Repeating Space III

{"bannedTokens":[],"prefix":"uniform vec2 iResolution;\nuniform float iGlobalTime;\n\nfloat getDistanceFromPoint(vec3 point);\nvec3 draw_line(float d);\nfloat draw_solid(float d);\nvec3 draw_distance(float d, vec2 p);\n\nmat3 calcLookAtMatrix(vec3 origin, vec3 target, float roll) {\n  vec3 rr = vec3(sin(roll), cos(roll), 0.0);\n  vec3 ww = normalize(target - origin);\n  vec3 uu = normalize(cross(ww, rr));\n  vec3 vv = normalize(cross(uu, ww));\n\n  return mat3(uu, vv, ww);\n}\n\nvec3 calcNormal(vec3 pos, float eps) {\n  const vec3 v1 = vec3( 1.0,-1.0,-1.0);\n  const vec3 v2 = vec3(-1.0,-1.0, 1.0);\n  const vec3 v3 = vec3(-1.0, 1.0,-1.0);\n  const vec3 v4 = vec3( 1.0, 1.0, 1.0);\n\n  return normalize( v1 * getDistanceFromPoint( pos + v1*eps ) +\n                    v2 * getDistanceFromPoint( pos + v2*eps ) +\n                    v3 * getDistanceFromPoint( pos + v3*eps ) +\n                    v4 * getDistanceFromPoint( pos + v4*eps ) );\n}\n\nvec3 getRay(vec3 origin, vec3 target, vec2 screenPos, float lensLength) {\n  mat3 camMat = calcLookAtMatrix(origin, target, 0.0);\n  return normalize(camMat * vec3(screenPos, lensLength));\n}\n\nfloat intersectPlane(vec3 ro, vec3 rd, vec3 nor, float dist) {\n  float denom = dot(rd, nor);\n  float t = -(dot(ro, nor) + dist) / denom;\n\n  return t;\n}\n","suffix":"float beckmannDistribution(float x, float roughness) {\n  float NdotH = max(x, 0.0001);\n  float cos2Alpha = NdotH * NdotH;\n  float tan2Alpha = (cos2Alpha - 1.0) / cos2Alpha;\n  float roughness2 = roughness * roughness;\n  float denom = 3.141592653589793 * roughness2 * cos2Alpha * cos2Alpha;\n  return exp(tan2Alpha / roughness2) / denom;\n}\n\nfloat cookTorranceSpecular(\n  vec3 lightDirection,\n  vec3 viewDirection,\n  vec3 surfaceNormal,\n  float roughness,\n  float fresnel) {\n\n  float VdotN = max(dot(viewDirection, surfaceNormal), 0.0);\n  float LdotN = max(dot(lightDirection, surfaceNormal), 0.0);\n\n  //Half angle vector\n  vec3 H = normalize(lightDirection + viewDirection);\n\n  //Geometric term\n  float NdotH = max(dot(surfaceNormal, H), 0.0);\n  float VdotH = max(dot(viewDirection, H), 0.000001);\n  float x = 2.0 * NdotH / VdotH;\n  float G = min(1.0, min(x * VdotN, x * LdotN));\n\n  //Distribution term\n  float D = beckmannDistribution(NdotH, roughness);\n\n  //Fresnel term\n  float F = pow(1.0 - VdotN, fresnel);\n\n  //Multiply terms and done\n  return  G * F * D / max(3.14159265 * VdotN * LdotN, 0.000001);\n}\n\nvoid main() {\n  vec2 uv = 2.0 * gl_FragCoord.xy / iResolution - 1.0;\n  vec3 ro = vec3(sin(0.0), 1.0, cos(0.0));\n  vec3 ta = vec3(0);\n  vec3 rd = getRay(ro, ta, uv, 2.0);\n\n  float t = -1.0;\n  float mind = 0.01;\n  float maxd = 10.0;\n  float latest = 1.0;\n  for (int i = 0; i < 30; i++) {\n    if (latest < mind || t > maxd) break;\n    t += (latest = getDistanceFromPoint(ro + rd * t));\n  }\n\n  float tPlane = intersectPlane(ro, rd, vec3(0, 1, 0), 0.0);\n\n  if (tPlane > -0.5 && tPlane < t) {\n    vec3 pos = ro + rd * tPlane;\n    gl_FragColor = vec4(draw_distance(getDistanceFromPoint(pos) - 0.0125, pos.xz), 1);\n  } else\n  if (t > maxd) {\n    gl_FragColor = vec4(0, 0, 0, 1);\n  } else {\n    vec3 pos = ro + rd * t;\n    vec3 normal = calcNormal(pos, 0.002);\n    vec3 ldir = normalize(vec3(0, 1, 0.2));\n    float mag = max(0.2, dot(normal, ldir));\n\n    mag = pow(mag, 0.3545);\n    mag *= 1.75;\n    //mag = 0.0;\n\n    gl_FragColor = vec4(mag * vec3(0.95, 0.45, 0.15), 1);\n    gl_FragColor.rgb += cookTorranceSpecular(ldir, -rd, normal, 1.0, 3.25) * 1.5;\n  }\n}\n\nvec3 draw_line(float d) {\n  const float aa = 3.0;\n  const float thickness = 0.0025;\n  return vec3(smoothstep(0.0, aa / iResolution.y, max(0.0, abs(d) - thickness)));\n}\n\nfloat draw_solid(float d) {\n  return smoothstep(0.0, 3.0 / iResolution.y, max(0.0, d));\n}\n\nvec3 draw_distance(float d, vec2 p) {\n  float t = clamp(d * 0.85, 0.0, 1.0);\n  vec3 grad = mix(vec3(1, 0.8, 0.5), vec3(0.3, 0.8, 1), t);\n\n  float d0 = abs(1.0 - draw_line(mod(d + 0.1, 0.2) - 0.1).x);\n  float d1 = abs(1.0 - draw_line(mod(d + 0.025, 0.05) - 0.025).x);\n  float d2 = abs(1.0 - draw_line(d).x);\n  vec3 rim = vec3(max(d2 * 0.85, max(d0 * 0.25, d1 * 0.06125)));\n\n  grad -= rim * clamp(1.25 - d, 0.0, 1.0);\n  grad -= 1.0 - clamp(1.25 - d * 0.25, 0.0, 1.0);\n  grad -= mix(vec3(0.05, 0.35, 0.35), vec3(0.0), draw_solid(d));\n\n  return grad;\n}\n","question":"float getDistanceFromPoint(vec3 point) {\n  vec3 offset = vec3(0.75, 0, 0) * abs(sin(iGlobalTime * 0.1));\n  float radius = 0.1;\n\n  return 0.0;\n}\n","solution":"float getDistanceFromPoint(vec3 point) {\n  vec3 offset = vec3(0.75, 0, 0) * abs(sin(iGlobalTime * 0.1));\n  float radius = 0.1;\n\n  float angle = atan(point.z, point.x);\n  float dist = length(point.xz);\n  float count = 5.0;\n  float pi = 3.14159265;\n  float tau = pi * 2.0;\n  float period = tau / count;\n\n  angle = mod(angle + period * 0.5, period) - period * 0.5;\n  point.xz = vec2(\n    dist * cos(angle),\n    dist * sin(angle)\n  );\n\n  return length(point - offset) - radius;\n}\n","name":"15-repeating-space"}