Level of detail (LOD) group node based on screen space coverage. More...

#include <SLNodeLOD.h>

Inheritance diagram for SLNodeLOD:

Public Member Functions
	SLNodeLOD (const SLstring &name="NodeLOD")

void	addChildLOD (SLNode *child, SLfloat minLodLimit, SLubyte levelForSM=0)
	Adds an LOD node with forced decreasing min LOD coverage. More...

virtual void	cullChildren3D (SLSceneView *sv)
	Culls the LOD children by evaluating the the screen space coverage. More...

Public Member Functions inherited from SLNode
	SLNode (const SLstring &name="Node")
	Construct a new SLNode::SLNode object. More...

	SLNode (SLMesh *mesh, const SLstring &name="Node")

	SLNode (SLMesh *mesh, const SLVec3f &translation, const SLstring &name)

	~SLNode () override

virtual void	cull3DRec (SLSceneView *sv)

virtual void	cull2DRec (SLSceneView *sv)

virtual bool	hitRec (SLRay *ray)

virtual void	statsRec (SLNodeStats &stats)

virtual SLNode *	copyRec ()

virtual SLAABBox &	updateAABBRec (SLbool updateAlsoAABBinOS)

virtual void	dumpRec ()

void	setDrawBitsRec (SLuint bit, SLbool state)

void	setPrimitiveTypeRec (SLGLPrimitiveType primitiveType)

virtual void	addMesh (SLMesh *mesh)

virtual void	drawMesh (SLSceneView *sv)
	Draws the single mesh. More...

bool	removeMesh ()
	Returns true if a mesh was assigned and set it to nullptr. More...

bool	removeMesh (SLMesh *mesh)
	Returns true if the passed mesh was assigned and sets it to nullptr. More...

SLint	numChildren ()

void	addChild (SLNode *child)

bool	insertChild (SLNode insertC, SLNode afterC)

void	deleteChildren ()

bool	deleteChild ()

bool	deleteChild (SLNode *child)

bool	deleteChild (const SLstring &name)

bool	removeChild (SLNode *child)
	remove child from vector of children. Removes false if not found, else true. More...

template<typename T >
T *	find (const SLstring &name="", SLbool findRecursive=true)

template<typename T >
T *	findChild (const SLstring &name="", SLbool findRecursive=true)

template<typename T >
deque< T * >	findChildren (const SLstring &name="", SLbool findRecursive=true, SLbool canContain=false)

deque< SLNode * >	findChildren (const SLMesh *mesh, SLbool findRecursive=true)

deque< SLNode * >	findChildren (SLuint drawbit, SLbool findRecursive=true)

SLVec3f	translationOS () const

SLVec3f	forwardOS () const

SLVec3f	rightOS () const

SLVec3f	upOS () const

SLVec3f	axisXOS () const

SLVec3f	axisYOS () const

SLVec3f	axisZOS () const

SLVec3f	translationWS () const

SLVec3f	forwardWS () const

SLVec3f	rightWS () const

SLVec3f	upWS () const

SLVec3f	axisXWS () const

SLVec3f	axisYWS () const

SLVec3f	axisZWS () const

void	translation (const SLVec3f &pos, SLTransformSpace relativeTo=TS_parent)

void	translation (SLfloat x, SLfloat y, SLfloat z, SLTransformSpace relativeTo=TS_parent)

void	rotation (const SLQuat4f &rot, SLTransformSpace relativeTo=TS_parent)

void	rotation (SLfloat angleDeg, const SLVec3f &axis, SLTransformSpace relativeTo=TS_parent)

void	scaling (SLfloat s)

void	scaling (SLfloat x, SLfloat y, SLfloat z)

void	scaling (const SLVec3f &scaling)

void	lookAt (SLfloat targetX, SLfloat targetY, SLfloat targetZ, SLfloat upX=0, SLfloat upY=1, SLfloat upZ=0, SLTransformSpace relativeTo=TS_world)

void	lookAt (const SLVec3f &target, const SLVec3f &up=SLVec3f::AXISY, SLTransformSpace relativeTo=TS_world)

void	translate (const SLVec3f &vec, SLTransformSpace relativeTo=TS_object)

void	translate (SLfloat x, SLfloat y, SLfloat z, SLTransformSpace relativeTo=TS_object)

void	rotate (const SLQuat4f &rot, SLTransformSpace relativeTo=TS_object)

void	rotate (SLfloat angleDeg, const SLVec3f &axis, SLTransformSpace relativeTo=TS_object)

void	rotate (SLfloat angleDeg, SLfloat x, SLfloat y, SLfloat z, SLTransformSpace relativeTo=TS_object)

void	rotateAround (const SLVec3f &point, SLVec3f &axis, SLfloat angleDeg, SLTransformSpace relativeTo=TS_world)

void	scale (SLfloat s)

void	scale (SLfloat x, SLfloat y, SLfloat z)

void	scale (const SLVec3f &scale)

void	scaleToCenter (SLfloat maxDim)

void	setInitialState ()

void	resetToInitialState ()

void	parent (SLNode *p)

void	entityID (SLint entityID)

void	om (const SLMat4f &mat)

void	animation (SLAnimation *a)

void	castsShadows (SLbool castsShadows)

virtual void	needUpdate ()

void	needWMUpdate ()

void	needAABBUpdate ()

void	isSelected (bool isSelected)

void	minLodCoverage (SLfloat minLodCoverage)

void	levelForSM (SLubyte lfsm)

void	onUpdateCB (function< void()> callbackFunc)

