LPainter Class Reference

#include <LPainter.h>

Utility for Painting Operations. More...

Detailed Description

Utility for Painting Operations.

The LPainter class offers basic methods for 2D rendering without the need to use OpenGL functions directly. It can draw texture rects or solid colors, clear the screen and set the viewport.
Its goal is to abstract the rendering API, allowing for portable compositors, independent of the renderer used.
Currently, the library only offers the OpenGL ES 2.0 renderer, but in the future others such as Vulkan, Pixman, etc. could be incorporated.
Each LOutput has its own LPainter, which can be accessed from LOutput::painter().

Note

You are not obligated to use LPainter methods for rendering. You have the flexibility to use OpenGL functions and your custom shaders if preferred, or leverage the LScene and LView classes for efficient rendering.

Coordinate System

When specifying the destination rect for your painting operations, you must use surface coordinates. LPainter automatically scales the content for you, taking into account the scale factor of the texture you are drawing and the scale factor of the destination framebuffer.

The coordinate space in which the content is rendered is the same as that used to arrange the outputs. For instance, if you want to paint something in the upper-left corner of an LOutput, you must consider the LOutput's position.

Note

When rendering into an LRenderBuffer, you should also consider its position, similar to how you do with outputs.

Public Member Functions
void	bindFramebuffer (LFramebuffer *framebuffer)
	Bind the specified framebuffer for rendering. More...
LFramebuffer *	boundFramebuffer () const
	Retrieve the currently bound framebuffer. More...
void	drawTexture (const LTexture *texture, const LRect &src, const LRect &dst, Float32 srcScale=1.0f, Float32 alpha=1.0f)
	Draw a texture. More...
void	drawTexture (const LTexture *texture, Int32 srcX, Int32 srcY, Int32 srcW, Int32 srcH, Int32 dstX, Int32 dstY, Int32 dstW, Int32 dstH, Float32 srcScale=1.0f, Float32 alpha=1.0f)
	Draw a texture. More...
void	drawColorTexture (const LTexture *texture, const LRGBF &color, const LRect &src, const LRect &dst, Float32 srcScale=1.0f, Float32 alpha=1.0f)
	Draw a texture with a custom solid color. More...
void	drawColorTexture (const LTexture *texture, Float32 r, Float32 g, Float32 b, Int32 srcX, Int32 srcY, Int32 srcW, Int32 srcH, Int32 dstX, Int32 dstY, Int32 dstW, Int32 dstH, Float32 srcScale=1.0f, Float32 alpha=1.0f)
	Draw a texture with a custom solid color. More...
void	drawColor (const LRect &dst, Float32 r, Float32 g, Float32 b, Float32 a)
	Draw a solid color rect. More...
void	drawColor (Int32 dstX, Int32 dstY, Int32 dstW, Int32 dstH, Float32 r, Float32 g, Float32 b, Float32 a)
	Draw a solid color rect. More...
void	setViewport (const LRect &rect)
	Set the viewport. More...
void	setViewport (Int32 x, Int32 y, Int32 w, Int32 h)
	Sets the viewport. More...
void	setClearColor (Float32 r, Float32 g, Float32 b, Float32 a)
	Set the clear color. More...
void	setColorFactor (Float32 r, Float32 g, Float32 b, Float32 a)
	Set the color factor. More...
void	clearScreen ()
	Clear the framebuffer. More...
void	bindProgram ()
	Bind the internal LPainter program. More...

Member Function Documentation

bindFramebuffer()

void bindFramebuffer

(

LFramebuffer *

framebuffer

)

Bind the specified framebuffer for rendering.

This method binds the provided framebuffer for rendering, allowing subsequent rendering operations to be performed on it.

Note

Output framebuffers are automatically bound prior a LOutput::paintGL() event.

Parameters

framebuffer

The framebuffer to be bound.

boundFramebuffer()

LFramebuffer * boundFramebuffer

(

)

const

Retrieve the currently bound framebuffer.

This method returns a pointer to the currently bound framebuffer for rendering.

Returns

A pointer to the currently bound framebuffer.

drawTexture() [1/2]

void drawTexture	(	const LTexture *	texture,
		const LRect &	src,
		const LRect &	dst,
		Float32	srcScale = 1.0f,
		Float32	alpha = 1.0f
	)

Draw a texture.

This method allows you to draw a texture or sub-rect of a texture on the bound frambuffer.

Note

Using 1 as the srcScale means that the src rect is in buffer coordinates.

Parameters

texture	Texture to draw.
src	The portion of the texture to draw specified in surface coordinates.
dst	The destination rect where the texture will be drawn specified in surface coordinates.
srcScale	Scaling factor for the source texture (default is 1.0).
alpha	Alpha value for blending the texture (range [0.0, 1.0]).

drawTexture() [2/2]

void drawTexture	(	const LTexture *	texture,
		Int32	srcX,
		Int32	srcY,
		Int32	srcW,
		Int32	srcH,
		Int32	dstX,
		Int32	dstY,
		Int32	dstW,
		Int32	dstH,
		Float32	srcScale = 1.0f,
		Float32	alpha = 1.0f
	)

Draw a texture.

This method allows you to draw a texture or sub-rect of a texture on the bound frambuffer.

Note

Using 1 as the srcScale means that the src rect is in buffer coordinates.

