Created
June 6, 2013 04:25
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-- StencilMask | |
-- Use this function to perform your initial setup | |
function setup() | |
parameter.boolean("Negative",false) | |
img=readImage("Cargo Bot:Starry Background") | |
stencilImg=readImage("Planet Cute:Character Princess Girl") | |
m=mesh() | |
u=m:addRect(0,0,img.width,img.height) | |
m:setRectTex(u,0,0,1,1) | |
m.texture=img | |
m.shader = shader(stencilShader.vertexShader, stencilShader.fragmentShader) | |
m.shader.texture2=stencilImg | |
m.shader.negative=Negative | |
end | |
function draw() | |
background(200) | |
pushMatrix() | |
translate(300,300) | |
m.shader.negative=Negative | |
m:draw() | |
popMatrix() | |
end | |
stencilShader = { | |
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; | |
uniform lowp sampler2D texture2; | |
uniform bool negative; | |
//The interpolated vertex color for this fragment | |
varying lowp vec4 vColor; | |
//The interpolated texture coordinate for this fragment | |
varying highp vec2 vTexCoord; | |
void main() | |
{ | |
//Sample the texture at the interpolated coordinate | |
lowp vec4 col1 = texture2D( texture, vTexCoord ); | |
lowp vec4 col2 = texture2D( texture2, vTexCoord ); | |
if (negative) | |
{if (col2.a>0.) gl_FragColor = col1; else discard;} | |
else if (col2.a==0.) gl_FragColor = col1; else discard; | |
} | |
]]} |
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