SLNode *	parent ()

SLint	depth () const

SLint	entityID () const

const SLMat4f &	om ()

const SLMat4f &	initialOM ()

const SLMat4f &	updateAndGetWM () const

const SLMat4f &	updateAndGetWMI () const

SLDrawBits *	drawBits ()

SLbool	drawBit (SLuint bit)

SLAABBox *	aabb ()

SLAnimation *	animation ()

SLbool	castsShadows ()

SLMesh *	mesh ()

SLVNode &	children ()

const SLAnimSkeleton *	skeleton ()
	Returns the first skeleton found in the meshes. More...

void	updateRec ()

virtual void	doUpdate ()

bool	updateMeshSkins (bool forceCPUSkinning, const std::function< void(SLMesh *)> &cbInformNodes)
	Update all skinned meshes recursively. More...

void	updateMeshAccelStructs ()

void	updateMeshMat (std::function< void(SLMaterial *m)> setMat, bool recursive)
	Updates the mesh material recursively with a material lambda. More...

void	setMeshMat (SLMaterial *mat, bool recursive)
	Set the mesh material recursively. More...

bool	isSelected ()

SLfloat	minLodCoverage ()

SLubyte	levelForSM ()

Public Member Functions inherited from SLObject
	SLObject (const SLstring &Name="", const SLstring &url="")

virtual	~SLObject ()

void	name (const SLstring &Name)

void	url (const SLstring &url)

const SLstring &	name () const

const SLstring &	url () const

Public Member Functions inherited from SLEventHandler
	SLEventHandler ()

virtual	~SLEventHandler ()

virtual SLbool	onMouseDown (const SLMouseButton button, const SLint x, const SLint y, const SLKey mod)

virtual SLbool	onMouseUp (const SLMouseButton button, const SLint x, const SLint y, const SLKey mod)

virtual SLbool	onMouseMove (const SLMouseButton button, const SLint x, const SLint y, const SLKey mod)

virtual SLbool	onDoubleClick (const SLMouseButton button, const SLint x, const SLint y, const SLKey mod)

virtual SLbool	onMouseWheel (const SLint delta, const SLKey mod)

virtual SLbool	onTouch2Down (const SLint x1, const SLint y1, const SLint x2, const SLint y2)

virtual SLbool	onTouch2Move (const SLint x1, const SLint y1, const SLint x2, const SLint y2)

virtual SLbool	onTouch2Up (const SLint x1, const SLint y1, const SLint x2, const SLint y2)

virtual SLbool	onTouch3Down (const SLint x1, const SLint y1)

virtual SLbool	onTouch3Move (const SLint x1, const SLint y1)

virtual SLbool	onTouch3Up (const SLint x1, const SLint y1)

virtual SLbool	onKeyPress (const SLKey key, const SLKey mod)

virtual SLbool	onKeyRelease (const SLKey key, const SLKey mod)

virtual SLbool	onRotationPYR (const SLfloat pitchRAD, const SLfloat yawRAD, const SLfloat rollRAD)

void	mouseRotationFactor (SLfloat rf)

SLfloat	mouseRotationFactor ()

Additional Inherited Members
Static Public Attributes inherited from SLNode
static SLuint	numWMUpdates = 0
	NO. of calls to updateWMRec per frame. More...

static unsigned int	instanceIndex = 0
	??? More...

Protected Attributes inherited from SLNode
SLNode *	_parent
	pointer to the parent node More...

SLVNode	_children
	vector of children nodes More...

SLMesh *	_mesh
	pointer to a single mesh More...

SLint	_depth
	depth of the node in a scene tree More...

SLint	_entityID
	ID in the SLVEntity graph for Data Oriented Design. More...

SLMat4f	_om
	object matrix for local transforms More...

SLMat4f	_initialOM
	the initial om state More...

SLMat4f	_wm
	world matrix for world transform More...

SLMat4f	_wmI
	inverse world matrix More...

SLbool	_isWMUpToDate
	is the WM of this node still valid More...

SLbool	_isWMIUpToDate
	is the inverse WM of this node still valid More...

SLbool	_isAABBUpToDate
	is the saved aabb still valid More...

bool	_castsShadows
	flag if meshes of node should cast shadows More...

bool	_isSelected
	flag if node and one or more of its meshes are selected More...

SLDrawBits	_drawBits
	node level drawing flags More...

SLAABBox	_aabb
	axis aligned bounding box More...

SLAnimation *	_animation
	animation of the node More...

