GIDEROS LUA SHADERS DISCOVERY

MoKaLux

Ok, time to have some more fun with gideros: GIDEROS LUA SHADERS

I am playing around to see what I can understand from the gideros lua shader demo.
I have mixed two shaders wave + bloom and I see that I can get the outline of the character already
So my goal has become to "code" a shader to have the outline of my character
Please don't help me yet.
Relax cafe category

rrraptor

Im thinking about visual shader editor using ImGui and node editor.
It works with lua already (but only in docking branch )
https://github.com/MultiPain/Gideros_ImGui/blob/952ddd90a3cb54b8bdc4b3b793d2ad303025c6bb/main.cpp#L10346
So, I can give it a try.

MoKaLux

still trying to understand shaders
For normal shaders (glsl for example), I need 2 files: 1 for the vertex shader and 1 for the fragment shader. Then we pass them to Shader.new(...).

For lua shaders, we must include (or link to) Gideros\Library\luashader files in our projects. Then we write our vertex shader and our fragment shader in lua. Then lua shaders calls Shader.new(...).

Is that correct? I am trying to sort out shaders in the wiki

PS: there is a typo in luashader.lua?

function Shader.lua(vf,ff,opt,uniforms,attrs,varying,funcs,const,debug) local lang=Shader.getShaderLanguage() local mtd=Shader["lua_"..lang] assert(mtd,"Language not supported: "..lang) local _vshader,_fshader=mtd(vf,ff,opt,uniforms,attrs,varying,funcs or {},const) if funcs then for _,fg in ipairs(funcs) do fg.code=nil end end if debug then print("VSHADER_CODE:\n".._vshader) print("FSHADER_CODE:\n".._fshader) end if not vdebug then return Shader.new(_vshader,_fshader,Shader.FLAG_FROM_CODE|opt,uniforms,attrs) end end

vdebug is never declared?

hgy29

Oops, a left-over of a debug. The whole condition should be removed.

MoKaLux

I need your help guys implementing a shader which draws an outline of a sprite, shader experts to the rescue please

I have this old outline shader made by great mister rrraptor

--!NEEDS:luashader/luashader.lua   local function makeEffect(name, vshader, fshader) ... end   Effect={}   -- <a href="https://forum.giderosmobile.com/profile/rrraptor" rel="nofollow">@rrraptor</a> V1 -- 1px outline Effect.outline = makeEffect( "Outline", function (vVertex, vColor, vTexCoord) local vertex = hF4(vVertex, 0.0, 1.0) fTexCoord = vTexCoord return vMatrix*vertex end, function () local outlinesize = 1 local tc = fTexCoord - fTextureInfo.zw local original = lF4(fColor) * texture2D(fTexture, tc) if original.a == 0 then local step = 1.57079632679 -- math.pi/2 -- perfect for 1 to 2 pixels outline for theta = 0, 6.28318530718, step do -- 2 PI local offset = lF2(fTextureInfo.z * cos(theta) * outlinesize, fTextureInfo.w * sin(theta) * outlinesize) local frag = lF4(fColor) * texture2D(fTexture, tc + offset) if frag.a ~= 0 then original = lF4(0, 0, 0, frag.a) -- change outline color here end end end return original end )

It works great prior gideros 2022.1. My problem is I still don't understand nothing about shaders and I would like to port it to newer gideros version 2022.3.1

This is my attempt but gideros doesn't like it and throws errors:

local Outline1Effect=Core.class(ShaderEffect) ShaderEffect.Outline1=Outline1Effect   makeEffect("Outline1", vertexShader, function (vVertex, vColor, vTexCoord): Shader local vertex = hF4(vVertex, 0.0, 1.0) fTexCoord = vTexCoord return vMatrix*vertex   THIS HAS BEEN REMOVED, NSFW ;-)

I tried to understand the other shaders as an example but I couldn't wrap my head around those, somebody please help me

MoKaLux

oh that works and it was easier than I thought

hgy29 you are so kind to us, I knew it since day 1 but this shader thing, you gave everything to make our lifes simpler. I trully respect the LOVE you put in gideros and its users (us). So thank you, thank you, thank you.

