TITLE Rose Window PROMPT A generative stained-glass rose window in a dark stone nave, on a full-bleed Canvas 2D. Each window is unique, built by an algorithm with gothic logic (radial symmetry, nested rings of tracery, petals and foils), and lit from behind by a sun whose position the viewer controls; the coloured light falls through the window onto the stone floor. Concept: generative art with architecture and light: the wow is the glowing glass and the pool of colour it throws. Mood: monumental, hushed, devotional without religious iconography (purely geometric and botanical motifs). Palette: stone darkness #08070A with cool grey masonry highlights (#2A2830, #3A3842), lead came lines near-black #0B0A0C, and glass jewel tones: ruby #B3202A, cobalt #1B4FA0, gold #E0A100, emerald #2E8B57, amethyst #6C2A7A, with small amounts of pale "white" glass #E9E2CF. Dark page. Generation: choose a symmetry order n from {8, 10, 12, 16} and build the window as concentric zones: a central oculus (a rosette or star), an inner ring of n petals (lancet or teardrop shapes with trefoil heads), a middle ring of 2n smaller lights, an outer ring of roundels and spandrel pieces filling the gaps, all bounded by a thick stone ring with carved mouldings. Each compartment is subdivided into individual glass pieces by leading (subdivide petals with curved bands, borders with small rectangular quarries, diamonds, a vine or wave motif), so there are several hundred pieces. Colour assignment follows rules, not noise: a dominant pair (e.g. ruby and cobalt as in medieval glass) alternating by ring and position, gold accents on borders and centres, greens in foliage bands, consistent across the n-fold symmetry. Each piece has slight hue/brightness variation, streaks and tiny bubbles (per-piece radial gradient and a few speckles), and painted grisaille detail lines on some pieces (thin dark strokes). Stone tracery between lights is drawn with a bevel (light and dark edges). Light: the sun position (pointer/finger position, or slow automatic drift from east to west if idle) determines: (1) each glass piece's brightness: a soft hotspot of brilliance moves across the window opposite the sun, with halation: bright pieces bloom slightly over the lead lines (additive blurred pass); (2) the projection: the signature moment: the whole window is cast as a skewed, stretched, blurred pool of coloured light onto the stone floor beneath, with a soft bounce of its average colour spilling up the foot of the wall (draw the window image row by row through the floor's perspective with shear/scale according to sun angle, with blur and additive blending, over visible flagstones so the joints show through), sliding and lengthening as the sun moves; dust motes drift and sparkle inside the invisible light shaft between window and floor, tinted by the colour they pass through. Architecture: the window sits high in a wall of large ashlar blocks with subtle mortar lines; a pointed arch moulding frames it; below, the floor recedes in perspective with flagstones; two column silhouettes at the sides for scale. Interaction: move to place the sun; click/tap or press Space to "commission a new window": the lead lines of the new design draw themselves in from the centre outward (animated strokes), then the glass is "glazed" in ring by ring, each piece lighting up like being set into place, 1.5–2.5s total with staggering; this also plays on load. A small control cycles time of day: dawn (warm low light, long projection), noon (shorter, intense), dusk (red-gold), night (moonlight: desaturated blue glass, faint projection). Keyboard: arrows move the sun, T also cycles the hour. A small sun (or crescent moon at night) glyph replaces the cursor and marks where the sun stands. Opus numbers count upward from 0231 and each number always yields the same window. Typography: minimal, inscription-like: tiny carved-looking capitals with wide tracking in pale stone colour at the base of the wall: "ROSE WINDOW · ORDER XII · OPUS 0231" updating with each window's order and number, in a classical serif (Trajan-like fallback: Georgia/"Times New Roman" caps). A designed hint, "move the sun · click for a new window", cut into a floor slab and fading after use. Reduced motion: no mote drift; new windows appear with a simple fade. Performance: render glass to an offscreen canvas once per window; per frame only composite lighting and projection. DESCRIPTION A hushed stone nave seen from the floor: a wall of ashlar blocks, a pointed arch with carved mouldings, two dark columns, and high in the wall a rose window whose several hundred pieces of ruby, cobalt, gold, emerald, amethyst and pale glass are generated afresh by gothic rules of symmetry, nested rings, lancets, foils and roundels. The viewer holds the sun. As it moves, a hotspot of brilliance travels across the glass, bright pieces bloom over their leads, and the whole window is thrown down as a long, soft, skewed pool of colour across the flagstones, with tinted dust sparkling in the shaft between. Each new commission is drawn in lead from the centre outward and then glazed ring by ring, every piece flaring as it is set, while a carved inscription records its order and opus number. VISUAL TECHNIQUES - Full-bleed Canvas 2D scene composited from pre-rendered layers (wall, floor joints, columns, glass, leads, stone tracery) - Seeded procedural window generator: polar lancets with pointed or round heads, cusped foils traced as unions of circles, circle-packed roundels and eyelets, quarry and diamond borders - Rule-based colour assignment (dominant pair alternating by ring and position, gold borders and centres, foliage bands) with per-piece hue jitter - Per-piece glass rendering: off-centre radial gradient, blown-glass streaks, seed bubbles, dark matting near the lead, painted grisaille strokes - Stone tracery with per-edge directional bevel shading and concentric carved mouldings, cut out with destination-out - Per-frame lighting with multiply, saturation and color-dodge blend passes plus a downsampled additive halation pass - Row-by-row perspective projection of the lit window onto the floor with shear, stretch, blur and additive blending; flagstone joints redrawn over the light - Dust motes placed in the three-dimensional light shaft, coloured by sampling the glass they pass beneath, with twinkling star glints - Animated lead strokes using dash offsets, staggered glazing with additive setting flares, cross-fade from the previous window - Four eased times of day (dawn, noon, dusk, moonlit night) retinting glass, masonry and projection - Inscription and floor-slab hint set in tracked serif capitals with carved text shadows and CSS perspective INTERACTION MODEL Moving the pointer (or dragging a finger) places the sun: the hotspot on the glass, the halation, the dust and the pool of colour on the floor all follow with a soft lag, the pool sliding sideways opposite the sun and lengthening as the sun sinks. Left idle, the sun drifts slowly from east to west by itself, fading at each horizon. A click, tap, Space or Enter commissions a new window: the old one fades, leads draw themselves outward from the centre, then the glass is set ring by ring and the inscription re-cuts itself with the new order and opus number. Arrow keys nudge the sun (Shift for larger steps). The dial at the lower right, or the T key, cycles dawn, noon, dusk and night. The hint cut into the floor slab dims once the sun has been moved and disappears after the first commission. With reduced motion, motes hold still, the sun does not drift, and new windows arrive with a simple fade.