d8ab3c9bd3
Always access the data through the member `q`. This makes the code independent of architecture endian decisions.
198 lines
4.2 KiB
C++
198 lines
4.2 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <https://www.dxx-rebirth.com/>.
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* It is copyright by its individual contributors, as recorded in the
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* project's Git history. See COPYING.txt at the top level for license
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* terms and a link to the Git history.
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*/
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/* Maths.h library header file */
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#pragma once
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#include <cstdint>
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#include <optional>
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#include <stdlib.h>
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#include "pstypes.h"
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#define D_RAND_MAX 32767
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#include <cstddef>
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#include "dsx-ns.h"
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#include <array>
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namespace dcx {
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void d_srand (unsigned int seed);
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[[nodiscard]]
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int d_rand (); // Random number function which returns in the range 0-0x7FFF
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//=============================== FIXED POINT ===============================
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typedef int64_t fix64; //64 bits int, for timers
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typedef int32_t fix; //16 bits int, 16 bits frac
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typedef int16_t fixang; //angles
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typedef struct quadint // integer 64 bit, previously called "quad"
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{
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int64_t q;
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}
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quadint;
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//Convert an int to a fix/fix64 and back
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static constexpr fix i2f(const int &i)
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{
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return i << 16;
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}
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static constexpr int f2i(const fix &f)
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{
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return f >> 16;
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}
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//Convert fix to float and float to fix
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static constexpr float f2fl(const fix &f)
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{
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return static_cast<float>(f) / static_cast<float>(65536.0);
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}
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static constexpr double f2db(const fix &f)
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{
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return static_cast<double>(f) / 65536.0;
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}
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static constexpr fix fl2f(const float &f)
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{
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return static_cast<fix>(f * 65536);
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}
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//Some handy constants
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#define f0_0 0
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#define f1_0 0x10000
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#define f2_0 0x20000
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#define f3_0 0x30000
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#define f10_0 0xa0000
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#define f0_5 0x8000
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#define f0_1 0x199a
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//Get the int part of a fix, with rounding
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static constexpr int f2ir(const fix &f)
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{
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return (f + f0_5) >> 16;
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}
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#define F0_0 f0_0
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#define F1_0 f1_0
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#define F2_0 f2_0
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#define F3_0 f3_0
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#define F10_0 f10_0
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#define F0_5 f0_5
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#define F0_1 f0_1
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//multiply two fixes, return a fix(64)
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[[nodiscard]]
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fix64 fixmul64 (fix a, fix b);
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/* On x86/amd64 for Windows/Linux, truncating fix64->fix is free. */
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[[nodiscard]]
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static inline fix fixmul(fix a, fix b)
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{
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return static_cast<fix>(fixmul64(a, b));
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}
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//divide two fixes, return a fix
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[[nodiscard]]
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fix fixdiv (fix a, fix b);
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//multiply two fixes, then divide by a third, return a fix
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[[nodiscard]]
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fix fixmuldiv (fix a, fix b, fix c);
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//multiply two fixes, and add 64-bit product to a quadint
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static inline void fixmulaccum (quadint * q, const fix &a, const fix &b)
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{
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q->q += static_cast<int64_t>(a) * static_cast<int64_t>(b);
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}
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//extract a fix from a quadint product
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[[nodiscard]]
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static inline fix fixquadadjust (const quadint *q)
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{
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return static_cast<fix>(q->q >> 16);
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}
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//computes the square root of a long, returning a short
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[[nodiscard]]
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ushort long_sqrt (int32_t a);
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//computes the square root of a quadint, returning a long
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[[nodiscard]]
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uint32_t quad_sqrt (quadint);
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//computes the square root of a fix, returning a fix
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[[nodiscard]]
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fix fix_sqrt (fix a);
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struct fix_sincos_result
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{
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fix sin, cos;
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};
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[[nodiscard]]
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fix_sincos_result fix_sincos(fixang);
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//compute sine and cosine of an angle, filling in the variables
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//either of the pointers can be NULL
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[[nodiscard]]
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fix fix_sin(fixang a);
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[[nodiscard]]
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fix fix_cos(fixang a);
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[[nodiscard]]
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fix fix_fastsin(fixang a); //no interpolation
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//compute inverse sine & cosine
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[[nodiscard]]
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fixang fix_asin (fix v);
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[[nodiscard]]
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fixang fix_acos (fix v);
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//given cos & sin of an angle, return that angle.
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//parms need not be normalized, that is, the ratio of the parms cos/sin must
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//equal the ratio of the actual cos & sin for the result angle, but the parms
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//need not be the actual cos & sin.
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//NOTE: this is different from the standard C atan2, since it is left-handed.
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[[nodiscard]]
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fixang fix_atan2 (fix cos, fix sin);
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[[nodiscard]]
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std::optional<int32_t> checkmuldiv(fix a, fix b, fix divisor);
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extern const std::array<uint8_t, 256> guess_table;
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extern const std::array<int16_t, 256> sincos_table;
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extern const std::array<ushort, 258> asin_table;
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extern const std::array<ushort, 258> acos_table;
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static inline void clamp_fix_lh(fix& f, const fix& low, const fix& high)
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{
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if (f < low)
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f = low;
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else if (high < f)
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f = high;
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}
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static inline void clamp_fix_symmetric(fix& f, const fix& bound)
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{
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clamp_fix_lh(f, -bound, bound);
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}
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}
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