------------------------------------------------------------------------
--
-- THE GCREW TEAM PRESENTS...
--
--      pero mecawen... que es esto???
--
--
------------------------------------------------------------------------

-- SEGUN LUAPLAYER, las funciones
drect = image:fillRect
dfrect = image:fillRect; -- no se k version de luadev tienes , asi k por si las moscas...
dline = image:fillRect;
System.setHigh() ; -- esto requiere power... xD

-- CAMBIAR RESOLUCION? PARECE DE VERDAD XD
thewid = 8;
themode = 1;
theconfig = { {60, 8, "High-speed FULL"}, {120, 4, "Medium FULL"}, {240, 2, "LOW FULL"}, {480,1, "XTREME GRAPHICS"}, {240,1, "Half extreme"}, {120,2, "half doubled"} }


--
-- PREPARAR NUESTRO BONITO ENTORNO 3D...
--

-- MAPA DEL MUND0:
-- 0 <- implica NO HAY NADA.
-- X <- cuaquier numero indica textura numero (X-1).
WORLD_MAP = {
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
    { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
};

-- Definimos nuestro entorno de "raytracing", para ello...
-- Definimos el rayo en "ray".
-- Inicializaremos las texturas, y definiremos su tamaño cuadrado en "tex".
-- También hemos de definir la posicion del jugador en "pos".
-- Y la rotación de jugador en "rot".
CAM = {
    ray = { height=32, a=math.rad(60), w=60, h=272, distance=277 },
    tex = {
        --img = image.loadsprite("textures.png",64,64),
        size = 64
        },
    pos = { x=6.5,y=5.5 },
    rot = 0,
}

--
--CAM.ray.distance = ((CAM.ray.w / 2) / math.tan(CAM.ray.a / 2));

function raytrace()
    -- cast all rays here
    local sina = math.sin(CAM.rot);
    local cosa = math.cos(CAM.rot);
    local u = cosa - sina;
    local v = sina + cosa;
    local du = 2 * sina / CAM.ray.w;
    local dv = -2 * cosa / CAM.ray.w;

    -- nuestra ventana es de CAM.ray.w pixels de ancho, por lo que, por cada "columna.."
    for col=0,CAM.ray.w,1 do
        -- palante como los de alicante
        local uu = (u < 0) and -u or u;
        local vv = (v < 0) and -v or v;
        local duu = 1 / uu;
        local dvv = 1 / vv;
        local stepx = math.floor((u < 0) and -1 or 1);
        local stepy = math.floor((v < 0) and -1 or 1);

        -- donde toy?
        local px = CAM.pos.x;
        local py = CAM.pos.y;
        local mapx = math.floor(px);
        local mapy = math.floor(py);

        -- varis varis
        local texture = 0;
        local hitdist = 0.1;
        local texofs = 0;
        local dark = false

        -- lineas de direccion...
        local distx = (u > 0) and (mapx + 1 - px) * duu or (px - mapx) * duu;
        local disty = (v > 0) and (mapy + 1 - py) * dvv or (py - mapy) * dvv;

        -- hasta que me ahostie
        while (texture <= 0) do
            if (distx > disty) then
                -- mas cerca en y
                hitdist = disty;
                disty = disty + dvv;
                mapy = mapy + stepy;
                if ( mapy >= #WORLD_MAP ) then mapy = #WORLD_MAP; end
                if ( mapy < 1 ) then mapy = 1; end
                if (mapy <= 1) or (mapy >= (#WORLD_MAP -1)) then texture = 1; else texture = WORLD_MAP[mapy][mapx]; end
                if (texture > 0) then
                    dark = true;
                    if (stepy > 0) then
                        local ofs = px + u * (mapy - py) / v;
                        texofs = ofs - math.floor(ofs);
                    else
                        local ofs = px + u * (mapy + 1 - py) / v;
                        texofs = ofs - math.floor(ofs);
                    end
                end
            else
                -- mas cerca en x
                hitdist = distx;
                distx = distx + duu;
                mapx = mapx + stepx;
                if ( mapx > #WORLD_MAP[1] ) then mapx = #WORLD_MAP[1]; end
                if ( mapx < 1 ) then mapx = 1; end
                if (mapx <= 1 or mapx >= #WORLD_MAP[1]) then texture = 1; else texture = WORLD_MAP[mapy][mapx]; end
                if (texture > 0) then
                    if (stepx > 0) then
                        local ofs = py + v * (mapx - px) / u;
                        texofs = ofs - math.floor(ofs);
                    else
                        local ofs = py + v * (mapx + 1 - px) / u;
                        texofs = math.ceil(ofs) - ofs;
                    end
                end
            end
        end