After starting afresh I realised I had everything at my disposal in the gideros samples

So I picked the shader example and it was using the same logic as previous gideros (which I was more used to) with minor tweaks. And, to my surprise, I had clear explanations of what was not working!!! (hgy29 super kindness in action):

1st attempt:
FragmentShader:
0(28) : error C0000: syntax error, unexpected '~', expecting ',' or ')' at token "~"
0(34) : error C1503: undefined variable "original"
0(36) : error C0000: syntax error, unexpected '}' at token "}"

2nd attempt:
FragmentShader:
0(28) : error C7011: implicit cast from "float" to "bool"
0(28) : error C1020: invalid operands to "=="

And the working result:

Effect={}   -- <a href="https://forum.giderosmobile.com/profile/hgy29" rel="nofollow">@hgy29</a> Effect.none=makeEffect("None", function (vVertex,vColor,vTexCoord) : Shader local vertex = hF4(vVertex,0.0,1.0) fTexCoord=vTexCoord return vMatrix*vertex end, function () : Shader local frag=lF4(fColor)*texture2D(fTexture, fTexCoord) if (frag.a==0.0) then discard() end return frag end)   -- <a href="https://forum.giderosmobile.com/profile/rrraptor" rel="nofollow">@rrraptor</a> V1 luau -- 1px outline Effect.outline=makeEffect("Outline", function (vVertex,vColor,vTexCoord) : Shader local vertex = hF4(vVertex,0.0,1.0) fTexCoord = vTexCoord return vMatrix*vertex end, function () : Shader local outlinesize=1 local tc=fTexCoord-fTextureInfo.zw local original=lF4(fColor)*texture2D(fTexture, tc) if (original.a==0) then local step = 1.57079632679 -- math.pi/2 -- perfect for 1 to 2 pixels outline -- local step = 0.78539816339 -- math.pi/4 -- perfect for 3 to 4 pixels outline -- local step = 0.39269908169 -- PI/8 -- ok for 4+ pixels outline for theta = 0, 6.28318530718, step do -- 2 PI local offset = lF2(fTextureInfo.z * cos(theta) * outlinesize, fTextureInfo.w * sin(theta) * outlinesize) local frag = lF4(fColor)*texture2D(fTexture, tc+offset) -- if frag.a ~= 0 then -- if (not frag.a == 0) then if frag.a==0 then --discard() else original=lF4(0,0,0, frag.a) -- change outline color here end end end return original end)

I will let you do the cleaning

I wish you all the best, a special thought for our friend Oleg and his people, and my best wishes to you Nicolas (alias hgy29)

PS: this outline shader is the work of genius mister RRRAPTOR, THANK YOU!

Viva Gideros Luau, Peace &

MoKaLux

and here is a sample use case:

function TheStage:xRenderTarget() -- first render target so we can apply shaders local rt = RenderTarget.new(self.canvasw or 8, self.canvash or 8) local rbmp = Bitmap.new(rt) rt:clear(0x0, 0) rt:draw(self.camera.view) if self.outline then rbmp:setShader(Effect.outline) end -- then the actual output image self.rt2:clear(0x0, 0) self.rt2:draw(rbmp) self.bmprt:setTexture(self.rt2) -- to show actual frame in the app (not needed for the output image) end

...

hgy29

I think there is a bug in the luau shader compiler, it doesn’t seem to translate properly the ~= operator into != in C

Yan

spriteOutline = {}   spriteOutline.VS_GL = [[   uniform highp mat4 vMatrix;   attribute highp vec3 vVertex; attribute mediump vec2 vTexCoord;   varying mediump vec2 fTexCoord;   void main() { vec4 vertex = vec4(vVertex, 1.0); gl_Position = vMatrix*vertex; fTexCoord = vTexCoord; } ]]   spriteOutline.FS_GL = [[   #ifdef GL_ES precision highp float; #endif   const float offseta = 0.010;   uniform lowp vec4 fColor; uniform mediump vec4 fTexSize; uniform lowp sampler2D fTexture;   uniform lowp int fSwitch;   varying mediump vec2 fTexCoord;   vec4 getSample(float x, float y, float offset, float num) { vec4 result = vec4(0); float size = 360.0 / num;   for (float a; a <= 360.0; a += size) { vec2 coord = vec2(cos(a) * offset + x, sin(a) * offset + y);   result += texture2D(fTexture, coord); }   return result; }   void main() { vec4 col = texture2D(fTexture, fTexCoord);   float nums = 32.0;   if (fSwitch == 1) { vec4 nb = getSample(fTexCoord.x, fTexCoord.y, 0.020, nums);   if (col.a > 0. && nb.a < nums) { col.a = nb.a / nums; col.r = nb.a / nums; col.g = 0.0; col.b = 0.0; } }   gl_FragColor = col; } ]]   spriteOutline.Shader=Shader.new(spriteOutline.VS_GL,spriteOutline.FS_GL,Shader.FLAG_FROM_CODE, { {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="fSwitch",type=Shader.CINT,vertex=false}, }, { {name="vVertex",type=Shader.DFLOAT,mult=3,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}, });

Thats all.

MoKaLux

dear gideros people, do you know if it is possible to change the lighting color in the 3dbase shader (3DLighting.lua)?
There are those values

local color0 = lF4(g_Color) local LightingShaderConstants={ -- I can add my own variables here (for example specular...) XXX {name="g_MVPMatrix",type=Shader.CMATRIX,sys=Shader.SYS_WVP, vertex=true}, {name="g_MVMatrix",type=Shader.CMATRIX,sys=Shader.SYS_WORLD, vertex=true}, {name="g_NMatrix",type=Shader.CMATRIX,sys=Shader.SYS_WIT3, vertex=true}, {name="g_LMatrix",type=Shader.CMATRIX, vertex=true}, {name="g_Color",type=Shader.CFLOAT4,mult=1,sys=Shader.SYS_COLOR}, ... if OPT_TEXTURED then color0 = color0*texture2D(g_Texture,texCoord) end local color1 = lF3(0.5, 0.5, 0.5) local normal = normalize(normalCoord)   local diff = max(0.0, dot(normal, lightDir)) local spec =0.0 -- specular XXX -- calculate shadow local shadow=1.0 if OPT_SHADOWS then shadow = ShadowCalculation(lightSpace,FragCoord) end if (diff>=1) then -- 0 = ugly light halo!, >=1 = no ugly light halo! new 20220629 XXX local nh = max(0.0, dot(reflect(-lightDir,normal),viewDir)) spec = pow(nh, 32.0)*shadow -- specular default = 32 (good value) end   diff=max(diff*shadow,ambient); local frag = lF4(color0.rgb * diff + color1 * spec, color0.a) return frag

I believe the light color is WHITE but I don't see anywhere in the shader files where the color is set (3DShaders.lua, luashader.lua, ... ?)

Can somebody point me in the right direction? Thank you for your help

MoKaLux

MoKaLux said:

dear gideros people, do you know if it is possible to change the lighting color in the 3dbase shader (3DLighting.lua)?

A beginning of an answer it seems to be in 3DShaders.lua

local color0 = lF4(g_Color) local mycolor = lF4(1.0,0.0,0.0,1.0) --< here? -- if OPT_TEXTURED then color0 = color0*texture2D(g_Texture,texCoord) end if OPT_TEXTURED then color0 = color0*texture2D(g_Texture,texCoord)*mycolor end

to be continued...

MoKaLux

How could I pass some external values (parameters) to work in this lua shader please?
3DShaders.lua

function D3._FLUA_Shader() : Shader --mat3 cotangent_frame(vec3 N, vec3 p, vec2 uv) function cotangent_frame(N,p,uv) --// récupère les vecteurs du triangle composant le pixel local dp1 = dFdx( p ) ... end   --vec3 perturb_normal( vec3 N, vec3 V, vec2 texcoord ) function perturb_normal( N, V, texcoord ) --// N, la normale interpolée et --// V, le vecteur vue (vertex dirigé vers l'œil) local ret=hF3(0,0,0) ... end ... if OPT_NORMMAP then normal=perturb_normal(normal, viewDir, texCoord) end   local diff = max(0.0, dot(normal, lightDir)) -- 0.0 => CHANGE THIS ONE? local spec = 0.0 -- => MAYBE THIS ONE TOO? -- calculate shadow local shadow=1.0 -- 1.0, 0.5, -- this seems to control the shadow width, in practice this blows the light! if (diff>=1) then local nh = max(0.0, dot(reflect(-lightDir,normal),viewDir)) spec = pow(nh, 64.0)*shadow -- => 64.0 AND MAYBE THIS ONE TOO? end diff=max(diff*shadow,ambient);   local frag = lF4(color0.rgb * diff + color1 * spec, color0.a)   return frag end

Some pointers please Thank you

EDIT: https://wiki.gideros.rocks/index.php/Shader:setConstant

hgy29

Yes, you can use Shader.setConstant if you want to set a property on a shader for all sprites that use this shader, or Sprite:setShaderConstant if you want to set a constant specifically for a given Sprite

MoKaLux

in Lua Shader, how can I use round, trunc, ..?

round round(x) Returns a value equal to the nearest integer to x.
https://wiki.gideros.rocks/index.php/Lua_Shader_Common_Functions

Some functions seem not implemented?

I tried with this code:

frag.r += (round(frag.r * colors - dither) / colors) * c frag.g += (round(frag.g * colors - dither) / colors) * c frag.b += (round(frag.b * colors - dither) / colors) * c --frag.r += (floor(frag.r * colors - dither) / colors) * c -- this works

Error: luashader/luau_codegen.lua:54: Unknown global round

I tried with math.round but not working

Is there a work around please?

