Touch Explosion 2d

gistfile1.txt

--# Main
-- Explosion

-- Use this function to perform your initial setup
function setup()
    --first generate a spherical mesh radius 1 around the origin
    --this uses an isosphere primitive code I made some time ago, but any sphere will do with sufficient vertices
    --the parameter to Sphere is how much to subdivide the faces (more vertices, slower performance)
    sphere = Primitive:Sphere(3)
    --attach the explosion shader to the mesh
    sphere.shader = shader(ExplosionShader.vertexShader,ExplosionShader.fragmentShader)
    --the texture gives the color gradient for the fire
    --get from http://www.clicktorelease.com/blog/vertex-displacement-webgl-glsl-perlin-noise-three-js/explosion.png
    sphere.shader.texture = readImage("Dropbox:explosion")
    
    size = 0.0
    
    --since this is being run as "2d" the standard projection matrix clips it.  This tweaked matrix makes it show
    --but I don't understand the maths, I just tweaked it till it worked.
    tweakOrthoProjMatrix = projectionMatrix()
    tweakOrthoProjMatrix[11] = -.001
    
    --an array to hold the currently active explosions
    bang = {}
end

function touched(touch)
    if touch.state == BEGAN then
        --add an explosion when it's touched
        table.insert(bang, {x = touch.x, y = touch.y, extraOffset = math.random(5000), startTime = ElapsedTime})
    end
end

-- This function gets called once every frame
function draw()
    output.clear()
    --print(1/DeltaTime)
    --print(size)
    -- This sets a dark background color 
    background(0, 0, 0)
    
    -- Do your drawing here
    --set the custom projection matrix
    projectionMatrix(tweakOrthoProjMatrix)
    for k,v in pairs(bang) do
        --get an arbitrary time to drive the animation
        time = ElapsedTime - v.startTime
        --move to touch location and scale to have a growing explosion
        translate(v.x, v.y)
        scale(30*time)
        --pass time information to the shader for animation
        sphere.shader.push = time / 5
        sphere.shader.offset = .4 * ElapsedTime + v.extraOffset
        sphere:draw()
        resetMatrix()
        if time > 4 then
          --remove expired explosions to avoid degrading performance
          bang[k] = nil
        end
    end
end


--shader is based on http://www.clicktorelease.com/blog/vertex-displacement-noise-3d-webgl-glsl-three-js
ExplosionShader = {
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;

uniform float offset;

//
// GLSL textureless classic 3D noise "cnoise",
// with an RSL-style periodic variant "pnoise".
// Author:  Stefan Gustavson (stefan.gustavson@liu.se)
// Version: 2011-10-11
//
// Many thanks to Ian McEwan of Ashima Arts for the
// ideas for permutation and gradient selection.
//
// Copyright (c) 2011 Stefan Gustavson. All rights reserved.
// Distributed under the MIT license. See LICENSE file.
// https://github.com/ashima/webgl-noise
//

vec3 mod289(vec3 x)
{
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec4 mod289(vec4 x)
{
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec4 permute(vec4 x)
{
  return mod289(((x*34.0)+1.0)*x);
}

vec4 taylorInvSqrt(vec4 r)
{
  return 1.79284291400159 - 0.85373472095314 * r;
}

vec3 fade(vec3 t) {
  return t*t*t*(t*(t*6.0-15.0)+10.0);
}

// Classic Perlin noise
float cnoise(vec3 P)
{
  vec3 Pi0 = floor(P); // Integer part for indexing
  vec3 Pi1 = Pi0 + vec3(1.0); // Integer part + 1
  Pi0 = mod289(Pi0);
  Pi1 = mod289(Pi1);
  vec3 Pf0 = fract(P); // Fractional part for interpolation
  vec3 Pf1 = Pf0 - vec3(1.0); // Fractional part - 1.0
  vec4 ix = vec4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
  vec4 iy = vec4(Pi0.yy, Pi1.yy);
  vec4 iz0 = Pi0.zzzz;
  vec4 iz1 = Pi1.zzzz;

