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Diffstat (limited to 'Podium/p_math.c')
| -rw-r--r-- | Podium/p_math.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/Podium/p_math.c b/Podium/p_math.c new file mode 100644 index 0000000..928738b --- /dev/null +++ b/Podium/p_math.c @@ -0,0 +1,255 @@ +PODEF +int p_ceil(float x) +{ + int base = (int) x; + return (x > base) ? base + 1 : base; +} + +PODEF float +p_cosf(float x) +{ + x += 1.57079632679f; + + while (x > P_PI) x -= P_PI2; + while (x < -P_PI) x += P_PI2; + + const float B = 4.0f / P_PI; + const float C = -4.0f / P_PI_POW2; + + float y = B * x + C * x * (x < 0 ? -x : x); + + const float P = 0.225f; + y = P * (y * (y < 0 ? -y : y) - y) + y; + + return y; +} + +PODEF float +p_sinf(float x) +{ + while (x > P_PI) x -= P_PI2; + while (x < -P_PI) x += P_PI2; + + const float B = 4.0f / P_PI; + const float C = -4.0f / (P_PI_POW2); + + float y = B * x + C * x * (x < 0 ? -x : x); + + const float P = 0.225f; + y = P * (y * (y < 0 ? -y : y) - y) + y; + + return y; +} + +PODEF Vec2f +p_vec2f(float x, float y) +{ + return (Vec2f) { .x = x, .y = y }; +} + +PODEF Vec2f +p_vec2f_add(Vec2f a, Vec2f b) +{ + return (Vec2f) { + .x = a.x + b.x, + .y = a.y + b.y, + }; +} + +PODEF float +p_vec2f_cross(Vec2f a, Vec2f b) +{ + // axby − aybx + return a.x * b.y - a.y * b.x; +} + +PODEF float +p_vec2f_dot(Vec2f a, Vec2f b) +{ + // a · b = ax × bx + ay × by + return a.x * b.x + a.y * b.y; +} + +PODEF Vec2f +p_vec2f_mult(Vec2f a, float b) +{ + return (Vec2f) { + .x = a.x * b, + .y = a.y * b, + }; +} + +PODEF Vec2f +p_vec2f_sub(Vec2f a, Vec2f b) +{ + return (Vec2f) { + .x = a.x - b.x, + .y = a.y - b.y, + }; +} + +PODEF Vec2i +p_vec2i(float x, float y) +{ + return (Vec2i) { .x = x, .y = y }; +} + +PODEF Vec2i +p_vec2i_add(Vec2i a, Vec2i b) +{ + return (Vec2i) { + .x = a.x + b.x, + .y = a.y + b.y, + }; +} + +PODEF float +p_vec2i_cross(Vec2i a, Vec2i b) +{ + // axby − aybx + return a.x * b.y - a.y * b.x; +} + +PODEF float +p_vec2i_dot(Vec2i a, Vec2i b) +{ + // a · b = ax × bx + ay × by + return a.x * b.x + a.y * b.y; +} + +PODEF Vec2i +p_vec2i_mult(Vec2i a, float b) +{ + return (Vec2i) { + .x = a.x * b, + .y = a.y * b, + }; +} + +PODEF Vec2i +p_vec2i_sub(Vec2i a, Vec2i b) +{ + return (Vec2i) { + .x = a.x - b.x, + .y = a.y - b.y, + }; +} + +PODEF Vec3f +p_vec3f(float x, float y, float z) +{ + return (Vec3f) { .x = x, .y = y, .z = z }; +} + +PODEF P_Mat4 +p_mat4_identity(void) +{ + P_Mat4 res = {0}; + res.m[0] = 1.0f; + res.m[5] = 1.0f; + res.m[10] = 1.0f; + res.m[15] = 1.0f; + return res; +} + +PODEF P_Mat4 +p_mat4_mul(P_Mat4 a, P_Mat4 b) +{ + P_Mat4 res = {0}; + for (int col = 0; col < 4; ++col) { + for (int row = 0; row < 4; ++row) { + float sum = 0.0f; + for (int k = 0; k < 4; ++k) { + sum += a.m[k * 4 + row] * b.m[col * 4 + k]; + } + res.m[col * 4 + row] = sum; + } + } + return res; +} + +PODEF P_Mat4 +p_mat4_translate(Vec3f v) +{ + P_Mat4 res = p_mat4_identity(); + res.m[12] = v.x; + res.m[13] = v.y; + res.m[14] = v.z; + return res; +} + +PODEF P_Mat4 +p_mat4_translate_by(P_Mat4 m, Vec3f v) +{ + P_Mat4 res = m; + res.m[12] = m.m[0] * v.x + m.m[4] * v.y + m.m[8] * v.z + m.m[12]; + res.m[13] = m.m[1] * v.x + m.m[5] * v.y + m.m[9] * v.z + m.m[13]; + res.m[14] = m.m[2] * v.x + m.m[6] * v.y + m.m[10] * v.z + m.m[14]; + res.m[15] = m.m[3] * v.x + m.m[7] * v.y + m.m[11] * v.z + m.m[15]; + return res; +} + +PODEF P_Mat4 +p_mat4_rotate_x(float rad) +{ + P_Mat4 res = p_mat4_identity(); + float c = p_cosf(rad); + float s = p_sinf(rad); + res.m[5] = c; + res.m[6] = s; + res.m[9] = -s; + res.m[10] = c; + return res; +} + +PODEF P_Mat4 +p_mat4_rotate_x_by(P_Mat4 m, float rad) +{ + return p_mat4_mul(m, p_mat4_rotate_x(rad)); +} + +PODEF P_Mat4 +p_mat4_rotate_y(float rad) +{ + P_Mat4 res = p_mat4_identity(); + float c = p_cosf(rad); + float s = p_sinf(rad); + res.m[0] = c; + res.m[2] = -s; + res.m[8] = s; + res.m[10] = c; + return res; +} + +PODEF P_Mat4 +p_mat4_rotate_y_by(P_Mat4 m, float rad) +{ + return p_mat4_mul(m, p_mat4_rotate_y(rad)); +} + +PODEF P_Mat4 +p_mat4_rotate_z(float rad) +{ + P_Mat4 res = p_mat4_identity(); + float c = p_cosf(rad); + float s = p_sinf(rad); + res.m[0] = c; + res.m[1] = s; + res.m[4] = -s; + res.m[5] = c; + return res; +} + +PODEF P_Mat4 +p_mat4_perspective(float fov_rad, float aspect, float near_z, float far_z) +{ + P_Mat4 res = {0}; + float tan_half_fov = p_sinf(fov_rad * 0.5f) / p_cosf(fov_rad * 0.5f); + + res.m[0] = 1.0f / (aspect * tan_half_fov); + res.m[5] = 1.0f / tan_half_fov; + res.m[10] = far_z / (near_z - far_z); + res.m[11] = -1.0f; + res.m[14] = (near_z * far_z) / (near_z - far_z); + return res; +} |