const Frustum& Camera::GetFrustum() const
{
// Use projection_ instead of GetProjection() so that Y-flip has no effect. Update first if necessary
if (projectionDirty_)
UpdateProjection();
if (frustumDirty_)
{
if (customProjection_)
frustum_.Define(projection_ * GetView());
else
{
// If not using a custom projection, prefer calculating frustum from projection parameters instead of matrix
// for better accuracy
if (!orthographic_)
frustum_.Define(fov_, aspectRatio_, zoom_, GetNearClip(), GetFarClip(), GetEffectiveWorldTransform());
else
frustum_.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), GetFarClip(), GetEffectiveWorldTransform());
}
frustumDirty_ = false;
}
return frustum_;
}
Frustum Camera::GetViewSpaceFrustum() const
{
Frustum ret;
if (!orthographic_)
ret.Define(fov_, aspectRatio_, zoom_, GetNearClip(), farClip_);
else
ret.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), farClip_);
return ret;
}
const Frustum& Camera::GetFrustum() const
{
if (frustumDirty_)
{
const Matrix3x4& worldTransform = node_ ? node_->GetWorldTransform() : Matrix3x4::IDENTITY;
if (!orthographic_)
frustum_.Define(fov_, aspectRatio_, zoom_, GetNearClip(), farClip_, worldTransform);
else
frustum_.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), farClip_, worldTransform);
frustumDirty_ = false;
}
return frustum_;
}
void Camera::GetFrustumSize(Vector3& near, Vector3& far) const
{
near.z_ = GetNearClip();
far.z_ = farClip_;
if (!orthographic_)
{
float halfViewSize = tanf(fov_ * M_DEGTORAD * 0.5f) / zoom_;
near.y_ = near.z_ * halfViewSize;
near.x_ = near.y_ * aspectRatio_;
far.y_ = far.z_ * halfViewSize;
far.x_ = far.y_ * aspectRatio_;
}
else
{
float halfViewSize = orthoSize_ * 0.5f / zoom_;
near.y_ = far.y_ = halfViewSize;
near.x_ = far.x_ = near.y_ * aspectRatio_;
}
if (flipVertical_)
{
near.y_ = -near.y_;
far.y_ = -far.y_;
}
}
const Frustum& Camera::GetFrustum() const
{
if (frustumDirty_)
{
Matrix3x4 worldTransform = GetEffectiveWorldTransform();
if (!orthographic_)
frustum_.Define(fov_, aspectRatio_, zoom_, GetNearClip(), farClip_, worldTransform);
else
frustum_.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), farClip_, worldTransform);
frustumDirty_ = false;
}
return frustum_;
}
Vector3 Camera::ScreenToWorldPoint(const Vector3& screenPos) const
{
Ray ray = GetScreenRay(screenPos.x_, screenPos.y_);
Vector3 viewSpaceDir = (GetView() * Vector4(ray.direction_, 0.0f));
float rayDistance = (Max(screenPos.z_ - GetNearClip(), 0.0f) / viewSpaceDir.z_);
return ray.origin_ + ray.direction_ * rayDistance;
}
bool Camera::ObjectFrustumCulling( const RenderObject& obj )
{
const AABB& aabb = obj.m_worldAABB;
//物体坐标转换到相机空间进行裁减
VEC4 pos(aabb.GetCenter(), 1.0f);
Common::Transform_Vec4_By_Mat44(pos, pos, GetViewMatrix());
float n = GetNearClip();
float f = GetFarClip();
float fov = GetFov();
float half_w = n * std::tan(fov/2);
float half_h = half_w / GetAspectRatio();
//检测前后面
if(-pos.z+aabb.m_boundingRadius <= n || -pos.z-aabb.m_boundingRadius >= f)
return true;
//检测左右面
float planeX = half_w * pos.z / -n;
if(pos.x - planeX >= aabb.m_boundingRadius ||
pos.x + aabb.m_boundingRadius <= -planeX)
return true;
//检测上下面
float planeY = half_h * pos.z / -n;
if(pos.y - planeY >= aabb.m_boundingRadius ||
pos.y + aabb.m_boundingRadius <= -planeY)
return true;
return false;
}
Frustum Camera::GetViewSpaceFrustum() const
{
if (projectionDirty_)
UpdateProjection();
Frustum ret;
if (customProjection_)
ret.Define(projection_);
else
{
if (!orthographic_)
ret.Define(fov_, aspectRatio_, zoom_, GetNearClip(), GetFarClip());
else
ret.DefineOrtho(orthoSize_, aspectRatio_, zoom_, GetNearClip(), GetFarClip());
}
return ret;
}
void Camera::_BuildProjMatrix()
{
/* 这是第一个版本的透视投影矩阵,即"蛮干"求解法.
