Terrain.lua

--# Main
-- Terrain

function setup()
    displayMode(FULLSCREEN)
    forward, right, up = vec3(0,0,1), vec3(-1,0,0), vec3(0,1,0)
    t = Terrain()
    A = 0
end

function draw()
    background(40, 40, 50)

    perspective(45, WIDTH/HEIGHT, .1, 500000)
    local m = matrix()
        :rotate(RotationRate.z, forward.x,forward.y,forward.z)
        :rotate(-RotationRate.x, right.x,right.y,right.z)
        :rotate(-RotationRate.y, up.x,up.y,up.z)
    forward, right, up = mult(m,forward),mult(m,right),mult(m,up)
    camera(0,0,0, forward.x,forward.y,forward.z, up.x, up.y, up.z)
    rotate(A,0,1,0)

    translate(0,-1000,0)
    rotate(-90,1,0,0)
    t:draw()
end

function mult(m, v) -- matrix multiplication
    return vec3(
        m[1]*v.x+m[2]*v.y+m[3]*v.z,
        m[5]*v.x+m[6]*v.y+m[7]*v.z,
        m[9]*v.x+m[10]*v.y+m[11]*v.z
    )
end

function touched(touch)
    if touch.state == MOVING then
        A = A + touch.deltaX*.2
    end
end
--# Terrain
Terrain = class()

function Terrain:init(x)
    local d,s = 1000,100
    self.m = mesh()
    for y=-s,s do
        for x=-s,s do
            self.m:addRect(x*d,y*d,d,d)
        end
    end
    self.m.texture = readImage("Cargo Bot:Crate Yellow 1")
    self.m.shader = S
end

function Terrain:draw()
    self.m:draw()
end

--# Perlin
Perlin = [[
//
// Description : Array and textureless GLSL 2D simplex noise function.
//      Author : Ian McEwan, Ashima Arts.
//  Maintainer : ijm
//     Lastmod : 20110822 (ijm)
//     License : Copyright (C) 2011 Ashima Arts. 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;
}

vec2 mod289(vec2 x) {
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec3 permute(vec3 x) {
  return mod289(((x*34.0)+1.0)*x);
}

float snoise(vec2 v)
  {
  const vec4 C = vec4(0.211324865405187,  // (3.0-sqrt(3.0))/6.0
                      0.366025403784439,  // 0.5*(sqrt(3.0)-1.0)
                     -0.577350269189626,  // -1.0 + 2.0 * C.x
                      0.024390243902439); // 1.0 / 41.0
// First corner
  vec2 i  = floor(v + dot(v, C.yy) );
  vec2 x0 = v -   i + dot(i, C.xx);

// Other corners
  vec2 i1;
  //i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
  //i1.y = 1.0 - i1.x;
  i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
  // x0 = x0 - 0.0 + 0.0 * C.xx ;
  // x1 = x0 - i1 + 1.0 * C.xx ;
  // x2 = x0 - 1.0 + 2.0 * C.xx ;
  vec4 x12 = x0.xyxy + C.xxzz;
  x12.xy -= i1;

// Permutations
  i = mod289(i); // Avoid truncation effects in permutation
  vec3 p = permute( permute( i.y + vec3(0.0, i1.y, 1.0 ))
                + i.x + vec3(0.0, i1.x, 1.0 ));

  vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0);
  m = m*m ;
  m = m*m ;

// Gradients: 41 points uniformly over a line, mapped onto a diamond.
// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)

  vec3 x = 2.0 * fract(p * C.www) - 1.0;
  vec3 h = abs(x) - 0.5;
  vec3 ox = floor(x + 0.5);
  vec3 a0 = x - ox;

// Normalise gradients implicitly by scaling m
// Approximation of: m *= inversesqrt( a0*a0 + h*h );
  m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );

// Compute final noise value at P
  vec3 g;
  g.x  = a0.x  * x0.x  + h.x  * x0.y;
  g.yz = a0.yz * x12.xz + h.yz * x12.yw;
  return 130.0 * dot(m, g);
}
]]
--# Shader

S = shader(Perlin .. [[
        uniform mat4 modelViewProjection;
        attribute vec4 position;
        attribute vec4 color;
        attribute vec2 texCoord;
        uniform vec3 pos;
        varying lowp vec4 vColor;
        varying highp vec2 vTexCoord;
        
        void main() {
            vColor = color;
            vTexCoord = texCoord;
            vec4 p = position;
            p.z = p.z + snoise(p.xy*.001)*20. +
            snoise((p.xy-vec2(1.,1.))*.0001)*1000. +
            snoise((p.xy-vec2(1.,1.))*.00002)*5000.;
            gl_Position = modelViewProjection * p;
        }
    ]], [[
        uniform lowp sampler2D texture;
        varying lowp vec4 vColor;
        varying highp vec2 vTexCoord;
         
        void main() {
            lowp vec4 res = texture2D(texture, vTexCoord);
            gl_FragColor = res * vColor;
        }
    ]])