

@@ -1,7 +1,7 @@
 /*******************************************************************************************
 *
 *   raylib easings (header only file)
-*   
+*
 *   Useful easing functions for values animation
 *
 *   This header uses:
@@ -32,31 +32,31 @@
 *
 *   Robert Penner License
 *   ---------------------------------------------------------------------------------
-*   Open source under the BSD 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, 
+*   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, 
+*       - 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 
+*       - 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 
+*       - 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 
+*   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.
 *   ---------------------------------------------------------------------------------
 *
@@ -90,7 +90,7 @@
     #define EASEDEF extern
 #endif
 
-#include <math.h>       // Required for: sin(), cos(), sqrt(), pow()
+#include <tgmath.h>       // Required for: sin(), cos(), sqrt(), pow()
 
 #ifndef PI
     #define PI 3.14159265358979323846f //Required as PI is not always defined in math.h
@@ -107,153 +107,153 @@ EASEDEF float EaseLinearOut(float t, float b, float c, float d) { return (c*t/d
 EASEDEF float EaseLinearInOut(float t,float b, float c, float d) { return (c*t/d + b); }
 
 // Sine Easing functions
-EASEDEF float EaseSineIn(float t, float b, float c, float d) { return (-c*cos(t/d*(PI/2)) + c + b); }
-EASEDEF float EaseSineOut(float t, float b, float c, float d) { return (c*sin(t/d*(PI/2)) + b); }
-EASEDEF float EaseSineInOut(float t, float b, float c, float d) { return (-c/2*(cos(PI*t/d) - 1) + b); }
+EASEDEF float EaseSineIn(float t, float b, float c, float d) { return (-c*cos(t/d*(PI/2.0f)) + c + b); }
+EASEDEF float EaseSineOut(float t, float b, float c, float d) { return (c*sin(t/d*(PI/2.0f)) + b); }
+EASEDEF float EaseSineInOut(float t, float b, float c, float d) { return (-c/2.0f*(cos(PI*t/d) - 1.0f) + b); }
 
 // Circular Easing functions
-EASEDEF float EaseCircIn(float t, float b, float c, float d) { t /= d; return (-c*(sqrt(1 - t*t) - 1) + b); }
-EASEDEF float EaseCircOut(float t, float b, float c, float d) { t = t/d - 1; return (c*sqrt(1 - t*t) + b); }
-EASEDEF float EaseCircInOut(float t, float b, float c, float d) 
+EASEDEF float EaseCircIn(float t, float b, float c, float d) { t /= d; return (-c*(sqrt(1.0f - t*t) - 1.0f) + b); }
+EASEDEF float EaseCircOut(float t, float b, float c, float d) { t = t/d - 1.0f; return (c*sqrt(1.0f - t*t) + b); }
+EASEDEF float EaseCircInOut(float t, float b, float c, float d)
 {
-    if ((t/=d/2) < 1) return (-c/2*(sqrt(1 - t*t) - 1) + b);
-    t -= 2; return (c/2*(sqrt(1 - t*t) + 1) + b);
+    if ((t/=d/2.0f) < 1.0f) return (-c/2.0f*(sqrt(1.0f - t*t) - 1.0f) + b);
+    t -= 2.0f; return (c/2.0f*(sqrt(1.0f - t*t) + 1.0f) + b);
 }
 
 // Cubic Easing functions
 EASEDEF float EaseCubicIn(float t, float b, float c, float d) { t /= d; return (c*t*t*t + b); }
-EASEDEF float EaseCubicOut(float t, float b, float c, float d) { t = t/d-1; return (c*(t*t*t + 1) + b); }
-EASEDEF float EaseCubicInOut(float t, float b, float c, float d) 
-{ 
-    if ((t/=d/2) < 1) return (c/2*t*t*t + b);
-    t -= 2; return (c/2*(t*t*t + 2) + b);
+EASEDEF float EaseCubicOut(float t, float b, float c, float d) { t = t/d - 1.0f; return (c*(t*t*t + 1.0f) + b); }
+EASEDEF float EaseCubicInOut(float t, float b, float c, float d)
+{
+    if ((t/=d/2.0f) < 1.0f) return (c/2.0f*t*t*t + b);
+    t -= 2.0f; return (c/2.0f*(t*t*t + 2.0f) + b);
 }
 