Parameters

texture	Texture to draw.
srcX	X-coordinate of the source rect.
srcY	Y-coordinate of the source rect.
srcW	Width of the source rect.
srcH	Height of the source rect.
dstX	X-coordinate of the destination rect.
dstY	Y-coordinate of the destination rect.
dstW	Width of the destination rect.
dstH	Height of the destination rect.
srcScale	Scaling factor for the source texture (default is 1.0).
alpha	Alpha value for blending the texture (range [0.0, 1.0]).

drawColorTexture() [1/2]

void drawColorTexture	(	const LTexture *	texture,
		const LRGBF &	color,
		const LRect &	src,
		const LRect &	dst,
		Float32	srcScale = 1.0f,
		Float32	alpha = 1.0f
	)

Draw a texture with a custom solid color.

This method draws a rect or sub-rect of a texture, replacing its original color while maintaining its alpha channel.

Note

Using 1 as the srcScale means that the src rect is in buffer coordinates.

Parameters

texture	Texture to draw.
color	The solid color that will replace the original texture color.
src	The portion of the texture to draw specified in surface coordinates.
dst	The destination rect where the texture will be drawn specified in surface coordinates.
srcScale	Scaling factor for the source texture (default is 1.0).
alpha	Alpha value for blending the texture (range [0.0, 1.0]).

drawColorTexture() [2/2]

void drawColorTexture	(	const LTexture *	texture,
		Float32	r,
		Float32	g,
		Float32	b,
		Int32	srcX,
		Int32	srcY,
		Int32	srcW,
		Int32	srcH,
		Int32	dstX,
		Int32	dstY,
		Int32	dstW,
		Int32	dstH,
		Float32	srcScale = 1.0f,
		Float32	alpha = 1.0f
	)

Draw a texture with a custom solid color.

This method draws a rect or sub-rect of a texture, replacing its original color while maintaining its alpha channel.

Note

Using 1 as the srcScale means that the src rect is in buffer coordinates.

Parameters

texture	Texture to draw.
r	The red component of the solid color (0.0 to 1.0).
g	The green component of the solid color (0.0 to 1.0).
b	The blue component of the solid color (0.0 to 1.0).
srcX	X-coordinate of the source rect.
srcY	Y-coordinate of the source rect.
srcW	Width of the source rect.
srcH	Height of the source rect.
dstX	X-coordinate of the destination rect.
dstY	Y-coordinate of the destination rect.
dstW	Width of the destination rect.
dstH	Height of the destination rect.
srcScale	Scaling factor for the source texture (default is 1.0).
alpha	Alpha value for blending the texture (range [0.0, 1.0]).

drawColor() [1/2]

void drawColor	(	const LRect &	dst,
		Float32	r,
		Float32	g,
		Float32	b,
		Float32	a
	)

Draw a solid color rect.

This method draws a solid colored rect.

Parameters

dst	The destination rect where the color will be drawn specified in surface coordinates.
r	Red component value (range [0.0, 1.0]).
g	Green component value (range [0.0, 1.0]).
b	Blue component value (range [0.0, 1.0]).
a	Alpha component value (range [0.0, 1.0]).

drawColor() [2/2]

void drawColor	(	Int32	dstX,
		Int32	dstY,
		Int32	dstW,
		Int32	dstH,
		Float32	r,
		Float32	g,
		Float32	b,
		Float32	a
	)

Draw a solid color rect.

This method draws a solid colored rect.

Parameters

dstX	X-coordinate of the destination rect.
dstY	Y-coordinate of the destination rect.
dstW	Width of the destination rect.
dstH	Height of the destination rect.
r	Red component value (range [0.0, 1.0]).
g	Green component value (range [0.0, 1.0]).
b	Blue component value (range [0.0, 1.0]).
a	Alpha component value (range [0.0, 1.0]).

setViewport() [1/2]

void setViewport

(

const LRect &

rect

)

Set the viewport.

Note

This method should be used if you are working with your own shaders/programs.

setViewport() [2/2]

void setViewport	(	Int32	x,
		Int32	y,
		Int32	w,
		Int32	h
	)

Sets the viewport.

Note

This method should be used if you are working with your own shaders/programs.

setClearColor()

void setClearColor	(	Float32	r,
		Float32	g,
		Float32	b,
		Float32	a
	)

Set the clear color.

This method sets the clear color used when calling clearScreen().

Parameters

r	Value of the red component (range [0.0, 1.0]).
g	Value of the green component (range [0.0, 1.0]).
b	Value of the blue component (range [0.0, 1.0]).
a	Value of the alpha component (range [0.0, 1.0]).

setColorFactor()

void setColorFactor	(	Float32	r,
		Float32	g,
		Float32	b,
		Float32	a
	)

Set the color factor.

This method allows you to set a color factor that influences the resulting color of every painting operation. By default, the color factor is (1.0, 1.0, 1.0, 1.0), which has no effect on the colors.

Parameters

r	Value of the red component (range [0.0, 1.0]).
g	Value of the green component (range [0.0, 1.0]).
b	Value of the blue component (range [0.0, 1.0]).
a	Value of the alpha component (range [0.0, 1.0]).

clearScreen()

void clearScreen

(

)

Clear the framebuffer.

This method clears the bound framebuffer using the color set with setClearColor().

bindProgram()

void bindProgram

(

)

Bind the internal LPainter program.

Note

This method should be used if you are working with your own OpenGL programs and want to use the LPainter methods again.