add easing module

include/pocketpy/interpreter/modules.h

@@ -9,3 +9,4 @@ void pk__add_module_random();
 void pk__add_module_json();
 void pk__add_module_gc();
 void pk__add_module_time();
+void pk__add_module_easing();

src/interpreter/vm.c

@@ -203,6 +203,7 @@ void VM__ctor(VM* self) {
     pk__add_module_json();
     pk__add_module_gc();
     pk__add_module_time();
+    pk__add_module_easing();
 
     // add python builtins
     do {

src/modules/easing.c

@@ -0,0 +1,251 @@
+#include "pocketpy/pocketpy.h"
+#include "pocketpy/interpreter/vm.h"
+
+#include "math.h"
+
+// https://easings.net/
+
+const double kPi = 3.1415926545;
+
+static double easeLinear(double x) { return x; }
+
+static double easeInSine(double x) { return 1.0 - cos(x * kPi / 2); }
+
+static double easeOutSine(double x) { return sin(x * kPi / 2); }
+
+static double easeInOutSine(double x) { return -(cos(kPi * x) - 1) / 2; }
+
+static double easeInQuad(double x) { return x * x; }
+
+static double easeOutQuad(double x) { return 1 - pow(1 - x, 2); }
+
+static double easeInOutQuad(double x) {
+    if(x < 0.5) {
+        return 2 * x * x;
+    } else {
+        return 1 - pow(-2 * x + 2, 2) / 2;
+    }
+}
+
+static double easeInCubic(double x) { return x * x * x; }
+
+static double easeOutCubic(double x) { return 1 - pow(1 - x, 3); }
+
+static double easeInOutCubic(double x) {
+    if(x < 0.5) {
+        return 4 * x * x * x;
+    } else {
+        return 1 - pow(-2 * x + 2, 3) / 2;
+    }
+}
+
+static double easeInQuart(double x) { return pow(x, 4); }
+
+static double easeOutQuart(double x) { return 1 - pow(1 - x, 4); }
+
+static double easeInOutQuart(double x) {
+    if(x < 0.5) {
+        return 8 * pow(x, 4);
+    } else {
+        return 1 - pow(-2 * x + 2, 4) / 2;
+    }
+}
+
+static double easeInQuint(double x) { return pow(x, 5); }
+
+static double easeOutQuint(double x) { return 1 - pow(1 - x, 5); }
+
+static double easeInOutQuint(double x) {
+    if(x < 0.5) {
+        return 16 * pow(x, 5);
+    } else {
+        return 1 - pow(-2 * x + 2, 5) / 2;
+    }
+}
+
+static double easeInExpo(double x) { return x == 0 ? 0 : pow(2, 10 * x - 10); }
+
+static double easeOutExpo(double x) { return x == 1 ? 1 : 1 - pow(2, -10 * x); }
+
+static double easeInOutExpo(double x) {
+    if(x == 0) {
+        return 0;
+    } else if(x == 1) {
+        return 1;
+    } else if(x < 0.5) {
+        return pow(2, 20 * x - 10) / 2;
+    } else {
+        return (2 - pow(2, -20 * x + 10)) / 2;
+    }
+}
+
+static double easeInCirc(double x) { return 1 - sqrt(1 - pow(x, 2)); }
+
+static double easeOutCirc(double x) { return sqrt(1 - pow(x - 1, 2)); }
+
+static double easeInOutCirc(double x) {
+    if(x < 0.5) {
+        return (1 - sqrt(1 - pow(2 * x, 2))) / 2;
+    } else {
+        return (sqrt(1 - pow(-2 * x + 2, 2)) + 1) / 2;
+    }
+}
+
+static double easeInBack(double x) {
+    const double c1 = 1.70158;
+    const double c3 = c1 + 1;
+    return c3 * x * x * x - c1 * x * x;
+}
+
+static double easeOutBack(double x) {
+    const double c1 = 1.70158;
+    const double c3 = c1 + 1;
+    return 1 + c3 * pow(x - 1, 3) + c1 * pow(x - 1, 2);
+}
+
+static double easeInOutBack(double x) {
+    const double c1 = 1.70158;
+    const double c2 = c1 * 1.525;
+    if(x < 0.5) {
+        return (pow(2 * x, 2) * ((c2 + 1) * 2 * x - c2)) / 2;
+    } else {
+        return (pow(2 * x - 2, 2) * ((c2 + 1) * (x * 2 - 2) + c2) + 2) / 2;
+    }
+}
+
+static double easeInElastic(double x) {
+    const double c4 = (2 * kPi) / 3;
+    if(x == 0) {
+        return 0;
+    } else if(x == 1) {
+        return 1;
+    } else {
+        return -pow(2, 10 * x - 10) * sin((x * 10 - 10.75) * c4);
+    }
+}
+
+static double easeOutElastic(double x) {
+    const double c4 = (2 * kPi) / 3;
+    if(x == 0) {
+        return 0;
+    } else if(x == 1) {
+        return 1;
+    } else {
+        return pow(2, -10 * x) * sin((x * 10 - 0.75) * c4) + 1;
+    }
+}
+
+static double easeInOutElastic(double x) {
