noom7.lua

-- title:  Mode7
-- author: MonstersGoBoom and Nopy
-- desc:   Mode7
-- script: lua

-- utility scripts

local math_sin = math.sin
local math_cos = math.cos
local math_rad = math.rad 
local math_min = math.min
local math_max = math.max
local math_abs = math.abs
local math_atan2 = math.atan2
local clock = 0

function pal(c0,c1) if(c0==nil and c1==nil)then for i=0,15 do poke4(0x3FF0*2+i,i)end else poke4(0x3FF0*2+c0,c1)end end
function findCloseRGB(a,b,c)local d=99999999;local e=0;for f=0,15 do local g=peek(0x3fc0+f*3)local h=peek(0x3fc0+f*3+1)local i=peek(0x3fc0+f*3+2)local j=math.sqrt(math.pow(a-g,2)+math.pow(b-h,2)+math.pow(c-i,2))if j<=d then d=j;e=f end end;return e end
function lerp(a,b,amount) return a + (b - a) * amount end

-- Here's the fzero/mario cart floor mode7

local cam =
{
		x=0,
		y=64,
		z=20, -- elevation
		r=0, 
		rs=0,
		ms = 0,
		horizon=60, --pitch
  --fog = {32,128,200},
		fog = {0x00,0x00,0x00},		
--		fogFar = 3.,
--		fogOn = true,
		rotationSpeed = 0.5,
		movementSpeed = 0.2,
}

-- now call this First
function cam:Init()
	cam.map = {}
	for y=0,135 do
		for x=0,239 do
			cam.map[1 + (x + (y*240))] = mget(x,y)
		end
	end
	cam:UpdateFog()
end

-- helpers
function cam:mget(x,y)
	x=(x//1)%240
	y=(y//1)%136
	return cam.map[1 + (x + (y*240))]	--	use cam.map now
end

function cam:mset(x,y,val)
	x=(x//1)%240
	y=(y//1)%136
	cam.map[1 + (x + (y*240))] = val
end

-- transform 3d point to cam space
function cam:Transform(ox,oy,oz)
   local c = cam.c
   local s = cam.s 
   local dx,dy,dz = ox-cam.x,oy-cam.y,oz-cam.z
   local z = dx*c + dy*-s
   local tx = dx*s + dy*c
   local ty = dz
   if( z > 0 ) then
	  tx = (tx*120) / z + 120
	  ty = (ty*68)  / -z + cam.horizon
			if 	tx < -100 or
					tx > 340 or
					ty < -100 or
					ty > 235 then
						return false,-999,-999
					end
   	  return true,tx,ty,z
   end
   return false,-999,-999	
end

-- draw ground
function cam:Render()
  local s,c = math_sin(math_rad(cam.r)),math_cos(math_rad(cam.r))
	cam.s = s
	cam.c = c
	rect(0,0,240,cam.horizon+2,cam.cls)
	rect(0,cam.horizon+2,240,136-cam.horizon,0)

	local sy_step = 1./68.
	local sy = sy_step

	-- split the view 
	-- top part is double wide pixels, and fogable
	cam.horizon2 = cam.horizon + ((136-cam.horizon)/4)//1
	
	for y=cam.horizon,cam.horizon2 do	   
		local t = cam.z / sy
		sy = sy+sy_step   

		local V,V_step = (-c - s)*t + cam.y,(4/240)*c*t
		local U,U_step = (-s + c)*t + cam.x,(4/240)*s*t

		cam:Fog(8-(t//cam.horizon))
		
		for x=0,239,2 do
			local iU =(U//1)  --  quick floor
			local iV =(V//1)  --  
			local mU = math_abs(iU>>3)
			local mV = math_abs(iV>>3)
			if mU<240 and mV<136 then
				local id = cam.map[1 + (mU + (mV*240))]	--	use cam.map now
				if id then
				   local spram_addr=2*0x4000+(id<<6)+(iU&7)+((iV&7)<<3)
					 co = peek4(spram_addr)
					 rect(x,y,2,1,co)
				end
			end
			V = V + V_step
			U = U + U_step            
		end
	end

	-- bottom part is normal and unfogged
	local scr_addr=2*0x0000 + cam.horizon2*240
	pal()
	for y=cam.horizon2,135 do	   
		local t = cam.z / sy
		sy = sy+sy_step   

		local V,V_step = (-c - s)*t + cam.y,(2/240)*c*t
		local U,U_step = (-s + c)*t + cam.x,(2/240)*s*t
		
		for x=0,239 do
			local iU =(U//1)  --  quick floor
			local iV =(V//1)  --  
			local mU = math_abs(iU>>3)
			local mV = math_abs(iV>>3)
			if mU<240 and mV<136 then
				local id = cam.map[1 + (mU + (mV*240))] -- use cam map
				if id then
				   local spram_addr=2*0x4000+(id<<6)+(iU&7)+((iV&7)<<3)
				   co = peek4(spram_addr)
					 poke4(scr_addr,co) -- poke directly
				end
			end
			scr_addr = scr_addr+1
			V = V + V_step
			U = U + U_step            
		end
	end
end

