Nedim [Lexaloffle Blog Feed]

3D Raycaster help

Mon, 06 May 2024 08:53:15 UTC

I want to make my own raycaster game in picotron and I have been following this blog written for a pico-8 raycaster. I get an error when I run this and I am not sure what I should do to fix this issue. Help would be much appreciated.

Other than the code, all I did is make a sprite in slot 1 and draw a simple map in the map editor.

function _init()
    cam={
        x=12,
        y=12,
        a=0,
        w2d=2
    }
    scrx=0
end

function _update()
    controls()
end

function _draw()
    cls()
    map(0,0,0,0,16,16)
    circ(cam.x,cam.y,2,12)
    --for scrx=0,480 do
    --  raycast(cam,scrx)
    --end
    raycast(cam,240)
end

function controls()
    if btn(0) then
        cam.a+=0.01
    end
    if btn(1) then
        cam.a-=0.01
    end
    if btn(2) then
        cam.x+=cos(cam.a)*0.5
        cam.y+=sin(cam.a)*0.5
    end
    if btn(3) then
        cam.x+=cos(cam.a)*-0.25
        cam.y*=sin(cam.a)*-0.25
    end
end

function raycast(cam,scrx)
    local rayvx,rayvy=
        cam.vx-cam.vy*cam.w2d*(scrx-64)/128,
        cam.vy+cam.vx*cam.w2d*(scrx-64)/128

    -- distance traveled
    local dist=0
    -- current coordinates
    local x,y=cam.x,cam.y
    -- map cel coordinate and value
    local celx,cely=x8,y8
    local cel=mget(celx,cely)
    -- direction of ray
    local dirx,diry=
        sgn(rayvx),sgn(rayvy)

    -- distances across map cel
    local dist4x,dist4y=
        abs(8/rayvx),
        abs(8/rayvy)

    -- distances to next map cel
    local dx,dy=
        abs(4+4*dirx-x%8),
        abs(4+4*diry-y%8)
    local dist2x,dist2y=
        abs(dx/rayvx),
        abs(dy/rayvy)

    -- which direction / angle
    -- the wall was hit from
    local hita=0

    -- perform dda
    repeat

        if dist2x=64
end

Trouble reading mget()

Tue, 02 Apr 2024 15:53:02 UTC

I am trying to make a top down RPG in Picotron and I want to use a combination of mget() and fget() to make collision. I understand that fget is a bit weird in Picotron but mget is also acting strange as it only reads the sprite numbers of 4 sprites in a 2x2 formation on the 0,0 corner of my map.

Is anyone else experiencing this or could this just be me being silly?

Mouse map tile checker

Tue, 02 Apr 2024 15:44:44 UTC

I wrote a function that shows the mouse coordinates and sprite number of the map tile you are hovering over. I originally wrote this for myself to make checking the tiles on my map easier but figured I could share it in case anyone else finds it useful.

function debug_mouse()
    local mx,my = mouse()
    local x_offset=5
    local y_offset=5

    --window width and height
    local w=480
    local h=270

    --offset if box leaves screen
    if mx>w-20 then x_offset=-15 end
    if my>h-29 then y_offset=-24 end

    --draw debug text box
    rectfill(mx+x_offset-1,my+y_offset-1,mx+x_offset+14,my+y_offset+23,1)
    print(mx,mx+x_offset,my+y_offset,8)
    print(my,mx+x_offset,my+y_offset+8,9)
    print(mget(mx,my),mx+x_offset,my+y_offset+8*2,10)
end