EDIT: looking into luashader.lua

hgy29

@MoKaLux,

Shaders have floor() and ceil(), so trunc(n)=floor(n) if n is positive or ceil(n) otherwise.
round(n) is same as floor(n+0.5) for n positive and ceil(n+0.5) for n negative.

But you can add bindings for trunc and floor in luashader.lua, for all three languages (GLSL,HLSL and MSL)

MoKaLux

thank you hgy29, I almost got this cc0 godot shader working in Gideros
https://godotshaders.com/shader/color-reduction-and-dither/#comment-1927

Gideros:

-- attempted gideros Effect.emphasize = makeEffect("emphasize", function (vVertex, vColor, vTexCoord) : Shader local vertex = hF4(vVertex, 0.0, 1.0) fTexCoord = vTexCoord fVertex=vVertex.xy return vMatrix * vertex end, function () : Shader -- local colors = lF2(1.0, 16.0) -- local dither = lF2(0.0, 0.5) local colors = lF1(8.0) -- 8.0 local dither = lF1(0.5) -- 0.25 local frag = lF4(fColor) * texture2D(fTexture, fTexCoord) -- local a = floor(mod(UV.x / TEXTURE_PIXEL_SIZE.x, 2.0)) -- local b = floor(mod(UV.y / TEXTURE_PIXEL_SIZE.y, 2.0)) -- local a = floor(mod(fVertex.x / fTextureInfo.x, 2.0)) -- local b = floor(mod(fVertex.y / fTextureInfo.y, 2.0)) local a = floor(mod(fVertex.x / fTextureInfo.x, 2.0)) local b = floor(mod(fVertex.y / fTextureInfo.y, 2.0)) local c = mod(a + b, 2.0) -- 2.0   -- frag.r = (round(frag.r * colors + dither) / colors) * c -- frag.g = (round(frag.g * colors + dither) / colors) * c -- frag.b = (round(frag.b * colors + dither) / colors) * c frag.r = ((floor(frag.r * colors + dither)+0.5) / colors) * c frag.g = ((floor(frag.g * colors + dither)+0.5) / colors) * c frag.b = ((floor(frag.b * colors + dither)+0.5) / colors) * c c = 1.0 - c if c < 0 then -- frag.r += (round(frag.r * colors - dither) / colors) * c -- frag.g += (round(frag.g * colors - dither) / colors) * c -- frag.b += (round(frag.b * colors - dither) / colors) * c frag.r += ((ceil(frag.r * colors - dither)+0.5) / colors) * c frag.g += ((ceil(frag.g * colors - dither)+0.5) / colors) * c -- frag.b += (floor(fColor.b * colors - dither) / colors) * c frag.b += ((ceil(frag.b * colors - dither)+0.5) / colors) * c else -- frag.r += (round(frag.r * colors - dither) / colors) * c -- frag.g += (round(frag.g * colors - dither) / colors) * c -- frag.b += (round(frag.b * colors - dither) / colors) * c frag.r += ((floor(frag.r * colors - dither)+0.5) / colors) * c frag.g += ((floor(frag.g * colors - dither)+0.5) / colors) * c -- frag.b += (floor(fColor.b * colors - dither) / colors) * c frag.b += ((floor(frag.b * colors - dither)+0.5) / colors) * c end   if (frag.a == 0.0) then discard() end return frag end)

I think I got this cc0 one working as expected?
https://godotshaders.com/shader/256-colour-pixelation/
Gideros:

Effect.colour_pixelation2 = makeEffect("colour_pixelation2", function (vVertex, vColor, vTexCoord) : Shader local vertex = hF4(vVertex, 0.0, 1.0) fTexCoord = vTexCoord return vMatrix * vertex end, function () : Shader local resX = 128.0 -- 32 local resY = 128.0 -- 32 -- 0.100392156862 is the cube root of 255 local rgb255 = lF3(0.100392156862, 0.100392156862, 0.100392156862) local uvX = fTexCoord.x - mod(fTexCoord.x * resX, 1) / resX local uvY = fTexCoord.y - mod(fTexCoord.y * resY, 1) / resY local grid_uv = lF2(uvX, uvY) local frag = lF4(fColor) * texture2D(fTexture, grid_uv) if(frag.r < 1.0 and frag.g < 1.0 and frag.b < 1.0) then local remainder = mod(frag.rgb, rgb255) frag.rgb = frag.rgb - remainder end -- emphasize local e = lF1(1.15) frag.rgb = lF3(frag.r^e, frag.g^e, frag.b^e) if (frag.a == 0.0) then discard() end   return frag end)

Viva Gideros