functions.lua

--[[
	Late library for Minetest - Library adding temporary effects.
	(c) Pierre-Yves Rollo

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published
	by the Free Software Foundation, either version 2.1 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
--]]

-- Events
---------

local registered_events = {}

function late.event_register(event, func)
	if type(func) == 'function' then
		registered_events[event] = registered_events[event] or {}
		registered_events[event][#registered_events[event] + 1] = func
	end
end

function late.trigger_event(event, ...)
	if registered_events[event] then
		for _, func in ipairs(registered_events[event]) do
			func(...)
		end
	end
end

-- Colors
---------

local stdcolors = {
	aliceblue              = 0xf0f8ff,
	antiquewhite           = 0xfaebd7,
	aqua                   = 0x00ffff,
	aquamarine             = 0x7fffd4,
	azure                  = 0xf0ffff,
	beige                  = 0xf5f5dc,
	bisque                 = 0xffe4c4,
	black                  = 00000000,
	blanchedalmond         = 0xffebcd,
	blue                   = 0x0000ff,
	blueviolet             = 0x8a2be2,
	brown                  = 0xa52a2a,
	burlywood              = 0xdeb887,
	cadetblue              = 0x5f9ea0,
	chartreuse             = 0x7fff00,
	chocolate              = 0xd2691e,
	coral                  = 0xff7f50,
	cornflowerblue         = 0x6495ed,
	cornsilk               = 0xfff8dc,
	crimson                = 0xdc143c,
	cyan                   = 0x00ffff,
	darkblue               = 0x00008b,
	darkcyan               = 0x008b8b,
	darkgoldenrod          = 0xb8860b,
	darkgray               = 0xa9a9a9,
	darkgreen              = 0x006400,
	darkgrey               = 0xa9a9a9,
	darkkhaki              = 0xbdb76b,
	darkmagenta            = 0x8b008b,
	darkolivegreen         = 0x556b2f,
	darkorange             = 0xff8c00,
	darkorchid             = 0x9932cc,
	darkred                = 0x8b0000,
	darksalmon             = 0xe9967a,
	darkseagreen           = 0x8fbc8f,
	darkslateblue          = 0x483d8b,
	darkslategray          = 0x2f4f4f,
	darkslategrey          = 0x2f4f4f,
	darkturquoise          = 0x00ced1,
	darkviolet             = 0x9400d3,
	deeppink               = 0xff1493,
	deepskyblue            = 0x00bfff,
	dimgray                = 0x696969,
	dimgrey                = 0x696969,
	dodgerblue             = 0x1e90ff,
	firebrick              = 0xb22222,
	floralwhite            = 0xfffaf0,
	forestgreen            = 0x228b22,
	fuchsia                = 0xff00ff,
	gainsboro              = 0xdcdcdc,
	ghostwhite             = 0xf8f8ff,
	gold                   = 0xffd700,
	goldenrod              = 0xdaa520,
	gray                   = 0x808080,
	green                  = 0x008000,
	greenyellow            = 0xadff2f,
	grey                   = 0x808080,
	honeydew               = 0xf0fff0,
	hotpink                = 0xff69b4,
	indianred              = 0xcd5c5c,
	indigo                 = 0x4b0082,
	ivory                  = 0xfffff0,
	khaki                  = 0xf0e68c,
	lavender               = 0xe6e6fa,
	lavenderblush          = 0xfff0f5,
	lawngreen              = 0x7cfc00,
	lemonchiffon           = 0xfffacd,
	lightblue              = 0xadd8e6,
	lightcoral             = 0xf08080,
	lightcyan              = 0xe0ffff,
	lightgoldenrodyellow   = 0xfafad2,
	lightgray              = 0xd3d3d3,
	lightgreen             = 0x90ee90,
	lightgrey              = 0xd3d3d3,
	lightpink              = 0xffb6c1,
	lightsalmon            = 0xffa07a,
	lightseagreen          = 0x20b2aa,
	lightskyblue           = 0x87cefa,
	lightslategray         = 0x778899,
	lightslategrey         = 0x778899,
	lightsteelblue         = 0xb0c4de,
	lightyellow            = 0xffffe0,
	lime                   = 0x00ff00,
	limegreen              = 0x32cd32,
	linen                  = 0xfaf0e6,
	magenta                = 0xff00ff,
	maroon                 = 0x800000,
	mediumaquamarine       = 0x66cdaa,
	mediumblue             = 0x0000cd,
	mediumorchid           = 0xba55d3,
	mediumpurple           = 0x9370db,
	mediumseagreen         = 0x3cb371,
	mediumslateblue        = 0x7b68ee,
	mediumspringgreen      = 0x00fa9a,
	mediumturquoise        = 0x48d1cc,
	mediumvioletred        = 0xc71585,
	midnightblue           = 0x191970,
	mintcream              = 0xf5fffa,
	mistyrose              = 0xffe4e1,
	moccasin               = 0xffe4b5,
	navajowhite            = 0xffdead,
	navy                   = 0x000080,
	oldlace                = 0xfdf5e6,
	olive                  = 0x808000,
	olivedrab              = 0x6b8e23,
	orange                 = 0xffa500,
	orangered              = 0xff4500,
	orchid                 = 0xda70d6,
	palegoldenrod          = 0xeee8aa,
	palegreen              = 0x98fb98,
	paleturquoise          = 0xafeeee,
	palevioletred          = 0xdb7093,
	papayawhip             = 0xffefd5,
	peachpuff              = 0xffdab9,
	peru                   = 0xcd853f,
	pink                   = 0xffc0cb,
	plum                   = 0xdda0dd,
	powderblue             = 0xb0e0e6,
	purple                 = 0x800080,
	red                    = 0xff0000,
	rosybrown              = 0xbc8f8f,
	royalblue              = 0x4169e1,
	saddlebrown            = 0x8b4513,
	salmon                 = 0xfa8072,
	sandybrown             = 0xf4a460,
	seagreen               = 0x2e8b57,
	seashell               = 0xfff5ee,
	sienna                 = 0xa0522d,
	silver                 = 0xc0c0c0,
	skyblue                = 0x87ceeb,
	slateblue              = 0x6a5acd,
	slategray              = 0x708090,
	slategrey              = 0x708090,
	snow                   = 0xfffafa,
	springgreen            = 0x00ff7f,
	steelblue              = 0x4682b4,
	tan                    = 0xd2b48c,
	teal                   = 0x008080,
	thistle                = 0xd8bfd8,
	tomato                 = 0xff6347,
	turquoise              = 0x40e0d0,
	violet                 = 0xee82ee,
	wheat                  = 0xf5deb3,
	white                  = 0xffffff,
	whitesmoke             = 0xf5f5f5,
	yellow                 = 0xffff00,
    yellowgreen            = 0x9acd32,
}

