pixel texture rotation (pixel:setTextureRotation?)

MoKaLux · October 2020

is it possible to rotate a pixel texture please?

Tiled_Flow = Core.class(Sprite)
 
function Tiled_Flow:init()
	local tex = Texture.new("mytex.png", false, {wrap = TextureBase.REPEAT})
	self.img = Pixel.new(tex, 64, 64)
	self:addChild(self.img)
	self.flowx, self.flowy = 0, 0
	self.flowspeedx, self.flowspeedy = 1, 1
	self:addEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
end
 
function Tiled_Flow:onEnterFrame(e)
	self.flowx += self.flowspeedx or 0
	self.flowy += self.flowspeedy or 0
	self.img:setTexturePosition(self.flowx, self.flowy) -- this moves the texture on x and y
	-- is it possible to rotate the texture as well?
end

I tried using matrix but couldn't figure it out

MoKaLux · October 2020

For example I tried this but it doesn't rotate the texture:

Tiled_Flow = Core.class(Sprite)
 
function Tiled_Flow:init()
	local tex = Texture.new("mytex.png", false, {wrap = TextureBase.REPEAT})
	self.img = Pixel.new(tex, 64, 64)
	self:addChild(self.img)
	self.flowx, self.flowy = 0, 0
	self.flowspeedx, self.flowspeedy = 1, 1
	self.m = Matrix.new()
	self:addEventListener(Event.ENTER_FRAME, self.onEnterFrame, self)
end
 
function Tiled_Flow:onEnterFrame(e)
	self.flowx += self.flowspeedx or 0
	self.flowy += self.flowspeedy or 0
	self.img:setTexturePosition(self.flowx, self.flowy)
	-- the pixel texture won't rotate :-(
	self.m:setRotationX(self.flowx * 8)
	self.img:setTextureMatrix(self.m)
end

rrraptor · October 2020

I guess the only way is to write a shader?
I tried to use lua shaders, but I have no idea how to get/set mat4 elements in vertex shader.
@SinisterSoft can you help with that?)
Or something like that:

local tex = Texture.new("tileTexture.png", true, {wrap = Texture.REPEAT})
 
local spr = Pixel.new(tex, 512, 512) -- fake texture
spr:setAnchorPoint(.5, .5)
 
local view = Viewport.new()
view:setClip(0, 0, 128, 128)
view:setContent(spr)
stage:addChild(view)
 
local time = 0
stage:addEventListener("enterFrame", function(e)
	local dt = e.deltaTime
	time += dt
 
	spr:setRotation(spr:getRotation() + 50 * dt)
	spr:setPosition(
		spr:getX() + math.cos(time) * 100 * dt,
		spr:getY() + math.sin(time) * 100 * dt
	)
end)

MoKaLux · October 2020

thanks a bunch rrraptor, I wanted to add some "quick" effect but this will have to wait until I dive into shaders then

Oh I will also try your Viewport solution

hgy29 · October 2020

MoKaLux said:
For example I tried this but it doesn't rotate the texture:
Tiled_Flow = Core.class(Sprite)
	-- the pixel texture won't rotate :-(
	self.m:setRotationX(self.flowx * 8)
	self.img:setTextureMatrix(self.m)

There are two issues here: first setTextureMatrix doesn't do anything in gideros (I have just looked at the code and the function miss the important part, I have fixed it now). Second issue is that you should call setRotationZ(), not setRotationX()

MoKaLux · October 2020

I forgot to mention that I did try to rotate on X, Y and Z

Thank you for fixing it (and having updated reactPhysics3d

)

hgy29 · October 2020

Here is the same effect using luashaders:

--!NEEDS:luashader/luashader.lua
 
local function vertexShader(vVertex,vColor,vTexCoord)
	local vertex = hF4(vVertex,0.0,1.0)
	fTexCoord=(tMatrix*hF4(vTexCoord,0,1)).xy
	return vMatrix*vertex
end
 
local function fragmentShader()
	 local frag=lF4(fColor)*texture2D(fTexture, fTexCoord)
	 if (frag.a==0.0) then discard() end
	 return frag
end	
local myTextureShader=Shader.lua(vertexShader,fragmentShader,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="tMatrix",type=Shader.CMATRIX,vertex=true},
	},
	{
	{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},
	}
	)
 
local tex = Texture.new("mytex.png", true, {wrap = Texture.REPEAT})
 
local spr = Pixel.new(tex, 512, 512) -- fake texture
spr:setAnchorPoint(.5, .5)
spr:setShader(myTextureShader)
 
stage:addChild(spr)
stage:addEventListener("enterFrame", function(e) 
	local mat=Matrix.new()
	mat:setRotationZ(10 * os:timer())
	mat:setPosition(os:timer(),os:timer())
	spr:setShaderConstant("tMatrix",Shader.CMATRIX,1,mat:getMatrix())
end)

SinisterSoft · October 2020

Does this work with textures that wrap? If so, it could be very nice for effects.

MoKaLux · October 2020

SinisterSoft said:
Does this work with textures that wrap? If so, it could be very nice for effects.

yes, that's what I am after, I want to simulate a rolling water effect

MoKaLux · December 2020

There are two issues here: first setTextureMatrix doesn't do anything in gideros (I have just looked at the code and the function miss the important part, I have fixed it now). Second issue is that you should call setRotationZ(), not setRotationX()

feedback: it works now

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