Lighting Demo

--# Main
-- Cube
function setup()
    parameter.number("ambient", 0, 1, 0.1)
    parameter.number("diffuse", 0, 1, 1.0)
    parameter.number("specular", 0, 1, 1)
    parameter.color("lightColor", color(255,255,255,255))
    parameter.color("surfaceColor", color(191,41,85,255))
    allTextures = {
                    CAMERA,
                    "Cargo Bot:Crate Blue 2",
                    "Cargo Bot:Codea Icon",
                    "Small World:Store Extra Large",
                    "Small World:Windmill",
                  }
    
    cameraSource(CAMERA_FRONT)    
        
    cube = LitMesh()
    
    --vertices for the corners of the cube (stolen from 3d lab)
    local vertices = {
      vec3(-0.5, -0.5,  0.5), -- Left  bottom front
      vec3( 0.5, -0.5,  0.5), -- Right bottom front
      vec3( 0.5,  0.5,  0.5), -- Right top    front
      vec3(-0.5,  0.5,  0.5), -- Left  top    front
      vec3(-0.5, -0.5, -0.5), -- Left  bottom back
      vec3( 0.5, -0.5, -0.5), -- Right bottom back
      vec3( 0.5,  0.5, -0.5), -- Right top    back
      vec3(-0.5,  0.5, -0.5), -- Left  top    back
    }

    -- now construct a cube out of the vertices above
    cube.litMesh.vertices = {
      -- Front
      vertices[1], vertices[2], vertices[3],
      vertices[1], vertices[3], vertices[4],
      -- Right
      vertices[2], vertices[6], vertices[7],
      vertices[2], vertices[7], vertices[3],
      -- Back
      vertices[6], vertices[5], vertices[8],
      vertices[6], vertices[8], vertices[7],
      -- Left
      vertices[5], vertices[1], vertices[4],
      vertices[5], vertices[4], vertices[8],
      -- Top
      vertices[4], vertices[3], vertices[7],
      vertices[4], vertices[7], vertices[8],
      -- Bottom
      vertices[5], vertices[6], vertices[2],
      vertices[5], vertices[2], vertices[1],
    }
    
    --now texture it
    -- all the unique texture positions needed
    local texvertices = { vec2(0,0),
                          vec2(1,0),
                          vec2(0,1),
                          vec2(1,1) }
                
    -- apply the texture coordinates to each triangle
      
     cube.litMesh.texCoords = {
      -- Front
      texvertices[1], texvertices[2], texvertices[4],
      texvertices[1], texvertices[4], texvertices[3],
      -- Right
      texvertices[1], texvertices[2], texvertices[4],
      texvertices[1], texvertices[4], texvertices[3],
      -- Back
      texvertices[1], texvertices[2], texvertices[4],
      texvertices[1], texvertices[4], texvertices[3],
      -- Left
      texvertices[1], texvertices[2], texvertices[4],
      texvertices[1], texvertices[4], texvertices[3],
      -- Top
      texvertices[1], texvertices[2], texvertices[4],
      texvertices[1], texvertices[4], texvertices[3],
      -- Bottom
      texvertices[1], texvertices[2], texvertices[4],
      texvertices[1], texvertices[4], texvertices[3],
    }
    
    --setup vertex normals, tangents and binormals
    --only call this after vertexes and texture coordinates have been set on the mesh
    cube:deriveVertexNTB()
    
    cube:setLight(vec3(-2,2,-3), ambient, diffuse, specular, lightColor)
    cube:setEye(vec3(0,0,-3))
    cube:setColor(surfaceColor)
    
    doBumpMapUpdate = 0
    parameter.integer("Texture",0,5,0,changeTexture)
    parameter.integer("BumpMap",0,2,0,changeBumpMap)
    parameter.integer("xRotation",0,360)
    parameter.integer("yRotation",0,360)
    currentLocation = vec2(0,0)
end 

function changeBumpMap()
    if BumpMap == 0 or (BumpMap == 1 and Texture < 2) then
        cube:disableBumpMap()
    else
        if BumpMap == 1 then
            --generated from texture 
            bumpTexture = cube:generateTextureBumpMap(cubeTexture, 0.01)
            cube:setBumpMap(bumpTexture)
        end
        if BumpMap == 2 then
            --sphericalish
            bumpTexture = genCircularNormals(150)
            cube:setBumpMap(bumpTexture)
        end
    end 
end
    
function genCircularNormals(w)
    local t = image(w, w)
    r = w/1.5
    for x=1,w do
        for y=1,w do
            d = math.sqrt(((w/2-x)^2+(w/2-y)^2))
            if d <= r then
                angle = math.acos(d/r)
                z = r*math.sin(angle)
                v = (vec3(x-r,y-r,z):normalize()+vec3(1,1,1))/2*255