  vec4 ixy = permute(permute(ix) + iy);
  vec4 ixy0 = permute(ixy + iz0);
  vec4 ixy1 = permute(ixy + iz1);

  vec4 gx0 = ixy0 * (1.0 / 7.0);
  vec4 gy0 = fract(floor(gx0) * (1.0 / 7.0)) - 0.5;
  gx0 = fract(gx0);
  vec4 gz0 = vec4(0.5) - abs(gx0) - abs(gy0);
  vec4 sz0 = step(gz0, vec4(0.0));
  gx0 -= sz0 * (step(0.0, gx0) - 0.5);
  gy0 -= sz0 * (step(0.0, gy0) - 0.5);

  vec4 gx1 = ixy1 * (1.0 / 7.0);
  vec4 gy1 = fract(floor(gx1) * (1.0 / 7.0)) - 0.5;
  gx1 = fract(gx1);
  vec4 gz1 = vec4(0.5) - abs(gx1) - abs(gy1);
  vec4 sz1 = step(gz1, vec4(0.0));
  gx1 -= sz1 * (step(0.0, gx1) - 0.5);
  gy1 -= sz1 * (step(0.0, gy1) - 0.5);

  vec3 g000 = vec3(gx0.x,gy0.x,gz0.x);
  vec3 g100 = vec3(gx0.y,gy0.y,gz0.y);
  vec3 g010 = vec3(gx0.z,gy0.z,gz0.z);
  vec3 g110 = vec3(gx0.w,gy0.w,gz0.w);
  vec3 g001 = vec3(gx1.x,gy1.x,gz1.x);
  vec3 g101 = vec3(gx1.y,gy1.y,gz1.y);
  vec3 g011 = vec3(gx1.z,gy1.z,gz1.z);
  vec3 g111 = vec3(gx1.w,gy1.w,gz1.w);

  vec4 norm0 = taylorInvSqrt(vec4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
  g000 *= norm0.x;
  g010 *= norm0.y;
  g100 *= norm0.z;
  g110 *= norm0.w;
  vec4 norm1 = taylorInvSqrt(vec4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
  g001 *= norm1.x;
  g011 *= norm1.y;
  g101 *= norm1.z;
  g111 *= norm1.w;

  float n000 = dot(g000, Pf0);
  float n100 = dot(g100, vec3(Pf1.x, Pf0.yz));
  float n010 = dot(g010, vec3(Pf0.x, Pf1.y, Pf0.z));
  float n110 = dot(g110, vec3(Pf1.xy, Pf0.z));
  float n001 = dot(g001, vec3(Pf0.xy, Pf1.z));
  float n101 = dot(g101, vec3(Pf1.x, Pf0.y, Pf1.z));
  float n011 = dot(g011, vec3(Pf0.x, Pf1.yz));
  float n111 = dot(g111, Pf1);

  vec3 fade_xyz = fade(Pf0);
  vec4 n_z = mix(vec4(n000, n100, n010, n110), vec4(n001, n101, n011, n111), fade_xyz.z);
  vec2 n_yz = mix(n_z.xy, n_z.zw, fade_xyz.y);
  float n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x); 
  return 2.2 * n_xyz;
}

// Classic Perlin noise, periodic variant
float pnoise(vec3 P, vec3 rep)
{
  vec3 Pi0 = mod(floor(P), rep); // Integer part, modulo period
  vec3 Pi1 = mod(Pi0 + vec3(1.0), rep); // Integer part + 1, mod period
  Pi0 = mod289(Pi0);
  Pi1 = mod289(Pi1);
  vec3 Pf0 = fract(P); // Fractional part for interpolation
  vec3 Pf1 = Pf0 - vec3(1.0); // Fractional part - 1.0
  vec4 ix = vec4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
  vec4 iy = vec4(Pi0.yy, Pi1.yy);
  vec4 iz0 = Pi0.zzzz;
  vec4 iz1 = Pi1.zzzz;

