libft: add lerp functions

libft/ft_ilerp.c

@@ -0,0 +1,20 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_ilerp.c                                         :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: pbondoer <[email protected]>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2016/05/11 01:06:57 by pbondoer          #+#    #+#             */
+/*   Updated: 2016/05/11 01:42:28 by pbondoer         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+double	ft_ilerp(double val, double first, double second)
+{
+	if (val == first)
+		return (0.0);
+	if (val == second)
+		return (1.0);
+	return ((val - first) / (second - first));
+}

libft/ft_lerp.c

@@ -0,0 +1,18 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_lerp.c                                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: pbondoer <[email protected]>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2016/05/11 00:34:09 by pbondoer          #+#    #+#             */
+/*   Updated: 2016/05/11 01:42:49 by pbondoer         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+double	ft_lerp(double first, double second, double p)
+{
+	if (first == second)
+		return (first);
+	return (first + (second - first) * p);
+}

libft/ft_lerpi.c

@@ -0,0 +1,18 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_lerpi.c                                         :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: pbondoer <[email protected]>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2016/05/11 00:34:09 by pbondoer          #+#    #+#             */
+/*   Updated: 2016/05/11 01:43:03 by pbondoer         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+int		ft_lerpi(int first, int second, double p)
+{
+	if (first == second)
+		return (first);
+	return ((int)((double)first + (second - first) * p));
+}

libft/libft.h

@@ -6,7 +6,7 @@
 /*   By: pbondoer <[email protected]>          +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2015/11/24 19:59:25 by pbondoer          #+#    #+#             */
-/*   Updated: 2016/02/26 04:21:16 by pbondoer         ###   ########.fr       */
+/*   Updated: 2016/05/11 01:21:15 by pbondoer         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -88,4 +88,7 @@ int				ft_max(int a, int b);
 int				ft_abs(int i);
 int				ft_iswhitespace(char c);
 size_t			ft_countwords(char *str, char c);
+double			ft_lerp(double first, double second, double p);
+double			ft_ilerp(double val, double first, double second);
+int				ft_lerpi(int first, int second, double p);
 #endif