/* "ANSI.SYS // Torus" */ precision highp float; uniform vec2 resolution; uniform float time; uniform vec2 mouse; #define GRID_SIZE 10.0 // 2D Rotation Matrix mat2 rot(float a) { float s = sin(a), c = cos(a); return mat2(c, -s, s, c); } // Procedural ASCII character generator (Same language as Vol 1) 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 for the 3D Torus float map(vec3 p, vec2 m) { // Interactive rotations float rx = (m.y - 0.5) * 3.14; float ry = (m.x - 0.5) * 3.14 * 2.0 + time * 0.5; p.yz *= rot(rx); p.xz *= rot(ry); // Create the Torus shape vec2 q = vec2(length(p.xz) - 0.65, p.y); // Add a slight rippling "gear" texture to the geometry to catch the light float angle = atan(p.z, p.x); float ripple = 0.03 * sin(angle * 8.0 + time * 3.0); return length(q) - 0.25 + ripple; } // Compute 3D Normals vec3 getNormal(vec3 p, vec2 m) { vec2 e = vec2(0.001, 0.0); return normalize(vec3( map(p + e.xyy, m) - map(p - e.xyy, m), map(p + e.yxy, m) - map(p - e.yxy, m), map(p + e.yyx, m) - map(p - e.yyx, m) )); } void main(void) { // 1. Grid & Continuous Coordinate Setup 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); // Auto-animate if mouse is untouched vec2 m = mouse; if (length(m) < 0.01) { m = vec2(0.5 + 0.25 * cos(time * 0.4), 0.5 + 0.2 * sin(time * 0.3)); } // 2. Camera & Raymarching Setup vec3 ro = vec3(0.0, 0.0, 2.5); // Camera pulls back on Z axis vec3 rd = normalize(vec3(pGrid, -1.0)); // Ray direction based on ASCII grid float t = 0.0; vec3 p = vec3(0.0); bool hit = false; // Raymarch the Torus for(int i = 0; i < 60; i++) { p = ro + rd * t; float d = map(p, m); if (d < 0.001) { hit = true; break; } t += d; if (t > 5.0) break; } // 3. ASCII Lighting Calculation float brightness = 0.0; if (hit) { vec3 n = getNormal(p, m); // Primary Light: Emitted directly from the core (origin 0,0,0) vec3 coreLightDir = normalize(-p); float coreDiff = max(dot(n, coreLightDir), 0.0); // Secondary Light: Ambient top-light so the outside isn't pure black vec3 topLightDir = normalize(vec3(0.0, 1.0, 0.5)); float topDiff = max(dot(n, topLightDir), 0.0); brightness = coreDiff * 0.8 + topDiff * 0.3 + 0.05; } // Get the ASCII character value (0.0 or 1.0 for this cell) float charVal = getChar(cellUv, hit ? brightness : 0.0); // 4. Continuous Volumetric Core (The Glow) float orbDist = length(pCont); float pulse = sin(time * 3.0) * 0.02; // Breathing effect float orbRadius = 0.18 + pulse; float glow = 0.0; if (orbDist < orbRadius) { glow = 1.0; // Solid core } else { glow = exp(-(orbDist - orbRadius) * 14.0); // Smooth falloff } // 5. Z-Depth Compositing (Mixing ASCII & Glow) vec3 finalCol = vec3(0.0); if (hit) { if (t < 2.5) { // Foreground: The Torus is IN FRONT of the core. // Brilliant trick: Let the glow bleed through the empty black gaps of the ASCII grid! finalCol = mix(vec3(glow * 0.35), vec3(1.0), charVal); } else { // Background: The Torus is BEHIND the core. // The core fully obscures the background characters. finalCol = mix(vec3(charVal), vec3(1.0), glow); } } else { // Deep Space finalCol = vec3(glow); } // 6. Retro CRT Polish finalCol *= 0.85 + 0.15 * sin(gl_FragCoord.y * 2.5); // Scanlines float vignette = 1.0 - smoothstep(0.4, 1.5, length(pCont)); // Vignette finalCol *= vignette; finalCol *= 0.96 + 0.04 * sin(time * 40.0); // Micro-flicker gl_FragColor = vec4(finalCol, 1.0); }