它的缺陷在于为了变换出xy坐标都在[-1, 1]的CVV空间,
必须满足以下条件:
1.视距d=1.
2.fov=90度.
3.视口AspectRatio=1.
否则变换不出CVV.
MatProj = ( 1, 0, 0, 0
0, 1, 0, 0
0, 0, 1, 0
0, 0, 1/d, 0 )
投影变换加齐次除法后:
x' = x * d / z, y' = y * d / z */
//普适版投影矩阵.推导见: http://blog.csdn.net/popy007/article/details/1797121
float r,l,t,b;
r = m_nearClip*tanf(m_fov/2);
l = -r;
t = r/m_aspectRatio;
b= -t;
m_matProj.m00 = 2*m_nearClip/(r-l);
m_matProj.m01 = 0;
m_matProj.m02 = (r+l)/(r-l);
m_matProj.m03 = 0;
m_matProj.m10 = 0;
m_matProj.m11 = 2*m_nearClip/(t-b);
m_matProj.m12 = (t+b)/(t-b);
m_matProj.m13 = 0;
m_matProj.m20 = 0;
m_matProj.m21 = 0;
m_matProj.m22 = -(m_farClip+m_nearClip)/(m_farClip-m_nearClip);
m_matProj.m23 = -2*m_farClip*m_nearClip/(m_farClip-m_nearClip);
m_matProj.m30 = 0;
m_matProj.m31 = 0;
m_matProj.m32 = -1;
m_matProj.m33 = 0;
m_matInvProj = m_matProj.Inverse();
m_imagePlane_r = GetNearClip() * tanf(GetFov() / 2);
m_imagePlane_t = m_imagePlane_r / GetAspectRatio();
}
Frustum Camera::GetViewSpaceSplitFrustum(float nearClip, float farClip) const
{
Frustum ret;
nearClip = Max(nearClip, GetNearClip());
farClip = Min(farClip, farClip_);
if (farClip < nearClip)
farClip = nearClip;
if (!orthographic_)
ret.Define(fov_, aspectRatio_, zoom_, nearClip, farClip);
else
ret.DefineOrtho(orthoSize_, aspectRatio_, zoom_, nearClip, farClip);
return ret;
}
Frustum Camera::GetSplitFrustum(float nearClip, float farClip) const
{
Frustum ret;
Matrix3x4 worldTransform = GetEffectiveWorldTransform();
nearClip = Max(nearClip, GetNearClip());
farClip = Min(farClip, farClip_);
if (farClip < nearClip)
farClip = nearClip;
if (!orthographic_)
ret.Define(fov_, aspectRatio_, zoom_, nearClip, farClip, worldTransform);
else
ret.DefineOrtho(orthoSize_, aspectRatio_, zoom_, nearClip, farClip, worldTransform);
return ret;
}
Frustum Camera::GetSplitFrustum(float nearClip, float farClip) const
{
Frustum ret;
const Matrix3x4& worldTransform = node_ ? node_->GetWorldTransform() : Matrix3x4::IDENTITY;
nearClip = Max(nearClip, GetNearClip());
farClip = Min(farClip, farClip_);
if (farClip < nearClip)
farClip = nearClip;
if (!orthographic_)
ret.Define(fov_, aspectRatio_, zoom_, nearClip, farClip, worldTransform);
else
ret.DefineOrtho(orthoSize_, aspectRatio_, zoom_, nearClip, farClip, worldTransform);
return ret;
}
bool Camera::IsProjectionValid() const
{
return farClip_ > GetNearClip();
}
Matrix4 Camera::GetProjection(bool apiSpecific) const
{
Matrix4 ret(Matrix4::ZERO);
