Post chain: Shadertoy passes compiled by glslc; Crt, Ripple and Glitch rewritten as Shadertoy files

2026-10-01T03:12:15Z

Stage 9 of docs/render-pipeline.md. src/gui/Post.zig runs the chain over the finished frame: each pass reads the one before, ping-pong textures between, the last writes the window; an empty chain is the direct path. The prefix (shaders/post/prefix.glsl) is ghostty's uniform block, name for name and offset for offset (tested against a copy of its Uniforms, the selection colours by their GLSL names), at SDL GPU's bindings, y down. A user's file (Shader ) is compiled by glslc with compileGlsl's own flags on a thread of its own, taken in at the next loop step; errors name the file's own lines; a failed compile keeps the last good pipeline; glslc missing is said once. The bundled passes compile with the build, through the same prefix. Crt, Ripple and Glitch are Shadertoy files, rewritten: no barrel (input is identity, tested), everything in linear light and dithered, keyed to iTime. scene_effects, crt.zig and crt.frag.glsl are gone; the core keeps no clock for the chain. ShaderAnimation off|on|always drives redraw level A: the chain alone over the retained frame (34 us CPU a redraw, measured). Shared files touched: pardes.zig (nextWake loses the scene line, disableSceneEffects empties the chain, two tests), builtins.zig (one switch arm), ninep/ctl.zig (two switch arms), macos.zig (flags from the chain), gui.zig. Not touched: Messages.zig, mouse.zig, detached/*, host_io, tty.

shaders: -Dprebuilt-shaders, so a gui build needs no Vulkan SDK

2026-08-12T23:22:18Z

glslc is the one build input that wants a tool a stock machine does not have, and it is also the input that changes least often: eight GLSL files that have outlived several rewrites of everything around them. Asking every machine that wants to run the SDL shell for shaderc is the wrong trade. The SPIR-V is now COMMITTED, under shaders/prebuilt/, and -Dprebuilt-shaders embeds that copy instead of shelling out. The default stays the honest one -- compile the shaders that are actually in the tree -- because the flag trades a dependency for a freshness problem: with it on, the .glsl sources are not build inputs at all, so editing one changes nothing. `zig build shaders` is the other half, and it is deliberately independent of -Dplatform: it recompiles every shader and writes the result back into the tracked directory, so whoever changes a shader refreshes the cache on a machine that has the compiler and commits the diff. `jj diff shaders/prebuilt` after it is the freshness check -- empty means the cache was already current. The shader list is also spelled once now (gui_shaders): the eight embeds, the eight glslc runs and the refresh step all read it, so adding a shader is a name there plus the @embedFile in gui.zig, not three edits in two places. Verified: -Dplatform=gui -Dprebuilt-shaders builds with glslc absent from PATH, and image-harness passes on that binary -- real SDL GPU pipelines built from the committed SPIR-V, 512 source pixels read back. The default gui build still runs the eight glslc steps; tty runs none. The committed bytes are identical to a fresh glslc run, and `zig build shaders` is idempotent.

pardes.git/shaders/prebuilt/crt.vert.spv, branch main

Post chain: Shadertoy passes compiled by glslc; Crt, Ripple and Glitch rewritten as Shadertoy files

shaders: -Dprebuilt-shaders, so a gui build needs no Vulkan SDK