--- color_to_table
-- Converts a colorstring to a {r,g,b,a} table.
-- @param colorspec Can be a standard color name, a 32 bit integer or a table
-- @returns A {r,g,b,a} table
function late.color_to_table(colorspec)
	if type(colorspec) == 'string' then
		if string.sub(colorspec, 1, 1) == "#" then
			if string.len(colorspec) == 4 then
				return {
					r = tonumber("0x"..string.sub(colorspec, 2, 2)),
					g = tonumber("0x"..string.sub(colorspec, 3, 3)),
					b = tonumber("0x"..string.sub(colorspec, 4, 4)),
					a = 0xFF,
				}
			elseif string.len(colorspec) == 5 then
				return {
					r = tonumber("0x"..string.sub(colorspec, 2, 2)),
					g = tonumber("0x"..string.sub(colorspec, 3, 3)),
					b = tonumber("0x"..string.sub(colorspec, 4, 4)),
					a = tonumber("0x"..string.sub(colorspec, 5, 5)),
				}
			elseif string.len(colorspec) == 7 then
				return {
					r = tonumber("0x"..string.sub(colorspec, 2, 3)),
					g = tonumber("0x"..string.sub(colorspec, 4, 5)),
					b = tonumber("0x"..string.sub(colorspec, 6, 7)),
					a = 0xFF,
				}
			elseif string.len(colorspec) == 9 then
				return {
					r = tonumber("0x"..string.sub(colorspec, 2, 3)),
					g = tonumber("0x"..string.sub(colorspec, 4, 5)),
					b = tonumber("0x"..string.sub(colorspec, 6, 7)),
					a = tonumber("0x"..string.sub(colorspec, 8, 9)),
				}
			end
		else
			colorspec = stdcolors[colorspec]
			if colorspec then
				return {
					a = 0xFF,
					r = math.floor(colorspec / 0x10000 % 0x100),
					g = math.floor(colorspec / 0x100 % 0x100),
					b = math.floor(colorspec % 0x100),
				}
			end
			return nil
		end
	end

	if type(colorspec) == 'number' then
		return {
			a = math.floor(colorspec / 0x1000000 % 0x100),
			r = math.floor(colorspec / 0x10000 % 0x100),
			g = math.floor(colorspec / 0x100 % 0x100),
			b = math.floor(colorspec % 0x100),
		}
	end

	if type(colorspec) == 'table' then
		return {
			a = (colorspec.a or 0),
			r = (colorspec.r or 0),
			g = (colorspec.g or 0),
			b = (colorspec.b or 0),
		}
	end
end

--- color_to_rgb_texture
-- Converts a colorspec to a #RRGGBB string ready to use in textures
-- @param colorspec Can be a standard color name, a 32 bit integer or a table
-- @returns A "#RRGGBB" string
function late.color_to_rgb_texture(colorspec)
	local color = late.color_to_table(colorspec)
	return string.format("#%02x%02x%02x", color.r, color.g, color.b)
end

function late.color_to_rgba_texture(colorspec)
	local color = late.color_to_table(colorspec)
	return string.format("#%02x%02x%02x%02x", color.r, color.g, color.b, color.a)
end