From b026a6991cb87b870de07daa191b9fa87a2ac087 Mon Sep 17 00:00:00 2001 From: Jaime Ita Passos Date: Mon, 19 Apr 2021 15:52:07 -0300 Subject: [PATCH] Easing functions --- src/CMakeLists.txt | 2 + src/Makefile | 1 + src/m_easing.c | 399 +++++++++++++++++++++++++++++++++++++++++++++ src/m_easing.h | 95 +++++++++++ 4 files changed, 497 insertions(+) create mode 100644 src/m_easing.c create mode 100644 src/m_easing.h diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt index 87a0499b6..cd6e17386 100644 --- a/src/CMakeLists.txt +++ b/src/CMakeLists.txt @@ -32,6 +32,7 @@ set(SRB2_CORE_SOURCES m_bbox.c m_cheat.c m_cond.c + m_easing.c m_fixed.c m_menu.c m_misc.c @@ -101,6 +102,7 @@ set(SRB2_CORE_HEADERS m_cheat.h m_cond.h m_dllist.h + m_easing.h m_fixed.h m_menu.h m_misc.h diff --git a/src/Makefile b/src/Makefile index a4c3c4fdb..bdca6dc08 100644 --- a/src/Makefile +++ b/src/Makefile @@ -503,6 +503,7 @@ OBJS:=$(i_main_o) \ $(OBJDIR)/m_bbox.o \ $(OBJDIR)/m_cheat.o \ $(OBJDIR)/m_cond.o \ + $(OBJDIR)/m_easing.o \ $(OBJDIR)/m_fixed.o \ $(OBJDIR)/m_menu.o \ $(OBJDIR)/m_misc.o \ diff --git a/src/m_easing.c b/src/m_easing.c new file mode 100644 index 000000000..b3ea8842f --- /dev/null +++ b/src/m_easing.c @@ -0,0 +1,399 @@ +// SONIC ROBO BLAST 2 +//----------------------------------------------------------------------------- +// Copyright (C) 2020-2021 by Jaime "Lactozilla" Passos. +// +// This program is free software distributed under the +// terms of the GNU General Public License, version 2. +// See the 'LICENSE' file for more details. +//----------------------------------------------------------------------------- +/// \file m_easing.c +/// \brief Easing functions +/// Referenced from https://easings.net/ + +#include "m_easing.h" +#include "tables.h" +#include "doomdef.h" + +/* + For the computation of the logarithm, we choose, by trial and error, from among + a sequence of particular factors those, that when multiplied with the function + argument, normalize it to unity. For every factor chosen, we add up the + corresponding logarithm value stored in a table. The sum then corresponds to + the logarithm of the function argument. + + For the integer portion, we would want to choose + 2^i, i = 1, 2, 4, 8, ... + and for the factional part we choose + 1+2^-i, i = 1, 2, 3, 4, 5 ... + + The algorithm for the exponential is closely related and quite literally the inverse + of the logarithm algorithm. From among the sequence of tabulated logarithms for our + chosen factors, we pick those that when subtracted from the function argument ultimately + reduce it to zero. Starting with unity, we multiply with all the factors whose logarithms + we have subtracted in the process. The resulting product corresponds to the result of the exponentiation. + + Logarithms of values greater than unity can be computed by applying the algorithm to the reciprocal + of the function argument (with the negation of the result as