Recursive Sierpinski triangle (just a bit of fun)

@Chrisir I’ve been developing a ruby-processing equivalent of Shadertoy2processing on github so I used the shadertoy 3D sierpinski as a test:-
sierpinski

Runs at 60 fps for me linux box as before.

attr_reader :last_mouse_position, :mouse_click_state, :mouse_dragged
attr_reader :previous_time, :wrapper, :start

def settings
  size(640, 360, P2D)
end

def setup
  sketch_title '3D Sierpinski'
  @previous_time = 0.0
  @mouse_dragged = false
  @mouse_click_state = 0.0
  # Load the shader file from the "data" folder
  @wrapper = load_shader(data_path('sierpinski.glsl'))
  # Assume the dimension of the window will not change over time
  wrapper.set('iResolution', width.to_f, height.to_f, 0.0)
  @last_mouse_position = Vec2D.new(mouse_x.to_f, mouse_y.to_f)
  @start = java.lang.System.current_time_millis
end

def draw
  puts frame_rate if (frame_count % 300).zero?
  # shader playback time (in seconds)
  current_time = (java.lang.System.current_time_millis - start) / 1000.0
  wrapper.set('iTime', current_time)
  # mouse pixel coords. xy: current (if MLB down), zw: click
  if mouse_pressed?
    @last_mouse_position = Vec2D.new(mouse_x.to_f, mouse_y.to_f)
    @mouse_click_state = 1.0
  else
    @mouse_click_state = 0.0
  end
  wrapper.set('iMouse', last_mouse_position.x, last_mouse_position.y, mouse_click_state, mouse_click_state)
  shader(wrapper)
  # Draw the output of the shader onto a rectangle that covers the whole viewport.
  rect(0, 0, width, height)
end

Shader:-

// The MIT License
// Copyright © 2013 Inigo Quilez
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


#ifdef GL_ES
precision mediump float;
precision mediump int;
#endif

// ----------------------
// SHADERTOY UNIFORMS  -
// ----------------------

uniform vec3      iResolution;           // viewport resolution (in pixels)
uniform float     iTime;                 // shader playback time (in seconds)
uniform vec4      iMouse;                // mouse pixel coords. xy: current (if MLB down), zw: click

void mainImage( out vec4 fragColor, in vec2 fragCoord );

void main() {
    mainImage(gl_FragColor,gl_FragCoord.xy);
}

const vec3 va = vec3(  0.0,  0.57735,  0.0 );
const vec3 vb = vec3(  0.0, -1.0,  1.15470 );
const vec3 vc = vec3(  1.0, -1.0, -0.57735 );
const vec3 vd = vec3( -1.0, -1.0, -0.57735 );

// return distance and address
vec2 map( vec3 p )
{
	float a = 0.0;
    float s = 1.0;
    float r = 1.0;
    float dm;
    vec3 v;
    for( int i=0; i<8; i++ )
	{
	    float d, t;
		d = dot(p-va,p-va);              v=va; dm=d; t=0.0;
        d = dot(p-vb,p-vb); if( d<dm ) { v=vb; dm=d; t=1.0; }
        d = dot(p-vc,p-vc); if( d<dm ) { v=vc; dm=d; t=2.0; }
        d = dot(p-vd,p-vd); if( d<dm ) { v=vd; dm=d; t=3.0; }
		p = v + 2.0*(p - v); r*= 2.0;
		a = t + 4.0*a; s*= 4.0;
	}

	return vec2( (sqrt(dm)-1.0)/r, a/s );
}

const float precis = 0.0002;

vec3 intersect( in vec3 ro, in vec3 rd )
{
	vec3 res = vec3( 1e20, 0.0, 0.0 );

	float maxd = 5.0;

	// sierpinski
    float h = 1.0;
    float t = 0.5;
	float m = 0.0;
    vec2 r;
	for( int i=0; i<100; i++ )
    {
	    r = map( ro+rd*t );
        if( r.x<precis || t>maxd ) break;
		m = r.y;
        t += r.x;
    }

    if( t<maxd && r.x<precis )
		res = vec3( t, 2.0, m );

	return res;
}

vec3 calcNormal( in vec3 pos )
{
    vec3 eps = vec3(precis,0.0,0.0);
	return normalize( vec3(
           map(pos+eps.xyy).x - map(pos-eps.xyy).x,
           map(pos+eps.yxy).x - map(pos-eps.yxy).x,
           map(pos+eps.yyx).x - map(pos-eps.yyx).x ) );
}

float calcOcclusion( in vec3 pos, in vec3 nor )
{
	float ao = 0.0;
    float sca = 1.0;
    for( int i=0; i<8; i++ )
    {
        float h = 0.001 + 0.5*pow(float(i)/7.0,1.5);
        float d = map( pos + h*nor ).x;
        ao += -(d-h)*sca;
        sca *= 0.95;
    }
    return clamp( 1.0 - 0.8*ao, 0.0, 1.0 );
}

vec3 lig = normalize(vec3(1.0,0.7,0.9));

vec3 render( in vec3 ro, in vec3 rd )
{
    vec3 col = vec3(0.0);

	// raymarch
    vec3 tm = intersect(ro,rd);
    if( tm.y>0.5 )
    {
        // geometry
        vec3 pos = ro + tm.x*rd;
		vec3 nor = calcNormal( pos );
		vec3 maa = vec3( 0.0 );

        maa = 0.5 + 0.5*cos( 6.2831*tm.z + vec3(0.0,1.0,2.0) );

		float occ = calcOcclusion( pos, nor );

		// lighting
		float amb = (0.5 + 0.5*nor.y);
		float dif = max(dot(nor,lig),0.0);

        // lights
		vec3 lin = 1.5*amb*vec3(1.0) * occ;

		// surface-light interacion
		col = maa * lin;

	}

    // gamma
	col = pow( clamp(col,0.0,1.0), vec3(0.45) );

    return col;
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	vec2 q = fragCoord.xy / iResolution.xy;
    vec2 p = -1.0 + 2.0 * q;
    p.x *= iResolution.x/iResolution.y;
    vec2 m = vec2(0.5);
	if( iMouse.z>0.0 ) m = iMouse.xy/iResolution.xy;

    //-----------------------------------------------------
    // camera
    //-----------------------------------------------------

	float an = 3.2 + 0.5*iTime - 6.2831*(m.x-0.5);

	vec3 ro = vec3(2.5*sin(an),0.0,2.5*cos(an));
    vec3 ta = vec3(0.0,-0.5,0.0);
    vec3 ww = normalize( ta - ro );
    vec3 uu = normalize( cross(ww,vec3(0.0,1.0,0.0) ) );
    vec3 vv = normalize( cross(uu,ww));
	vec3 rd = normalize( p.x*uu + p.y*vv + 5.0*ww*m.y );

    vec3 col = render( ro, rd );

    fragColor = vec4( col, 1.0 );
}

void mainVR( out vec4 fragColor, in vec2 fragCoord, in vec3 fragRayOri, in vec3 fragRayDir )
{
    vec3 col = render( fragRayOri + vec3(0.0,-0.1,2.0), fragRayDir );

    fragColor = vec4( col, 1.0 );
}
// ----------------------------
//  SHADERTOY CODE ENDS HERE  -
// ----------------------------

The beauty of JRubyArt is that you can develop ruby code and shader code in atom, and test without leaving atom.

5 Likes