                t:set(x, y, v.x, v.y, v.z, 255)
            end             
        end
    end

    return t
end


function changeTexture()
    if Texture == 0 then
        --remove texture
        cube:setColor(surfaceColor)
    elseif Texture == 1 then
        cube:setTexture(CAMERA)
    else
        cubeTexture = readImage(allTextures[Texture])
        cube:setTexture(cubeTexture)
    end
    if BumpMap == 1 then
        doBumpMapUpdate = 30
    end
end                   


function draw()
    if CurrentTouch.state == MOVING then
        currentLocation.x = currentLocation.x + CurrentTouch.deltaX/500
        currentLocation.y = currentLocation.y + CurrentTouch.deltaY/500
    end    
    
    output.clear()
    print(1/DeltaTime)
    background(40, 40, 50)
    camera(0,0,-3,0,0,0)
    perspective()
    pushMatrix()
    translate(currentLocation.x, currentLocation.y, 0)
    rotate(xRotation,0,1,0)
    rotate(yRotation,1,0,0)
    --do rotation for touch
    cube:draw()
    popMatrix()
    
    if doBumpMapUpdate>0 then
        doBumpMapUpdate = doBumpMapUpdate - 1
        print(doBumpMapUpdate)
        if doBumpMapUpdate == 0 then
            changeBumpMap()
        end
    end
end


--# LitMesh
LitMesh = class()

--[[
    LitMesh provides a bumpmappable ADS (ambient/diffuse/specular) lighting enhanced class
    for meshes.
    
    usage:
setup()
    myObject = LitMesh()
    myObject.litMesh.vertices = some table of vertices
        -- this must be a multiple of 3 representing the triangles
        -- this is the normal mesh vertices array and can be manipulated as per docs
        -- eg myObject.litMesh:vertex(i, vec3(x,y,z))
        --    myObject.litMesh:setRect(i,x,y,w,h)
    myObject.litMesh.texCoords = some table of texture coordinates for the vertices
        -- this is the normal mesh texCoords array and can be
 manipulated as per the docs
        -- eg myObject.litMesh:texCoord(i, x, y)
        --    myObject.litMesh:setRectTex(i,s,t,w,h)
    --Once all vertexes and texture coordinates have been set call:
    myObject:deriveVertexNTB()
    -- you will need to make this call again if you modify any vertexes or texture coordinates
    --setup lighting
        --lightPosition is the location of the light in world space
        --eyePosition is the location of the camera in world space this is the eye vector in your camera() call
    myObject:setLight(vec3(lightPosition), ambient, diffuse, specular, lightColor)
    --set the eye position which is the eye vector from your camera statement
    myObject:setEye(vec3(eyePosition))
    --then either color or texture your mesh with one of
    myObject:setColor(color)
    myObject:setTexture(texture)
    --finally if you wish to use bumpmapping set a bumpmap
    myObject:setBumpMap(bumpMap)
    --a bumpMap is just an image with normal vectors encoded into the colors, these can be generated in tools like blender or photoshop
    --Alternately the LitMesh class contains (a poor performing) helper method for generating bumpMaps from your texture: - strength is how aggressive the edge mapping is 0.01 is a good start
    myObject:generateTextureBumpMap(texture, strength)
    --this could be used as a shortcut by:
    bumpTexture = cube:generateTextureBumpMap(cubeTexture, 0.01)
    myObject:setBumpMap(bumpTexture)
    
draw()
    --do all your normal drawing activity
    background(40, 40, 50)
    camera(eyex, eyey, eyez, lookatx, lookaty, lookatz)
    --if the camera eye is moving remember to do
    myObject:setEye(vec3(eyex, eyey, eyez))
    perspective()
    
    --object drawing
    pushMatrix()
    translate(x,y,z) --move centre of your mesh wherever
    rotate(angle,x,y,z) -- rotate your object about it's centre
    myObject:draw()
    popMatrix()
]]

function LitMesh:init()
    self.litMesh = mesh()
    self.litMesh.shader = shader(LitMesh.ADSLighting.vertexShader, LitMesh.ADSLighting.fragmentShader)
    self.litMesh.shader.useTexture = false
    self.litMesh.shader.useBumpMap = false
end

function LitMesh:draw()
    self.litMesh.shader.mInvModel = modelMatrix():inverse():transpose()
    self.litMesh:draw()
end

function LitMesh:setLight(lightPosition, ambient, diffuse, specular, lightColor)
    self.litMesh.shader.vLightPosition = lightPosition
    self.litMesh.shader.vAmbientMaterial = ambient  
    self.litMesh.shader.vDiffuseMaterial = diffuse
    self.litMesh.shader.vSpecularMaterial = specular
    self.litMesh.shader.lightColor = lightColor 
end

