Signed distance fields #

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//Esfera
float sdSphere( vec3 p, float s )
{
return length(p)-s;
}

//Caja
float sdBox( vec3 p, vec3 b )
{
vec3 q = abs(p) - b;
return length(max(q,0.0)) + min(max(q.x,max(q.y,q.z)),0.0);
}

//Tourus
float sdTorus( vec3 p, vec2 t )
{
vec2 q = vec2(length(p.xz)-t.x,p.y);
return length(q)-t.y;
}

//Cono
float sdCone( in vec3 p, in vec2 c, float h )
{
// c is the sin/cos of the angle, h is height
// Alternatively pass q instead of (c,h),
// which is the point at the base in 2D
vec2 q = h\*vec2(c.x/c.y,-1.0);

vec2 w = vec2( length(p.xz), p.y );
vec2 a = w - q*clamp( dot(w,q)/dot(q,q), 0.0, 1.0 );
vec2 b = w - q*vec2( clamp( w.x/q.x, 0.0, 1.0 ), 1.0 );
float k = sign( q.y );
float d = min(dot( a, a ),dot(b, b));
float s = max( k*(w.x*q.y-w.y*q.x),k*(w.y-q.y) );
return sqrt(d)\*sign(s);
}

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function drawShader() {
push();

    shader(rayMarchingShader);

    rayMarchingShader.setUniform('cameraDistance', easycam.getDistance());
    rayMarchingShader.setUniform('dMatrix', dMatrix().mat3);
    rayMarchingShader.setUniform('join', checkbox.checked());

    quad(-1, -1, 1, -1, 1, 1, -1, 1);

    pop();

}

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uniform bool join;

// Get the closest distance from p to world
float world(vec3 p) {
// Set point to initial camera distance
p /= 500.;

    // transform the point to simulate camera zoom
    p /= 1. / cameraDistance;

    // apply rotation and translation transformations from object
    p *= dMatrix;

    // sphere SDF translated on Y axis to see dMatrix effects
    float sphere1 = length(p - vec3(-.5, 0., 0.)) - .5;
    float sphere2 = length(p - vec3(0., 0., 0.)) - .5;

    if(join) return min(sphere1, sphere2);
    else return max(sphere1, sphere2);

}

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function drawShader() {
push();

    shader(rayMarchingShader);

    rayMarchingShader.setUniform('cameraDistance', easycam.getDistance());
    rayMarchingShader.setUniform('dMatrix', dMatrix().mat3);
    rayMarchingShader.setUniform('N', N);

    quad(-1, -1, 1, -1, 1, 1, -1, 1);

    pop();

}

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uniform float N;

// Aux function
float map(float value, float istart, float istop, float ostart, float ostop) {
return ostart + (ostop - ostart) \* ((value - istart) / (istop - istart));
}

// Mandelbulb SDF
float mandelbulbSDF(vec3 pos) {
vec3 p = pos;

    float r = 0.;
    float dw = 1.0;
    vec3 w = p;

    for(int l = 0; l < MAX_ITERATIONS; l++) {
        // get derivative of w
        dw = pow(r, float(N) - 1.) * float(N) * dw + 1.;

        // cartesian to polar
        r = length(w);
        float f = atan(w.y, w.x);
        float t = acos(w.z / r);

        float zr = pow(r, float(N));
        t *= float(N);
        f *= float(N);

        // Nylander formula
        w = p + zr * vec3(sin(t) * cos(f), sin(t) * sin(f), cos(t));

        // Check if r bounds
        if(r > 2.)
            break;
    }

    // Detail in function of camera distance
    float bandFactor = map(cameraDistance, 500., 300., 0.5, 1.);

    // Hubbard-Douady potential see https://iquilezles.org/articles/distancefractals/
    float dist = bandFactor * log(r) * r / dw;

    return dist;

}

// Get the closest distance from p to world
float world(vec3 p) {
// Set point to initial camera distance
p /= 500.;

    // transform the point to simulate camera zoom
    p /= 1. / cameraDistance;

    // apply rotation and translation transformations from object
    p *= dMatrix;

    // Distance from p to mandelbulb
    float mandelbulb = mandelbulbSDF(p);

    return mandelbulb;

}