Shader:setConstant
From GiderosMobile
Available since: Gideros 2015.06.30
Class: Shader
Description
Changes the value of a uniform from Lua code.
Shader:setConstant(uniformName,dataType,mult,data)
Parameters
uniformName: (string) the uniform name to change
dataType: (int) the type of data to set (one of the Shader.Cxxx constants)
mult: (number) number of elements of the given type to set
data: (varies) and the actual data to set, either as a table or as multiple arguments
Examples
setConstant in a loop
-- 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 setConstant 44 activated
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 = 0.0;
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)
stage:addChild(sprite)
