cpp-11-ray-trace-march-framework/aabb.h at master · blitzcode/cpp-11-ray-trace-march-framework · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

#ifndef AABB_H
#define AABB_H

#include "types.h"
#include "lin_alg.h"
#include "aabb_tri_internal.h"

inline bool IntersectPointAABB(Vec3f p, Vec3f aabb_min, Vec3f aabb_max)
{
    return p.x >= aabb_min.x && p.y >= aabb_min.y && p.z >= aabb_min.z &&
           p.x <= aabb_max.x && p.y <= aabb_max.y && p.z <= aabb_max.z;
}

inline bool IntersectTriAABB(Vec3f v0, Vec3f v1, Vec3f v2, Vec3f aabb_min, Vec3f aabb_max)
{
    // Wrapper, see aabb_tri_internal.h

    double center[3] = { (aabb_min.x + aabb_max.x) * 0.5f,
                         (aabb_min.y + aabb_max.y) * 0.5f,
                         (aabb_min.z + aabb_max.z) * 0.5f };

    double half_size[3] = { (aabb_max.x - aabb_min.x) * 0.5f,
                            (aabb_max.y - aabb_min.y) * 0.5f,
                            (aabb_max.z - aabb_min.z) * 0.5f };

    double tri[3][3] = { { v0.x, v0.y, v0.z },
                         { v1.x, v1.y, v1.z },
                         { v2.x, v2.y, v2.z } };

    return triBoxOverlap(center, half_size, tri) == 1;
}

inline bool IntersectRayAABB(
    Vec3f origin,
    Vec3f dir,
    Vec3f aabb_min,
    Vec3f aabb_max,
    float& tmin,
    float& tmax)
{
    // Amy Williams, Steve Barrus, R. Keith Morley, and Peter Shirley
    // "An Efficient and Robust Ray-Box Intersection Algorithm"
    // Journal of graphics tools, 10(1):49-54, 2005
    //
    // http://www.cs.utah.edu/~awilliam/box/

    // TODO: Can be pre-computed
    const Vec3f inv_direction(1.0f / dir.x, 1.0f / dir.y, 1.0f / dir.z);
    const int sign[3] =
    {
        (inv_direction.x < 0.0f) ? 1 : 0,
        (inv_direction.y < 0.0f) ? 1 : 0,
        (inv_direction.z < 0.0f) ? 1 : 0
    };

    const Vec3f aabb[2] = { aabb_min, aabb_max };

    tmin = (aabb[    sign[0]].x - origin.x) * inv_direction.x;
    tmax = (aabb[1 - sign[0]].x - origin.x) * inv_direction.x;

    float tymin = (aabb[    sign[1]].y - origin.y) * inv_direction.y;
    float tymax = (aabb[1 - sign[1]].y - origin.y) * inv_direction.y;

    if ((tmin > tymax) || (tymin > tmax))
        return false;
    if (tymin > tmin)
        tmin = tymin;
    if (tymax < tmax)
        tmax = tymax;

    float tzmin = (aabb[    sign[2]].z - origin.z) * inv_direction.z;
    float tzmax = (aabb[1 - sign[2]].z - origin.z) * inv_direction.z;

    if ((tmin > tzmax) || (tzmin > tmax))
        return false;
    if (tzmin > tmin)
        tmin = tzmin;
    if (tzmax < tmax)
        tmax = tzmax;

    return true;
}

inline bool IntersectRayAABB_Old(
    Vec3f origin,
    Vec3f dir,
    Vec3f aabb_min,
    Vec3f aabb_max,
    float& t)
{
    uint i, quadrant[3], which_plane;
    bool inside = true;
    float max_t[3], candidate_plane[3];

    for (i=0; i<3; i++)
    {
        if (origin.m_vec[i] < aabb_min.m_vec[i])
        {
            quadrant[i] = 1;
            candidate_plane[i] = aabb_min.m_vec[i];
            inside = false;
        }
        else if (origin.m_vec[i] > aabb_max.m_vec[i])
        {
            quadrant[i] = 1;
            candidate_plane[i] = aabb_max.m_vec[i];
            inside = false;
        }
        else
            quadrant[i] = 0;
    }

    if (inside)
    {
        t = 0.0f;
        return true;
    }

    for (i=0; i<3; i++)
    {
        if (quadrant[i] != 0 && std::abs(dir.m_vec[i]) > 0.00001f)
            max_t[i] = (candidate_plane[i] - origin.m_vec[i]) / dir.m_vec[i];
        else
            max_t[i] = -1.0f;
    }

    which_plane = 0;

    if (max_t[which_plane] < max_t[1])
        which_plane = 1;
    if (max_t[which_plane] < max_t[2])
        which_plane = 2;

    if (max_t[which_plane] < 0.0f)
        return false;

    for (i=0; i<3; i++)
    {
        if (which_plane != i)
        {
            origin.m_vec[i] = origin.m_vec[i] + max_t[which_plane] * dir.m_vec[i];

            if (origin.m_vec[i] < aabb_min.m_vec[i] - 0.00001f ||
                origin.m_vec[i] > aabb_max.m_vec[i] + 0.00001f)
            {
                return false;
            }
        }
        else
            origin.m_vec[i] = candidate_plane[i];
    }

    t = max_t[which_plane];
    return true;
}

#endif // AABB_H