From c6a5aaf5c4a020eaefe24943ecb6cf9d4eb26836 Mon Sep 17 00:00:00 2001 From: Gabriel Schneider Date: Mon, 28 Sep 2026 15:57:22 -0300 Subject: Post chain: Shadertoy passes compiled by glslc; Crt, Ripple and Glitch rewritten as Shadertoy files 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/post/ripple.glsl | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 shaders/post/ripple.glsl (limited to 'shaders/post/ripple.glsl') diff --git a/shaders/post/ripple.glsl b/shaders/post/ripple.glsl new file mode 100644 index 00000000..ffecbf70 --- /dev/null +++ b/shaders/post/ripple.glsl @@ -0,0 +1,49 @@ +// Ripple: the page as a still pool a slow swell crosses. Rings travel out +// from the middle of the window at a fixed speed in pixels, so they look +// the same at any size and frame rate; the displacement is at most a couple +// of pixels, so text stays readable, and it eases in over its first half +// second instead of snapping on. Each ring catches the light a little on its +// rising side, in linear light, and the result is dithered so the shading +// never bands. It is a Shadertoy file: pardes puts its prefix before it. + +const float TAU = 6.28318530718; +const float WAVELENGTH_PX = 150.0; +const float SPEED_PX = 55.0; // outward, per second +const float AMPLITUDE_PX = 2.2; +const float SHADE = 0.035; // light on a slope, linear +const float EASE_IN = 0.5; // seconds + +vec3 toLinear(vec3 c) { + return mix(pow((c + 0.055) / 1.055, vec3(2.4)), c / 12.92, lessThanEqual(c, vec3(0.04045))); +} + +vec3 toSrgb(vec3 c) { + c = max(c, vec3(0.0)); + return mix(1.055 * pow(c, vec3(1.0 / 2.4)) - 0.055, c * 12.92, lessThanEqual(c, vec3(0.0031308))); +} + +float ign(vec2 p) { + return fract(52.9829189 * fract(dot(p, vec2(0.06711056, 0.00583715)))); +} + +void mainImage(out vec4 fragColor, in vec2 fragCoord) { + vec2 size = iResolution.xy; + vec2 center = 0.5 * size; + vec2 offset = fragCoord - center; + float radius = length(offset); + float reach = 0.5 * length(size); + // Strongest a third of the way out, fading to nothing at the middle + // and at the edges, so the window's frame never wobbles. + float envelope = smoothstep(0.0, 0.18, radius / reach) * (1.0 - smoothstep(0.35, 0.95, radius / reach)); + float ease = smoothstep(0.0, EASE_IN, iTime); + float phase = (radius - iTime * SPEED_PX) * TAU / WAVELENGTH_PX; + float height = sin(phase); + float slope = cos(phase); + vec2 dir = offset / max(radius, 1e-3); + vec2 moved = fragCoord + dir * height * AMPLITUDE_PX * envelope * ease; + + vec4 s = texture(iChannel0, moved / size); + vec3 col = toLinear(s.rgb) * (1.0 + SHADE * slope * envelope * ease); + vec3 srgb = toSrgb(col) + (ign(fragCoord + float(iFrame % 64) * 5.588238) - 0.5) / 255.0; + fragColor = vec4(clamp(srgb, 0.0, 1.0), s.a); +} -- cgit v1.3