diff options
Diffstat (limited to 'include/godot_cpp/core/math.hpp')
| -rw-r--r-- | include/godot_cpp/core/math.hpp | 208 |
1 files changed, 161 insertions, 47 deletions
diff --git a/include/godot_cpp/core/math.hpp b/include/godot_cpp/core/math.hpp index 361395d..48d1283 100644 --- a/include/godot_cpp/core/math.hpp +++ b/include/godot_cpp/core/math.hpp @@ -38,20 +38,6 @@ #include <cmath> namespace godot { -namespace Math { - -// This epsilon should match the one used by Godot for consistency. -// Using `f` when `real_t` is float. -#define CMP_EPSILON 0.00001f -#define CMP_EPSILON2 (CMP_EPSILON * CMP_EPSILON) - -// This epsilon is for values related to a unit size (scalar or vector len). -#ifdef PRECISE_MATH_CHECKS -#define UNIT_EPSILON 0.00001 -#else -// Tolerate some more floating point error normally. -#define UNIT_EPSILON 0.001 -#endif #define Math_SQRT12 0.7071067811865475244008443621048490 #define Math_SQRT2 1.4142135623730950488016887242 @@ -62,32 +48,174 @@ namespace Math { #define Math_INF INFINITY #define Math_NAN NAN -// Windows badly defines a lot of stuff we'll never use. Undefine it. -#ifdef _WIN32 -#undef MIN // override standard definition -#undef MAX // override standard definition -#undef CLAMP // override standard definition -#endif +// Make room for our constexpr's below by overriding potential system-specific macros. +#undef ABS +#undef SIGN +#undef MIN +#undef MAX +#undef CLAMP // Generic ABS function, for math uses please use Math::abs. -#ifndef ABS -#define ABS(m_v) (((m_v) < 0) ? (-(m_v)) : (m_v)) -#endif +template <typename T> +constexpr T ABS(T m_v) { + return m_v < 0 ? -m_v : m_v; +} -#ifndef SIGN -#define SIGN(m_v) (((m_v) == 0) ? (0.0) : (((m_v) < 0) ? (-1.0) : (+1.0))) -#endif +template <typename T> +constexpr const T SIGN(const T m_v) { + return m_v == 0 ? 0.0f : (m_v < 0 ? -1.0f : +1.0f); +} -#ifndef MIN -#define MIN(m_a, m_b) (((m_a) < (m_b)) ? (m_a) : (m_b)) -#endif +template <typename T, typename T2> +constexpr auto MIN(const T m_a, const T2 m_b) { + return m_a < m_b ? m_a : m_b; +} + +template <typename T, typename T2> +constexpr auto MAX(const T m_a, const T2 m_b) { + return m_a > m_b ? m_a : m_b; +} + +template <typename T, typename T2, typename T3> +constexpr auto CLAMP(const T m_a, const T2 m_min, const T3 m_max) { + return m_a < m_min ? m_min : (m_a > m_max ? m_max : m_a); +} + +// Generic swap template. +#ifndef SWAP +#define SWAP(m_x, m_y) __swap_tmpl((m_x), (m_y)) +template <class T> +inline void __swap_tmpl(T &x, T &y) { + T aux = x; + x = y; + y = aux; +} +#endif // SWAP + +/* Functions to handle powers of 2 and shifting. */ + +// Function to find the next power of 2 to an integer. +static _FORCE_INLINE_ unsigned int next_power_of_2(unsigned int x) { + if (x == 0) { + return 0; + } + + --x; + x |= x >> 1; + x |= x >> 2; + x |= x >> 4; + x |= x >> 8; + x |= x >> 16; + + return ++x; +} + +// Function to find the previous power of 2 to an integer. +static _FORCE_INLINE_ unsigned int previous_power_of_2(unsigned int x) { + x |= x >> 1; + x |= x >> 2; + x |= x >> 4; + x |= x >> 8; + x |= x >> 16; + return x - (x >> 1); +} + +// Function to find the closest power of 2 to an integer. +static _FORCE_INLINE_ unsigned int closest_power_of_2(unsigned int x) { + unsigned int nx = next_power_of_2(x); + unsigned int px = previous_power_of_2(x); + return (nx - x) > (x - px) ? px : nx; +} + +// Get a shift value from a power of 2. +static inline int get_shift_from_power_of_2(unsigned int p_bits) { + for (unsigned int i = 0; i < 32; i++) { + if (p_bits == (unsigned int)(1 << i)) { + return i; + } + } + + return -1; +} + +template <class T> +static _FORCE_INLINE_ T nearest_power_of_2_templated(T x) { + --x; + + // The number of operations on x is the base two logarithm + // of the number of bits in the type. Add three to account + // for sizeof(T) being in bytes. + size_t num = get_shift_from_power_of_2(sizeof(T)) + 3; + + // If the compiler is smart, it unrolls this loop. + // If it's dumb, this is a bit slow. + for (size_t i = 0; i < num; i++) { + x |= x >> (1 << i); + } + + return ++x; +} + +// Function to find the nearest (bigger) power of 2 to an integer. +static inline unsigned int nearest_shift(unsigned int p_number) { + for (int i = 30; i >= 0; i--) { + if (p_number & (1 << i)) { + return i + 1; + } + } + + return 0; +} + +// constexpr function to find the floored log2 of a number +template <typename T> +constexpr T floor_log2(T x) { + return x < 2 ? x : 1 + floor_log2(x >> 1); +} + +// Get the number of bits needed to represent the number. +// IE, if you pass in 8, you will get 4. +// If you want to know how many bits are needed to store 8 values however, pass in (8 - 1). +template <typename T> +constexpr T get_num_bits(T x) { + return floor_log2(x); +} + +// Swap 16, 32 and 64 bits value for endianness. +#if defined(__GNUC__) +#define BSWAP16(x) __builtin_bswap16(x) +#define BSWAP32(x) __builtin_bswap32(x) +#define BSWAP64(x) __builtin_bswap64(x) +#else +static inline uint16_t BSWAP16(uint16_t x) { + return (x >> 8) | (x << 8); +} + +static inline uint32_t BSWAP32(uint32_t x) { + return ((x << 24) | ((x << 8) & 0x00FF0000) | ((x >> 8) & 0x0000FF00) | (x >> 24)); +} -#ifndef MAX -#define MAX(m_a, m_b) (((m_a) > (m_b)) ? (m_a) : (m_b)) +static inline uint64_t BSWAP64(uint64_t x) { + x = (x & 0x00000000FFFFFFFF) << 32 | (x & 0xFFFFFFFF00000000) >> 32; + x = (x & 0x0000FFFF0000FFFF) << 16 | (x & 0xFFFF0000FFFF0000) >> 16; + x = (x & 0x00FF00FF00FF00FF) << 8 | (x & 0xFF00FF00FF00FF00) >> 8; + return x; +} #endif -#ifndef CLAMP -#define CLAMP(m_a, m_min, m_max) (((m_a) < (m_min)) ? (m_min) : (((m_a) > (m_max)) ? m_max : m_a)) +namespace Math { + +// This epsilon should match the one used by Godot for consistency. +// Using `f` when `real_t` is float. +#define CMP_EPSILON 0.00001f +#define CMP_EPSILON2 (CMP_EPSILON * CMP_EPSILON) + +// This epsilon is for values related to a unit size (scalar or vector len). +#ifdef PRECISE_MATH_CHECKS +#define UNIT_EPSILON 0.00001 +#else +// Tolerate some more floating point error normally. +#define UNIT_EPSILON 0.001 #endif // Functions reproduced as in Godot's source code `math_funcs.h`. @@ -628,20 +756,6 @@ inline double pingpong(double value, double length) { return (length != 0.0) ? abs(fract((value - length) / (length * 2.0)) * length * 2.0 - length) : 0.0; } -inline unsigned int next_power_of_2(unsigned int x) { - if (x == 0) - return 0; - - --x; - x |= x >> 1; - x |= x >> 2; - x |= x >> 4; - x |= x >> 8; - x |= x >> 16; - - return ++x; -} - // This function should be as fast as possible and rounding mode should not matter. inline int fast_ftoi(float a) { static int b; |