lg_scene_graph.c File Reference

Functions
LG_SceneNode *	lg_scenenode_new (int id, const char *name, lg_scenenode_type type)
void	lg_scenenode_add_child (LG_SceneNode *node, LG_SceneNode *child)
void	lg_scenenode_remove_child (LG_SceneNode *node, LG_SceneNode *child)
void	lg_scenenode_free (LG_SceneNode *node)
LG_SceneNode *	lg_scenenode_get_root (LG_SceneNode *node)
int	lg_scenenode_remove_and_free_leaf (LG_SceneNode *node)
void	lg_scenenode_remove_and_free_all (LG_SceneNode *node)
void	lg_traverse_scene_graph (LG_SceneNode *node, int(*func)(LG_SceneNode *))
void	lg_traverse_scene_graph_2 (LG_SceneNode *node, int(*func)(LG_SceneNode *, LG_Scene *), LG_Scene *scene)
LG_SceneNode *	lg_scenenode_find_by_id (LG_SceneNode *node, int id)
LG_SceneNode *	lg_scenenode_find_by_name (LG_SceneNode *node, const char *name)
void	lg_scenenode_reset_local_matrix (LG_SceneNode *node)
void	lg_scenenode_set_local_matrix (LG_SceneNode *node, vec3_t scaling, vec3_t transl, LG_Quat rot)
void	lg_scenenode_update_local_matrix (LG_SceneNode *node, vec3_t scaling, vec3_t transl, LG_Quat rot)
void	lg_scenenode_update_world_matrix_tree (LG_SceneNode *node, mat4_t *parent_world_matrix)
void	lg_scenenode_set_world_matrix (LG_SceneNode *node, vec3_t scaling, vec3_t transl, LG_Quat rot)
void	lg_scenenode_attach_to_camera (LG_SceneNode *node, const LG_Camera *cam, vec3_t transl)
int	lg_scenenode_clone_worldm_l3dvb (LG_SceneNode *dest_node, LG_SceneNode *src_node)
void	lg_traverse_printout_scene_graph (LG_SceneNode *node, zboolean extra_info)
void	lg_scenenode_info (LG_SceneNode *node)
int	lg_scenenode_info2 (LG_SceneNode *node)
const char *	lg_scenenode_type_string (int type)

Detailed Description

    === Scene graph implementation ===

Function Documentation

lg_scenenode_new()

LG_SceneNode* lg_scenenode_new	(	int	id,
		const char *	name,
		lg_scenenode_type	type
	)

Create a new LG_SceneNode instance

local_matrix and world_matrix are initialized as id matrix

Parameters

id	Node's id
name	Node's name
type	One of ROOT, MESH, LINES3D, GRID, LANDSCAPE, SKYBOX, LIGHT, SHADER_ONLY, UNDEFINED
scene	A pointer to a LG_Scene

Returns

A pointer to a LG_SceneNode if OK, NULL on error - must be freed afterwards

lg_scenenode_add_child()

void lg_scenenode_add_child	(	LG_SceneNode *	node,
		LG_SceneNode *	child
	)

Add child node

Parameters

node	A pointer to a LG_SceneNode
child	A pointer to a LG_SceneNode

lg_scenenode_remove_child()

void lg_scenenode_remove_child	(	LG_SceneNode *	node,
		LG_SceneNode *	child
	)

Find and remove child by id (but doesn't free)

Parameters

node	A pointer to a LG_SceneNode
child	A pointer to a LG_SceneNode

lg_scenenode_free()

void lg_scenenode_free

(

LG_SceneNode *

node

)

Free a node and all allocated resources

You can also use lg_scenenode_free2() experimental macro, defined in lg_scenegraph.h

Parameters

node	A pointer to a LG_SceneNode

lg_scenenode_get_root()

LG_SceneNode* lg_scenenode_get_root

(

LG_SceneNode *

node

)

Get the root node

Parameters

node	A pointer to a LG_SceneNode

Returns

The root LG_SceneNode if OK, NULL on error

lg_scenenode_remove_and_free_leaf()

int lg_scenenode_remove_and_free_leaf

(

LG_SceneNode *

node

)

Remove and free a leaf node

Parameters

node	A pointer to a LG_SceneNode

Returns

LG_OK if OK, LG_ERROR if node is NULL, or node is not a leaf, or node is the root node

lg_scenenode_remove_and_free_all()

void lg_scenenode_remove_and_free_all

(

LG_SceneNode *

node

)

Remove and free all nodes but root

Parameters

node	A pointer to a LG_SceneNode

lg_traverse_scene_graph()

void lg_traverse_scene_graph	(	LG_SceneNode *	node,
		int(*)(LG_SceneNode *)	func
	)

Go from top to bottom, starting at node (may be different from the top node) - unsuitable (don't) to remove all nodes

Call (*func)(node) for each node

Parameters

node	A pointer to a LG_SceneNode
func	Func pointer

lg_traverse_scene_graph_2()

void lg_traverse_scene_graph_2	(	LG_SceneNode *	node,
		int(*)(LG_SceneNode *, LG_Scene *)	func,
		LG_Scene *	scene
	)

Same as above but with different func signature and extra scene arg

lg_scenenode_find_by_id()

