psph_force

Preseed demo SPH pass 4/4: pressure/viscosity/cohesion forces, XSPH smoothing, integration, and collision against the water stage — the oval lake (elliptic coping wall and a water-surface plane that landed spray rides on), the three-tier fountain island (round two-sided basin wall, plinth, three scallop-rimmed dish shells, pedestal segments, finial stem), and the plaza — plus a scripted sphere collider. Diffuses each particle's liquid tint toward its neighbors' at an agitation-scaled rate (colMix), so churning water blends the jet colors. A drain pump recycles all pooled water back out of the nozzles with fresh tint: the crown (crownW/jetV/crownSpread), sixteen articulated island rim nozzles (ringW/ringMask/ringV/ringVy, leaning by ringTilt*sin(ringPhase - k*ringStep) with a ringVyWave height wave), a twenty-four-nozzle line array down the lake's long axis (lineW/lineMask/lineVy/lineTilt/linePhase/lineStep/lineVyWave), and eight tier jets (sideN/sideV/sideVy) — with pumpP/seed timing the per-frame recycle, so the show runs continuously from a fixed particle budget. Writes render positions and tints (offset/parallel to the part's world center) into the rpos / rcol buffers.