tileshader

gistfile1.txt

function setup()
    parameter.integer("ChooseImage",1,3,1)
    parameter.integer("Fader",0,255,100)
    parameter.boolean("Mist",true)
    tileWidth,tileHeight=101,171
    img=CreateImage()
    m=mesh()
    m:addRect(0,0,img.width,img.height)
    m.texture=img
    m.shader=shader(tileShader.vertexShader,tileShader.fragmentShader)
end

function CreateImage()
    local img=image(tileWidth*3,tileHeight)
    setContext(img)
    spriteMode(CORNER)
    sprite("Planet Cute:Character Horn Girl",0,0)
    sprite("Planet Cute:Character Pink Girl",tileWidth,0)
    sprite("Planet Cute:Character Princess Girl",tileWidth*2,0)
    setContext()
    return img
end
    
function draw()
    background(220)
    --1 for mist, 0 for light/dark
    if Mist then m.shader.mist=1 else m.shader.mist=0 end
    m.shader.fade=Fader/255 -- low=more mist/dark, high=less mist/more light
    --tell shader which part of the image to fade, as fraction of width and height
    --set all to 0 if not needed
    local x1,y1=(ChooseImage-1)*tileWidth/img.width,0
    local x2,y2=x1+tileWidth/img.width,tileHeight/img.height
    m.shader.tile=vec4(x1,y1,x2,y2)
    --draw the mesh somewhere random
    pushMatrix()
    translate(200,300)
    m:draw()
    popMatrix()
end
 
tileShader = {
vertexShader = [[
//
// A basic vertex shader
//
 
//This is the current model * view * projection matrix
// Codea sets it automatically
uniform mat4 modelViewProjection;
 
//This is the current mesh vertex position, color and tex coord
// Set automatically
attribute vec4 position;
attribute vec4 color;
attribute vec2 texCoord;
 
//This is an output variable that will be passed to the fragment shader
varying lowp vec4 vColor;
varying highp vec2 vTexCoord;
varying vec4 vPos;
 
void main()
{
    //Pass the mesh color to the fragment shader
    vColor=color;
    vTexCoord = texCoord;
    vPos=position;
 
    //Multiply the vertex position by our combined transform
    gl_Position = modelViewProjection * position;
}
 
]],
fragmentShader = [[
//
// A basic fragment shader
//
 
//Default precision qualifier
precision highp float;
 
//This represents the current texture on the mesh
uniform lowp sampler2D texture;
uniform float fade;
uniform float mist;
uniform vec4 tile;
 
//The interpolated vertex color for this fragment
varying lowp vec4 vColor;
//varying vec4 vPos;
 
//The interpolated texture coordinate for this fragment
varying highp vec2 vTexCoord;
 
void main()
{
    //Sample the texture at the interpolated coordinate
    lowp vec4 col =texture2D( texture, vTexCoord) * vColor;
    if (col.a>0. && vTexCoord.x>=tile.x && vTexCoord.x<=tile.z && vTexCoord.y>=tile.y && vTexCoord.y<=tile.w)  
        {
        if (mist==0.) col.rgb = col.rgb*fade;
        else col=col*fade;
        }
    gl_FragColor =col;
}
 
]]}