+    const double c5 = (2 * kPi) / 4.5;
+    if(x == 0) {
+        return 0;
+    } else if(x == 1) {
+        return 1;
+    } else if(x < 0.5) {
+        return -(pow(2, 20 * x - 10) * sin((20 * x - 11.125) * c5)) / 2;
+    } else {
+        return (pow(2, -20 * x + 10) * sin((20 * x - 11.125) * c5)) / 2 + 1;
+    }
+}
+
+static double easeOutBounce(double x) {
+    const double n1 = 7.5625;
+    const double d1 = 2.75;
+    if(x < 1 / d1) {
+        return n1 * x * x;
+    } else if(x < 2 / d1) {
+        x -= 1.5 / d1;
+        return n1 * x * x + 0.75;
+    } else if(x < 2.5 / d1) {
+        x -= 2.25 / d1;
+        return n1 * x * x + 0.9375;
+    } else {
+        x -= 2.625 / d1;
+        return n1 * x * x + 0.984375;
+    }
+}
+
+static double easeInBounce(double x) { return 1 - easeOutBounce(1 - x); }
+
+static double easeInOutBounce(double x) {
+    return x < 0.5 ? (1 - easeOutBounce(1 - 2 * x)) / 2 : (1 + easeOutBounce(2 * x - 1)) / 2;
+}
+
+#define DEF_EASE(name)                                                                             \
+    static bool easing_##name(int argc, py_Ref argv) {                                             \
+        PY_CHECK_ARGC(1);                                                                          \
+        py_f64 t;                                                                                  \
+        if(!py_castfloat(argv, &t)) return false;                                                  \
+        py_newfloat(py_retval(), ease##name(t));                                                   \
+        return true;                                                                               \
+    }
+
+DEF_EASE(Linear)
+DEF_EASE(InSine)
+DEF_EASE(OutSine)
+DEF_EASE(InOutSine)
+DEF_EASE(InQuad)
+DEF_EASE(OutQuad)
+DEF_EASE(InOutQuad)
+DEF_EASE(InCubic)
+DEF_EASE(OutCubic)
+DEF_EASE(InOutCubic)
+DEF_EASE(InQuart)
+DEF_EASE(OutQuart)
+DEF_EASE(InOutQuart)
+DEF_EASE(InQuint)
+DEF_EASE(OutQuint)
+DEF_EASE(InOutQuint)
+DEF_EASE(InExpo)
+DEF_EASE(OutExpo)
+DEF_EASE(InOutExpo)
+DEF_EASE(InCirc)
+DEF_EASE(OutCirc)
+DEF_EASE(InOutCirc)
+DEF_EASE(InBack)
+DEF_EASE(OutBack)
+DEF_EASE(InOutBack)
+DEF_EASE(InElastic)
+DEF_EASE(OutElastic)
+DEF_EASE(InOutElastic)
+DEF_EASE(InBounce)
+DEF_EASE(OutBounce)
+DEF_EASE(InOutBounce)
+
+#undef DEF_EASE
+
+void pk__add_module_easing() {
+    py_GlobalRef mod = py_newmodule("easing");
+
+    py_bindfunc(mod, "Linear", easing_Linear);
+    py_bindfunc(mod, "InSine", easing_InSine);
+    py_bindfunc(mod, "OutSine", easing_OutSine);
+    py_bindfunc(mod, "InOutSine", easing_InOutSine);
+    py_bindfunc(mod, "InQuad", easing_InQuad);
+    py_bindfunc(mod, "OutQuad", easing_OutQuad);
+    py_bindfunc(mod, "InOutQuad", easing_InOutQuad);
+    py_bindfunc(mod, "InCubic", easing_InCubic);
+    py_bindfunc(mod, "OutCubic", easing_OutCubic);
+    py_bindfunc(mod, "InOutCubic", easing_InOutCubic);
+    py_bindfunc(mod, "InQuart", easing_InQuart);
+    py_bindfunc(mod, "OutQuart", easing_OutQuart);
+    py_bindfunc(mod, "InOutQuart", easing_InOutQuart);
+    py_bindfunc(mod, "InQuint", easing_InQuint);
+    py_bindfunc(mod, "OutQuint", easing_OutQuint);
+    py_bindfunc(mod, "InOutQuint", easing_InOutQuint);
+    py_bindfunc(mod, "InExpo", easing_InExpo);
+    py_bindfunc(mod, "OutExpo", easing_OutExpo);
+    py_bindfunc(mod, "InOutExpo", easing_InOutExpo);
+    py_bindfunc(mod, "InCirc", easing_InCirc);
+    py_bindfunc(mod, "OutCirc", easing_OutCirc);
+    py_bindfunc(mod, "InOutCirc", easing_InOutCirc);
+    py_bindfunc(mod, "InBack", easing_InBack);
+    py_bindfunc(mod, "OutBack", easing_OutBack);
+    py_bindfunc(mod, "InOutBack", easing_InOutBack);
+    py_bindfunc(mod, "InElastic", easing_InElastic);
+    py_bindfunc(mod, "OutElastic", easing_OutElastic);
+    py_bindfunc(mod, "InOutElastic", easing_InOutElastic);
+    py_bindfunc(mod, "InBounce", easing_InBounce);
+    py_bindfunc(mod, "OutBounce", easing_OutBounce);
+    py_bindfunc(mod, "InOutBounce", easing_InOutBounce);
+}