mode7.p8

-- draw a mode7 style floor 

scene = {x=10,y=10,z=140,hz=25,rot=0,spd=0}

-- fade table http://kometbomb.net/pico8/fadegen.html 

local fadetable={
 {0,0,129,129,129,129,1},
 {1,1,1,1,1,1,1},
 {2,2,133,133,133,1,1},
 {3,3,131,131,131,131,1},
 {4,4,132,5,133,133,1},
 {5,5,133,133,1,1,1},
 {6,13,13,13,141,5,1},
 {6,6,6,13,13,5,1},
 {8,136,136,2,2,133,1},
 {9,137,4,4,5,5,133},
 {10,138,138,134,5,5,133},
 {11,139,139,3,3,131,131},
 {12,12,140,140,140,131,1},
 {13,13,141,141,5,1,1},
 {14,134,134,141,141,141,1},
 {15,134,134,134,141,5,1}
}

function fade(i)
 for c=0,15 do
  if flr(i+1)>=8 then
   pal(c,1)
  else
   pal(c,fadetable[c+1][flr(i+1)])
  end
 end
end

-- draw the floor
function mode()
	scene.rot = scene.rot % 1
  -- grab cos and sin of scene angle
  c = cos(scene.rot)
	s = sin(scene.rot)

	local sy_step = 1 
	local sy = sy_step 

  -- reset palettes
	palt()
	pal()
	palt(0,false)
  --  draw blue under ( tline doesn't draw color zero ? ) 
  rectfill(0,scene.hz,127,127,1)
  --  draw sky 
  rectfill(0,0,127,scene.hz,13)

  for y=scene.hz,128 do	   
		local t = (scene.z / sy)
		sy = sy+sy_step   
		--  u v and edge uv step
    local v,v_step = (-c - s)*t + scene.y,(2/128)*c*t
		local u,u_step = (-s + c)*t + scene.x,(2/128)*s*t
		local ur = (((u_step)))
		local vr = (((v_step)))
		local zz =((t)/scene.hz)
		if (zz>0) then
			fade((t/6)%8)
			tline(0,y,127,y,u,v,ur,vr)
		end
	end
end

function _draw()
	cls(0)
	mode()
end

function _update()
	if btn(4) then 
		if btn(2) then 
			scene.z+=1
		end 
		if btn(3) then 
			scene.z-=1
		end 
	else
		if btn(0) then 
			scene.rot-=0.01
		end
		if btn(1) then 
			scene.rot+=0.01
		end
		if btn(2) then 
			scene.spd+=0.1
		end 
		if btn(3) then 
			scene.spd-=0.1
		end 
	end
	
	scene.x += cos(-scene.rot)*scene.spd
	scene.y += sin(-scene.rot)*scene.spd
	scene.spd*=0.8
	
end