diff options
Diffstat (limited to 'Math')
| -rw-r--r-- | Math/math.h | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/Math/math.h b/Math/math.h new file mode 100644 index 0000000..ce46b12 --- /dev/null +++ b/Math/math.h @@ -0,0 +1,343 @@ +/* =========================================================================== + * MATH - Copyright @ Vasco Alves - See LICENSE at the end of file. + * + * Linear algebra and math for games. + * No types. I'm tired of everyone having a Vec3 type. + * Ops write in place. + * Speed over accuracy. + * + * TYPES: + * - vec2 = float[2] + * - vec3 = float[3] + * - mat4 = float[16] column-major + * A pointer that is not backed correctly but the correct amount of memory + * is undefined behaviour and misuse of the library. + * + * =========================================================================== */ + +#ifndef GUNSTACK_MATH_H +#define GUNSTACK_MATH_H + +#define MATH_MAJOR "0" +#define MATH_MINOR "0" +#define MATH_PATCH "0" + +/* CHANGE LOG + * 0.0.0 - @vasco - prototyping + */ + +#define MATH_PI 3.14159265358979323846f +#define MATH_PI2 (2.0f * MATH_PI) +#define MATH_PI_HALF (MATH_PI * 0.5f) +#define MATH_PI_POW2 (MATH_PI * MATH_PI) + +#define MATH static inline + +MATH void math_ceil(float *x); +MATH void math_sinf(float *x); +MATH void math_cosf(float *x); + +MATH void math_vec2f(float *v, float x, float y); +MATH void math_vec2f_add(float *a, const float *b); +MATH void math_vec2f_sub(float *a, const float *b); +MATH void math_vec2f_mult(float *a, float s); +MATH void math_vec2f_dot(float *out, const float *a, const float *b); +MATH void math_vec2f_cross(float *out, const float *a, const float *b); + +MATH void math_vec3f(float *v, float x, float y, float z); +MATH void math_vec3f_add(float *a, const float *b); +MATH void math_vec3f_sub(float *a, const float *b); +MATH void math_vec3f_mult(float *a, float s); +MATH void math_vec3f_dot(float *out, const float *a, const float *b); +MATH void math_vec3f_cross(float *a, const float *b); + +MATH void math_mat4_identity(float *m); +MATH void math_mat4_mul(float *a, const float *b); +MATH void math_mat4_translate(float *m, const float *v); +MATH void math_mat4_translate_by(float *m, const float *v); +MATH void math_mat4_rotate_x(float *m, float rad); +MATH void math_mat4_rotate_x_by(float *m, float rad); +MATH void math_mat4_rotate_y(float *m, float rad); +MATH void math_mat4_rotate_y_by(float *m, float rad); +MATH void math_mat4_rotate_z(float *m, float rad); +MATH void math_mat4_perspective(float *m, float fov_rad, float aspect, float near_z, float far_z); + +void +math_ceil(float *x) +{ + int base = (int)*x; + *x = (*x > (float)base) ? (float)(base + 1) : (float)base; +} + +void +math_sinf(float *x) +{ + float y, B, C, P; + while (*x > MATH_PI) + *x -= MATH_PI2; + while (*x < -MATH_PI) + *x += MATH_PI2; + B = 4.0f / MATH_PI; + C = -4.0f / MATH_PI_POW2; + y = B * *x + C * *x * (*x < 0 ? -*x : *x); + P = 0.225f; + *x = P * (y * (y < 0 ? -y : y) - y) + y; +} + +void +math_cosf(float *x) +{ + *x += MATH_PI_HALF; + math_sinf(x); +} + +void +math_vec2f(float *v, float x, float y) +{ + v[0] = x; + v[1] = y; +} + +void +math_vec2f_add(float *a, const float *b) +{ + a[0] += b[0]; + a[1] += b[1]; +} + +void +math_vec2f_sub(float *a, const float *b) +{ + a[0] -= b[0]; + a[1] -= b[1]; +} + +void +math_vec2f_mult(float *a, float s) +{ + a[0] *= s; + a[1] *= s; +} + +void +math_vec2f_dot(float *out, const float *a, const float *b) +{ + *out = a[0] * b[0] + a[1] * b[1]; +} + +void +math_vec2f_cross(float *out, const float *a, const float *b) +{ + *out = a[0] * b[1] - a[1] * b[0]; +} + +void +math_vec3f(float *v, float x, float y, float z) +{ + v[0] = x; + v[1] = y; + v[2] = z; +} + +void +math_vec3f_add(float *a, const float *b) +{ + a[0] += b[0]; + a[1] += b[1]; + a[2] += b[2]; +} + +void +math_vec3f_sub(float *a, const float *b) +{ + a[0] -= b[0]; + a[1] -= b[1]; + a[2] -= b[2]; +} + +void +math_vec3f_mult(float *a, float s) +{ + a[0] *= s; + a[1] *= s; + a[2] *= s; +} + +void +math_vec3f_dot(float *out, const float *a, const float *b) +{ + *out = a[0] * b[0] + a[1] * b[1] + a[2] * b[2]; +} + +void +math_vec3f_cross(float *a, const float *b) +{ + float x = a[1] * b[2] - a[2] * b[1]; + float y = a[2] * b[0] - a[0] * b[2]; + float z = a[0] * b[1] - a[1] * b[0]; + a[0] = x; + a[1] = y; + a[2] = z; +} + +void +math_mat4_identity(float *m) +{ + int i; + for (i = 0; i < 16; i++) + m[i] = 0.0f; + m[0] = m[5] = m[10] = m[15] = 1.0f; +} + +void +math_mat4_mul(float *a, const float *b) +{ + float res[16]; + int col, row, k; + for (col = 0; col < 4; ++col) { + for (row = 0; row < 4; ++row) { + float sum = 0.0f; + for (k = 0; k < 4; ++k) + sum += a[k * 4 + row] * b[col * 4 + k]; + res[col * 4 + row] = sum; + } + } + for (k = 0; k < 16; k++) + a[k] = res[k]; +} + +void +math_mat4_translate(float *m, const float *v) +{ + math_mat4_identity(m); + m[12] = v[0]; + m[13] = v[1]; + m[14] = v[2]; +} + +void +math_mat4_translate_by(float *m, const float *v) +{ + m[12] = m[0] * v[0] + m[4] * v[1] + m[8] * v[2] + m[12]; + m[13] = m[1] * v[0] + m[5] * v[1] + m[9] * v[2] + m[13]; + m[14] = m[2] * v[0] + m[6] * v[1] + m[10] * v[2] + m[14]; + m[15] = m[3] * v[0] + m[7] * v[1] + m[11] * v[2] + m[15]; +} + +void +math_mat4_rotate_x(float *m, float rad) +{ + float c = rad, s = rad; + math_cosf(&c); + math_sinf(&s); + math_mat4_identity(m); + m[5] = c; + m[6] = s; + m[9] = -s; + m[10] = c; +} + +void +math_mat4_rotate_x_by(float *m, float rad) +{ + float r[16]; + math_mat4_rotate_x(r, rad); + math_mat4_mul(m, r); +} + +void +math_mat4_rotate_y(float *m, float rad) +{ + float c = rad, s = rad; + math_cosf(&c); + math_sinf(&s); + math_mat4_identity(m); + m[0] = c; + m[2] = -s; + m[8] = s; + m[10] = c; +} + +void +math_mat4_rotate_y_by(float *m, float rad) +{ + float r[16]; + math_mat4_rotate_y(r, rad); + math_mat4_mul(m, r); +} + +void +math_mat4_rotate_z(float *m, float rad) +{ + float c = rad, s = rad; + math_cosf(&c); + math_sinf(&s); + math_mat4_identity(m); + m[0] = c; + m[1] = s; + m[4] = -s; + m[5] = c; +} + +void +math_mat4_perspective(float *m, float fov_rad, float aspect, float near_z, float far_z) +{ + float half = fov_rad * 0.5f; + float c = half, s = half; + float tan_half_fov; + int i; + math_sinf(&s); + math_cosf(&c); + tan_half_fov = s / c; + for (i = 0; i < 16; i++) + m[i] = 0.0f; + m[0] = 1.0f / (aspect * tan_half_fov); + m[5] = 1.0f / tan_half_fov; + m[10] = far_z / (near_z - far_z); + m[11] = -1.0f; + m[14] = (near_z * far_z) / (near_z - far_z); +} + +#endif /* GUNSTACK_MATH_H */ + +/* +------------------------------------------------------------------------------ +This software is available under 2 licenses -- choose whichever you prefer. +------------------------------------------------------------------------------ +ALTERNATIVE A - MIT License +Copyright (c) 2026 Vasco Alves +Permission is hereby granted, free of charge, to any person obtaining a copy of +this software and associated documentation files (the "Software"), to deal in +the Software without restriction, including without limitation the rights to +use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies +of the Software, and to permit persons to whom the Software is furnished to do +so, subject to the following conditions: +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. +------------------------------------------------------------------------------ +ALTERNATIVE B - Public Domain (www.unlicense.org) +This is free and unencumbered software released into the public domain. +Anyone is free to copy, modify, publish, use, compile, sell, or distribute this +software, either in source code form or as a compiled binary, for any purpose, +commercial or non-commercial, and by any means. +In jurisdictions that recognize copyright laws, the author or authors of this +software dedicate any and all copyright interest in the software to the public +domain. We make this dedication for the benefit of the public at large and to +the detriment of our heirs and successors. We intend this dedication to be an +overt act of relinquishment in perpetuity of all present and future rights to +this software under copyright law. +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN +ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +------------------------------------------------------------------------------ +*/ |