function LitMesh:setEye(eyePosition)
    self.litMesh.shader.vEyePosition = eyePosition
end

function LitMesh:setTexture(texture)
    self.litMesh.shader.useTexture = true
    self.litMesh.texture = texture
end

function LitMesh:disableBumpMap()
    self.litMesh.shader.useBumpMap = false
end

function LitMesh:setBumpMap(bumpMap)
    self.litMesh.shader.useBumpMap = true
    self.litMesh.shader.bumpMap = bumpMap
end

function LitMesh:setColor(surfaceColor)
    --assumes the reason you are setting the color is because you don't want to use a texture
    self.litMesh.texture = nil
    self.litMesh.shader.useTexture = false
    self.litMesh:setColors(surfaceColor)
end

function LitMesh:deriveVertexNTB()
    --this will calculate the tangent, binormal and from those the normal for each vertex, these will all be stored in buffers
    --assumes that the surfaces have their texture coordinates set (even if being left untextured)
    --tangent is the X axis on the plane of the surface relative to textures
    --binormal is the Y axis on the plane of the surface relative to textures
    --normal is the surface normal
    local texCoordBuffer = self.litMesh:buffer("texCoord")

    if texCoordBuffer.length == self.litMesh.size then
        useTexCoords = true
    else
        useTexCoords = false
    end
    local normalBuffer = self.litMesh:buffer("normal")
    normalBuffer:resize(self.litMesh.size)
    local tangentBuffer = self.litMesh:buffer("tangent")
    tangentBuffer:resize(self.litMesh.size)
    local binormalBuffer = self.litMesh:buffer("binormal")
    binormalBuffer:resize(self.litMesh.size)
    local tangent,binormal, normal
    for i=1, self.litMesh.size/3 do
        --calculate the surface vectors
        local v1 = self.litMesh:vertex(i*3-1) - self.litMesh:vertex(i*3-2)
        local v2 = self.litMesh:vertex(i*3) - self.litMesh:vertex(i*3-2)
        --calculate the texture space vectors
        if useTexCoords then
            local tuV = vec2(self.litMesh:texCoord(i*3-1).x - self.litMesh:texCoord(i*3-2).x, self.litMesh:texCoord(i*3).x - self.litMesh:texCoord(i*3-2).x)
            local tvV = vec2(self.litMesh:texCoord(i*3-1).y - self.litMesh:texCoord(i*3-2).y, self.litMesh:texCoord(i*3).y - self.litMesh:texCoord(i*3-2).y)
            --calculate denominator
            local den=1/(tuV.x*tvV.y - tuV.y*tvV.x)
            --tangent
            tangent = vec3((tvV.y*v1.x - tvV.x*v2.x)*den, (tvV.y*v1.y - tvV.x*v2.y)*den, (tvV.y*v1.z - tvV.x*v2.z)*den):normalize()
            binormal = vec3((tuV.x*v2.x - tuV.y*v1.x)*den, (tuV.x*v2.y - tuV.y*v1.y)*den, (tuV.x*v2.z - tuV.y*v1.z)*den):normalize()
            normal = tangent:cross(binormal):normalize()
        else
            tangent = v1:normalize()
            normal = v1:normalize():cross(v2:normalize()):normalize()
            binormal = normal:cross(tangent):normalize() 
        end
            
        for j=i*3-2,i*3 do
            normalBuffer[j] = normal
            binormalBuffer[j] = binormal
            tangentBuffer[j] = tangent
        end
    end
end

function LitMesh:generateTextureBumpMap(source, strength)
    local t = image(source.width, source.height)
    for y=2,source.height-1 do
        for x=2,source.width-1 do
            r,g,b,a = source:get(x-1,y)
            xLeft = (0.3*r+0.59*g+0.11*b)*strength
            r,g,b,a = source:get(x+1,y)
            xRight = (0.3*r+0.59*g+0.11*b)*strength
            r,g,b,a = source:get(x,y-1)
            yUp = (0.3*r+0.59*g+0.11*b)*strength
            r,g,b,a = source:get(x,y+1)
            yDown = (0.3*r+0.59*g+0.11*b)*strength
            xDelta = ((xLeft-xRight)+1)*127.5
            yDelta = ((yUp - yDown)+1)*127.5
            t:set(x,y,color(xDelta,yDelta,255,255))
        end
    end
    for y=1,source.height do
        t:set(1,y,color(0,0,255,255))
        t:set(source.width,y,color(0,0,255,255))
    end
    for x=1,source.width do
        t:set(x,1,color(0,0,255,255))
        t:set(x,source.height,color(0,0,255,255))
    end
    return t
end


