Lua Shader Examples
From GiderosMobile
Parent: Writing Lua Shaders
Requirements: In order to use Lua Shaders you need to include luashader standard library in your projects luashader standard library is available in your Gideros installation folder under Library
Shader Saturate - by Hgy29
function vssaturate(vVertex, vColor, vTexCoord) : Shader
local vertex = hF4(vVertex, 0.0, 1.0)
fTexCoord = vTexCoord
return vMatrix * vertex
end
function fssaturate() : Shader
local frad = (1 + sin(fTime*7)) * 0.5
local frag = lF4(fColor) * texture2D(fTexture, fTexCoord)
local coef = lF3(0.2125, 0.7154, 0.0721)
local dp = dot(frag.rgb, coef)
if fSwitch == 22 then -- switched via lua code
frag.rgb = mix(frag.rgb, frag.rgb / dp, frad)
end
if (frag.a == 0.0) then discard() end
return frag
end
local saturate = Shader.lua(vssaturate, fssaturate, 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="fTextureInfo", type=Shader.CFLOAT4, sys=Shader.SYS_TEXTUREINFO, vertex=false},
{name="fTime", type=Shader.CFLOAT, sys=Shader.SYS_TIMER, vertex=false},
{name="fSwitch", type=Shader.CINT, vertex=false}, -- Uniform value will be changed in lua code
},
{
{name="vVertex", type=Shader.DFLOAT, mult=2, slot=0, offset=0},
{name="vColor", type=Shader.DUBYTE, mult=4, slot=1, offset=0},
{name="vTexCoord", type=Shader.DFLOAT, mult=2, slot=2, offset=0},
},
{
{name="fTexCoord", type=Shader.CFLOAT2},
}
)
-- bg color
application:setBackgroundColor(0x909090)
-- a texture and a bitmap
local tex = Texture.new("gfx/test.png")
local bmp = Bitmap.new(tex, true)
--local bmp2 = bmp:clone()
local bmp2 = Bitmap.new(tex, true)
-- position
bmp:setPosition(32*4, 32*4)
bmp2:setPosition(32*4, 32*8)
-- lua shader
bmp:setShader(saturate)
bmp2:setShader(saturate)
bmp:setShaderConstant("fSwitch", Shader.CINT, 1, 22) -- switch is on
bmp2:setShaderConstant("fSwitch", Shader.CINT, 1, -38) -- switch is off
-- order
stage:addChild(bmp)
stage:addChild(bmp2)
-- loop
stage:addEventListener(Event.ENTER_FRAME, function(e)
bmp:setX(bmp:getX() + 0.5)
if bmp:getX() > 400 then bmp:setX(-80) end
end)
Rain drops demo - by Hgy29
Rain drops shader effect
-- Custom shader for a plain colored pixel (BASIC PROGRAM)
local shader=StandardShaders:getShaderSpecification(Shader.SHADER_PROGRAM_BASIC)
-- We will need vertex position in fragment shader
function shader:vertexShader(vVertex,vColor,vTexCoord) : Shader
local vertex = hF4(vVertex,0.0,1.0)
fVertex=vVertex.xy
return vMatrix*vertex
end
-- Fragment shader will compute caustics and ripples
function shader:fragmentShader() : Shader
local tp = hF2(1.0/32.0,1.0/16.0)
local mt = fVertex/1024.0
local p = mod(mt*6.28, 6.28)-360.0
local i = p
local c = 1.0
local inten = .005
for n=1,3 do
local t = fTime*0.5 * (1.0 - (3.0 / hF1(n)))
i = p + hF2(cos(t - i.x) + sin(t + i.y), sin(t - i.y) + cos(t + i.x))
c += 1.0/length(hF2(p.x / (sin(i.x+t)/inten),p.y / (cos(i.y+t)/inten)))
end
for n=1,32 do
local fr=fRippleT[n]
if (fr>0.0) then
local pd=length(fVertex-fRippleC[n])
local rd=1.0-smoothstep(0.0,128.0,pd)
if (rd>0.0) then
local td=(fTime-fr)*10.0
local dr=min(1.0,max(0.0,1.0-abs(td-(1.0-rd)*20.0)/10.0))
c+=sin(rd*20.0+td)*rd*dr
end
end
end
c /= 3
c = (1.5-c^.5)^4
return lF4((hF4(c,c,c,1.0) + hF4(0.0, 0.3, 0.5, 1.0))*fColor)
end
-- Add our custom constants and inter-stage varibale
local NDROPS=32
table.insert(shader.uniforms,{name="fRippleC",type=Shader.CFLOAT2,vertex=false,mult=NDROPS})
table.insert(shader.uniforms,{name="fTime",type=Shader.CFLOAT,sys=Shader.SYS_TIMER,vertex=false})
table.insert(shader.uniforms,{name="fRippleT",type=Shader.CFLOAT,vertex=false,mult=NDROPS})
table.insert(shader.varying,{name="fVertex",type=Shader.CFLOAT2})
-- A plain blue screen wide Pixel with our shader
local ax,ay,aw,ah=application:getLogicalBounds()
local p=Pixel.new(0x5678CD,1,aw-ax,ah-ay) p:setPosition(ax,ay)
p:setShader(shader:build())
stage:addChild(p)
-- Main loop: create random rain drops
local drop=0
local dropsP,dropsT={},{}
for i=1,NDROPS do dropsP[i*2-1]=0 dropsP[i*2]=0 dropsT[i]=0 end
Core.asyncCall(function()
while true do
Core.yield(.05)
drop+=1
if drop==(NDROPS+1) then drop=1 end
dropsP[drop*2-1]=math.random(aw-ax)
dropsP[drop*2]=math.random(ah-ay)
dropsT[drop]=os:timer()
p:setShaderConstant("fRippleC",Shader.CFLOAT2,NDROPS,dropsP)
p:setShaderConstant("fRippleT",Shader.CFLOAT,NDROPS,dropsT)
end
end)
