gl::GLText Class Reference

Render SDL_ttf text into an OpenGL texture and display it on screen. More...

#include <gl.hpp>

Collaboration diagram for gl::GLText:

Public Member Functions
	GLText ()
	Default constructor.
void	init (int w, int h)
	Initialise internal state with the viewport dimensions.
GLuint	createText (const std::string &text, TTF_Font *font, SDL_Color color, int &textWidth, int &textHeight, bool solid=true)
	Rasterise a string to an OpenGL texture.
void	renderText (GLuint texture, float x, float y, int textWidth, int textHeight, int screenWidth, int screenHeight)
	Draw a pre-created text texture at a given position.
void	printText_Solid (const mx::Font &f, float x, float y, const std::string &text)
	Convenience: create and immediately draw solid text.
void	printText_Blended (const mx::Font &f, float x, float y, const std::string &text)
	Convenience: create and immediately draw blended (anti-aliased) text.
void	setColor (SDL_Color col)
	Set the colour used for subsequent printText calls.

Private Attributes
ShaderProgram	textShader
	Internal text quad shader.
SDL_Color	color = {255,255,255,255}
	Current text colour.
int	w = 0
int	h = 0
	Viewport dimensions.

Detailed Description

Render SDL_ttf text into an OpenGL texture and display it on screen.

Manages a simple text shader and provides helpers that rasterise a string to an SDL_Surface, upload it as an OpenGL texture, and draw a screen-space quad at the specified position.

Definition at line 181 of file gl.hpp.

Constructor & Destructor Documentation

GLText()

gl::GLText::GLText

(

)

Default constructor.

Definition at line 881 of file gl.cpp.

Member Function Documentation

createText()

GLuint gl::GLText::createText	(	const std::string &	text,
		TTF_Font *	font,
		SDL_Color	color,
		int &	textWidth,
		int &	textHeight,
		bool	solid = true )

Rasterise a string to an OpenGL texture.

Parameters

text	String to render.
font	SDL_ttf font handle.
color	Text colour.
textWidth	Output: texture pixel width.
textHeight	Output: texture pixel height.
solid	If true, use solid (fast) rendering; otherwise blended.

Returns

GL texture ID.

Definition at line 898 of file gl.cpp.

References color, mx::Texture::flipSurface(), and mx::system_err.

Referenced by printText_Blended(), and printText_Solid().

init()

void gl::GLText::init	(	int	w,
		int	h )

Initialise internal state with the viewport dimensions.

Parameters

w	Viewport width in pixels.
h	Viewport height in pixels.

Definition at line 885 of file gl.cpp.

References gl::ftSource, h, textShader, gl::vSource, and w.

printText_Blended()

void gl::GLText::printText_Blended	(	const mx::Font &	f,
		float	x,
		float	y,
		const std::string &	text )

Convenience: create and immediately draw blended (anti-aliased) text.

Parameters

f	mx::Font reference.
x	X position.
y	Y position.
text	String to render.

Definition at line 984 of file gl.cpp.

References color, createText(), h, renderText(), textShader, w, and mx::Font::wrapper().

printText_Solid()

void gl::GLText::printText_Solid	(	const mx::Font &	f,
		float	x,
		float	y,
		const std::string &	text )

Convenience: create and immediately draw solid text.

Parameters

f	mx::Font reference.
x	X position.
y	Y position.
text	String to render.

Definition at line 970 of file gl.cpp.

References color, createText(), h, renderText(), textShader, w, and mx::Font::wrapper().

renderText()

void gl::GLText::renderText	(	GLuint	texture,
		float	x,
		float	y,
		int	textWidth,
		int	textHeight,
		int	screenWidth,
		int	screenHeight )

Draw a pre-created text texture at a given position.

Parameters

texture	GL texture ID from createText().
x	Destination X (pixels).
y	Destination Y (pixels).
textWidth	Texture pixel width.
textHeight	Texture pixel height.
screenWidth	Current viewport width.
screenHeight	Current viewport height.

Definition at line 939 of file gl.cpp.

References h, textShader, and w.

Referenced by printText_Blended(), and printText_Solid().

setColor()

void gl::GLText::setColor

(

SDL_Color

col

)

Set the colour used for subsequent printText calls.

Parameters

col	SDL_Color.

Definition at line 894 of file gl.cpp.

References color.

Member Data Documentation

color

SDL_Color gl::GLText::color = {255,255,255,255}

private

Current text colour.

Definition at line 242 of file gl.hpp.

Referenced by createText(), printText_Blended(), printText_Solid(), and setColor().

h

int gl::GLText::h = 0

private

Viewport dimensions.

Definition at line 243 of file gl.hpp.

Referenced by init(), printText_Blended(), printText_Solid(), and renderText().

textShader

ShaderProgram gl::GLText::textShader

private

Internal text quad shader.

Definition at line 241 of file gl.hpp.

Referenced by init(), printText_Blended(), printText_Solid(), and renderText().

w

int gl::GLText::w = 0

private

Definition at line 243 of file gl.hpp.

Referenced by init(), printText_Blended(), printText_Solid(), and renderText().

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

• gl.hpp
• gl.cpp