3D box 2

gistfile1.txt

--# Main
displayMode(FULLSCREEN)
function setup()
    size,radius=200,10
    pos=vec3(0,0,0) --assumes centre of box is (0,0,0)
    CreateScene()
    notStarted=true
end

function touched(t)
    if t.state==ENDED then
        local v=vec3(math.random()*6-3,math.random()*6-3,math.random()*6-3):normalize()*5
        velocity=velocity+v
        notStarted=false
    end
end

function CreateScene() --size is size of 3D box
    local img=readImage("SpaceCute:Background")--:copy(4,4,62,62)
    box=CreateBlock(size,size,size,color(255),vec3(0,0,0),img) 
    ball=CreateSphere(radius,readImage("Cargo Bot:Starry Background"),color(255))
    velocity=vec3(0,0,0)
end

function AdjustPos()
    local p=pos+velocity
    --check for collisions with each axis wall
    local f=0
    --x
    if p.x-radius<-size/2 then --collided with left wall
        f=(-size/2-p.x+radius)/velocity.x --backtrack by this fraction of the last movement
        velocity.x=-velocity.x --reverse x velocity
    elseif p.x+radius>size/2 then --right wall
        f=(p.x+radius-size/2)/velocity.x
        velocity.x=-velocity.x
    end
    --y
    if p.y-radius<-size/2 then
        f=(-size/2-p.y+radius)/velocity.y
        velocity.y=-velocity.y
    elseif p.y+radius>size/2 then
        f=(p.y+radius-size/2)/velocity.y
        velocity.y=-velocity.y
    end
    --z
    if p.z-radius<-size/2 then
        f=(-size/2-p.z+radius)/velocity.z
        velocity.z=-velocity.z
    elseif p.z+radius>size/2 then
        f=(p.z+radius-size/2)/velocity.z
        velocity.z=-velocity.z
    end
    pos=pos+velocity*(1-f)
end

function draw()
    background(220)
    perspective(90)
    AdjustPos() print(pos)
    camera(0,0,0,pos.x,pos.y,pos.z)
    box:draw()
    pushMatrix()
    translate(pos:unpack())
    ball:draw()
    popMatrix()
    if notStarted then
        ortho()
        viewMatrix(matrix())
        text(
        [[You are at the centre of a box with a red ball.
You can't see anything because the ball is around you
Touch the screen to push the ball in a random direction
and the camera will follow its movement.
Touch the screen to push it again.]],WIDTH/2,HEIGHT/2)
    end
end

--# Utility

function CreateBlock(w,h,d,col,pos,tex) --width,height,depth,colour,position,texture
    local x,X,y,Y,z,Z=pos.x-w/2,pos.x+w/2,pos.y-h/2,pos.y+h/2,pos.z-d/2,pos.z+d/2
    local v={vec3(x,y,Z),vec3(X,y,Z),vec3(X,Y,Z),vec3(x,Y,Z),vec3(x,y,z),vec3(X,y,z),vec3(X,Y,z),vec3(x,Y,z)}
    local vert={v[1],v[2],v[3],v[1],v[3],v[4],v[2],v[6],v[7],v[2],v[7],v[3],v[6],v[5],v[8],v[6],v[8],v[7],
                v[5],v[1],v[4],v[5],v[4],v[8],v[4],v[3],v[7],v[4],v[7],v[8],v[5],v[6],v[2],v[5],v[2],v[1]}
    local texCoords
    if tex then    
        local t={vec2(0,0),vec2(1,0),vec2(0,1),vec2(1,1)}            
        texCoords={t[1],t[2],t[4],t[1],t[4],t[3],t[1],t[2],t[4],t[1],t[4],t[3],t[1],t[2],t[4],t[1],t[4],t[3],
                   t[1],t[2],t[4],t[1],t[4],t[3],t[1],t[2],t[4],t[1],t[4],t[3],t[1],t[2],t[4],t[1],t[4],t[3]}
    end
    local n={vec3(0,0,1),vec3(1,0,0),vec3(0,0,-1),vec3(-1,0,0),vec3(1,0,0),vec3(-1,0,0)}
    local norm={}
    for i=1,6 do for j=1,6 do norm[#norm+1]=n[i] end end
    local ms = mesh()
    ms.vertices = vert
    ms.normals=norm
    if tex then ms.texture,ms.texCoords = tex,texCoords end
    ms:setColors(col or color(255))
    return ms
end  