-- build the fog tables

function cam:UpdateFog()
	cam.fogLookup = {}
	for y=1,8 do
		cam.fogLookup[y] = {}
		local amount = (8-y)/8
		--trace(amount)
		for x=1,16 do
			local i = x -1
			local	dr = peek(0x3fc0+(i*3))
			local dg = peek(0x3fc0+(i*3)+1)
			local db = peek(0x3fc0+(i*3)+2)
			local r =lerp( dr,cam.fog[1], amount)
			local g =lerp( dg,cam.fog[2], amount)
			local b =lerp( db,cam.fog[3], amount)
			i = findCloseRGB(r//1,g//1,b//1)
--			trace(r .. "," .. g .. "," .. b .. "=" .. i)
			cam.fogLookup[y][x] = i
		end
	end
-- this is the rect clear color
	cam.cls = findCloseRGB(cam.fog[1],cam.fog[2],cam.fog[3])
end

function cam:Fog(i)
	if i<1 then i = 1 end
	if i>8 then i = 8 end
	for x=1,16 do
		local ind = x-1
		poke4(0x3FF0*2+ind,cam.fogLookup[i][x])
	end		
end


-- rotating thingy 
function rspr(sx,sy,scale,angle,mx,my,mw,mh,key,useMap)
	--  this is fixed , to make a textured quad
	--  X , Y , U , V
--	local svc ={{-1,-1, 0,0},
--							{ 1,-1, 0.9999999,0},
--							{-1,1,  0,1.0},
--							{ 1,1,  1.0,1.0}}

	local sv ={{-1,-2, 0,0},
							{ 1,-2, 0.9999999,0},
							{-1,0,  0,1.0},
							{ 1,0,  1.0,1.0}}


	local rp = {} --  rotated points storage

	local a = -angle
	local s = math_sin(a)
	local c = math_cos(a)

	--  the scale is mw ( map width ) * 4 * scale 
	--  mapwidth is * 4 because we actually want HALF width to center the image
	local scalex = (mw*4) * scale
	local scaley = (mh<<2) * scale
	--  rotate the quad points
	for p=1,#sv do 
		-- apply scale
		local _sx = sv[p][1] * scalex 
		local _sy = sv[p][2] * scaley
		-- apply rotation
		local rx = _sx * c - _sy * s
		local ry = _sx * s + _sy * c
		-- apply transform
		sv[p][1] = rx + sx
		sv[p][2] = ry + sy
		-- scale UV's 
		sv[p][3] = ((mx*8) + (sv[p][3] * mw*8))//1
		sv[p][4] = ((my*8) + (sv[p][4] * mh*8))//1
	end
		-- draw two triangles for the quad
	textri( sv[1][1],sv[1][2],
					sv[2][1],sv[2][2],
					sv[3][1],sv[3][2],
					sv[1][3],sv[1][4],
					sv[2][3],sv[2][4],
					sv[3][3],sv[3][4],
					useMap,key)

	textri( sv[2][1],sv[2][2],
					sv[3][1],sv[3][2],
					sv[4][1],sv[4][2],
					sv[2][3],sv[2][4],
					sv[3][3],sv[3][4],
					sv[4][3],sv[4][4],
					useMap,key)
end
	

cam:Init()

function TIC()

	--elevate
   if btn(6) then 
	  cam.z = cam.z + 1
   end
   --descend
   if btn(4) then 
	  cam.z = math_max( 1, cam.z - 1)
   end

   --pitch
   if btn(7) then 
	  cam.horizon = math_min(135-20,cam.horizon + 1)
   end
   if btn(5) then 
	  cam.horizon = math_max(20,cam.horizon - 1)
   end


   --rotation
   if btn(2) then 
	  cam.rs = cam.rs + cam.rotationSpeed
   end
   if btn(3) then 
	  cam.rs = cam.rs - cam.rotationSpeed
   end
   cam.r = cam.r + cam.rs
   cam.rs = cam.rs * 0.9

   --movement
   if btn(0) then
	  cam.ms = cam.ms + cam.movementSpeed
   end			
   if btn(1) then
	  cam.ms = cam.ms - cam.movementSpeed
   end			

   --update camera
   
   local fwd = math_rad(cam.r+90)
   cam.x = cam.x + (math_sin(fwd)*cam.ms) 
   cam.y = cam.y + (math_cos(fwd)*cam.ms) 
   cam.ms = cam.ms * 0.9

   cam:Render()

	 --draw a sprites
	 -- inserting into sprite array 
	 -- X,Y,Z,U,V,W,H,key
	 sprites = {}
	 
	 for i = 1, 32 do
		 local ox,oy,oz = 64,64, 12 + math_sin(i*10+(clock*5))*16
		 local p = 1
		 
		 ox = 256+math_sin(clock+i)*64
		 oy = 256+math_cos(clock+i)*64
		 if i&1==1 then p=3 end
		 
		 local incam,tx,ty,tz= cam:Transform(ox,oy,oz)
		 if incam==true then
			 table.insert(sprites,{tx,ty,tz,0,p,2,2,0})		
		 end
	 end
	 --	trees 
	 for y = 0, 15 do
		 for x = 0, 15 do
			 local ox,oy,oz = 64+x*16,64+y*16, 0
			 local incam,tx,ty,tz= cam:Transform(ox,oy,oz)
			 if incam==true then
				 table.insert(sprites,{tx,ty,tz,0,5,2,2,0})		
			 end
		 end
	 end
 
	 -- now sort them out , fog em 
	 table.sort(sprites, function(a,b) return a[3]>b[3] end)
	 for i = 1, #sprites do
		 pos = sprites[i]
		 cam:Fog(8-(pos[3]//cam.horizon))
		 local w = pos[6]*8
		 rspr( 	pos[1],	--	x
		 				pos[2],	--  y
						w/pos[3], -- scaler
						0,				--	angle 
						pos[4],		--	position in sprram U
						pos[5],		--	^^ V
						pos[6],		--	width 
						pos[7],		--	height
						pos[8],		--	colorkey
						false)
	 end	
	 --	reset indices
	 pal()		
	 clock = clock + 0.01
end