LitMesh.ADSLighting = {
--shader()
vertexShader = [[
uniform mat4 modelViewProjection;
uniform mat4 mInvModel;
uniform vec3 vEyePosition;
uniform vec3 vLightPosition;

attribute vec4 position;
attribute vec4 color;
attribute vec2 texCoord;
attribute vec3 normal;
attribute vec3 tangent;
attribute vec3 binormal;

varying lowp vec4 vColor;
varying mediump vec2 vTexCoord;
varying mediump vec3 lightDirection;
varying mediump vec3 eyeDirection; 

void main()
{
    mat3 tangentMatrix = mat3(tangent, binormal, normal);
    
    //convert the positions to object space, then get direction, then convert to tangent space
    lightDirection = (normalize((vec4(vLightPosition,1) * mInvModel) - position).xyz
        * tangentMatrix).xyz;
    eyeDirection = (normalize((vec4(vEyePosition,1) * mInvModel) - position).xyz
        * tangentMatrix).xyz;

    vColor = color;
    vTexCoord = vec2(texCoord.x, texCoord.y);

    gl_Position = modelViewProjection * position;
}
]],

fragmentShader = [[
precision mediump float;

uniform lowp sampler2D texture;
uniform lowp sampler2D bumpMap;
uniform bool useTexture;
uniform bool useBumpMap;

varying highp vec2 vTexCoord;
varying lowp vec4 vColor;
varying mediump vec3 lightDirection;
varying mediump vec3 eyeDirection; 

uniform float vAmbientMaterial;
uniform float vDiffuseMaterial;
uniform float vSpecularMaterial;
uniform vec4 lightColor;


// Returns the specular component of the color
vec4 GetSpecularColor(vec3 vTransformedNormal)
{
    //normalise because interpolation may have broken it
    vec3 vLightDirection = normalize(lightDirection);
    vec3 vCameraDirection = normalize(eyeDirection);

    // Calculate the reflection vector between the incoming light and the
    // normal (incoming angle = outgoing angle)
    vec3 vReflection = reflect( -vLightDirection, vTransformedNormal );
 
    // Calculate specular component
    // Based on the dot product between the reflection vector and the camera
    // direction.
    float spec = pow( max( 0.0, dot( vCameraDirection, vReflection )), 32.0 );
 
    return lowp vec4( lightColor.r * spec, lightColor.g * spec, lightColor.b * spec, 1.0 ) * vSpecularMaterial;
}
 
// Ambient color component of vertex
vec4 GetAmbientColor(vec4 texCol)
{
    lowp vec4 vAmbientColor;
    vAmbientColor.xyz = texCol.rgb * lightColor.rgb * vAmbientMaterial;
    vAmbientColor.a = 1.0;
    
    return vAmbientColor;
}
 
// Diffuse Color component of vertex
vec4 GetDiffuseColor(vec3 vTransformedNormal, vec4 texCol)
{
    vec3 vLightDirection = normalize(normalize(lightDirection));
    
    // Calculate Diffuse intensity
    float fDiffuseIntensity = max( 0.0, dot( vTransformedNormal, vLightDirection ));
 
    // Calculate resulting Color
    lowp vec4 vDiffuseColor;
    vDiffuseColor.xyz = texCol.rgb * lightColor.rgb * fDiffuseIntensity * vDiffuseMaterial;
    vDiffuseColor.a = 1.0;
    
    return vDiffuseColor;
}

void main()
{
    mediump vec3 curNormal;
    if (useBumpMap) {
        lowp vec4 bump = texture2D( bumpMap, vTexCoord );
        if (bump.x == 0.0 && bump.y == 0.0 && bump.z == 0.0) discard;
        curNormal = normalize(vec3(bump.x, bump.y, bump.z)*2.0-vec3(1.0,1.0,1.0));
    }
    else {
        curNormal = vec3(0.0,0.0,1.0);
    }
    lowp vec4 curCol;
    if (useTexture) {
        curCol = texture2D( texture, vTexCoord);
        if (curCol.a == 0.0) discard;
    }
    else {
        curCol = vColor;
    }
    
    
    lowp vec4 ambientColor = GetAmbientColor(curCol);
    lowp vec4 diffuseColor = GetDiffuseColor(curNormal, curCol);
    lowp vec4 specularColor = GetSpecularColor(curNormal);
    
    // Combine into final color
    lowp vec4 outColor;
    outColor = ambientColor + diffuseColor + specularColor;

    //Set the output color to the texture color
    gl_FragColor = outColor;
}
]]
}

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