function CreateSphere(r,tex,col,nx,ny)
    local vertices,tc = Sphere_OptimMesh(nx or 40,ny or 20)
    vertices = Sphere_WarpVertices(vertices)
    for i=1,#vertices do vertices[i]=vertices[i]*r end
    local ms = mesh()
    ms.vertices=vertices
    if tex then ms.texture,ms.texCoords=tex,tc end
    ms:setColors(col or color(255))
    return ms
end

function Sphere_OptimMesh(nx,ny)
    local v,t={},{}
    local k,s,x,y,x1,x2,i1,i2,sx,sy=0,1,0,0,{},{},0,0,nx/ny,1/ny
    local c = vec3(1,0.5,0)
    local m1,m2
    for y=0,ny-1 do
        local nx1 = math.floor( nx * math.abs(math.cos(( y*sy-0.5)*2 * math.pi/2)) )
        if nx1<6 then nx1=6 end
        local nx2 = math.floor( nx * math.abs(math.cos(((y+1)*sy-0.5)*2 * math.pi/2)) ) 
        if nx2<6 then nx2=6 end
        x1,x2 = {},{}
        for i1 = 1,nx1 do x1[i1] = (i1-1)/(nx1-1)*sx end  x1[nx1+1] = x1[nx1]
        for i2 = 1,nx2 do x2[i2] = (i2-1)/(nx2-1)*sx end  x2[nx2+1] = x2[nx2]
        local i1,i2,n,nMax,continue=1,1,0,0,true
        nMax = nx*2+1
        while continue do
            m1,m2=(x1[i1]+x1[i1+1])/2,(x2[i2]+x2[i2+1])/2
            if m1<=m2 then 
                v[k+1],v[k+2],v[k+3]=vec3(x1[i1],sy*y,1)-c,vec3(x1[i1+1],sy*y,1)-c,vec3(x2[i2],sy*(y+1),1)-c
                t[k+1],t[k+2],t[k+3]=vec2(-x1[i1]/2,sy*y) ,vec2(-x1[i1+1]/2,sy*y),vec2(-x2[i2]/2,sy*(y+1))
                if i1<nx1 then i1 = i1 +1 end
            else
                v[k+1],v[k+2],v[k+3]=vec3(x1[i1],sy*y,1)-c,vec3(x2[i2],sy*(y+1),1)-c,vec3(x2[i2+1],sy*(y+1),1)-c
                t[k+1],t[k+2],t[k+3]=vec2(-x1[i1]/2,sy*y),vec2(-x2[i2]/2,sy*(y+1)),vec2(-x2[i2+1]/2,sy*(y+1))
                if i2<nx2 then i2 = i2 +1 end
            end        
            if i1==nx1 and i2==nx2 then continue=false end
            k,n=k+3,n+1
            if n>nMax then continue=false  end
        end
    end   
    return v,t
end

function Sphere_WarpVertices(verts)
    local m = matrix(0,0,0,0, 0,0,0,0, 1,0,0,0, 0,0,0,0)
    local vx,vy,vz,vm        
    for i,v in ipairs(verts) do
        vx,vy = v[1], v[2]
        vm = m:rotate(180*vy,1,0,0):rotate(180*vx,0,1,0)
        vx,vy,vz = vm[1],vm[5],vm[9]
        verts[i] = vec3(vx,vy,vz)
    end    
    return verts
end