Offscreen rendering. More...

#include <easy3d/viewer/offscreen.h>

Inheritance diagram for OffScreen:

Public Member Functions
	OffScreen (int width=800, int height=600)
	Constructor.

Camera manipulation.
Camera *	camera ()
	Returns the camera used by the offscreen renderer. See `Camera`.

const Camera *	camera () const
	Returns the camera used by the offscreen renderer. See `Camera`.

bool	render (const std::string &file_name, float scaling=1.0f, int samples=4, int back_ground=1, bool expand=true) const
	Render the current scene into an image file. Supported image format: png, jpg, bmp, and tga.

Other properties
void	resize (int w, int h)
	Set/Change the size of the offscreen renderer.

int	width () const
	Returns the width of the offscreen renderer.

int	height () const
	Returns the height of the offscreen renderer.

void	set_background_color (const easy3d::vec4 &color)
	Set the background color of the offscreen renderer.

const easy3d::vec4 &	background_color () const
	Query the background color of the offscreen renderer.

Drawable management
Drawable *	add_drawable (std::shared_ptr< Drawable > drawable)
	Add a drawable to the offscreen renderer. On success, the offscreen renderer will be in charge of its memory management.

bool	delete_drawable (Drawable *drawable)

const std::vector< std::shared_ptr< Drawable > > &	drawables () const
	Query the drawables managed by this offscreen renderer.

void	clear_scene ()
	Delete all visual contents of the offscreen renderer (all models and drawables).

Model management
bool	delete_model (Model *model)
	Delete a model. The memory of the model will be released and its existing drawables also be deleted.

const std::vector< std::shared_ptr< Model > > &	models () const
	Query the models managed by this offscreen renderer.

Model *	current_model () const
	Query the active model.

virtual Model *	add_model (const std::string &file_name, bool create_default_drawables=true)
	Add a model from a file to the offscreen renderer. On success, the offscreen renderer will be in charge of the memory management of the model. The loaded model can be accessed by the 'current_model()' method.

Model *	add_model (std::shared_ptr< Model > model, bool create_default_drawables=true)
	Add an existing model to the offscreen renderer. On success, the offscreen renderer will be in charge of its memory management.

Additional Inherited Members
Model *	add_model (std::shared_ptr< Model > model, bool create_default_drawables=true)
	Add an existing model to the viewer to be visualized. On success, the viewer will be in charge of the memory management of the model.

Detailed Description

Offscreen rendering.

To use offscreen rendering, simply create an instance of OffScreen and call the render() method, e.g.,

OffScreen os;
if (!os.add_model("bunny.ply")) {
    LOG(ERROR) << "failed to load model";
    return EXIT_FAILURE;
}
... when necessary, access the camera and modify the view here.
bool success = os.render("image.png");

Constructor & Destructor Documentation

◆ OffScreen()

OffScreen	(	int	width = 800,
		int	height = 600 )

explicit

Constructor.

Parameters

width	The width of the offscreen renderer, which can be changed by calling resize() after construction.
height	The height of the offscreen renderer, which can be changed by calling resize() after construction.

Member Function Documentation

◆ add_drawable()

Drawable * add_drawable ( std::shared_ptr< Drawable > drawable )

Add a drawable to the offscreen renderer. On success, the offscreen renderer will be in charge of its memory management.

The use of drawables for visualization is quite flexible. Drawables are typically created for rendering 3D models (e.g., point clouds, meshes, graphs) and a 3D model is usually loaded from a file or generated by an algorithm. This method allows the user to visualize drawables without defining a 3D model.

Parameters

drawable The pointer to the drawable.

Returns: The pointer of the drawable added to the viewer.

◆ background_color()

const easy3d::vec4 & background_color ( ) const

Query the background color of the offscreen renderer.

Returns: The background color of the offscreen renderer

◆ current_model()

Model * current_model ( ) const

Query the active model.

The offscreen renderer can manage multiple models, and only one model is actively being processed. This method is used to identify this active model.

Returns: The active model.

◆ delete_drawable()

bool delete_drawable ( Drawable * drawable )

Delete the drawable from the offscreen renderer. The related drawables will also be deleted.

Parameters

drawable The pointer to the drawable.

Returns: True if the drawable has been deleted.

◆ delete_model()

bool delete_model ( Model * model )

virtual

Delete a model. The memory of the model will be released and its existing drawables also be deleted.

Parameters

model The pointer to the model.

Returns: True if the model has been deleted.

Reimplemented from Viewer.