  vec4 ixy = permute(permute(ix) + iy);
  vec4 ixy0 = permute(ixy + iz0);
  vec4 ixy1 = permute(ixy + iz1);

  vec4 gx0 = ixy0 * (1.0 / 7.0);
  vec4 gy0 = fract(floor(gx0) * (1.0 / 7.0)) - 0.5;
  gx0 = fract(gx0);
  vec4 gz0 = vec4(0.5) - abs(gx0) - abs(gy0);
  vec4 sz0 = step(gz0, vec4(0.0));
  gx0 -= sz0 * (step(0.0, gx0) - 0.5);
  gy0 -= sz0 * (step(0.0, gy0) - 0.5);

  vec4 gx1 = ixy1 * (1.0 / 7.0);
  vec4 gy1 = fract(floor(gx1) * (1.0 / 7.0)) - 0.5;
  gx1 = fract(gx1);
  vec4 gz1 = vec4(0.5) - abs(gx1) - abs(gy1);
  vec4 sz1 = step(gz1, vec4(0.0));
  gx1 -= sz1 * (step(0.0, gx1) - 0.5);
  gy1 -= sz1 * (step(0.0, gy1) - 0.5);

  vec3 g000 = vec3(gx0.x,gy0.x,gz0.x);
  vec3 g100 = vec3(gx0.y,gy0.y,gz0.y);
  vec3 g010 = vec3(gx0.z,gy0.z,gz0.z);
  vec3 g110 = vec3(gx0.w,gy0.w,gz0.w);
  vec3 g001 = vec3(gx1.x,gy1.x,gz1.x);
  vec3 g101 = vec3(gx1.y,gy1.y,gz1.y);
  vec3 g011 = vec3(gx1.z,gy1.z,gz1.z);
  vec3 g111 = vec3(gx1.w,gy1.w,gz1.w);

  vec4 norm0 = taylorInvSqrt(vec4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
  g000 *= norm0.x;
  g010 *= norm0.y;
  g100 *= norm0.z;
  g110 *= norm0.w;
  vec4 norm1 = taylorInvSqrt(vec4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
  g001 *= norm1.x;
  g011 *= norm1.y;
  g101 *= norm1.z;
  g111 *= norm1.w;

  float n000 = dot(g000, Pf0);
  float n100 = dot(g100, vec3(Pf1.x, Pf0.yz));
  float n010 = dot(g010, vec3(Pf0.x, Pf1.y, Pf0.z));
  float n110 = dot(g110, vec3(Pf1.xy, Pf0.z));
  float n001 = dot(g001, vec3(Pf0.xy, Pf1.z));
  float n101 = dot(g101, vec3(Pf1.x, Pf0.y, Pf1.z));
  float n011 = dot(g011, vec3(Pf0.x, Pf1.yz));
  float n111 = dot(g111, Pf1);

  vec3 fade_xyz = fade(Pf0);
  vec4 n_z = mix(vec4(n000, n100, n010, n110), vec4(n001, n101, n011, n111), fade_xyz.z);
  vec2 n_yz = mix(n_z.xy, n_z.zw, fade_xyz.y);
  float n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x); 
  return 2.2 * n_xyz;
}

varying float noise;

float turbulence( vec3 p ) {
    float w = 100.0;
    float t = -.5;
    for (float f = 1.0 ; f <= 10.0 ; f++ ){
        float power = pow( 2.0, f );
        t += abs( pnoise( vec3( power * p ), vec3( 10.0, 10.0, 10.0 ) ) / power );
    }
    return t;
}

void main() {

    // get a turbulent 3d noise using the normal, normal to high freq
    noise = -1.0 * turbulence( 0.5 * position.xyz + offset );
    // get a 3d noise using the position, low frequency
    float b = 5.0 * pnoise( 1.3 * (position.xyz) + vec3( 2.0 * offset ), vec3( 100.0 ) );
    // compose both noises
    float displacement = -10. * noise + b;
    
    vec3 newPosition = position.xyz + ((position.xyz * displacement) / 20.0);
    gl_Position = modelViewProjection * vec4( newPosition, 1.0 );

