1 files changed, 31 insertions, 0 deletions
diff --git a/include/interpolate.h b/include/interpolate.h
new file mode 100755
index 0000000..1f79405
--- /dev/null
+++ b/include/interpolate.h
@@ -0,0 +1,31 @@
+// Math for Game Programmers: Fast and Funky 1D Nonlinear Transformations
+//   https://www.youtube.com/watch?v=mr5xkf6zSzk
+
+#ifndef INTERPOLATE_H
+#define INTERPOLATE_H 
+
+#define smooth_start_2( t ) ( t * t )
+#define smooth_start_3( t ) ( smooth_start_2( t ) * t )
+#define smooth_start_4( t ) ( smooth_start_3( t ) * t )
+#define smooth_start_5( t ) ( smooth_start_4( t ) * t )
+#define smooth_start_6( t ) ( smooth_start_5( t ) * t )
+
+#define smooth_stop_2( t ) ( flip( smooth_start_2( flip( t ) ) ) )
+#define smooth_stop_3( t ) ( flip( smooth_start_3( flip( t ) ) ) )
+#define smooth_stop_4( t ) ( flip( smooth_start_4( flip( t ) ) ) )
+#define smooth_stop_5( t ) ( flip( smooth_start_5( flip( t ) ) ) )
+#define smooth_stop_6( t ) ( flip( smooth_start_6( flip( t ) ) ) )
+
+#define smooth_step_3( t ) ( crossfade( smooth_start_2( t ), smooth_stop_2( t ), t ) ) 
+#define mix( a, b, b_weight ) ( a + b_weight * ( b - a ) )
+#define crossfade( a, b, t ) ( a + t * ( b - a ) )
+#define scale( a, t ) ( t * a )
+#define reverse_scale( a, t ) ( ( 1 - t ) * a )
+
+#define arch_2( t ) ( scale( flip( t ), t ) )
+#define smooth_start_arch_3( t ) ( scale( arch_2( t ), t ) )
+#define smooth_stop_arch_3( t ) ( reverse_scale( arch_2( t ), t ) )
+
+#define flip( x ) ( 1 - x )
+
+#endif
+\ No newline at end of file