CAO: Add Colored Text Sprite

[EvidenceBKidscode]

This PR offered by Kidscode allows to create entity sprites with native colored text.

Demo: https://www.youtube.com/watch?v=to2BMSdGwlo

Documentation

Click to expand

Declare a text sprite entity

Sample

initial_properties = {
	visual = "text_sprite",
	visual_size = {x = 1.0, y = 1.0},
	mesh = "{orange}{1.5}K{1}idscode rocks\n{#0FF/#00F}Érîthréà\n{#ABCDEF/#456789}Eûphôriâ\n\nÉqt{0.5}Éqt{1.2}Éqt\n{orange/red}\\\\\\{\\^\\}^0.1;0.2;0.0;0.0;0.0;1.0;0.22",
	colors = { "#F080F0FF", "#F01020FF", "#80808080", "#40404080" },
},

...
	
obj:set_sprite_text(""\\\\\\{\\^\\}\n\n{orange}Kidscode\n{#0FF/#00F}Érîthréà\n{#ABCDEF/#456789}Eûphôriâ");

Parameters

• visual_size: X scale, Y scale
• mesh: text, border size, X padding, Y padding, X offset, Y offset, spacing, base line offset
• colors: text top color, text bottom color, background color, border color

The text separator is the circumflex.

The value separator is the semicolon.

Values

• border size: tells the size of the border (in character height unit)
• X/Y padding: tells how much padding is added between the text and the border (in character size unit)
• X/Y offset: tells how much offset is added to the text position inside the frame (in character size unit)
• spacing: tells how much space is added between contiguous characters (1.0 by default)
• base line offset: tells where the base line is located (from 0.0 to 1.0)

The actual text frame width is computed from the frame height and longest text line width.

The text can contains named or hexadecimal colors between accolades.
Hexadecimal colors start by a hash mark, and can contain 3 or 6 hexadecimal digits.
Both the top and bottom colors can be provided, by separating them with a slash character.

The text can also contain scales between accolades.
The default scale is 1.0.

Special characters can be escaped by preceding them with a backslash character.

[SmallJoker]

So the current trend is to modify & migrate all Irrlicht sources to our code base?
Don't get me wrong - entities with text that do not require a bitmap font (and a mod to "render") is a great idea and looks amazing. How much of the Irrlicht code was changed to achieve this?

[Desour]

Maybe related: #1367

[SmallJoker]

Same here. Struct declaration is OK in the header, but the definition should really be in string.cpp.

[SmallJoker]

What kind of color/size encoding is this? It doesn't look like anything known in Minetest.
There are text colorizing functions for both - foreground and background (latter kinda broken). Also HTML tags are now a thing. Why did you decide on this brackets-value notation?

[celeron55]

http://irc.minetest.net/minetest-dev/2020-03-06#i_5648818