void Frustum::Enclose(const Frustum& other)
{
vec3 n = glm::normalize(other._origin - other._at);
vec3 u = glm::normalize(cross(other._up, n));
vec3 v = glm::normalize(cross(n, u));
if (_type == Projection::PERSPECTIVE)
Orient(_origin, other.GetCenter(), _up);
mat4 m = GetViewMatrix();
vec3 p[8];
if (other._type == Projection::PERSPECTIVE)
{
float dy = other._near * tanf(radians(other._fovy) / 2.0f);
float dx = other._ar * dy;
vec3 c = other._origin - n * other._near;
p[0] = c + u * dx + v * dy;
p[1] = c - u * dx + v * dy;
p[2] = c - u * dx - v * dy;
p[3] = c + u * dx - v * dy;
dy = other._far * tanf(glm::radians(other._fovy) / 2.0f);
dx = other._ar * dy;
c = other._origin - n * other._far;
p[4] = c + u * dx + v * dy;
p[5] = c - u * dx + v * dy;
p[6] = c - u * dx - v * dy;
p[7] = c + u * dx - v * dy;
}
else
{
vec3 c = other._origin - n * other._near;
p[0] = c + u * other._xmax + v * other._ymax;
p[1] = c + u * other._xmax + v * other._ymin;
p[2] = c + u * other._xmin + v * other._ymax;
p[3] = c + u * other._xmin + v * other._ymin;
c = other._origin - n * other._far;
p[4] = c + u * other._xmax + v * other._ymax;
p[5] = c + u * other._xmax + v * other._ymin;
p[6] = c + u * other._xmin + v * other._ymax;
p[7] = c + u * other._xmin + v * other._ymin;
}
if (_type == Projection::PERSPECTIVE)
{
_fovy = 0.0f;
_far = 0.0f;
_near = std::numeric_limits<float>::max();
float maxHorizAngle = 0.0f;
for (int i = 0; i < 8; i++)
{
vec4 pt = m * vec4(p[i], 1.0f);
if (pt.z < 0.0f)
{
float d = -pt.z;
float angle = atanf(fabs(pt.x) / d);
if (angle > maxHorizAngle)
maxHorizAngle = angle;
angle = glm::degrees(atanf(fabs(pt.y) / d));
if (angle * 2.0f > _fovy)
_fovy = angle * 2.0f;
if (_near > d)
_near = d;
if (_far < d)
_far = d;
}
}
float h = (_near * tanf(glm::radians(_fovy) / 2.0f))*2.0f;
float w = (_near * tanf(maxHorizAngle)) * 2.0f;
_ar = w / h;
}
else
{
_xmin = _ymin = _near = std::numeric_limits<float>::max();
_xmax = _ymax = _far = std::numeric_limits<float>::min();
for (int i = 0; i < 8; i++)
{
vec4 pt = m * vec4(p[i], 1.0f);
if (_xmin > pt.x)
_xmin = pt.x;
if (_xmax < pt.x)
_xmax = pt.x;
if (_ymin > pt.y)
_ymin = pt.y;
if (_ymax < pt.y)
_ymax = pt.y;
if (_near > -pt.z)
_near = -pt.z;
if (_far < -pt.z)
_far = -pt.z;
}
}
}