SLfloat	_minLodCoverage
	Min. LOD coverage for visibility (0.0 < _minLodCoverage < 1.0) More...

SLubyte	_levelForSM
	Level of LOD to use for shadow mapping (0 = the visible one will be drawn) More...

function< void()>	_onUpdateCB
	Optional lambda callback once per update. More...

Protected Attributes inherited from SLObject
SLstring	_name
	name of an object More...

SLstring	_url
	uniform resource locator More...

Protected Attributes inherited from SLEventHandler
SLfloat	_mouseRotationFactor
	Mouse rotation sensibility. More...

SLfloat	_keyboardDeltaPos
	Delta dist. for keyboard translation. More...

Detailed Description

Level of detail (LOD) group node based on screen space coverage.

An LOD group node can be used to improve the rendering performance for a mesh is very detailed and has thousands for vertices and triangles. Such a details mesh doesn't need to be detailed in full resolution if the mesh is displayed far away from the camera because you can see all triangles anyway. We therefore need to create multiple levels of details with lower no. of triangles and vertices. You have to create these lower resolution version of an original mesh in an external program such as Blender that has multiple decimation algorithms for this purpose.
See the method addChildLOD for more information how to add the levels.

Definition at line 27 of file SLNodeLOD.h.

Constructor & Destructor Documentation

◆ SLNodeLOD()

SLNodeLOD::SLNodeLOD ( const SLstring & name = "NodeLOD" )

inlineexplicit

Definition at line 30 of file SLNodeLOD.h.

30 : SLNode(name) { ; }

SLNode::SLNode

SLNode(const SLstring &name="Node")

Construct a new SLNode::SLNode object.

Definition: SLNode.cpp:40

SLObject::name

const SLstring & name() const

Definition: SLObject.h:38

Member Function Documentation

◆ addChildLOD()

void SLNodeLOD::addChildLOD	(	SLNode *	childToAdd,
		SLfloat	minLodCoverage,
		SLubyte	levelForSM = `0`
	)

Adds an LOD node with forced decreasing min LOD coverage.

The coverage value is the ratio of the nodes bounding rectangle in screen space to the full viewport. The minLodCoverage value must be > 0.0 and < 1.0 and < than the minLodCoverage of the last node in the LOD group. If the first child node has e.g. a minLodCoverage of 0.1 it means that it will be visible if its bounding rectangle covers more then 10% of the viewport. The first child node in the group must be the one with the highest resolution.

Remarks: It is important that during instantiation NO OpenGL functions (gl*) get called because this constructor will be most probably called in a parallel thread from within an SLScene::registerAssetsToLoad or SLScene::assemble function. All objects that get rendered have to do their OpenGL initialization when they are used the first time during rendering in the main thread.

Parameters

childToAdd	LOD child node pointer to add
minLodCoverage	A value > 0 and < 1 and < than the minLodCoverage of the last node in the LOD group
levelForSM	Level to use for shadow mapping (0 uses the active level)

Definition at line 32 of file SLNodeLOD.cpp.

 {
     assert(minLodCoverage > 0.0f &&
            minLodCoverage < 1.0f &&
            "SLNodeLOD::addChildLOD min. LOD limit must be > 0 and < 1");
  
     if (!_children.empty() &&
         _children[_children.size() - 1]->minLodCoverage() <= minLodCoverage)
         SL_EXIT_MSG("SLNodeLOD::addChildLOD: A new child LOD node must have a smaller LOD limit than the last one.");
  
     childToAdd->minLodCoverage(minLodCoverage);
     childToAdd->levelForSM(levelForSM);
     addChild(childToAdd);
  
     /* Set new node hidden, so they won't be shadowed if they are outside
      * the view frustum. Only the LOD algorithm in cullChildren3D can make
      * them visible */
     childToAdd->drawBits()->set(SL_DB_HIDDEN, true);
 }

◆ cullChildren3D()

void SLNodeLOD::cullChildren3D ( SLSceneView * sv )

virtual

Culls the LOD children by evaluating the the screen space coverage.

Reimplemented from SLNode.

Definition at line 55 of file SLNodeLOD.cpp.

 {
     if (!_children.empty())
     {
         SLfloat rectCoverage = _aabb.rectCoverageInSS();
  
         // Set visibility (draw-bit SL_DB_HIDDEN) for each level
         for (SLint i = 0; i < _children.size(); ++i)
         {
             bool isVisible;
  
             if (i == 0)
                 isVisible = rectCoverage >= _children[i]->minLodCoverage();
             else
                 isVisible = rectCoverage < _children[i - 1]->minLodCoverage() &&
                             rectCoverage >= _children[i]->minLodCoverage();
  
             _children[i]->drawBits()->set(SL_DB_HIDDEN, !isVisible);
             _aabb.isVisible(isVisible);
  
             // cull check only the visible level
             if (isVisible)
                 _children[i]->cull3DRec(sv);
         }
     }
 }

The documentation for this class was generated from the following files: