tilershader

gistfile1.txt

function setup()
    img=readImage("Platformer Art:Block Brick")
    --note that when parameter values change, CreateMesh will be called
    --and this will rebuild the mesh at the new size
    parameter.integer("MeshWidth",20,700,100,CreateMesh)
    parameter.integer("MeshHeight",20,700,100,CreateMesh)
    print("Slide the sliders to change the size of the mesh")
end

function CreateMesh()
    --CreateMesh will be called for the first time when the parameters are defined above, which creates
    --a problem with the first one, because MeshHeight hasn't been defined yet (it's the second one!). So
    --the first line below just returns if we're not ready to build it yet. So the MeshHeight parameter
    --will also call CreateMesh, and this time it will be ok to continue. After this, this function will
    --only be called if the user changes size.
    if MeshHeight==nil then return end
    --clear any existing mesh
    if m~=nil then m:clear() else m=mesh() end
    m.texture=img
    --calculate how many images will fit into our mesh
    nx,ny=MeshWidth/img.width,MeshHeight/img.height
    --create the mesh, one big rectangle with 6 vertices
    v,t={},{}
    v[1]=vec3(0,0,0)                  t[1]=vec2(0,0)
    v[2]=vec3(MeshWidth,0,0)          t[2]=vec2(nx,0)
    v[3]=vec3(MeshWidth,MeshHeight,0) t[3]=vec2(nx,ny)
    v[4]=vec3(MeshWidth,MeshHeight,0) t[4]=vec2(nx,ny)
    v[5]=vec3(0,MeshHeight,0)         t[5]=vec2(0,ny)
    v[6]=vec3(0,0,0)                  t[6]=vec2(0,0)
    m.vertices=v
    m.texCoords=t
    m:setColors(color(255))
    m.shader = shader(TilerShader.vertexShader, TilerShader.fragmentShader)
end

function draw()
    background(200)
    pushMatrix()
    translate(10,10)
    m:draw()
    popMatrix()
end


TilerShader = {
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()
{
    //Sample the texture at the interpolated coordinate
    lowp vec4 col = texture2D( texture, vec2(mod(vTexCoord.x,1.0), mod(vTexCoord.y,1.0))) * vColor;

    //Set the output color to the texture color
    gl_FragColor = col;
}

]]}