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Diffstat (limited to 'src/maths/maths.h')
-rw-r--r-- | src/maths/maths.h | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/src/maths/maths.h b/src/maths/maths.h new file mode 100644 index 0000000..7352aeb --- /dev/null +++ b/src/maths/maths.h @@ -0,0 +1,200 @@ +/** + * @file maths.h + * @author your name (you@domain.com) + * @brief + * @version 0.1 + * @date 2024-02-24 + * @copyright Copyright (c) 2024 + */ +#pragma once + +#include <math.h> +#include "maths_types.h" + +// --- Vector Implementations + +// Dimension 3 +static inline vec3 vec3_create(f32 x, f32 y, f32 z) { return (vec3){ x, y, z }; } +static inline vec3 vec3_add(vec3 a, vec3 b) { return (vec3){ a.x + b.x, a.y + b.y, a.z + b.z }; } +static inline vec3 vec3_sub(vec3 a, vec3 b) { return (vec3){ a.x - b.x, a.y - b.y, a.z - b.z }; } +static inline vec3 vec3_mult(vec3 a, f32 s) { return (vec3){ a.x * s, a.y * s, a.z * s }; } +static inline vec3 vec3_div(vec3 a, f32 s) { return (vec3){ a.x / s, a.y / s, a.z / s }; } + +static inline f32 vec3_len_squared(vec3 a) { return (a.x * a.x) + (a.y * a.y) + (a.z * a.z); } +static inline f32 vec3_len(vec3 a) { return sqrtf(vec3_len_squared(a)); } +static inline vec3 vec3_negate(vec3 a) { return (vec3){ -a.x, -a.y, -a.z }; } +static inline vec3 vec3_normalise(vec3 a) { + f32 length = vec3_len(a); + return vec3_div(a, length); +} + +static inline f32 vec3_dot(vec3 a, vec3 b) { return a.x * b.x + a.y * b.y + a.z * b.z; } +static inline vec3 vec3_cross(vec3 a, vec3 b) { + return ( + vec3){ .x = a.y * b.z - a.z * b.y, .y = a.z * b.x - a.x * b.z, .z = a.x * b.y - a.y * b.x }; +} + +#define VEC3_ZERO ((vec3){ .x = 0.0, .y = 0.0, .z = 0.0 }) +#define VEC3_X ((vec3){ .x = 1.0, .y = 0.0, .z = 0.0 }) +#define VEC3_NEG_X ((vec3){ .x = -1.0, .y = 0.0, .z = 0.0 }) +#define VEC3_Y ((vec3){ .x = 0.0, .y = 1.0, .z = 0.0 }) +#define VEC3_NEG_Y ((vec3){ .x = 0.0, .y = -1.0, .z = 0.0 }) +#define VEC3_Z ((vec3){ .x = 0.0, .y = 0.0, .z = 1.0 }) +#define VEC3_NEG_Z ((vec3){ .x = 0.0, .y = 0.0, .z = -1.0 }) + +// TODO: Dimension 2 +static inline vec2 vec2_create(f32 x, f32 y) { return (vec2){ x, y }; } + +// TODO: Dimension 4 +#define VEC4_ZERO ((vec4){ .x = 0.0, .y = 0.0, .z = 0.0, .w = 0.0 }) + +// --- Matrix Implementations + +static inline mat4 mat4_ident() { + return (mat4){ .data = { 1.0, 0., 0., 0., 0., 1., 0., 0., 0., 0., 1., 0., 0., 0., 0., 1.0 } }; +} + +static inline mat4 mat4_translation(vec3 position) { + mat4 out_matrix = mat4_ident(); + out_matrix.data[12] = position.x; + out_matrix.data[13] = position.y; + out_matrix.data[14] = position.z; + return out_matrix; +} + +static inline mat4 mat4_scale(f32 scale) { + mat4 out_matrix = mat4_ident(); + out_matrix.data[0] = scale; + out_matrix.data[5] = scale; + out_matrix.data[10] = scale; + return out_matrix; +} + +static inline mat4 mat4_mult(mat4 lhs, mat4 rhs) { + mat4 out_matrix = mat4_ident(); + + const f32 *m1_ptr = lhs.data; + const f32 *m2_ptr = rhs.data; + f32 *dst_ptr = out_matrix.data; + + for (i32 i = 0; i < 4; ++i) { + for (i32 j = 0; j < 4; ++j) { + *dst_ptr = m1_ptr[0] * m2_ptr[0 + j] + m1_ptr[1] * m2_ptr[4 + j] + m1_ptr[2] * m2_ptr[8 + j] + + m1_ptr[3] * m2_ptr[12 + j]; + dst_ptr++; + } + m1_ptr += 4; + } + + return out_matrix; +} + +/** @brief Creates a perspective projection matrix */ +static inline mat4 mat4_perspective(f32 fov_radians, f32 aspect_ratio, f32 near_clip, + f32 far_clip) { + f32 half_tan_fov = tanf(fov_radians * 0.5f); + mat4 out_matrix = { .data = { 0 } }; + out_matrix.data[0] = 1.0f / (aspect_ratio * half_tan_fov); + out_matrix.data[5] = 1.0f / half_tan_fov; + out_matrix.data[10] = -((far_clip + near_clip) / (far_clip - near_clip)); + out_matrix.data[11] = -1.0f; + out_matrix.data[14] = -((2.0f * far_clip * near_clip) / (far_clip - near_clip)); + return out_matrix; +} + +/** @brief Creates an orthographic projection matrix */ +static inline mat4 mat4_orthographic(f32 left, f32 right, f32 bottom, f32 top, f32 near_clip, + f32 far_clip) { + // source: kohi game engine. + mat4 out_matrix = mat4_ident(); + + f32 lr = 1.0f / (left - right); + f32 bt = 1.0f / (bottom - top); + f32 nf = 1.0f / (near_clip - far_clip); + + out_matrix.data[0] = -2.0f * lr; + out_matrix.data[5] = -2.0f * bt; + out_matrix.data[10] = 2.0f * nf; + + out_matrix.data[12] = (left + right) * lr; + out_matrix.data[13] = (top + bottom) * bt; + out_matrix.data[14] = (far_clip + near_clip) * nf; + + return out_matrix; +} + +static inline mat4 mat4_look_at(vec3 position, vec3 target, vec3 up) { + mat4 out_matrix; + vec3 z_axis; + z_axis.x = target.x - position.x; + z_axis.y = target.y - position.y; + z_axis.z = target.z - position.z; + + z_axis = vec3_normalise(z_axis); + vec3 x_axis = vec3_normalise(vec3_cross(z_axis, up)); + vec3 y_axis = vec3_cross(x_axis, z_axis); + + out_matrix.data[0] = x_axis.x; + out_matrix.data[1] = y_axis.x; + out_matrix.data[2] = -z_axis.x; + out_matrix.data[3] = 0; + out_matrix.data[4] = x_axis.y; + out_matrix.data[5] = y_axis.y; + out_matrix.data[6] = -z_axis.y; + out_matrix.data[7] = 0; + out_matrix.data[8] = x_axis.z; + out_matrix.data[9] = y_axis.z; + out_matrix.data[10] = -z_axis.z; + out_matrix.data[11] = 0; + out_matrix.data[12] = -vec3_dot(x_axis, position); + out_matrix.data[13] = -vec3_dot(y_axis, position); + out_matrix.data[14] = vec3_dot(z_axis, position); + out_matrix.data[15] = 1.0f; + + return out_matrix; +} + +// ... + +// --- Quaternion Implementations + +// --- Transform Implementations + +#define TRANSFORM_DEFAULT \ + ((transform){ .position = VEC3_ZERO, \ + .rotation = (quat){ .x = 0., .y = 0., .z = 0., .w = 0. }, \ + .scale = 1.0, \ + .is_dirty = false }) + +static transform transform_create(vec3 pos, quat rot, f32 scale) { + return (transform){ .position = pos, .rotation = rot, .scale = scale, .is_dirty = false }; +} + +static inline mat4 transform_to_mat(transform *tf) { + // TODO: rotation + return mat4_mult(mat4_translation(tf->position), mat4_scale(tf->scale)); +} + +// --- Sizing asserts + +_Static_assert(alignof(vec3) == 4, "vec3 is 4 byte aligned"); +_Static_assert(sizeof(vec3) == 12, "vec3 is 12 bytes so has no padding"); + +_Static_assert(alignof(vec4) == 4, "vec4 is 4 byte aligned"); + +// --- Some other types +typedef struct u32x3 { + union { + struct { + u32 x; + u32 y; + u32 z; + }; + struct { + u32 r; + u32 g; + u32 b; + }; + }; +} u32x3; +#define u32x3(x, y, z) ((u32x3){ x, y, z }) |