◆ drawables()

const std::vector< std::shared_ptr< Drawable > > & drawables ( ) const

Query the drawables managed by this offscreen renderer.

Returns: The drawables managed by this offscreen renderer.

◆ models()

const std::vector< std::shared_ptr< Model > > & models ( ) const

Query the models managed by this offscreen renderer.

Returns: The models managed by this offscreen renderer.

◆ render()

bool render	(	const std::string &	file_name,
		float	scaling = 1.0f,
		int	samples = 4,
		int	back_ground = 1,
		bool	expand = true ) const

Render the current scene into an image file. Supported image format: png, jpg, bmp, and tga.

This function renders the scene into a framebuffer and takes a snapshot of the framebuffer. It allows the snapshot image to have a dimension different from the offscreen renderer, and it has no limit on the image size (if memory allows).

Parameters

file_name	The image file name.
scaling	The scaling factor that determines the size of the image (default to 1.0, same size as the offscreen renderer), i.e., image_width = width() * scaling; image_height = height() * scaling;
samples	The required number of samples for antialiased rendering (which can be different from that of the default framebuffer). The default value is 4.
back_ground	Determines the background color. 0: current color; 1: white; 2: transparent.
expand	Expand the frustum to ensure the image aspect ratio.

Returns: true on success and false otherwise.

◆ resize()

void resize	(	int	w,
		int	h )

Set/Change the size of the offscreen renderer.

Parameters

w/h	The requested width/height (in pixels) of the offscreen renderer.

◆ set_background_color()

void set_background_color ( const easy3d::vec4 & color )

Set the background color of the offscreen renderer.

Parameters

color The background color.

Friends And Related Symbol Documentation

◆ add_model() [1/2]

Model * add_model	(	const std::string &	file_name,
		bool	create_default_drawables = true )

Add a model from a file to the offscreen renderer. On success, the offscreen renderer will be in charge of the memory management of the model. The loaded model can be accessed by the 'current_model()' method.

This method loads a model into the offscreen renderer. It allows the user to control if default drawables will be created. The default drawables are

for point clouds: "vertices".
for surface meshes: "faces", "vertices", "edges", "borders", and "locks".
for graphs: "vertices" and "edges".
polyhedral meshes: "faces:border"， "faces:interior"， "vertices"， and "edges". These drawables are usually sufficient for basic rendering of the model. In case the default drawables don't meet the particular visualization purpose, you can set 'create_default_drawables' to false and create your needed drawables by calling model->renderer()->add_[type]_drawable(). Here the [type] must be one of "points", "lines", and "triangles'.
Parameters

file_name The string of the file name.

create_default_drawables If true, the default drawables will be created.

Returns
The pointer to the model added to the offscreen renderer (nullptr if failed). (Model*, bool).

Reimplemented from Viewer.

◆ add_model() [2/2]

Model * add_model	(	std::shared_ptr< Model >	model,
		bool	create_default_drawables = true )

Add an existing model to the offscreen renderer. On success, the offscreen renderer will be in charge of its memory management.

This method adds a model into the offscreen renderer. It allows the user to control if default drawables will be created. The default drawables are

for point clouds: "vertices".
for surface meshes: "faces", "vertices", "edges", "borders", and "locks".
for graphs: "vertices" and "edges".
polyhedral meshes: "faces:border"， "faces:interior"， "vertices"， and "edges". These drawables are usually sufficient for basic rendering of the model. In case the default drawables don't meet the particular visualization purpose, you can set 'create_default_drawables' to false and create your needed drawables by calling model->renderer()->add_[type]_drawable(). Here the [type] must be one of "points", "lines", and "triangles'.
Parameters

model The pointer to the model.

create_default_drawables If true, the default drawables will be created.

Returns
The pointer to the model added to the offscreen renderer (nullptr if failed). (const std::string&, bool).

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

G:/3_code/Easy3D/easy3d/viewer/offscreen.h
G:/3_code/Easy3D/easy3d/viewer/offscreen.cpp

file_name	The string of the file name.
create_default_drawables	If true, the default drawables will be created.

model	The pointer to the model.
create_default_drawables	If true, the default drawables will be created.

Public Member Functions

Model management

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ OffScreen()

Member Function Documentation

◆ add_drawable()

◆ background_color()

◆ current_model()

◆ delete_drawable()

◆ delete_model()

◆ drawables()

◆ models()

◆ render()

◆ resize()

◆ set_background_color()

Friends And Related Symbol Documentation

◆ add_model() [1/2]

◆ add_model() [2/2]