 // Quadratic Easing functions
 EASEDEF float EaseQuadIn(float t, float b, float c, float d) { t /= d; return (c*t*t + b); }
-EASEDEF float EaseQuadOut(float t, float b, float c, float d) { t /= d; return (-c*t*(t - 2) + b); }
-EASEDEF float EaseQuadInOut(float t, float b, float c, float d) 
+EASEDEF float EaseQuadOut(float t, float b, float c, float d) { t /= d; return (-c*t*(t - 2.0f) + b); }
+EASEDEF float EaseQuadInOut(float t, float b, float c, float d)
 {
     if ((t/=d/2) < 1) return (((c/2)*(t*t)) + b);
-    t--; return (-c/2*(((t - 2)*t) - 1) + b);
+	return (-c/2.0f*(((t - 1.0f)*(t - 3.0f)) - 1.0f) + b);
 }
 
 // Exponential Easing functions
-EASEDEF float EaseExpoIn(float t, float b, float c, float d) { return (t == 0) ? b : (c*pow(2, 10*(t/d - 1)) + b); }
-EASEDEF float EaseExpoOut(float t, float b, float c, float d) { return (t == d) ? (b + c) : (c*(-pow(2, -10*t/d) + 1) + b);    }
-EASEDEF float EaseExpoInOut(float t, float b, float c, float d) 
+EASEDEF float EaseExpoIn(float t, float b, float c, float d) { return (t == 0.0f) ? b : (c*pow(2.0f, 10.0f*(t/d - 1.0f)) + b); }
+EASEDEF float EaseExpoOut(float t, float b, float c, float d) { return (t == d) ? (b + c) : (c*(-pow(2.0f, -10.0f*t/d) + 1.0f) + b);    }
+EASEDEF float EaseExpoInOut(float t, float b, float c, float d)
 {
-    if (t == 0) return b;
+    if (t == 0.0f) 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);
+    if ((t/=d/2.0f) < 1.0f) return (c/2.0f*pow(2.0f, 10.0f*(t - 1.0f)) + b);
+
+	return (c/2.0f*(-pow(2.0f, -10.0f*(t - 1.0f)) + 2.0f) + b);
 }
 
 // Back Easing functions
-EASEDEF float EaseBackIn(float t, float b, float c, float d) 
+EASEDEF 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);
+    return (c*(postFix)*t*((s + 1.0f)*t - s) + b);
 }
 
 EASEDEF float EaseBackOut(float t, float b, float c, float d)
-{    
+{
     float s = 1.70158f;
-    t = t/d - 1;
-    return (c*(t*t*((s + 1)*t + s) + 1) + b);
+    t = t/d - 1.0f;
+    return (c*(t*t*((s + 1.0f)*t + s) + 1.0f) + b);
 }
 
 EASEDEF float EaseBackInOut(float t, float b, float c, float d)
 {
     float s = 1.70158f;
-    if ((t/=d/2) < 1) 
+    if ((t/=d/2.0f) < 1.0f)
     {
         s *= 1.525f;
-        return (c/2*(t*t*((s + 1)*t - s)) + b);
+        return (c/2.0f*(t*t*((s + 1.0f)*t - s)) + b);
     }
-    
-    float postFix = t-=2;
+
+    float postFix = t-=2.0f;
     s *= 1.525f;
-    return (c/2*((postFix)*t*((s + 1)*t + s) + 2) + b);
+    return (c/2.0f*((postFix)*t*((s + 1.0f)*t + s) + 2.0f) + b);
 }
 
