Custom Shader Examples
From GiderosMobile
Parent: Writing Custom Shaders
Note: not all shaders will display correctly in html5
A Grey Shader
The code below defines a Grey shader consisting of:
- mycshaders/vShaderGrey.glsl vertex shader
- mycshaders/fShaderGrey.glsl fragment shader
Here the shader files are in the assets/mycshaders directory.
GLSL Vertex Shader: mycshaders/vShaderGrey.glsl
uniform highp mat4 vMatrix;
attribute highp vec3 vVertex;
attribute mediump vec2 vTexCoord;
varying mediump vec2 fTexCoord;
void main() {
vec4 vertex = vec4(vVertex, 0.8); // vertex coords, scale
gl_Position = vMatrix*vertex;
fTexCoord = vTexCoord;
}
GLSL Fragment Shader: mycshaders/fShaderGrey.glsl
//precision highp float;
#ifdef GLES2
precision highp float;
#endif
uniform lowp vec4 fColor;
uniform lowp sampler2D fTexture;
varying mediump vec2 fTexCoord;
void main() {
lowp vec4 frag = fColor*texture2D(fTexture, fTexCoord);
float color;
if (frag.a == 0.0) {
gl_FragColor = vec4(1.0, 0.5, 1.0, 1.0); // purple
} else {
color = dot(frag.rgb, vec3(0.299, 0.587, 0.114));
gl_FragColor = vec4(color, color, color, frag.a); // gray
}
}
Lua Code
-- open gl shader
local shadergrey = Shader.new("mycshaders/vShaderGrey", "mycshaders/fShaderGrey", 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="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},
}
)
application:setBackgroundColor(0x333333)
local bitmap = Bitmap.new(Texture.new("gfx/test.png"))
local bitmap2 = Bitmap.new(Texture.new("gfx/arrow_0001.png"))
-- position
bitmap:setPosition(32*1, 32*4)
bitmap2:setPosition(32*6, 32*1)
-- shaders
bitmap:setShader(shadergrey)
bitmap2:setShader(shadergrey)
-- order
stage:addChild(bitmap)
stage:addChild(bitmap2)
A Wave Shader
The code below defines a Wave shader consisting of:
- mycshaders/vShaderWave.glsl vertex shader
- mycshaders/fShaderWave.glsl fragment shader
Here the shader files are in the assets/mycshaders directory.
GLSL Vertex Shader: mycshaders/vShaderWave.glsl
attribute vec4 POSITION0;
attribute vec2 TEXCOORD0;
uniform mat4 g_MVPMatrix;
varying vec2 texCoord;
void main()
{
gl_Position = g_MVPMatrix * POSITION0;
texCoord = TEXCOORD0;
}
GLSL Fragment Shader: mycshaders/fShaderWave.glsl
uniform lowp sampler2D g_Texture;
uniform lowp vec4 g_Color;
uniform highp float time;
varying highp vec2 texCoord;
void main()
{
highp vec2 tc = texCoord.xy;
// highp float dist = cos(tc.x * 24.0 - time * 4.0) * 0.02;
highp float dist = cos(tc.x * 2.0 - time * 8.0) * 0.02;
highp vec2 uv = tc + dist;
gl_FragColor = g_Color * texture2D(g_Texture, uv);
}
Lua Code
-- open gl shader
local shaderwave = Shader.new("mycshaders/vShaderWave", "mycshaders/fShaderWave", 0,
{
{name="g_MVPMatrix", type=Shader.CMATRIX, sys=Shader.SYS_WVP, vertex=true},
{name="g_Color", type=Shader.CFLOAT4, mult=1, sys=Shader.SYS_COLOR},
{name="g_Texture", type=Shader.CTEXTURE, mult=1, vertex=false},
{name="time", type=Shader.CFLOAT, mult=1, vertex=false}
},
{
{name="POSITION0", type=Shader.DFLOAT, mult=3, slot=0, offset=0},
{name="vColor", type=Shader.DUBYTE, mult=0, slot=1, offset=0},
{name="TEXCOORD0", type=Shader.DFLOAT, mult=2, slot=2, offset=0}
}
)
application:setBackgroundColor(0x333333)
local bitmap = Bitmap.new(Texture.new("gfx/test.png"))
local bitmap2 = bitmap:clone()
-- position
bitmap:setPosition(32*1, 32*4)
bitmap2:setPosition(32*6, 32*1)
-- shaders
bitmap:setShader(shaderwave)
bitmap2:setShader(shaderwave)
-- order
stage:addChild(bitmap)
stage:addChild(bitmap2)
-- loop
local timer = 0
stage:addEventListener(Event.ENTER_FRAME, function(e)
timer += 0.018
shaderwave:setConstant("time", Shader.CFLOAT, 1, timer)
bitmap:setX(bitmap:getX() + 1)
if bitmap:getX() > 400 then bitmap:setX(-80) end
end)
An Outline Shader FLAG_FROM_CODE
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 == 44) // fSwitch can be changed in code, 44 is some random value for documentation purposes
{
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},
}
)
local sprite = Bitmap.new(Texture.new("gfx/test.png"))
--spriteOutline.Shader:setConstant("fSwitch", Shader.CINT, 1, 44) -- set fSwitch value to be 44
sprite:setShader(spriteOutline.Shader)
sprite:setShaderConstant("fSwitch", Shader.CINT, 1, 44) -- set fSwitch value to be 44
stage:addChild(sprite)
A Pulsing Effect Shader FLAG_FROM_CODE - by Hgy29
local shaderV=[[
attribute highp vec3 vVertex;
attribute mediump vec2 vTexCoord;
uniform highp mat4 vMatrix;
varying mediump vec2 fTexCoord;
void main() {
vec4 vertex = vec4(vVertex,1.0);
gl_Position = vMatrix*vertex;
fTexCoord=vTexCoord;
}
]]
local scanlinesF=[[
uniform lowp sampler2D fTexture;
varying mediump vec2 fTexCoord;
uniform mediump vec4 fTextureSize;
uniform mediump float fTime;
lowp vec3 hsv2rgb(vec3 c) {
lowp vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
lowp vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}
void main() {
mediump vec4 pixel=texture2D(fTexture, fTexCoord);
mediump vec4 frag=pixel;
mediump vec2 centerDir=normalize((fTextureSize.xy/2.0-fTexCoord)/fTextureSize.xy)*fTextureSize.zw;
for (int k=-5;k<=5;k++)
frag=frag+texture2D(fTexture, fTexCoord-centerDir*float(k));
frag=frag/12.0;
if (frag.a<=0.0) discard;
if (pixel.a>=1.0)
gl_FragColor = pixel;
else
gl_FragColor = vec4(hsv2rgb(vec3(frag.a/2.0+fTime*2.0,0.7,1.0)),frag.a);
}
]]
local result,reply=pcall(Shader.new,shaderV,scanlinesF,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="fTextureSize",type=Shader.CFLOAT4,sys=Shader.SYS_TEXTUREINFO,vertex=false},
{name="fTime",type=Shader.CFLOAT,sys=Shader.SYS_TIMER,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}, })
PulsingEffect=reply
application:setBackgroundColor(0x442200)
local mysprite = Bitmap.new(Texture.new("gfx/checkbox.png"))
local mysprite2 = Bitmap.new(Texture.new("gfx/clock_hand_h.png"))
local mysprite3 = Bitmap.new(Texture.new("gfx/clock_hand_m.png"))
local mysprite4 = Bitmap.new(Texture.new("gfx/test.png"))
-- position
mysprite:setPosition(32*6, 32*3.35)
mysprite2:setPosition(32*10, 32*2)
mysprite3:setPosition(32*14, 32*2)
mysprite4:setPosition(32*10, 32*8)
-- order
stage:addChild(mysprite)
stage:addChild(mysprite2)
stage:addChild(mysprite3)
stage:addChild(mysprite4)
if not result then
print("Shader Compilation error:"..reply)
else
mysprite:setShader(PulsingEffect)
mysprite2:setShader(PulsingEffect)
mysprite3:setShader(PulsingEffect)
mysprite4:setShader(PulsingEffect)
end
Shadertoy Code Viewer (glsl)
This code reads Shadertoy shaders (no texture, no mouse). Simply replace the code in the local shadertoycode variable
https://www.shadertoy.com/view/MsjSW3
https://www.shadertoy.com/view/Xt2SDc
...
Full Shadertoy Gideros Viewer: https://forum.gideros.rocks/discussion/comment/66639#Comment_66639
Note: Shadertoy shaders are copyrighted
local function loadShader(xshader)
local vs = [[
attribute vec4 POSITION0;
attribute vec2 TEXCOORD0;
uniform mat4 g_MVPMatrix;
varying vec2 fragCoord;
varying vec2 texCoord;
void main()
{
texCoord = TEXCOORD0;
gl_Position = g_MVPMatrix * POSITION0;
}
]]
local ps = [[
#extension GL_OES_standard_derivatives : enable
#extension GL_EXT_shader_texture_lod : enable
vec4 texture2DGrad(sampler2D s, in vec2 uv, vec2 gx, vec2 gy) {
return texture2D(s, uv);
}
vec4 texture2DLod(sampler2D s, in vec2 uv, in float lod) {
return texture2D(s, uv);
}
uniform vec4 iResolution; // viewport resolution (in pixels)
uniform float iGlobalTime; // shader playback time (in seconds)
uniform float iTime; // shader playback time (in seconds)
uniform float iTimeDelta; // render time (in seconds)
uniform int iFrame; // shader playback frame
uniform float iChannelTime[4]; // channel playback time (in seconds)
uniform vec4 iMouse; // mouse pixel coords. xy: current (if MLB down), zw: click
uniform sampler2D iChannel0; // input channel #0. XX = 2D/Cube
uniform sampler2D iChannel1; // input channel #1. XX = 2D/Cube
