PSprites

--!NEEDS:luashader/luashader.lua
 
Palettes=Core.class()
function Palettes:init(d)
	self.texture=RenderTarget.new(256,256)	-- 256 palettes of 256 colours
	if d then stage:addChild(Bitmap.new(self.texture)) end
end
 
function Palettes:exit()
	self.texture=nil
end
 
function Palettes:getBase()
	return self.texture
end
 
function Palettes:setColor(p,c,rgb,a)
	if self.texture then
		local alpha=a or 1
		if type(rgb)=="table" then
			local t=self.texture
			for loop=1,#rgb do
				t:clear(rgb[loop],alpha,c&0xff,p&0xff,1,1)
				c+=1
			end
		else
			self.texture:clear(rgb,alpha,c&0xff,p&0xff,1,1)
		end
	end
end
 
function Palettes:getColor(p,c,l)
	if self.texture then
		if l==nil then
			return self.texture:getPixel(c&0xff,p&0xff)
		else
			local t=self.texture
			local rgb,a=t:getPixel(c&0xff,p&0xff)
			l-=1
			c+=1
			local p={rgb}
			for loop=1,l do
				p[#p+1]=t:getPixel(c&0xff,p&0xff)
				c+=1
			end
			return p,a
		end	
	end
end
 
function Palettes:setColors(p,c,rgb)
	if self.texture then
		local t=self.texture
		for loop=1,#rgb do
			self.texture:clear(rgb[loop,1],rgb[loop,2],c&0xff,p&0xff,1,1)
			c+=1
		end
	end
end
 
function Palettes:getColors(p,c,l)
	local p={}
	if self.texture then
		local t=self.texture
 
		for loop=1,l do
			p[loop]={t:getPixel(c&0xff,p&0xff)}
			c+=1
		end
	end
	return p	
end
 
local function vertex(vVertex,vColor,vTexCoord)
	local vertex = hF4(vVertex,0.0,1.0)
	fTexCoord=vTexCoord
	return vMatrix*vertex
end
 
local function fragment()
	local colour8=texture2D(fTexture,fTexCoord)
	local index=lF2(colour8.r,fPalette)
	local frag=texture2D(fPalettes,index)
	if (frag.a==0.0) then discard() end
	return frag
end
 
local shader=Shader.lua(vertex,fragment,0,{
			{name="vMatrix",type=Shader.CMATRIX,sys=Shader.SYS_WVP,vertex=true},
			{name="fColor",type=Shader.CFLOAT4,sys=Shader.SYS_COLOR,vertex=false},
			{name="fTexture",type=Shader.CTEXTURE,vertex=false},
			{name="fPalettes",type=Shader.CTEXTURE,vertex=false},
			{name="fPalette",type=Shader.CFLOAT2,vertex=false},
			},
			{
			{name="vVertex",type=Shader.DFLOAT,mult=2,slot=0,offset=0},
			{name="vColor",type=Shader.DUBYTE,mult=0,slot=1,offset=0},
			{name="vTexCoord",type=Shader.DFLOAT,mult=2,slot=2,offset=0},
			},
			{
			{name="fTexCoord",type=Shader.CFLOAT2},
			}
			)
 
PSprite=Core.class(Sprite)
function PSprite:init(b,w,h,f,r)
	self.w=w
	self.h=h
	self.base=b:getBase()
	self.palette=0
	local texture=RenderTarget.new(w,h,f,r,false,false,TextureBase.Y8)
	self.texture=texture
	texture:clear(0x800000,1)
	local pixel=Pixel.new(texture)
	self.pixel=pixel
	pixel:setTexture(self.base,1)
	pixel:setShader(shader)
	self.pixel:setShaderConstant("fPalette",Shader.CFLOAT,1,0)
	self:addChild(pixel)
end
 
function PSprite:exit()
	self.pixel=nil
	self.texture=nil
end
 
function PSprite:setBase(b)
	if self.base~=b then
		self.base=b
		self.pixel:setTexture(self.base,1)
	end
end
 
function PSprite:getBase()
	return self.base
end
 
function PSprite:setPalette(p)
	if self.palette~=p then
		self.palette=p
		self.pixel:setShaderConstant("fPalette",Shader.CFLOAT,1,p&0xff)
	end
end
 
function PSprite:getPalette()
	return self.palette
end
 
function PSprite:clear(c)
	self.texture:clear(((c or 0)&0xff)<<16,1)
end
 
function PSprite:setPixel(x,y,c)
	self.texture:clear(((c or 0)&0xff)<<16,1,x,y,1,1)
end
 
application:setBackgroundColor(0x000000)
application:setKeepAwake(true)
 
palettes=Palettes.new(true)
local p={}
for loop=0,255 do
	p[#p+1]=math.random(0xffffff)
end
 
palettes:setColor(0,0,p)
 
pSprite=PSprite.new(palettes,256,256)
 
stage:addChild(pSprite)
for y=0,255 do
	for x=0,255 do
		pSprite:setPixel(x,y,x)  -- set the palette colour to the same value as x
	end
end</pre>