 // Bounce Easing functions
-EASEDEF float EaseBounceOut(float t, float b, float c, float d) 
+EASEDEF float EaseBounceOut(float t, float b, float c, float d)
 {
-    if ((t/=d) < (1/2.75f)) 
+    if ((t/=d) < (1.0f/2.75f))
     {
         return (c*(7.5625f*t*t) + b);
-    } 
-    else if (t < (2/2.75f)) 
+    }
+    else if (t < (2.0f/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)) 
+    }
+    else if (t < (2.5/2.75))
     {
         float postFix = t-=(2.25f/2.75f);
         return (c*(7.5625f*(postFix)*t + 0.9375f) + b);
-    } 
-    else 
+    }
+    else
     {
         float postFix = t-=(2.625f/2.75f);
         return (c*(7.5625f*(postFix)*t + 0.984375f) + b);
     }
 }
 
-EASEDEF float EaseBounceIn(float t, float b, float c, float d) { return (c - EaseBounceOut(d-t, 0, c, d) + b); }
-EASEDEF float EaseBounceInOut(float t, float b, float c, float d) 
+EASEDEF float EaseBounceIn(float t, float b, float c, float d) { return (c - EaseBounceOut(d - t, 0.0f, c, d) + b); }
+EASEDEF 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);
+    if (t < d/2.0f) return (EaseBounceIn(t*2.0f, 0.0f, c, d)*0.5f + b);
+    else return (EaseBounceOut(t*2.0f - d, 0.0f, c, d)*0.5f + c*0.5f + b);
 }
 
 // Elastic Easing functions
-EASEDEF float EaseElasticIn(float t, float b, float c, float d) 
+EASEDEF float EaseElasticIn(float t, float b, float c, float d)
 {
-    if (t == 0) return b;
-    if ((t/=d) == 1) return (b + c);
-    
+    if (t == 0.0f) return b;
+    if ((t/=d) == 1.0f) 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 a = c;
+    float s = p/4.0f;
+    float postFix = a*pow(2.0f, 10.0f*(t-=1.0f));
+
+    return (-(postFix*sin((t*d-s)*(2.0f*PI)/p )) + b);
 }
 
 EASEDEF float EaseElasticOut(float t, float b, float c, float d)
 {
-    if (t == 0) return b;
-    if ((t/=d) == 1) return (b + c);
-    
+    if (t == 0.0f) return b;
+    if ((t/=d) == 1.0f) 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 a = c;
+    float s = p/4.0f;
+
+    return (a*pow(2.0f,-10.0f*t)*sin((t*d-s)*(2.0f*PI)/p) + c + b);
 }
 
 EASEDEF float EaseElasticInOut(float t, float b, float c, float d)
 {
-    if (t == 0) return b;
-    if ((t/=d/2) == 2) return (b + c);
-    
+    if (t == 0.0f) return b;
+    if ((t/=d/2.0f) == 2.0f) return (b + c);
+
     float p = d*(0.3f*1.5f);
     float a = c;
-    float s = p/4;
+    float s = p/4.0f;
 
-    if (t < 1) 
+    if (t < 1.0f)
     {
-        float postFix = a*pow(2, 10*(t-=1));
-        return -0.5f*(postFix*sin((t*d-s)*(2*PI)/p)) + b;
+        float postFix = a*pow(2.0f, 10.0f*(t-=1.0f));
+        return -0.5f*(postFix*sin((t*d-s)*(2.0f*PI)/p)) + b;
     }
-    
-    float postFix = a*pow(2, -10*(t-=1));
-    
-    return (postFix*sin((t*d-s)*(2*PI)/p)*0.5f + c + b);
+
+    float postFix = a*pow(2.0f, -10.0f*(t-=1.0f));
+
+    return (postFix*sin((t*d-s)*(2.0f*PI)/p)*0.5f + c + b);
 }
 
 #ifdef __cplusplus