appropriate), likewise exponentiation with + negative function arguments requires us negate the function argument and compute the reciprocal at the end. +*/ + +static fixed_t logtabdec[FRACBITS] = +{ + 0x95c1, 0x526a, 0x2b80, 0x1663, + 0xb5d, 0x5b9, 0x2e0, 0x170, + 0xb8, 0x5c, 0x2e, 0x17, + 0x0b, 0x06, 0x03, 0x01 +}; + +static fixed_t fixlog2(fixed_t a) +{ + UINT32 x = a, y = 0; + INT32 t, i, shift = 8; + + if (x > FRACUNIT) + x = FixedDiv(FRACUNIT, x); + + // Integer part + // 1<<19 = 0x80000 + // 1<<18 = 0x40000 + // 1<<17 = 0x20000 + // 1<<16 = 0x10000 + +#define dologtab(i) \ + t = (x << shift); \ + if (t < FRACUNIT) \ + { \ + x = t; \ + y += (1 << (19 - i)); \ + } \ + shift /= 2; + + dologtab(0) + dologtab(1) + dologtab(2) + dologtab(3) + +#undef dologtab + + // Decimal part + for (i = 0; i < FRACBITS; i++) + { + t = x + (x >> (i + 1)); + if (t < FRACUNIT) + { + x = t; + y += logtabdec[i]; + } + } + + if (a <= FRACUNIT) + return -y; + + return y; +} + +// Notice how this is symmetric to fixlog2. +static INT32 fixexp(fixed_t a) +{ + UINT32 x, y; + fixed_t t, i, shift = 8; + + // Underflow prevention. + if (a <= -15 * FRACUNIT) + return 0; + + x = (a < 0) ? (-a) : (a); + y = FRACUNIT; + + // Integer part (see fixlog2) +#define dologtab(i) \ + t = x - (1 << (19 - i)); \ + if (t >= 0) \ + { \ + x = t; \ + y <<= shift; \ + } \ + shift /= 2; + + dologtab(0) + dologtab(1) + dologtab(2) + dologtab(3) + +#undef dologtab + + // Decimal part + for (i = 0; i < FRACBITS; i++) + { + t = (x - logtabdec[i]); + if (t >= 0) + { + x = t; + y += (y >> (i + 1)); + } + } + + if (a < 0) + return FixedDiv(FRACUNIT, y); + + return y; +} + +#define fixpow(x, y) fixexp(FixedMul((y), fixlog2(x))) +#define fixintmul(x, y) FixedMul((x) * FRACUNIT, y) +#define fixintdiv(x, y) FixedDiv(x, (y) * FRACUNIT) +#define fixinterp(start, end, t) FixedMul((FRACUNIT - (t)), start) + FixedMul(t, end) + +#define EASINGFUNC(type) fixed_t Easing_ ## type (fixed_t start, fixed_t end, fixed_t t) + +// +// Linear +// + +EASINGFUNC(Linear) +{ + return fixinterp(start, end, t); +} + +// +// Sine +// + +// This is equivalent to calculating (x * pi) and converting the result from radians into degrees. +#define fixang(x) FixedMul((x), 180*FRACUNIT) + +EASINGFUNC(InSine) +{ + fixed_t c = fixang(t / 2); + fixed_t x = FRACUNIT - FINECOSINE(FixedAngle(c)>>ANGLETOFINESHIFT); + return fixinterp(start, end, x); +} + +EASINGFUNC(OutSine) +{ + fixed_t c = fixang(t / 2); + fixed_t x = FINESINE(FixedAngle(c)>>ANGLETOFINESHIFT); + return fixinterp(start, end, x); +} + +EASINGFUNC(InOutSine) +{ + fixed_t c = fixang(t); + fixed_t x = -(FINECOSINE(FixedAngle(c)>>ANGLETOFINESHIFT) - FRACUNIT) / 2; + return fixinterp(start, end, x); +} + +#undef fixang + +// +// Quad +// + +EASINGFUNC(InQuad) +{ + return fixinterp(start, end, FixedMul(t, t)); +} + +EASINGFUNC(OutQuad) +{ + return fixinterp(start, end, FRACUNIT - FixedMul(FRACUNIT - t, FRACUNIT - t)); +} + +EASINGFUNC(InOutQuad) +{ + fixed_t x = t < (FRACUNIT/2) + ? fixintmul(2, FixedMul(t, t)) + : FRACUNIT - fixpow(FixedMul(-2*FRACUNIT, t) + 2*FRACUNIT, 2*FRACUNIT) / 2; + return fixinterp(start, end, x); +} + +// +// Cubic +// + +EASINGFUNC(InCubic) +{ + fixed_t x = FixedMul(t, FixedMul(t, t)); + return fixinterp(start, end, x); +} + +EASINGFUNC(OutCubic) +{ + return fixinterp(start, end, FRACUNIT - fixpow(FRACUNIT - t, 3*FRACUNIT)); +} + +EASINGFUNC(InOutCubic) +{ + fixed_t x = t < (FRACUNIT/2) + ? fixintmul(4, FixedMul(t, FixedMul(t, t))) + : FRACUNIT - fixpow(fixintmul(-2, t) + 2*FRACUNIT, 3*FRACUNIT) / 2; + return fixinterp(start, end, x); +} + +// +// "Quart" +// + +EASINGFUNC(InQuart) +{ + fixed_t x = FixedMul(FixedMul(t, t), FixedMul(t, t)); + return fixinterp(start, end, x); +} + +EASINGFUNC(OutQuart) +{ + fixed_t x = FRACUNIT - fixpow(FRACUNIT - t, 4 * FRACUNIT); + return fixinterp(start, end, x); +} + +EASINGFUNC(InOutQuart) +{ + fixed_t x = t < (FRACUNIT/2) + ? fixintmul(8, FixedMul(FixedMul(t, t), FixedMul(t, t))) + : FRACUNIT - fixpow(fixintmul(-2, t) + 2*FRACUNIT, 4*FRACUNIT) / 2; + return fixinterp(start, end, x); +} + +// +// "Quint" +// + +EASINGFUNC(InQuint) +{ + fixed_t x = FixedMul(t, FixedMul(FixedMul(t, t), FixedMul(t, t))); + return fixinterp(start, end, x); +} + +EASINGFUNC(OutQuint) +{ + fixed_t x = FRACUNIT - fixpow(FRACUNIT - t, 5 * FRACUNIT); + return fixinterp(start, end, x); +} + +EASINGFUNC(InOutQuint) +{ + fixed_t x = t < (FRACUNIT/2) + ? FixedMul(16*FRACUNIT, FixedMul(t, FixedMul(FixedMul(t, t), FixedMul(t, t)))) + : FRACUNIT - fixpow(fixintmul(-2, t) + 2*FRACUNIT, 5*FRACUNIT) / 2; + return fixinterp(start, end, x); +} + +// +// Exponential +// + +EASINGFUNC(InExpo) +{ + fixed_t x = (!t) ? 0 : fixpow(2*FRACUNIT, fixintmul(10, t) - 10*FRACUNIT); + return fixinterp(start, end, x); +} + +EASINGFUNC(OutExpo) +{ + fixed_t x = (t >= FRACUNIT) ? FRACUNIT + : FRACUNIT - fixpow(2*FRACUNIT, fixintmul(-10, t)); + return fixinterp(start, end, x); +} + +EASINGFUNC(InOutExpo) +{ + fixed_t x; + + if (!t) + x = 0; + else if (t >= FRACUNIT) + x = FRACUNIT; + else + { + if (t < FRACUNIT / 2) + { + x = fixpow(2*FRACUNIT, fixintmul(20, t) - 10*FRACUNIT); + x = fixintdiv(x, 2); + } + else + { + x = fixpow(2*FRACUNIT, fixintmul(-20, t) + 10*FRACUNIT); + x = fixintdiv((2*FRACUNIT) - x, 2); + } + } + + return fixinterp(start, end, x); +} + +// +// "Back" +// + +#define EASEBACKCONST1 111514 // 1.70158 +#define EASEBACKCONST2 99942 // 1.525 + +EASINGFUNC(InBack) +{ + const fixed_t c1 = EASEBACKCONST1; + const fixed_t c3 = c1 + FRACUNIT; + fixed_t x = FixedMul(FixedMul(t, t), FixedMul(c3, t) - c1); + return fixinterp(start, end, x); +} + +EASINGFUNC(OutBack) +{ + const fixed_t c1 = EASEBACKCONST1; + const fixed_t c3 = c1 + FRACUNIT; + fixed_t x; + t -= FRACUNIT; + x = FRACUNIT + FixedMul(FixedMul(t, t), FixedMul(c3, t) + c1); + return fixinterp(start, end, x); +} + +static fixed_t DoEaseInOutBack(fixed_t