2 * Copyright 2018-2020 Iwo 'Outfrost' Bujkiewicz
4 * This Source Code Form is subject to the terms of the Mozilla Public
5 * License, v. 2.0. If a copy of the MPL was not distributed with this
6 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
14 Transform identity() {
15 return (Transform) { .a1 = 1.0f, .a2 = 0.0f, .a3 = 0.0f, .a4 = 0.0f,
16 .b1 = 0.0f, .b2 = 1.0f, .b3 = 0.0f, .b4 = 0.0f,
17 .c1 = 0.0f, .c2 = 0.0f, .c3 = 1.0f, .c4 = 0.0f,
18 .d1 = 0.0f, .d2 = 0.0f, .d3 = 0.0f, .d4 = 1.0f };
21 Transform multiply(Transform t1, Transform t2) {
22 GLfloat* a = (GLfloat*) &t1;
23 GLfloat* b = (GLfloat*) &t2;
25 GLfloat* c = (GLfloat*) &result;
27 for (size_t row = 0; row < 4; ++row) {
28 for (size_t col = 0; col < 4; ++col) {
30 a[(row * 4) + 0] * b[(0 * 4) + col]
31 + a[(row * 4) + 1] * b[(1 * 4) + col]
32 + a[(row * 4) + 2] * b[(2 * 4) + col]
33 + a[(row * 4) + 3] * b[(3 * 4) + col];
39 void translate(Transform* transform, Vector vec) {
40 *transform = multiply(
41 (Transform) { .a1 = 1.0f, .a2 = 0.0f, .a3 = 0.0f, .a4 = vec.x,
42 .b1 = 0.0f, .b2 = 1.0f, .b3 = 0.0f, .b4 = vec.y,
43 .c1 = 0.0f, .c2 = 0.0f, .c3 = 1.0f, .c4 = vec.z,
44 .d1 = 0.0f, .d2 = 0.0f, .d3 = 0.0f, .d4 = 1.0f },
48 void rotate(Transform* transform, Vector axis, float angle) {
49 axis = normalized(axis);
53 float sinA = sinf(angle);
54 float cosA = cosf(angle);
55 float omcA = 1 - cosA;
57 *transform = multiply(
58 (Transform) { l*l*omcA + cosA, m*l*omcA - n*sinA, n*l*omcA + m*sinA, 0.0f,
59 l*m*omcA + n*sinA, m*m*omcA + cosA, n*m*omcA - l*sinA, 0.0f,
60 l*n*omcA - m*sinA, m*n*omcA + l*sinA, n*n*omcA + cosA, 0.0f,
61 0.0f, 0.0f, 0.0f, 1.0f },
66 return (Vector) { 0.0f, 0.0f, 0.0f };
69 Vector addVectors(Vector v1, Vector v2) {
70 return (Vector) { v1.x + v2.x, v1.y + v2.y, v1.z + v2.z };
73 Vector subtractVectors(Vector v1, Vector v2) {
74 return (Vector) { v1.x - v2.x, v1.y - v2.y, v1.z - v2.z };
77 Vector crossProduct(Vector v1, Vector v2) {
78 return (Vector) { .x = (v1.y * v2.z) - (v1.z * v2.y),
79 .y = (v1.z * v2.x) - (v1.x * v2.z),
80 .z = (v1.x * v2.y) - (v1.y * v2.x) };
83 float dotProduct(Vector v1, Vector v2) {
84 return (v1.x * v2.x) + (v1.y * v2.y) + (v1.z * v2.z);
87 Vector scaleVector(Vector vec, float scale) {
88 return (Vector) { vec.x * scale,
93 Vector growVectorNoFlip(Vector vec, float amount) {
94 float mag = magnitude(vec);
95 float factor = (mag + amount) / mag;
99 return scaleVector(vec, factor);
102 Vector clampMagnitude(Vector vec, float maxMagnitude) {
103 float m = magnitude(vec);
104 if (m > maxMagnitude) {
105 vec = scaleVector(vec, maxMagnitude / m);
110 float magnitude(Vector vec) {
111 return sqrtf(vec.x * vec.x + vec.y * vec.y + vec.z * vec.z);
114 Vector applyTransform(Transform transform, Vector vec) {
115 GLfloat* a = (GLfloat*) &transform;
116 GLfloat b[4] = { vec.x, vec.y, vec.z, 1.0f };
119 for (size_t row = 0; row < 4; ++row) {
121 a[(row * 4) + 0] * b[0]
122 + a[(row * 4) + 1] * b[1]
123 + a[(row * 4) + 2] * b[2]
124 + a[(row * 4) + 3] * b[3];
126 return (Vector) { c[0], c[1], c[2] };
129 Vector translationOf(Transform transform) {
130 return (Vector) { transform.a4, transform.b4, transform.c4 };
133 Vector normalized(Vector vec) {
134 float m = magnitude(vec);
138 return (Vector) { vec.x / m, vec.y / m, vec.z / m };
141 float clamp(float x, float lower, float upper) {
142 return fmax(lower, fmin(upper, x));