From 4452a8f467765cbfa0dd0444a9bf416ac8bd0bf5 Mon Sep 17 00:00:00 2001 From: Gabriel Schneider Date: Tue, 29 Sep 2026 05:44:11 -0300 Subject: G4: bloom, vignette and grain in the post chain MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Three bundled Shadertoy passes beside Crt, each `Bloom|Vignette|Grain 0..3` (off by default, nothing drawn while off), in shaders/post/: - Bloom: what is brighter than the page (a channel's linear peak over 0.75/0.7/0.6 and over the page's own + 0.15, so a light page does not bloom) glows, 2/3.5/5% (ยง8.2's budget). The glow is a dual Kawase blur in RGBA16F textures at half size and down, 3/4/5 steps by level (shaders/bloom-down, bloom-up; Post.bloomChain), composited in linear light and dithered. - Vignette: round, from halfway to a corner, 10/18/28% at the far corners, in linear light, dithered. - Grain: a still, triangular-spread grain of 1.5/3/5 of 255 on page-coloured pixels only, a logical pixel big; still, so it asks for no frames. Focus rule: the shell passes every bundled pass the rectangles of the tags with their grips, the column and workspace tags, the notices and the cursor (pardesSpare, at most 32, neighbours on one row merged), and a bundled pass leaves them as they are; and a per-theme ceiling (pardesCap, Post.capsOf) keeps the page's text and the selection's text at min(their contrast, 4.5) under each pass at its strongest. User files get no ceiling and no spared rectangles. Fix found on the way: SDL GPU binds at most 4 KiB of a uniform block, so every Shadertoy colour after iPalette (iBackgroundColor, iForegroundColor, the cursor and selection colours, iPalette[>=4]) read zero. The prefix's block is cut in three (Globals, Palette, Colors) with ghostty's names and order, each pushed as a slice of the one struct; pardes's own block moves to binding 3. Tests: the caps hold over every native theme; each uniform slice fits 4 KiB; the prefix's members in ghostty's order across its blocks. Gates: tty/gui unit-test and core-test pass; snap fails only nested-optout; GUI goldens 01-08 byte-identical (09-18 wait on wkzlsqvy, as in somtrmsz); web builds. Feel review material: .scratch/render/{bloom,vignette,grain}/ (levels on forge, dusk, acme, crops, a levels mp4). --- docs/render-pipeline.md | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'docs/render-pipeline.md') diff --git a/docs/render-pipeline.md b/docs/render-pipeline.md index 7c94fbea..b8f735d9 100644 --- a/docs/render-pipeline.md +++ b/docs/render-pipeline.md @@ -460,7 +460,9 @@ Mirror ghostty 1.3.2 (`zig-pkg/ghostty-*/src/renderer/shadertoy.zig`, iBackgroundColor, iForegroundColor, iCursorColor, iCursorText, iSelectionForegroundColor, iSelectionBackgroundColor; CURSORSTYLE_* defines; `#define texture2D texture`), but SDL GPU bindings: `iChannel0` at set 2 - binding 0, the block at set 3 binding 0. `main()` calls + binding 0, the block at set 3 bindings 0 to 2 (cut before and after + iPalette: SDL GPU binds at most 4 KiB of a block, so one block left + the colours after the palette at zero until G4), pardes's own at 3. `main()` calls `mainImage(_fragColor, gl_FragCoord.xy)`. Trap found: ghostty's Zig `Uniforms` (shadertoy.zig:13) orders selection_background before selection_foreground while its GLSL block orders Foreground before Background, -- cgit v1.3