source: abuse/trunk/src/lol/matrix.cpp @ 509

Last change on this file since 509 was 509, checked in by Sam Hocevar, 11 years ago

core: import matrix.h from the Lol Engine. It's going to be useful.

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1//
2// Lol Engine
3//
4// Copyright: (c) 2010-2011 Sam Hocevar <sam@hocevar.net>
5//   This program is free software; you can redistribute it and/or
6//   modify it under the terms of the Do What The Fuck You Want To
7//   Public License, Version 2, as published by Sam Hocevar. See
8//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
9//
10
11#if defined HAVE_CONFIG_H
12#   include "config.h"
13#endif
14
15#include <cstdlib> /* free() */
16#include <cstring> /* strdup() */
17
18#include "lol/matrix.h"
19
20namespace lol
21{
22
23static inline float det3(float a, float b, float c,
24                         float d, float e, float f,
25                         float g, float h, float i)
26{
27    return a * (e * i - h * f)
28         + b * (f * g - i * d)
29         + c * (d * h - g * e);
30}
31
32static inline float cofact3(mat4 const &mat, int i, int j)
33{
34    return det3(mat[(i + 1) & 3][(j + 1) & 3],
35                mat[(i + 2) & 3][(j + 1) & 3],
36                mat[(i + 3) & 3][(j + 1) & 3],
37                mat[(i + 1) & 3][(j + 2) & 3],
38                mat[(i + 2) & 3][(j + 2) & 3],
39                mat[(i + 3) & 3][(j + 2) & 3],
40                mat[(i + 1) & 3][(j + 3) & 3],
41                mat[(i + 2) & 3][(j + 3) & 3],
42                mat[(i + 3) & 3][(j + 3) & 3]) * (((i + j) & 1) ? -1.0f : 1.0f);
43}
44
45template<> float mat4::det() const
46{
47    float ret = 0;
48    for (int n = 0; n < 4; n++)
49        ret += (*this)[n][0] * cofact3(*this, n, 0);
50    return ret;
51}
52
53template<> mat4 mat4::invert() const
54{
55    mat4 ret;
56    float d = det();
57    if (d)
58    {
59        d = 1.0f / d;
60        for (int j = 0; j < 4; j++)
61            for (int i = 0; i < 4; i++)
62                ret[j][i] = cofact3(*this, i, j) * d;
63    }
64    return ret;
65}
66
67template<> void mat4::printf() const
68{
69#if 0
70    mat4 const &p = *this;
71
72    Log::Debug("[ %6.6f %6.6f %6.6f %6.6f\n",
73               p[0][0], p[1][0], p[2][0], p[3][0]);
74    Log::Debug("  %6.6f %6.6f %6.6f %6.6f\n",
75               p[0][1], p[1][1], p[2][1], p[3][1]);
76    Log::Debug("  %6.6f %6.6f %6.6f %6.6f\n",
77               p[0][2], p[1][2], p[2][2], p[3][2]);
78    Log::Debug("  %6.6f %6.6f %6.6f %6.6f ]\n",
79               p[0][3], p[1][3], p[2][3], p[3][3]);
80#endif
81}
82
83template<> mat4 mat4::ortho(float left, float right, float bottom,
84                            float top, float near, float far)
85{
86    float invrl = (right != left) ? 1.0f / (right - left) : 0.0f;
87    float invtb = (top != bottom) ? 1.0f / (top - bottom) : 0.0f;
88    float invfn = (far != near) ? 1.0f / (far - near) : 0.0f;
89
90    mat4 ret(0.0f);
91    ret[0][0] = 2.0f * invrl;
92    ret[1][1] = 2.0f * invtb;
93    ret[2][2] = -2.0f * invfn;
94    ret[3][0] = - (right + left) * invrl;
95    ret[3][1] = - (top + bottom) * invtb;
96    ret[3][2] = - (far + near) * invfn;
97    ret[3][3] = 1.0f;
98    return ret;
99}
100
101template<> mat4 mat4::frustum(float left, float right, float bottom,
102                              float top, float near, float far)
103{
104    float invrl = (right != left) ? 1.0f / (right - left) : 0.0f;
105    float invtb = (top != bottom) ? 1.0f / (top - bottom) : 0.0f;
106    float invfn = (far != near) ? 1.0f / (far - near) : 0.0f;
107
108    mat4 ret(0.0f);
109    ret[0][0] = 2.0f * near * invrl;
110    ret[1][1] = 2.0f * near * invtb;
111    ret[2][0] = (right + left) * invrl;
112    ret[2][1] = (top + bottom) * invtb;
113    ret[2][2] = - (far + near) * invfn;
114    ret[2][3] = -1.0f;
115    ret[3][2] = -2.0f * far * near * invfn;
116    return ret;
117}
118
119template<> mat4 mat4::perspective(float theta, float width,
120                                  float height, float near, float far)
121{
122    float t1 = tanf(theta / 2.0f);
123    float t2 = t1 * height / width;
124
125    return frustum(-near * t1, near * t1, -near * t2, near * t2, near, far);
126}
127
128template<> mat4 mat4::translate(float x, float y, float z)
129{
130    mat4 ret(1.0f);
131    ret[3][0] = x;
132    ret[3][1] = y;
133    ret[3][2] = z;
134    return ret;
135}
136
137template<> mat4 mat4::rotate(float theta, float x, float y, float z)
138{
139    float st = sinf(theta);
140    float ct = cosf(theta);
141
142    float len = sqrtf(x * x + y * y + z * z);
143    float invlen = len ? 1.0f / len : 0.0f;
144    x *= invlen;
145    y *= invlen;
146    z *= invlen;
147
148    float mtx = (1.0f - ct) * x;
149    float mty = (1.0f - ct) * y;
150    float mtz = (1.0f - ct) * z;
151
152    mat4 ret(1.0f);
153
154    ret[0][0] = x * mtx + ct;
155    ret[0][1] = x * mty + st * z;
156    ret[0][2] = x * mtz - st * y;
157
158    ret[1][0] = y * mtx - st * z;
159    ret[1][1] = y * mty + ct;
160    ret[1][2] = y * mtz + st * x;
161
162    ret[2][0] = z * mtx + st * y;
163    ret[2][1] = z * mty - st * x;
164    ret[2][2] = z * mtz + ct;
165
166    return ret;
167}
168
169} /* namespace lol */
170
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