uniform sampler2D iChannel2; // input channel #2. XX = 2D/Cube
uniform sampler2D iChannel3; // input channel #3. XX = 2D/Cube
uniform vec4 iDate; // (year, month, day, time in seconds)
uniform float iSampleRate; // sound sample rate (i.e., 44100)
varying vec2 texCoord;
varying vec2 fragCoord;
#ifdef GL_ES
precision mediump float;
#endif
]] .. xshader[1] .. [[
void main() {
vec4 color = vec4(0.0,0.0,0.0,1.0);
mainImage(color, gl_FragCoord.xy);
color.w = 1.0;
gl_FragColor = color;
}
]]
return Shader.new(vs, ps, Shader.FLAG_FROM_CODE,
{
{name="g_MVPMatrix",type=Shader.CMATRIX,sys=Shader.SYS_WVP, vertex=true},
{name="g_Color",type=Shader.CFLOAT4,mult=1,sys=Shader.SYS_COLOR},
{name="iResolution",type=Shader.CFLOAT4,mult=1,vertex=false},
{name="iGlobalTime",type=Shader.CFLOAT,mult=1,vertex=false},
{name="iTime",type=Shader.CFLOAT,mult=1,vertex=false},
{name="iTimeDelta",type=Shader.CFLOAT,mult=1,vertex=false},
{name="iFrame",type=Shader.CINT,mult=1,vertex=false},
{name="iChannelTime",type=Shader.CFLOAT,mult=1,vertex=false},
{name="iMouse",type=Shader.CFLOAT4,mult=1,vertex=false},
{name="iDate",type=Shader.CFLOAT4,mult=1,vertex=false},
{name="iSampleRate",type=Shader.CFLOAT,mult=1,vertex=false},
{name="iChannel0",type=Shader.CTEXTURE,mult=1,vertex=false},
{name="iChannel1",type=Shader.CTEXTURE,mult=1,vertex=false},
{name="iChannel2",type=Shader.CTEXTURE,mult=1,vertex=false},
{name="iChannel3",type=Shader.CTEXTURE,mult=1,vertex=false},
},
{
{name="POSITION0",type=Shader.DFLOAT,mult=3,slot=0,offset=0},
{name="vColor",type=Shader.DUBYTE,mult=0,slot=1,offset=0},
{name="TEXCOORD0",type=Shader.DFLOAT,mult=2,slot=2,offset=0},
}
)
end
function Shadertoy(xcode, width, height)
local effect = assert(loadShader(xcode))
local sprite
if application:getDeviceOrientation() == "Portrait" then
sprite = Pixel.new(nil, width, height)
else -- landscape
sprite = Pixel.new(nil, height, width)
end
sprite:setShader(effect)
local frame, time = 0, 0
stage:addEventListener(Event.ENTER_FRAME, function(event)
if xcapture then return end
frame = frame + 1
local t = time
local d = os.date("*t")
local s = d.hour * 3600 + d.min * 60 + d.sec
effect:setConstant("iResolution", Shader.CFLOAT4, 1, width, height, 0, 0)
effect:setConstant("iSampleRate", Shader.CFLOAT, 1, 44100)
effect:setConstant("iGlobalTime", Shader.CFLOAT, 1, t)
effect:setConstant("iTime", Shader.CFLOAT, 1, t)
effect:setConstant("iTimeDelta", Shader.CFLOAT, 1, event.deltaTime)
effect:setConstant("iFrame", Shader.CINT, 1, frame)
effect:setConstant("iChannelTime", Shader.CFLOAT, 4, t, t, t, t)
effect:setConstant("iDate", Shader.CFLOAT4, 1, d.year, d.month, d.day, s)
time = time + event.deltaTime
end)
return sprite
end
local w, h = application:getDeviceWidth(), application:getDeviceHeight()
local shadertoycode = [[
// Ether by nimitz 2014 (twitter: @stormoid)
// https://www.shadertoy.com/view/MsjSW3
// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
// Contact the author for other licensing options
#define t iTime
mat2 m(float a){float c=cos(a), s=sin(a);return mat2(c,-s,s,c);}
float map(vec3 p){
p.xz*= m(t*0.4);p.xy*= m(t*0.3);
vec3 q = p*2.+t;
return length(p+vec3(sin(t*0.7)))*log(length(p)+1.) + sin(q.x+sin(q.z+sin(q.y)))*0.5 - 1.;
}
void mainImage( out vec4 fragColor, in vec2 fragCoord ){
vec2 p = fragCoord.xy/iResolution.y - vec2(.9,.5);
vec3 cl = vec3(0.);
float d = 2.5;
for(int i=0; i<=5; i++) {
vec3 p = vec3(0,0,5.) + normalize(vec3(p, -1.))*d;
float rz = map(p);
float f = clamp((rz - map(p+.1))*0.5, -.1, 1. );
vec3 l = vec3(0.1,0.3,.4) + vec3(5., 2.5, 3.)*f;
cl = cl*l + smoothstep(2.5, .0, rz)*.7*l;
d += min(rz, 1.);
}
fragColor = vec4(cl, 1.);
}
]]
local ok, image
if application:getDeviceOrientation() == "Portrait" then
ok, image = pcall(Shadertoy, {shadertoycode}, w, h)
else
ok, image = pcall(Shadertoy, {shadertoycode}, h, w) -- landscape
end
if ok then stage:addChild(image) else image = nil print("shader error") end
