/* "ANSI.SYS // Collision" */ precision highp float; uniform vec2 resolution; uniform float time; uniform vec2 mouse; #define GRID_SIZE 9.0 #define MAX_STEPS 80 #define MAX_DIST 20.0 // 2D Rotation Matrix mat2 rot(float a) { float s = sin(a), c = cos(a); return mat2(c, -s, s, c); } // Procedural ASCII character generator (The ANSI.SYS standard) float getChar(vec2 uv, float brightness) { uv = uv * 2.0 - 1.0; float dotC = step(length(uv), 0.3); float dashC = step(abs(uv.y), 0.15) * step(abs(uv.x), 0.6); float plusC = max(step(abs(uv.x), 0.15)*step(abs(uv.y),0.8), step(abs(uv.y), 0.15)*step(abs(uv.x),0.8)); float crossC = max(step(abs(abs(uv.x)-abs(uv.y)), 0.15), 0.0) * step(max(abs(uv.x),abs(uv.y)),0.8); float boxC = step(max(abs(uv.x),abs(uv.y)), 0.8) - step(max(abs(uv.x),abs(uv.y)), 0.5); float solidC = step(max(abs(uv.x),abs(uv.y)), 0.8); if (brightness < 0.10) return 0.0; if (brightness < 0.25) return dotC; if (brightness < 0.40) return dashC; if (brightness < 0.60) return plusC; if (brightness < 0.75) return crossC; if (brightness < 0.90) return boxC; return solidC; } // Signed Distance Field: The ASCII Lattice & The Boolean Void float map(vec3 p, vec3 voidPos) { // 1. The Void's destructive field (World Space) // The cut radius is slightly LARGER than the visual black hole, // creating a glowing "Accretion Disk" wall where it bites into the geometry. float voidCut = length(p - voidPos) - 1.0; // 2. The Tech Lattice (Local Rotating Space) vec3 q = p; q.xy *= rot(time * 0.2); q.xz *= rot(time * 0.35); // Base object: A large Sphere float core = length(q) - 2.5; // Carve an infinite 3D grid out of the sphere to create a complex lattice vec3 gridP = mod(q, 0.6) - 0.3; float holes = length(gridP.xy) - 0.22; holes = min(holes, length(gridP.xz) - 0.22); holes = min(holes, length(gridP.yz) - 0.22); core = max(core, -holes); // Sphere minus grid = Lattice // 3. BOOLEAN SUBTRACTION: The Black Hole eats the Lattice core = max(core, -voidCut); return core; } // Compute 3D Normals vec3 getNormal(vec3 p, vec3 voidPos) { vec2 e = vec2(0.01, 0.0); return normalize(vec3( map(p + e.xyy, voidPos) - map(p - e.xyy, voidPos), map(p + e.yxy, voidPos) - map(p - e.yxy, voidPos), map(p + e.yyx, voidPos) - map(p - e.yyx, voidPos) )); } void main(void) { // 1. Grid & Continuous Coordinates vec2 gridPos = floor(gl_FragCoord.xy / GRID_SIZE) * GRID_SIZE; vec2 cellUv = fract(gl_FragCoord.xy / GRID_SIZE); vec2 pGrid = (gridPos + GRID_SIZE * 0.5 - 0.5 * resolution.xy) / min(resolution.x, resolution.y); vec2 pCont = (gl_FragCoord.xy - 0.5 * resolution.xy) / min(resolution.x, resolution.y); // 2. Interactive Void Setup vec2 m = mouse; if (length(m) < 0.01) { // Auto-pilot figure-8 if untouched m = vec2(0.5 + 0.35 * sin(time * 0.8), 0.5 + 0.25 * cos(time * 0.5)); } m = (m - 0.5) * 2.0; // Range -1.0 to 1.0 // The Void moves in X/Y based on mouse. // It oscillates autonomously on Z so it physically dives IN and OUT of the 3D lattice! vec3 voidPos = vec3(m.x * 3.5, m.y * 3.0, 1.0 + 1.8 * sin(time * 1.5)); // 3. Camera Setup vec3 ro = vec3(0.0, 0.0, 6.0); vec3 rdGrid = normalize(vec3(pGrid, -1.2)); // Quantized ray vec3 rdCont = normalize(vec3(pCont, -1.2)); // Smooth ray // 4. Raymarching the ASCII Grid float t = 0.0; vec3 p = vec3(0.0); bool hit = false; for(int i = 0; i < MAX_STEPS; i++) { p = ro + rdGrid * t; float d = map(p, voidPos); if (d < 0.01) { hit = true; break; } t += d * 0.8; if (t > MAX_DIST) break; } // 5. Lighting the Cut Geometry float charVal = 0.0; if (hit) { vec3 n = getNormal(p, voidPos); // The Void acts as a massive Point Light. // Because the void literally carves the geometry, the normals of the CUT EDGES point directly at it. vec3 lightDir = normalize(voidPos - p); float diff = max(dot(n, lightDir), 0.0); // Intensity skyrockets the closer the geometry is to the event horizon float distToVoid = length(voidPos - p) - 1.0; float burnIntensity = exp(-distToVoid * 6.0); float ambient = 0.05 + max(dot(n, normalize(vec3(1.0, 1.0, 1.0))), 0.0) * 0.15; float brightness = (diff * burnIntensity * 1.5) + ambient; // Generate discrete text charVal = getChar(cellUv, brightness); } // 6. Continuous Math: The Perfect Black Hole vec3 finalCol = vec3(0.0); // Mathematical ray-sphere intersection for the pure black Event Horizon float visualRadius = 0.75; // Smaller than the 3D cut (1.0), revealing the glowing inner walls! vec3 L = voidPos - ro; float tca = dot(L, rdCont); float d2 = dot(L, L) - tca * tca; float distToRay = sqrt(max(d2, 0.0)); bool hitVoid = (distToRay < visualRadius && tca > 0.0); float voidDepth = hitVoid ? tca - sqrt(visualRadius * visualRadius - d2) : MAX_DIST; if (hitVoid && voidDepth < t) { // The pure mathematical Void perfectly occludes the ASCII behind it. Pure Black. finalCol = vec3(0.0); } else { // Output the ASCII geometry finalCol = vec3(charVal); // Add the Continuous Corona Glow mathematically bleeding over the grid float corona = exp(-(distToRay - visualRadius) * 6.0); // Deep background glow if staring into empty space if (!hit) corona += exp(-(distToRay - visualRadius) * 1.5) * 0.4; finalCol += vec3(corona); } // 7. Retro CRT Polish finalCol = clamp(finalCol, 0.0, 1.0); finalCol *= 0.85 + 0.15 * sin(pCont.y * resolution.y * 3.0); // Scanlines float vignette = 1.0 - smoothstep(0.5, 2.5, length(pCont)); // Vignette finalCol *= vignette; finalCol *= 0.96 + 0.04 * sin(time * 45.0); // Terminal micro-flicker gl_FragColor = vec4(finalCol, 1.0); }