Unigine::LoadingScreen Class

Header:

#include <UnigineLoadingScreen.h>

A singleton that controls the settings of the loading screen. Demonstration of it gives Unigine the time to load all world nodes and resources. You can also show your own loading screen when needed.

A loading screen displays a texture that is usually divided into two parts stacked vertically — the initial and final pictures — which are gradually blended from the beginning up to the end of loading to show the progress. Blending is performed based on the alpha channel of the outro (lower) part of the texture so pseudo-animation can be created using the alpha channel: regions of the lower half with small alpha values will be shown first, regions with larger alpha values will be shown last.

Example

Here's a code example on how to add your own loading screens for application and world loading.

To show your loading screen on system logic initialization before a world is loaded, define it inside the init() method of the System Logic:

Source code (C++)

// AppSystemLogic.cpp

#include "UnigineLoadingScreen.h"
#include "UnigineApp.h"

using namespace Unigine;

/* ... */
int AppSystemLogic::init() {
	// define new transform for loading screen texture
	Math::vec4 transform = Math::vec4(1.0f, 1.0f, 0.0f, 0.0f);

	// enable the loading screen
	LoadingScreen::setEnabled(true);
	
	// set transform to the loading screen texture
	LoadingScreen::setTransform(transform);

	// compute the aspect ratio to show the corresponding texture
	float aspect_ratio = (float)App::getWidth() / (float)App::getHeight();

	// if the aspect ratio is 4:3 show the following loading screen
	// during world loading
	if (aspect_ratio < 1.5f) {
		LoadingScreen::setTexturePath("textures/splash_4x3.png");
	}
	else {
		// if the aspect ratio is 16:9 show this loading screen
		// during world loading
		LoadingScreen::setTexturePath("textures/splash_16x9.png");
	}
	// set the text to be displayed on the loading screen
	// with a certain displacement along the X and Y axes
	LoadingScreen::setText("<xy x=\"%50\" dx=\"0\" y=\"%50\" dy=\"0\"/>LOADING_PROGRESS");
	
	// set duration (in milliseconds) and display the loading screen on world loading
	float duration = 5000.0f;
	float begin = clock();

	while (clock() - begin < duration)
		LoadingScreen::render((clock() - begin) / duration * 100.0f);
	
	// disable the loading screen
	LoadingScreen::setEnabled(false);
	
	return 1;
}

/* ... */

A loading screen defined in the init() method of the World Logic will be shown right after a world is loaded:

Source code (C++)

// AppWorldLogic.cpp
#include "UnigineLoadingScreen.h"

using namespace Unigine;

/* ... */
int AppWorldLogic::init() {
	// define new transform for loading screen
	Math::vec4 transform = Math::vec4(1.0f, 1.0f, 0.0f, 0.0f);

	// enable the loading screen
	LoadingScreen::setEnabled(true);
	
	// set the text to be displayed on the loading screen,
	// specifying a color, a font, and a certain displacement along the X and Y axes
	LoadingScreen::setText("<p align=\"center\"><font size=\"20\" color=\"#FF0000FF\">CUSTOM LOADING TEXT</font></p>");
	
	// set duration (in milliseconds) and display the loading screen on world loading
	float duration = 5000.0f;
	float begin = clock();

	while (clock() - begin < duration)
		LoadingScreen::render((clock() - begin) / duration * 100.0f);

	// disable the loading screen
	LoadingScreen::setEnabled(false);
	
	return 1;
}

/* ... */

Methods:

Name	Description View: Sort by:
setEnabled	Specifies if manual rendering of the loading screen can be started or should be stopped.
isEnabled	Returns a value indicating if manual rendering of a loading screen is allowed.
setThreshold	Sets the amount of blur in the alpha channel when interpolating between states of the loading screen.
getThreshold	Returns the amount of blur in the alpha channel when interpolating between states of the loading screen.
setTexturePath	Sets the path to a texture for custom loading screens.
getTexturePath	Returns the path to the texture for loading screens.
setTransform	Sets transformation of the loading screen texture.
getTransform	Returns transformation of the loading screen texture.
setBackgroundColor	Sets the background color of the loading screen.
getBackgroundColor	Returns the background color of loading screens.
setText	Sets the text of the loading screen.
getText	Returns the text of the loading screen.
setFontPath	Sets the path to the font used to render the text.
getFontPath	Returns the path to the font used to render the text.
getProgress	Returns the current progress state.
getMessage	Returns the text message representing the current loading stage.
setMessageLoadingWorld	Sets a message to be displayed on world loading.
getMessageLoadingWorld	Returns the current message displayed on world loading.
setMessageShadersCompilation	Sets a message to be displayed on shaders compilation.
getMessageShadersCompilation	Returns the current message displayed on shaders compilation.
setImage	Sets an image for a custom loading screen.
renderInterface	Renders a static loading screen.
render	Renders the loading screen in the current progress state and with the current stage message.
renderForce	Renders the loading screen regardless of whether the manual rendering is allowed or not.
addRenderBeginCallback	Adds a callback function that will be executed when rendering of the loading screen begins.
removeRenderBeginCallback	Removes the specified callback from the list of render begin callbacks.
clearRenderBeginCallbacks	Clears all added render begin callbacks.
addRenderEndCallback	Adds a callback function that will be executed when rendering of the loading screen ends.
removeRenderEndCallback	Removes the specified callback from the list of render end callbacks.
clearRenderEndCallbacks	Clears all added render end callbacks.

