A shader on a source runs per particle and stops at each quad, so a glow or blur across the whole cloud was not possible. A source now has a second shader row that is laid over everything it draws at once. - New rows Field shader, Field width and Field height (256) on a particle source. The size rows show only while a field shader is picked (new `shownWhenSet` on a row definition). - The particles are drawn into a RenderTexture of the frame, and a sprite mesh wearing the field shader draws that picture. The frame is centred on the source and turns and grows with it. - UV run 0 to 1 across the frame. Texture color, Texture alpha and Sample texture read the picture of the particles. - The picture has as many device pixels as the frame covers on screen, at most 2048 per side. A frame off screen draws no pass. - The field shader's Padding and Vertex output do nothing: the frame is the edge, and its corners stay put as on a nine-sliced sprite. - A name both shaders declare is one row, and both uniforms read it. - The scene view draws the frame dashed round a selected source. The Particles tab preview wears the field shader too. - `tools/perf-field-shaders.mjs` measures 1, 10 and 50 sources. On the HD 630 they ran at 60.0, 60.0 and 57.6 fps against 60.1, 60.0 and 59.2 without, one run per row. Tests: - Gate: 223 files, 3460 tests (3452 + 8), CHECK EXIT 0. - e2e 31: 43 checks, 3 of them new. Sum 1707 is computed (1704 + 3). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>