        -- Textura y distancia resuelta...

        local ph = (CAM.tex.size / hitdist) * CAM.ray.distance;
        ph = math.abs( (3-hitdist) * CAM.ray.h / 3 );
        --CAM.tex.img:setframe(texture-1);
        --CAM.tex.img:resize(ph,ph);

        -- El rectangulo en la pantalla es...
        local pr = { x=col, y=(136-(ph/2)), h=ph, w=1 }
        local hd = math.max(math.min(hitdist,2.55),0);
        local hdd = 2.55 - hd;
        local c = Color.new((hdd*100),(hdd*100),(hdd*100),255);
        dfrect(col*thewid,(136-(ph/2)),thewid,ph,c);

        u = u + du;
        v = v + dv;
        --CAM.tex.img:blit(pr.x,pr.y,1,0,1,ph);
    end
end

function mapdraw()
    for i=1,#WORLD_MAP do
        for x=1,#WORLD_MAP[i] do
            if WORLD_MAP[i][x] == 1 then drect(240+(i*10),x*10,10,10,0xFFFFFFFF); end
            if WORLD_MAP[i][x] == 0 then drect(240+(i*10),x*10,10,10,0x00FF00FF); end
            if ((CAM.pos.x > x and CAM.pos.x < x+1) and (CAM.pos.y > i and CAM.pos.y < i+1)) then
                if CAM.rot <= 0.6 or CAM.rot >= 5.9 then dfrect(240+((i+0)*10)+3,((x+1)*10)+3,3,3,Color.new(255,0,0));
                elseif CAM.rot > 0.6 and CAM.rot <= 2.3 then dfrect(240+((i+1)*10)+3,((x+0)*10)+3,3,3,Color.new(255,0,0));
                elseif CAM.rot > 2.3 and CAM.rot < 3.8 then dfrect(240+((i-0)*10)+3,((x-1)*10)+3,3,3,Color.new(255,0,0));
                else dfrect(240+((i-1)*10)+3,((x)*10)+3,3,3,Color.new(255,0,0)); end
                dfrect(240+(i*10),x*10,10,10,Color.new(255,0,0));
            end
        end
    end
end

mapnabled = true;
oldpad=Controls.read(9
while true do
    pad = Controls.read();
    raytrace();
    if mapnabled then mapdraw(); end
    screen:print(10,10,"Lua RayCaster 0.01 @ "..screen.fps().."fps");
    screen:print(10,30,"Resolution: "..theconfig[themode][3]);
    screen.waitVblankStart()
    screen.flip();
    if pad:select() and oldpad:select() ~= pad:select() then mapnabled = not mapnabled; end
    if pad:r() then CAM.rot = math.deg(CAM.rot) + 5; if CAM.rot > 360 then CAM.rot = CAM.rot - 360; end CAM.rot = math.rad(CAM.rot); end
    if pad:l() then CAM.rot = math.deg(CAM.rot) - 5; if CAM.rot < 0 then CAM.rot = CAM.rot + 360; end CAM.rot = math.rad(CAM.rot); end
    if pad:start() and oldpad:start() ~= pad:start() then
        themode = themode + 1; if themode > #theconfig then themode = 1; end
        CAM.ray.w = theconfig[themode][1];
        thewid = theconfig[themode][2];
    end
    if pad:up() then CAM.pos.x = CAM.pos.x - 0.1; end
    if pad:down() then CAM.pos.x = CAM.pos.x + 0.1; end
    if pad:right() then CAM.pos.y = CAM.pos.y + 0.1; end
     oldpad = pad
end