LoadingScreen Class

Members

void setEnabled ( bool enabled ) #

Specifies if manual rendering of the loading screen can be started or should be stopped.

Notice

setEnabled() is used only together with the corresponding render functions (render()). It cannot be used to enable or disable rendering of the loading screen during the initialization stage of the engine.

Arguments

bool enabled - true to enable manual rendering of a custom loading screen; false to disable.

bool isEnabled ( ) const#

Returns a value indicating if manual rendering of a loading screen is allowed.

Return value

true if the rendering of the loading screen is enabled; otherwise, false.

void setThreshold ( int threshold ) #

Sets the amount of blur in the alpha channel when interpolating between states of the loading screen.

Notice

By default, the Threshold value is set to 16.

Arguments

int threshold - amount of blur in the [0, 255] range.

int getThreshold ( ) const#

Returns the amount of blur in the alpha channel when interpolating between states of the loading screen.

Return value

amount of blur.

void setTexturePath ( const char * path ) #

Sets the path to a texture for custom loading screens.

Arguments

const char * path - Path to a file with the custom loading screen texture. If NULL (0) is passed, no texture will be used.

const char * getTexturePath ( ) const#

Returns the path to the texture for loading screens.

Return value

Path to the texture of the loading screens.

void setImage ( const Ptr<Image> & image ) #

Sets an image for a custom loading screen.

Arguments

const Ptr<Image> & image - Image smart pointer to an image to be used as a custom loading screen.

void setTransform ( const Math::vec4 & transform ) #

Sets transformation of the loading screen texture.

Arguments

const Math::vec4 & transform - Transformation of the loading screen texture:
1. Texture size multiplier.
2. Window size multiplier.
3. Horizontal position in the [0.0f, 1.0f] range.
4. Vertical position in the [0.0f, 1.0f] range.

Math::vec4 getTransform ( ) const#

Returns transformation of the loading screen texture.

Return value

transformation of the texture.

void setBackgroundColor ( const Math::vec4 & color ) #

Sets the background color of the loading screen.

Arguments

const Math::vec4 & color - Background color.

Math::vec4 getBackgroundColor ( ) const#

Returns the background color of loading screens.

Return value

Background color.

void setText ( const char * text ) #

Sets the text of the loading screen.

Arguments

const char * text - Text of the loading screen. Can be either a plain or rich text. A number of aliases is available:
- UNIGINE_COPYRIGHT — the UNIGINE copyright text.
- UNIGINE_VERSION — the current UNIGINE version.
- LOADING_PROGRESS — the loading progress going from 0 to 100.
- LOADING_WORLD — the world being loaded (if any).

const char * getText ( ) const#

Returns the text of the loading screen.

Return value

Text of the loading screen.

void setFontPath ( const char * path ) #

Sets the path to the font used to render the text.

Arguments

const char * path - Path to the font (True Type Font).

const char * getFontPath ( ) const#

Returns the path to the font used to render the text.

Return value

Path to the font.

void renderInterface ( ) #

Renders a static loading screen. Such a screen does not display any progress.

void render ( ) #

Renders the loading screen in the current progress state and with the current stage message.

void render ( int progress ) #

Renders a custom loading screen in a given progress state. Use this function in a loop to create a gradual change between the initial (upper opaque part) and the final states (bottom transparent part) of the loading screen texture.

Arguments

int progress - Progress of alpha blending between 2 screens stored in the texture. The value in range [0;100] sets an alpha channel threshold, according to which pixels from the initial (opaque) or final (transparent) screen in the texture are rendered. By the value of 0, the initial screen is loaded. By the value of 100, the final screen is loaded.

void render ( int progress, const char * message ) #

Renders a custom loading screen in a given progress state and prints a given message. Use this function in a loop to create a gradual change between the initial (upper opaque part) and the final states (bottom transparent part) of the loading screen texture, while printing a custom loading stage.

Arguments

int progress - Progress of alpha blending between 2 loading screens stored in the texture. The value in range [0;100] sets an alpha channel threshold, according to which pixels from the initial (opaque) or final (transparent) loading screen in the texture are rendered. By the value of 0, the initial screen is loaded. By the value of 100, the final screen is loaded.
const char * message - message to print representing the loading stage.

void renderForce ( ) #

Renders the loading screen regardless of whether the manual rendering is allowed or not.

void renderForce ( const char * message ) #

Renders the loading screen regardless of whether the manual rendering is allowed or not and prints a given message.