LG_SceneNode* lg_scenenode_find_by_id	(	LG_SceneNode *	node,
		int	id
	)

Find (first ?) occurence of node by id (traversing the graph top to bottom from provided node)

Parameters

node	Node
id	Node's id

Returns

First found node or NULL

lg_scenenode_find_by_name()

LG_SceneNode* lg_scenenode_find_by_name	(	LG_SceneNode *	node,
		const char *	name
	)

Find (first ?) occurence of node by name (traversing the graph top to bottom from provided node)

Parameters

node	Node
name	Node's name

Returns

First found node or NULL

lg_scenenode_reset_local_matrix()

void lg_scenenode_reset_local_matrix

(

LG_SceneNode *

node

)

=== Scene graph matrix ops ===

Reset node's local_matrix to id matrix

Parameters

node	A pointer to a LG_SceneNode

lg_scenenode_set_local_matrix()

void lg_scenenode_set_local_matrix	(	LG_SceneNode *	node,
		vec3_t	scaling,
		vec3_t	transl,
		LG_Quat	rot
	)

Set node's local matrix

Order is always scaling / transl. / rot.

Parameters

node	A pointer to a LG_SceneNode
scaling	Scaling vec3_t vector
transl	Translation vec3_t vector
rot	Rotation LG_Quat quaternion

lg_scenenode_update_local_matrix()

void lg_scenenode_update_local_matrix	(	LG_SceneNode *	node,
		vec3_t	scaling,
		vec3_t	transl,
		LG_Quat	rot
	)

Update node's local matrix

Order is always scaling / transl. / rot.

Parameters

node	A pointer to a LG_SceneNode
scaling	Scaling vec3_t vector
transl	Translation vec3_t vector
rot	Rotation LG_Quat quaternion

lg_scenenode_update_world_matrix_tree()

void lg_scenenode_update_world_matrix_tree	(	LG_SceneNode *	node,
		mat4_t *	parent_world_matrix
	)

Update (compute from local_matrix) world matrix of node (if transf matrix != NULL) AND children, recursively

Parameters

node	A pointer to a LG_SceneNode
parent_world_matrix	A pointer to a mat4_t transformation matrix

lg_scenenode_set_world_matrix()

void lg_scenenode_set_world_matrix	(	LG_SceneNode *	node,
		vec3_t	scaling,
		vec3_t	transl,
		LG_Quat	rot
	)

Set world matrix of node (only this one) from local_matrix and 3 transfomation vectors

Order is always scaling / transl. / rot.

For special case uses, like attaching a node to a cam

Parameters

node	A pointer to a LG_SceneNode
scaling	Scaling vec3_t vector
transl	Translation vec3_t vector
rot	Rotation LG_Quat quaternion

lg_scenenode_attach_to_camera()

void lg_scenenode_attach_to_camera	(	LG_SceneNode *	node,
		const LG_Camera *	cam,
		vec3_t	transl
	)

Attach node to camera

Modify node's world_matrix to locate it relatively to the camera

Easier to use than lg_scenenode_set_world_matrix()

 lg_scenenode_set_world_matrix(node, vec3(1.0, 1.0, 1.0), cam->position, cam->orientation);
 // vs
 lg_scenenode_attach_to_camera(node, cam, {0.0, 1.0, -1.0});

Parameters

node	A pointer to a LG_SceneNode
cam	A pointer to a LG_Camera
transl	Translation relatively to the cam position

lg_scenenode_clone_worldm_l3dvb()

int lg_scenenode_clone_worldm_l3dvb	(	LG_SceneNode *	dest_node,
		LG_SceneNode *	src_node
	)

'Clone' node's draw_stuff

• Copy drawing stuff from src_node to dest_node, more precisely:

src_node         ->          dest_node
 
  world_matrix                 world_matrix
  mesh->b_cuboid_l3d_vb        lines3d_vb

• Only if src_node->type == MESH and dest_node->type == LINES3D

This line:

src_node->mesh->b_cuboid_l3d_vb -> dest_node->lines3d_vb

makes this func convenient to draw a mesh bounding cuboid

Parameters

dest_node	Pointer to dest node
src_node	Pointer to src node

Returns

LG_OK if OK, LG_ERROR otherwise

lg_traverse_printout_scene_graph()

void lg_traverse_printout_scene_graph	(	LG_SceneNode *	node,
		zboolean	extra_info
	)

Go from top to bottom

Print out tree structure (quite nicely) -> node->name (node->id)

Parameters

node	A pointer to a LG_SceneNode
extra_info	If TRUE, print out extra info (node->id so far)

lg_scenenode_info()

void lg_scenenode_info

(

LG_SceneNode *

node

)

Print out LG_SceneNode info

Parameters

node	A pointer to a LG_SceneNode

lg_scenenode_info2()

int lg_scenenode_info2

(

LG_SceneNode *

node

)

Print out LG_SceneNode info

Same as above func but returns (int)0, so suitable to use with lg_traverse_scene_graph()

Parameters

node	A pointer to a LG_SceneNode

lg_scenenode_type_string()

const char* lg_scenenode_type_string

(

int

type

)

Return string for scenenode type (enum)

Parameters

type	Scenenode type as an int (lg_scenenode_type enum)

Returns

Scenenode type as a string