Ports renderer/{generic,cell,row,link,State,Overlay,image,Thread}.zig:
- generic.rs builds GPU cell buffers from terminal RenderState each
frame: backgrounds, shaped text runs with glyph atlases and nerd font
constraints, all cursor styles, decorations via sprites, selection and
search colors, min-contrast, bold/faint/blink handling, preedit,
padding extension, background image, custom shader uniforms, link
hover underlines, scrollbar and health reporting.
- The renderer thread updates CPU-side state only and asks the host to
redraw; the app runtime calls draw_frame from the GLArea render signal
(the GL context lives on the GTK thread, as in Ghostty).
- ghostty_renderer::state::{State, SharedState} is the canonical shared
renderer state (termio's interim copy will switch to it).
Deviations: overlay uses a direct RGBA rasterizer instead of z2d; bg
images decode with png/jpeg-decoder instead of wuffs; zero-length link
matches advance by one char (Zig would loop forever).
Kitty image rendering is implemented in image::State but not yet called
from generic::update_kitty (raced with the terminal-side wiring).
Test Plan:
- cargo test -p ghostty-renderer (69 unit + 9 headless EGL tests that
render a Terminal through the full pipeline and check pixels)
Ports the terminal-independent half of ZIG/src/renderer (OpenGL only):
- opengl/*: buffers, frames, pipelines, render passes, samplers,
targets, textures and the OpenGL GraphicsAPI backend on top of glow;
the GTK GLArea glue is replaced by a get_proc_address loader closure
- the GLSL shaders, copied verbatim and embedded; uniform/vertex structs
as bytemuck Pod types with std140 offsets asserted in tests
- shadertoy custom shaders converted with naga (GLSL in -> validate ->
GLSL 430 out) instead of glslang + spirv-cross
- size (screen/grid/cell/padding math), cursor style logic, backend
health, options and message types
The crate opts into unsafe_code = "deny"; unsafe glow calls live only in
opengl/gl.rs. A headless EGL integration test builds every pipeline and
the converted shadertoy shaders on Mesa and reads back rendered pixels.
Note: Zig's shadertoy Uniforms order the selection background/foreground
colors opposite to the GLSL block (likely an upstream bug); kept as in
Zig for parity and recorded in the notes.
Deferred to the next renderer pass: generic, cell, image, link, row,
State, Thread, Overlay (need terminal render state).
Test Plan:
- cargo test -p ghostty-renderer (33 tests incl. tests/egl_headless.rs)
ddidderr