transparent

gistfile1.txt

function setup()
    m1=CreateMesh("Planet Cute:Character Princess Girl")
    m2=CreateMesh("Planet Cute:Character Pink Girl")
    m2.shader = shader(TransparentShader.vertexShader, TransparentShader.fragmentShader)
    m3=CreateMesh("Cargo Bot:Starry Background")
end
   
function CreateMesh(imgName)
   local img=readImage(imgName)  
    local m=mesh()
    m.texture=img
    local u=m:addRect(-img.width/2,-img.height/2,img.width,img.height)
    m:setRectTex(u,0,0,1,1)
    m:setColors(color(255))
    return m
end  

function draw()
   background(220)
   perspective()
   camera(0,20,200,0,0,0)
   pushMatrix()
   translate(0,0,-200)
   m1:draw()
   popMatrix()
   pushMatrix()
   translate(100,0,-200)
   m2:draw()
   popMatrix()
   pushMatrix()
   translate(120,20,-250)
   m3:draw()
   popMatrix()
end

TransparentShader = {
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;

void main()
{
    //Pass the mesh color to the fragment shader
    vColor = color;
    vTexCoord = texCoord;

    //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;

//The interpolated vertex color for this fragment
varying lowp vec4 vColor;

//The interpolated texture coordinate for this fragment
varying highp vec2 vTexCoord;

void main()
{
    lowp vec4 col=texture2D(texture, vTexCoord);
    if (col.a<0.2) discard;
    else gl_FragColor = col * vColor;
}

]]}