Sprite Class Reference

Higher-level representation of an image. More...

#include <jngl/sprite.hpp>

Classes
class	Batch
	While this object is alive, don't do any other draw calls. Should never outlive its Sprite. More...
class	Loader
	Use this class to load a Sprite asynchronously. More...

Public Types
enum class	LoadType : uint8_t { NORMAL , HALF , THREADED }

Public Member Functions
	Sprite (const ImageData &, double scale, std::optional< std::string_view > filename=std::nullopt)
	Creates a Sprite from ImageData and scales it by scale.
	Sprite (const uint8_t *bytes, size_t width, size_t height)
	The sprite data is stored as packed RGBA bytes in an array, where the size of the array needs to be calculated as width * height * 4.
	Sprite (const std::string &filename, LoadType loadType=LoadType::NORMAL)
void	step () override
	Does nothing.
void	draw () const override
	Draws the Sprite, centered by default.
void	draw (Mat3 modelview, const ShaderProgram *=nullptr) const
	Draws the image centered using modelview.
void	draw (Mat3 modelview, Alpha, const ShaderProgram *=nullptr) const
void	draw (Mat3 modelview, Rgba color) const
	Draws the sprite but multiplies each pixel's color with color.
void	draw (const ShaderProgram *shaderProgram) const
	Draws the sprite using the specified shader program.
Batch	batch (const ShaderProgram *shaderProgram=nullptr) const
	Allows to draw the Sprite multiple times at different locations in an efficient way.
void	drawScaled (float xfactor, float yfactor, const ShaderProgram *shaderProgram=nullptr) const
	Draws the image scaled by xfactor and yfactor
void	drawClipped (float xstart, float xend, float ystart, float yend) const
void	drawClipped (Vec2 start, Vec2 end) const
	Draw a cutout of the sprite. drawClipped({0, 0}, {1, 1}) would draw it normally.
void	drawMesh (const std::vector< Vertex > &vertexes, const ShaderProgram *=nullptr) const
	Draws a list of triangles with the sprite's texture on it using the global modelview from jngl::modelview()
void	drawMesh (Mat3 modelview, const std::vector< Vertex > &vertexes, const ShaderProgram *=nullptr) const
	Draws a list of triangles with the sprite's texture on it, ignores the Sprite's position.
void	setBytes (const unsigned char *)
Public Member Functions inherited from Drawable
	Drawable (const Drawable &)=default
Drawable &	operator= (const Drawable &)=default
	Drawable (Drawable &&)=default
Drawable &	operator= (Drawable &&)=default
virtual void	setPos (double x, double y)
	Sets the position of the top-left of the Drawable.
template<class Vect >
void	setPos (Vect p)
	Sets the position of the top-left of the Drawable.
jngl::Vec2	getCenter () const
	Returns the position of the center of the Drawable.
virtual void	setCenter (double x, double y)
	Centers the Sprite at (x, y)
template<class Vect >
void	setCenter (Vect c)
	Centers the Sprite at c (e.g. jngl::Vec2)
double	getLeft () const
	Returns the distance from the left side of the screen.
void	setLeft (double x)
double	getTop () const
	Returns the distance from the top of the screen.
void	setTop (double y)
double	getRight () const
	Returns the distance from the right side of the screen.
void	setRight (double x)
double	getBottom () const
	Returns the distance from the bottom of the screen.
void	setBottom (double y)
double	getX () const
void	setX (double)
double	getY () const
void	setY (double)
Vec2	getSize () const
	Returns {width, height} in screen coordinates.
float	getWidth () const
	Returns the width in screen coordinates.
float	getHeight () const
	Returns the height in screen coordinates.
void	drawBoundingBox () const
	Draws a red box around the Drawable.
bool	contains (jngl::Vec2 point) const
	Returns whether point is inside the bounding box.

Static Public Member Functions
static const Shader &	vertexShader ()
	Returns a reference to JNGL's default vertex shader used to draw textures.

Public Attributes
std::shared_ptr< Finally >	loader
	Function which actually loads the sprite.

Additional Inherited Members
Protected Attributes inherited from Drawable
Vec2	position
float	width = 0
float	height = 0

Detailed Description

Higher-level representation of an image.

Definition at line 25 of file sprite.hpp.

Inheritance diagram for Sprite:

Collaboration diagram for Sprite:

Member Enumeration Documentation

LoadType

enum class LoadType : uint8_t

strong

Definition at line 27 of file sprite.hpp.