// Whether to construct matrix using OpenGL or Direct3D clip space convention
#ifdef URHO3D_OPENGL
bool openGLFormat = apiSpecific;
#else
bool openGLFormat = false;
#endif
if (!orthographic_)
{
float nearClip = GetNearClip();
float h = (1.0f / tanf(fov_ * M_DEGTORAD * 0.5f)) * zoom_;
float w = h / aspectRatio_;
float q, r;
if (openGLFormat)
{
q = (farClip_ + nearClip) / (farClip_ - nearClip);
r = -2.0f * farClip_ * nearClip / (farClip_ - nearClip);
}
else
{
q = farClip_ / (farClip_ - nearClip);
r = -q * nearClip;
}
ret.m00_ = w;
ret.m02_ = projectionOffset_.x_ * 2.0f;
ret.m11_ = h;
ret.m12_ = projectionOffset_.y_ * 2.0f;
ret.m22_ = q;
ret.m23_ = r;
ret.m32_ = 1.0f;
}
else
{
// Disregard near clip, because it does not affect depth precision as with perspective projection
float h = (1.0f / (orthoSize_ * 0.5f)) * zoom_;
float w = h / aspectRatio_;
float q, r;
if (openGLFormat)
{
q = 2.0f / farClip_;
r = -1.0f;
}
else
{
q = 1.0f / farClip_;
r = 0.0f;
}
ret.m00_ = w;
ret.m03_ = projectionOffset_.x_ * 2.0f;
ret.m11_ = h;
ret.m13_ = projectionOffset_.y_ * 2.0f;
ret.m22_ = q;
ret.m23_ = r;
ret.m33_ = 1.0f;
}
if (flipVertical_)
ret = flipMatrix * ret;
return ret;
}
Matrix4 Camera::GetProjection(bool apiSpecific) const
{
Matrix4 ret(Matrix4::ZERO);
if (!orthographic_)
{
float nearClip = GetNearClip();
float h = (1.0f / tanf(fov_ * M_DEGTORAD * 0.5f)) * zoom_;
float w = h / aspectRatio_;
float q, r;
if (apiSpecific)
{
#ifdef USE_OPENGL
q = (farClip_ + nearClip) / (farClip_ - nearClip);
r = -2.0f * farClip_ * nearClip / (farClip_ - nearClip);
#else
q = farClip_ / (farClip_ - nearClip);
r = -q * nearClip;
#endif
}
else
{
q = farClip_ / (farClip_ - nearClip);
r = -q * nearClip;
}
ret.m00_ = w;
ret.m02_ = projectionOffset_.x_ * 2.0f;
ret.m11_ = h;
ret.m12_ = projectionOffset_.y_ * 2.0f;
ret.m22_ = q;
ret.m23_ = r;
ret.m32_ = 1.0f;
}
else
{
// Disregard near clip, because it does not affect depth precision as with perspective projection
float h = (1.0f / (orthoSize_ * 0.5f)) * zoom_;
float w = h / aspectRatio_;
float q, r;
if (apiSpecific)
{
#ifdef USE_OPENGL
q = 2.0f / farClip_;
r = -1.0f;
#else
q = 1.0f / farClip_;
r = 0.0f;
#endif
}
else
{
q = 1.0f / farClip_;
r = 0.0f;
}
ret.m00_ = w;
ret.m03_ = projectionOffset_.x_ * 2.0f;
ret.m11_ = h;
ret.m13_ = projectionOffset_.y_ * 2.0f;
ret.m22_ = q;
ret.m23_ = r;
ret.m33_ = 1.0f;
}
if (flipVertical_)
ret = flipMatrix * ret;
return ret;
}
