LÖVE

Code: Select all

local function distance(x,y,xx,yy)
    return math.sqrt(((x-xx)^2)+(y-yy)^2)
end

rand  = function(x)
    return math.random(-x, x)
end
ldraw = function(x,y,xx,yy)
    local drawLine = love.graphics.line
    local len =  distance(x,y,xx,yy)
    local nlen = len
    
    local lines = {}
    local nn = 15
    
    local ox, oy = x, y
    
    local min, max = 3,13
    local mx = math.random(min,max)
 
    while nlen>0 do
        local t = len/(math.random(min,max))
        if t > nlen then
            t = nlen
        end
        
        nlen = nlen - t
        
        local done = nlen<=0
        local line = {
            x = ox,
            
            y = oy,
            
            x2 = ox+(done and 0 or rand(nn)),
            y2 = oy+t,0+(done  and 0 or rand(nn))
        }
        ox,oy=line.x2, line.y2
        
        lines[#lines+1] = line
         
    end
     
    
    for xi = 1, #lines do
        local l = lines[xi]
        drawLine(l.x, l.y, l.x2, l.y2)
    end
end

love.draw = function()
    ldraw(100,10,100,300)--startx, starty, endx, endy
    --love.graphics.line(200,10,200,300)
end

Code: Select all

local source ={x=0, y=0}
local target ={x=800, y=600}

local lightning= {
  source=source,
  target=target,
  mainLine={source, target},
}

function addPoint (lightning, index) -- index = math.random(#lightning.mainLine -1)
  local x1=lightning.mainLine[index].x
  local y1=lightning.mainLine[index].y
  local x2=lightning.mainLine[index+1].x
  local y2=lightning.mainLine[index+1].y
  local t = 0.25 + 0.5*math.random()
  local x = x1+ t*(x2 - x1)
  local y = y1+ t*(y2 - y1)
  x = x + 0.25*(y2 - y1)* (math.random()-1)
  y = y + 0.25*(x2 - x1)* (math.random()-1)
  table.insert (lightning.mainLine, index+1, {x=x,y=y})
end

Code: Select all

local function choose(t)
    return t[math.random(#t)]
end

local function point_distance(x,y,xx,yy)
    return math.sqrt(((x-xx)^2)+(y-yy)^2)
end

local function point_direction(x,y,xx,yy)
    return -math.atan2(yy-y, xx-x)
end

random_range  = function(x,y)
    return math.random((y and x or -x), y or x)
end

array_length = function(t)
    return #t
end


function lengthdir_x(spd, ang)
    return spd*math.cos(ang)
end

function lengthdir_y(spd, ang)
    return spd*-math.sin(ang)
end

function draw_set_alpha(a)
    local r,g,b = love.graphics.getColor()
    love.graphics.setColor(r,g,b,a)
end


function set_color(rr,gg,bb,aa)
    
    local r,g,b,a = love.graphics.getColor()
    
    if not rr then
        return r, g, b, a
    end
    
    love.graphics.setColor(rr,gg,bb,aa)
    return r,g,b,a
end

function draw_line_width_colour(x1, y1, x2, y2,size,color1,color2)
    local r,g,b,a = set_color(color1)
    local p = love.graphics.getLineWidth()
    love.graphics.setLineWidth(sizge or p)
    love.graphics.line(x1,y1,x2,y2)
    set_color(r,g,b,a)
    love.graphics.setLineWidth(p)
end

function draw_circle_colour(x,y,r,c1,c2)
    local r,g,b,a = set_color(c1)
    love.graphics.circle("fill",x,y,r)
    set_color(r,g,b,a)
end

local c_white = {1,1,1}
function draw_lightning(x1, y1, x2, y2, branches, size, color)
    --draw_lightning(x, y, x2, y2, branches, size, colour)
    --
    --draws a lightning bolt from the given starting location to the given end location
    --
    --x = x of the bolt's start
    --y = y of the bolt's start
    --x2 = x of the bolt's end
    --y2 = y of the bolt's end
    --branches = true or false, if the lightning bolt branches into multiple smaller ones
    --size = pixel width of the lightning
    --colour = colour of the glow
    --
    --amusudan 23/5/2016
    --
    --feel free to use this in your project!
    --
    local dir = point_direction(x1,y1,x2,y2)
    local length = point_distance(x1,y1,x2,y2) --error(length)
    local colour = color;
    local _size = size;
    --make different segments
    local point = {};
    point[1] = 0;
    local i2 = 2;
    for i = 1, length do
        if (math.random() < .06) then
            point[i2] = i;
            i2 = i2+1;
        end
    end
    point[i2] = length;-- error(point[#point-0])
    local points = array_length(point);
    --draw segments
    local i2 = 2
    local difx = 0;
    local difx2 = 0;
    local dify = 0;
    local ii =0
    local dify2 = 0;    --error(points)
    local dis = 7
    for i2 = 2, points do
        local i2 = i2+ii
        difx = random_range(dis)
        dify = random_range(dis)
        local xx = x1 + lengthdir_x(point[i2 - 1],dir);
        local yy = y1 + lengthdir_y(point[i2 - 1],dir);
        local xx2 = x1 + lengthdir_x(point[i2],dir);
        local yy2 = y1 + lengthdir_y(point[i2],dir); --error(xx2..","..x1..",y2:"..yy2..","..y1..","..dir..","..point[i2])
        --create a branch
        if (math.random() < .15 and branches) then
            local bdir = dir + choose({random_range(-45,-25),random_range(45,25)});
            local blength = random_range(5,30);
            draw_lightning(xx + difx2, yy + dify2, xx + difx2 + lengthdir_x(blength,bdir), yy + dify2 + lengthdir_y(blength,bdir), false, _size, colour)
        end
        --draw the glow of the lightning
        set_color(1,1,1,.1)
        
        draw_line_width_colour(xx + difx2,yy + dify2,xx2 + difx,yy2 + dify, size + 5,colour,colour);
        draw_line_width_colour(xx + difx2,yy + dify2,xx2 + difx,yy2 + dify, size + 3,c_white,c_white);
        draw_line_width_colour(xx + difx2,yy + dify2,xx2 + difx,yy2 + dify, size + 1,c_white,c_white);
        draw_set_alpha(1)
        --draw the white center of the lightning
        draw_line_width_colour(xx + difx2,yy + dify2,xx2 + difx,yy2 + dify, size,c_white,c_white);
        --ii = ii+1;
        difx2 = difx;
        dify2 = dify;
    end
    --draw a glowing circle
    if (branches) then
        draw_set_alpha(.91);
        draw_circle_colour(x1,y1,size + 2.5,colour,colour,false);
        draw_circle_colour(x1,y1,size + 1.5,colour,colour,false);
        draw_circle_colour(x1,y1,size + .5,colour,colour,false);
        draw_set_alpha(1);
        draw_circle_colour(x1,y1,size,c_white,c_white,false);
    end
end

love.draw = function()
    love.graphics.scale(.5)
    --love.graphics.translate(0,500)
    local x = 100
    local y = 100
    local xx = 150
    local yy = 300

    --draw_line_width_colour(x,y,xx,yy,1,{0,1,0})
    draw_lightning(x,y,xx,yy,true,10)
end