Constructor & Destructor Documentation

Sprite() [1/2]

Sprite ( const ImageData & , double scale, std::optional< std::string_view > filename = std::nullopt )

explicit

Creates a Sprite from ImageData and scales it by scale.

When you want to draw an ImageData that hasn't been scaled, make sure to pass JNGL's scale factor so that it appears as the same size independent of the resolution of the user.

Example:

auto img = jngl::ImageData::load("foo.png");
auto sprite1 = std::make_unique<jngl::Sprite>(*img, jngl::getScaleFactor());
 
auto sprite2 = std::make_unique<jngl::Sprite>("foo.png");
 
assert(std::lround(sprite1.getWidth()) == std::lround(sprite2.getWidth()));

You may pass a filename, then JNGL will use that as a key for its internal texture cache, meaning that if there's already a file loaded with that name, it won't upload the passed ImageData to the GPU again.

Sprite() [2/2]

Sprite ( const std::string & filename, LoadType loadType = LoadType::NORMAL )

explicit

Deprecated

Use Loader instead

Member Function Documentation

step()

void step ( )

overridevirtual

Does nothing.

Implements Drawable.

draw() [1/4]

void draw ( ) const

overridevirtual

Draws the Sprite, centered by default.

Implements Drawable.

draw() [2/4]

void draw	(	Mat3	modelview,
		const ShaderProgram *	= nullptr ) const

Draws the image centered using modelview.

Parameters

shaderProgram

Passing nullptr uses the default.

draw() [3/4]

void draw	(	Mat3	modelview,
		Rgba	color ) const

Draws the sprite but multiplies each pixel's color with color.

If the sprite is mostly white, this will make it appear in the specified color. If it's black, nothing will change.

draw() [4/4]

void draw

(

const ShaderProgram *

shaderProgram

)

const

Draws the sprite using the specified shader program.

Parameters

shaderProgram

A pointer to the ShaderProgram object to use for drawing.

batch()

Batch batch

(

const ShaderProgram *

shaderProgram = nullptr

)

const

Allows to draw the Sprite multiple times at different locations in an efficient way.

This is pureley a performance optimisation. If it's fast enough, use Sprite::draw instead.

Example:

void MyWork::draw() const {
    auto batch = mySprite.batch();
    for (jngl::Vec2 position : positions) {
        batch.draw(jngl::modelview().translate(position));
    }
}

Parameters

shaderProgram

Passing nullptr uses the default.

drawScaled()

void drawScaled	(	float	xfactor,
		float	yfactor,
		const ShaderProgram *	shaderProgram = nullptr ) const

Draws the image scaled by xfactor and yfactor

Parameters

xfactor	Scale width by this factor
yfactor	Scale height by this factor
shaderProgram	Passing nullptr uses the default.

drawScaled(1, 1) would draw it normally. You can pass negative values to flip the image. For example drawScaled(-1, 1) would draw the image horizontally flipped.

Deprecated

Scale the modelview matrix instead using jngl::Mat3::scale

drawClipped()

void drawClipped	(	float	xstart,
		float	xend,
		float	ystart,
		float	yend ) const

Deprecated

Use new drawClipped(Vec2, Vec2) method instead

drawMesh()

void drawMesh	(	Mat3	modelview,
		const std::vector< Vertex > &	vertexes,
		const ShaderProgram *	= nullptr ) const

Draws a list of triangles with the sprite's texture on it, ignores the Sprite's position.

Example:

std::vector<jngl::Vertex> vertexes;
// mySprite is a Texture Atlas with two images next to each other.
// First image:
vertexes.emplace_back( 0,  0,   0, 0); // triangle 1
vertexes.emplace_back(10,  0, 0.5, 0);
vertexes.emplace_back(10, 10, 0.5, 1);
vertexes.emplace_back(10, 10, 0.5, 1); // triangle 2
vertexes.emplace_back( 0, 10, 0,   1);
vertexes.emplace_back( 0,  0, 0,   0);
// Second image:
vertexes.emplace_back(30,  0, 0.5, 0); // triangle 1
vertexes.emplace_back(40,  0,   1, 0);
vertexes.emplace_back(40, 10,   1, 1);
vertexes.emplace_back(40, 10,   1, 1); // triangle 2
vertexes.emplace_back(30, 10, 0.5, 1);
vertexes.emplace_back(30,  0, 0.5, 0);
mySprite.drawMesh(vertexes);

Parameters

shaderProgram

Passing nullptr uses the default.

Member Data Documentation

loader

std::shared_ptr<Finally> loader

Function which actually loads the sprite.

Definition at line 233 of file sprite.hpp.

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

• jngl/sprite.hpp