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#version 410 core
uniform vec2 u_resolution; // viewport resolution (in pixels)
uniform float u_time; // in seconds
uniform float u_xrot;
uniform float u_yrot;
uniform float u_zrot;
uniform sampler1D texFFT;
layout(location = 0) out vec4 out_color; // out_color must be written in order to see anything
const int MAX_STEP = 255;
const float MIN_DIST = 0.0;
const float MAX_DIST = 100.0;
const float EPSILON = 0.0001;
float f(float x, float z)
{
return 2.0;
}
// transformations
mat4 rotateX(float theta)
{
float c = cos(theta);
float s = sin(theta);
return mat4(
vec4(1, 0, 0, 0),
vec4(0, c, s, 0),
vec4(0, -s, c, 0),
vec4(0, 0, 0, 1)
);
}
// transformations
mat4 rotateY(float theta)
{
float c = cos(theta);
float s = sin(theta);
return mat4(
vec4(c, 0, s, 0),
vec4(0, 1, 0, 0),
vec4(-s, 0, c, 0),
vec4(0, 0, 0, 1)
);
}
// transformations
mat4 rotateZ(float theta)
{
float c = cos(theta);
float s = sin(theta);
return mat4(
vec4(c, s, 0, 0),
vec4(-s, c, 0, 0),
vec4(0, 0, 1, 0),
vec4(0, 0, 0, 1)
);
}
float tHeight(vec2 p)
{
return smoothstep(0.0, 200.0, p.y*20000)*5;
}
float torusSDF( vec3 p, vec2 t )
{
vec2 q = vec2(length(p.xz)-t.x,p.y);
float d1 = length(p)-0.4;
float d2 = tHeight(p.xy)*0.45;
return d1 + (d2/20);
}
vec3 transformScene(vec3 p)
{
//p = (inverse(rotateX(u_time*3)) * vec4(p, 1.0)).xyz;
p = (inverse(rotateX(u_xrot)) *
inverse(rotateY(u_yrot)) *
inverse(rotateZ(u_zrot)) * vec4(p, 1.0)).xyz;
return p;
}
// Standard distance function for the whole scene!
float sceneSDF(vec3 p)
{
p = transformScene(p);
//p = p * vec3(1.0, sin(u_time),1.0);
return torusSDF(p, vec2(0.3, 0.1));
}
vec3 estNormal(vec3 p)
{
return normalize(vec3(
sceneSDF(vec3(p.x + EPSILON, p.y, p.z)) - sceneSDF(vec3(p.x - EPSILON, p.y, p.z)),
sceneSDF(vec3(p.x, p.y + EPSILON, p.z)) - sceneSDF(vec3(p.x, p.y - EPSILON, p.z)),
sceneSDF(vec3(p.x, p.y, p.z + EPSILON)) - sceneSDF(vec3(p.x, p.y, p.z - EPSILON))
));
}
vec3 rayDirection(float fov, vec2 size, vec2 fragCoord)
{
vec2 xy = fragCoord - size / 2.0;
float z = size.y / tan(radians(fov) / 2.0);
return normalize(vec3(xy, -z));
}
// Raymarcher!
float march(vec3 eye, vec3 dir, float start, float end)
{
float depth = start;
for (int i=0; i<MAX_STEP; i++) {
float dist = sceneSDF(eye + depth * dir);
if (dist < 0.0001) {
return depth; // we're inside the scene
}
depth+=dist;
if (depth >= end) {
return end; // gone too far!
}
}
}
// Does something related to phong for each light that we want
vec3 phongLightContrib(vec3 kd, vec3 ks, float alpha, vec3 p, vec3 eye, vec3 lightPos, vec3 lightInt)
{
vec3 N = estNormal(p);
vec3 L = normalize(lightPos - p);
vec3 V = normalize(eye - p);
vec3 R = normalize(reflect(-L, N));
float dotLN = dot(L, N);
float dotRV = dot(R, V);
if (dotLN < 0.0) {return vec3(0.0);}
if (dotRV < 0.0) {return lightInt * (kd * dotLN);}
return lightInt * (kd * dotLN + ks * pow(dotRV, alpha));
}
vec3 phong(vec3 ka, vec3 kd, vec3 ks, float alpha, vec3 p, vec3 eye)
{
const vec3 ambientLux = vec3(0.3);
vec3 colour = ambientLux * ka;
vec3 light1Pos = vec3(-1.0, -1.2, 0.7);
vec3 light1Int = vec3(0.2);
vec3 light2Pos = vec3(0.8, 0.8, 1.2);
vec3 light2Int = vec3(0.55);
colour += phongLightContrib(kd, ks, alpha, p, eye, light1Pos, light1Int);
colour += phongLightContrib(kd, ks, alpha, p, eye, light2Pos, light2Int);
return colour;
}
void main(void)
{
vec3 dir = rayDirection(45.0, u_resolution.xy, gl_FragCoord.xy);
vec3 eye = vec3(0.0,0.0,5.0);
float dist = march(eye, dir, MIN_DIST, MAX_DIST);
if (dist > MAX_DIST - EPSILON) {out_color = vec4(0.1); return;}
vec3 p = eye + dist * dir;
vec3 colour;
vec3 Ka = vec3(0.0, 0.729, 0.745)*texture(texFFT, 0.123).r*1000; // ambient reflection constant
vec3 Kd = vec3(0.0, 0.467, 0.745); // diffuse reflection constant
vec3 Ks = vec3(0.0, 0.0, 0.0); // specular reflection constant
float shininess = 1.0;
colour = phong(Ka, Kd, Ks, shininess, p, eye);
if (transformScene(p).y< 0) {
vec3 Ka = vec3(0.2); // ambient reflection constant
vec3 Kd = vec3(0.95, 0.2, 0.1); // diffuse reflection constant
vec3 Ks = vec3(0.95, 0.2, 0.1); // specular reflection constant
float shininess = 300.0;
colour = phong(Ka, Kd, Ks, shininess, p, eye);
}
out_color = vec4(colour, 1.0);
}
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