start, fixed_t end, fixed_t t, fixed_t c2) +{ + fixed_t x; + + c2 += FRACUNIT; + + if (t < FRACUNIT / 2) + { + x = fixintmul(7, t) - c2; + x = fixintmul(2, x); + x = FixedMul(FixedMul(t, t), x); + } + else + { + t -= FRACUNIT; + x = fixintmul(2, fixintmul(7, t) + c2); + x = FixedMul(FixedMul(t, t), x); + x = FRACUNIT + x; + } + + return fixinterp(start, end, x); +} + +EASINGFUNC(InOutBack) +{ + return DoEaseInOutBack(start, end, t, EASEBACKCONST2); +} + +#undef EASINGFUNC + +// Function list + +#define EASINGFUNC(type) Easing_ ## type +#define COMMA , + +easingfunc_t easing_funclist[EASE_MAX] = +{ + EASINGFUNCLIST(COMMA) +}; + +// Function names + +#undef EASINGFUNC +#define EASINGFUNC(type) #type + +const char *easing_funcnames[EASE_MAX] = +{ + EASINGFUNCLIST(COMMA) +}; + +#undef COMMA +#undef EASINGFUNC diff --git a/src/m_easing.h b/src/m_easing.h new file mode 100644 index 000000000..e5571ece3 --- /dev/null +++ b/src/m_easing.h @@ -0,0 +1,95 @@ +// SONIC ROBO BLAST 2 +//----------------------------------------------------------------------------- +// Copyright (C) 2020-2021 by Jaime "Lactozilla" Passos. +// +// This program is free software distributed under the +// terms of the GNU General Public License, version 2. +// See the 'LICENSE' file for more details. +//----------------------------------------------------------------------------- +/// \file m_easing.h +/// \brief Easing functions + +#ifndef __M_EASING_H__ +#define __M_EASING_H__ + +#include "doomtype.h" +#include "m_fixed.h" + +typedef enum +{ + EASE_LINEAR = 0, + + EASE_INSINE, + EASE_OUTSINE, + EASE_INOUTSINE, + + EASE_INQUAD, + EASE_OUTQUAD, + EASE_INOUTQUAD, + + EASE_INCUBIC, + EASE_OUTCUBIC, + EASE_INOUTCUBIC, + + EASE_INQUART, + EASE_OUTQUART, + EASE_INOUTQUART, + + EASE_INQUINT, + EASE_OUTQUINT, + EASE_INOUTQUINT, + + EASE_INEXPO, + EASE_OUTEXPO, + EASE_INOUTEXPO, + + EASE_INBACK, + EASE_OUTBACK, + EASE_INOUTBACK, + + EASE_MAX, +} easing_t; + +typedef fixed_t (*easingfunc_t)(fixed_t, fixed_t, fixed_t); + +extern easingfunc_t easing_funclist[EASE_MAX]; +extern const char *easing_funcnames[EASE_MAX]; + +#define EASINGFUNCLIST(sep) \ + EASINGFUNC(Linear) sep \ + \ + EASINGFUNC(InSine) sep \ + EASINGFUNC(OutSine) sep \ + EASINGFUNC(InOutSine) sep \ + \ + EASINGFUNC(InQuad) sep \ + EASINGFUNC(OutQuad) sep \ + EASINGFUNC(InOutQuad) sep \ + \ + EASINGFUNC(InCubic) sep \ + EASINGFUNC(OutCubic) sep \ + EASINGFUNC(InOutCubic) sep \ + \ + EASINGFUNC(InQuart) sep \ + EASINGFUNC(OutQuart) sep \ + EASINGFUNC(InOutQuart) sep \ + \ + EASINGFUNC(InQuint) sep \ + EASINGFUNC(OutQuint) sep \ + EASINGFUNC(InOutQuint) sep \ + \ + EASINGFUNC(InExpo) sep \ + EASINGFUNC(OutExpo) sep \ + EASINGFUNC(InOutExpo) sep \ + \ + EASINGFUNC(InBack) sep \ + EASINGFUNC(OutBack) sep \ + EASINGFUNC(InOutBack) sep + +#define EASINGFUNC(type) fixed_t Easing_ ## type (fixed_t start, fixed_t end, fixed_t t); + +EASINGFUNCLIST() + +#undef EASINGFUNC + +#endif