Arguments

const char * message - message to print that represents the loading stage.

int getProgress ( ) const#

Returns the current progress state.

Return value

Progress state in the [0, 100] range.

const char * getMessage ( ) const#

Returns the text message representing the current loading stage.

Return value

Loading message.

void * addRenderBeginCallback ( Unigine::CallbackBase * func ) #

Adds a callback function that will be executed when rendering of the loading screen begins. The function is useful when you implement a custom loading screen rendering function, for example. The callback function must not take arguments.

Source code (C++)

// the callback function
void AppWorldLogic::render_begin_callback()
{
	/* .. */
}

int AppWorldLogic::init()
{
	// set the callback
	void * id = LoadingScreen::addRenderBeginCallback(MakeCallback(this,&AppWorldLogic::render_begin_callback));
	
	return 1;
}

Arguments

Unigine::CallbackBase * func - The pointer to the callback with no arguments.

Return value

ID of the last added callback of the specified type, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.

bool removeRenderBeginCallback ( void * id ) #

Removes the specified callback from the list of render begin callbacks.

Arguments

void * id - Callback ID obtained when adding it.

Return value

True if the callback with the given ID was removed successfully; otherwise false.

void clearRenderBeginCallbacks ( ) #

Clears all added render begin callbacks.

void * addRenderEndCallback ( Unigine::CallbackBase * func ) #

Adds a callback function that will be executed when rendering of the loading screen ends. The function is useful when you implement a custom loading screen rendering function, for example. The callback function must not take arguments.

Source code (C++)

// the callback function
void AppWorldLogic::render_end_callback()
{
	/* .. */
}

int AppWorldLogic::init()
{
	// set the callback
	void * id = LoadingScreen::addRenderEndCallback(MakeCallback(this,&AppWorldLogic::render_end_callback));
	
	return 1;
}

Arguments

Unigine::CallbackBase * func - The pointer to the callback with no arguments.

Return value

ID of the last added callback of the specified type, if the callback was added successfully; otherwise, nullptr. This ID can be used to remove this callback when necessary.

bool removeRenderEndCallback ( void * id ) #

Removes the specified callback from the list of render end callbacks.

Arguments

void * id - Callback ID obtained when adding it.

Return value

True if the callback with the given ID was removed successfully; otherwise false.

void clearRenderEndCallbacks ( ) #

Clears all added render end callbacks.

void setMessageLoadingWorld ( const char * world ) #

Sets a message to be displayed on world loading.

Arguments

const char * world - Message on world loading. The text aliases are also supported.

const char * getMessageLoadingWorld ( ) const#

Returns the current message displayed on world loading.

Return value

Message on world loading.

void setMessageShadersCompilation ( const char * compilation ) #

Sets a message to be displayed on shaders compilation.

Arguments

const char * compilation - Message on shaders compilation. The text aliases are also supported.

const char * getMessageShadersCompilation ( ) const#

Returns the current message displayed on shaders compilation.

Return value

Message on shaders compilation.

Last update: 2021-12-13

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Unigine::LoadingScreen Class

See Also#

Example

Methods:

LoadingScreen Class

Members

void setEnabled ( bool enabled ) #

Arguments

bool isEnabled ( ) const#

Return value

void setThreshold ( int threshold ) #

Arguments

int getThreshold ( ) const#

Return value

void setTexturePath ( const char * path ) #

Arguments

const char * getTexturePath ( ) const#

Return value

void setImage ( const Ptr<Image> & image ) #

Arguments

void setTransform ( const Math::vec4 & transform ) #

Arguments

Math::vec4 getTransform ( ) const#

Return value

void setBackgroundColor ( const Math::vec4 & color ) #

Arguments

Math::vec4 getBackgroundColor ( ) const#

Return value

void setText ( const char * text ) #

Arguments

const char * getText ( ) const#

Return value

void setFontPath ( const char * path ) #

Arguments

const char * getFontPath ( ) const#

Return value

void renderInterface ( ) #

void render ( ) #

void render ( int progress ) #

Arguments

void render ( int progress, const char * message ) #

Arguments

void renderForce ( ) #

void renderForce ( const char * message ) #

Arguments

int getProgress ( ) const#

Return value

const char * getMessage ( ) const#

Return value

void * addRenderBeginCallback ( Unigine::CallbackBase * func ) #

Arguments

Return value

bool removeRenderBeginCallback ( void * id ) #

Arguments

Return value

void clearRenderBeginCallbacks ( ) #

void * addRenderEndCallback ( Unigine::CallbackBase * func ) #

Arguments

Return value

bool removeRenderEndCallback ( void * id ) #

Arguments

Return value

void clearRenderEndCallbacks ( ) #

void setMessageLoadingWorld ( const char * world ) #

Arguments

const char * getMessageLoadingWorld ( ) const#

Return value

void setMessageShadersCompilation ( const char * compilation ) #

Arguments

const char * getMessageShadersCompilation ( ) const#

Return value