}

]],
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 push;

varying float noise;

void main() {

    // lookup vertically in the texture, using noise
    // to get the right RGB colour
    vec2 tPos = vec2( 0, 0.5 + 1.0 * noise - push);
    vec4 color = texture2D( texture, tPos );

    gl_FragColor = vec4( color.rgb, 1.0 );

}

]] }

--# Primitive
Primitive = class()

--primitves gives basic mesh building for cubes and isospheres
--triangles are wound consistently to avoid gl_facing issues

function Primitive:Cube()
    m = mesh()
    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
    m.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],
    }
    return m 
end

function Primitive:Sphere(depth)
    m = mesh()
    local t = (1 + math.sqrt(5)) / 2
    --all the vertices of an icosohedron
    local vertices = {
            vec3(-1 , t, 0):normalize(),
            vec3(1 , t, 0):normalize(),
            vec3(-1 , -t, 0):normalize(),
            vec3(1 , -t, 0):normalize(),
            
            vec3(0 , -1, t):normalize(),
            vec3(0 , 1, t):normalize(),
            vec3(0 , -1, -t):normalize(),
            vec3(0 , 1, -t):normalize(),
            
            vec3(t , 0, -1):normalize(),
            vec3(t , 0, 1):normalize(),
            vec3(-t , 0, -1):normalize(),
            vec3(-t , 0, 1):normalize()
        }
    --20 faces
    icovertices = {
            -- 5 faces around point 0
            vertices[1], vertices[12], vertices[6],
            vertices[1], vertices[6], vertices[2],
            vertices[1], vertices[2], vertices[8],
            vertices[1], vertices[8], vertices[11],
            vertices[1], vertices[11], vertices[12],
            
            -- 5 adjacent faces
            vertices[2], vertices[6], vertices[10],
            vertices[6], vertices[12], vertices[5],
            vertices[12], vertices[11], vertices[3],
            vertices[11], vertices[8], vertices[7],
            vertices[8], vertices[2], vertices[9],
            
            -- 5 faces around point 3
            vertices[4], vertices[10], vertices[5],
            vertices[4], vertices[5], vertices[3],
            vertices[4], vertices[3], vertices[7],
            vertices[4], vertices[7], vertices[9],
            vertices[4], vertices[9], vertices[10],
            
            --5 adjacent faces
            vertices[5], vertices[10], vertices[6],
            vertices[3], vertices[5], vertices[12],
            vertices[7], vertices[3], vertices[11],
            vertices[9], vertices[7], vertices[8],
            vertices[10], vertices[9], vertices[2]
        }
    
    local finalVertices = {}
    --divide each triangle into 4 sub triangles to make an isosphere     
    --this can be repeated (based on depth) for higher res spheres   
    for j=1,depth do
        for i=1,#icovertices/3 do
            midpoint1 = ((icovertices[i*3-2] + icovertices[i*3-1])/2):normalize()
            midpoint2 = ((icovertices[i*3-1] + icovertices[i*3])/2):normalize()
            midpoint3 = ((icovertices[i*3] + icovertices[i*3-2])/2):normalize()
            --triangle 1
            table.insert(finalVertices,icovertices[i*3-2])
            table.insert(finalVertices,midpoint1)
            table.insert(finalVertices,midpoint3)
            --triangle 2
            table.insert(finalVertices,midpoint1)
            table.insert(finalVertices,icovertices[i*3-1])
            table.insert(finalVertices,midpoint2)
            --triangle 3
            table.insert(finalVertices,midpoint2)
            table.insert(finalVertices,icovertices[i*3])
            table.insert(finalVertices,midpoint3)
            --triangle 4
            table.insert(finalVertices,midpoint1)
            table.insert(finalVertices,midpoint2)
            table.insert(finalVertices,midpoint3) 
        end
        icovertices = finalVertices
        finalVertices = {}
    end
    m.vertices = icovertices
    return m
end