How to Start #1

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marsultor · 2025-12-21T15:26:01-06:00

marsultor commented

2025-12-21 15:26:01 -06:00

Phase 0 — Define the “golden path”

Before writing real code, lock this in mentally:

I want one fullscreen layer-shell surface per output, with a working EGL context and a frame-callback-driven render loop.

Nothing else matters until this is rock-solid.

Phase 1 — Minimal fullscreen layer-shell client (NO GL)

Goal

Show a solid-color fullscreen surface on all outputs and keep it visible forever.

What you implement

wl_display connect
Registry bind:
- wl_compositor
- wl_output
- zwlr_layer_shell_v1
Output tracking
One wl_surface + zwlr_layer_surface_v1 per output

Hard requirements

Layer: overlay
Anchors: all sides
Exclusive zone: -1
Keyboard interactivity: exclusive

If this fails, your lock is not secure.

Success criteria

Covers all monitors
Cannot be obscured
Survives window creation/destruction
Survives workspace changes

👉 Stop here until this works perfectly.

Phase 2 — Frame callbacks (still NO GL)

Goal

Prove you can drive animation without busy-looping.

What you add

wl_surface_frame
A timer or monotonic clock
Redraw on frame callback

For now:

Alternate background color
Or move a rectangle in software (wl_shm)

Success criteria

CPU usage near zero when idle
Smooth updates
No tearing or flicker

If you can’t get frame callbacks right, GL will stutter later.

Phase 3 — EGL + OpenGL (still NO particles)

Goal

Clear the screen using OpenGL on every frame.

What you add

wayland-egl
EGLDisplay, EGLContext, EGLSurface
OpenGL ES context (3.1+)

Render loop:

frame callback →
  eglMakeCurrent →
  glClear →
  eglSwapBuffers →
  request next frame

Success criteria

No black frames
No crashes on resize
Works on all outputs
Context survives VT switch

At this point, you officially “own” the GPU as a client.

Phase 4 — One compute shader, zero text

Goal

Prove compute shaders work in your environment.

What you add

One SSBO
One compute shader that:
- writes a moving point
Render that point

Success criteria

GPU updates positions
CPU only supplies dt
No CPU-side vertex updates

This validates your “everything on GPU” rule.

Phase 5 — Text mask upload (CPU → GPU, ONCE)

Goal

Upload a bitmap and sample it in a shader.

What you add

FreeType + HarfBuzz
Rasterize one word (“LOCKED”)
Upload as R8 texture
Visualize mask as particles or points

Success criteria

Bitmap never changes per frame
No CPU readback
No per-frame uploads

Phase 6 — GPU particle spawn pass

Goal

Spawn particles from the text mask on the GPU.

What you add

Compute shader:
- Reads text texture
- Allocates particles
Fixed max particle count

Success criteria

Particle count matches glyph density
No CPU involvement
Deterministic layout

Phase 7 — Vector field + failure animation

Goal

Wrong password triggers chaos.

What you add

Vector field function
State uniform (locked / failed)
Forces applied only when failed

Success criteria

Visual response is immediate
Reset does not require regeneration

Phase 8 — Input + PAM

Goal

Make it real.

What you add

wl_keyboard
xkbcommon
PAM worker thread
Unlock signal to Hyprland

Render loop never blocks.

Phase 9 — Hardening

You handle:

Output hotplug
Suspend/resume
VT switch
Compositor restart
GL context loss

This is what separates demos from lockscreens.

# Phase 0 — Define the “golden path” Before writing real code, lock this in mentally: > **I want one fullscreen layer-shell surface per output, with a working EGL context and a frame-callback-driven render loop.** Nothing else matters until this is rock-solid. --- # Phase 1 — Minimal fullscreen layer-shell client (NO GL) ### Goal Show a solid-color fullscreen surface on **all outputs** and keep it visible forever. ### What you implement * `wl_display` connect * Registry bind: * `wl_compositor` * `wl_output` * `zwlr_layer_shell_v1` * Output tracking * One `wl_surface` + `zwlr_layer_surface_v1` **per output** ### Hard requirements * Layer: `overlay` * Anchors: all sides * Exclusive zone: `-1` * Keyboard interactivity: `exclusive` If this fails, your lock is not secure. ### Success criteria * Covers all monitors * Cannot be obscured * Survives window creation/destruction * Survives workspace changes 👉 **Stop here until this works perfectly.** --- # Phase 2 — Frame callbacks (still NO GL) ### Goal Prove you can drive animation **without busy-looping**. ### What you add * `wl_surface_frame` * A timer or monotonic clock * Redraw on frame callback For now: * Alternate background color * Or move a rectangle in software (wl_shm) ### Success criteria * CPU usage near zero when idle * Smooth updates * No tearing or flicker If you can’t get frame callbacks right, **GL will stutter later**. --- # Phase 3 — EGL + OpenGL (still NO particles) ### Goal Clear the screen using OpenGL on every frame. ### What you add * `wayland-egl` * `EGLDisplay`, `EGLContext`, `EGLSurface` * OpenGL ES context (3.1+) Render loop: ```text frame callback → eglMakeCurrent → glClear → eglSwapBuffers → request next frame ``` ### Success criteria * No black frames * No crashes on resize * Works on all outputs * Context survives VT switch At this point, you officially “own” the GPU **as a client**. --- # Phase 4 — One compute shader, zero text ### Goal Prove compute shaders work in your environment. ### What you add * One SSBO * One compute shader that: * writes a moving point * Render that point ### Success criteria * GPU updates positions * CPU only supplies `dt` * No CPU-side vertex updates This validates your “everything on GPU” rule. --- # Phase 5 — Text mask upload (CPU → GPU, ONCE) ### Goal Upload a bitmap and sample it in a shader. ### What you add * FreeType + HarfBuzz * Rasterize one word (“LOCKED”) * Upload as `R8` texture * Visualize mask as particles or points ### Success criteria * Bitmap never changes per frame * No CPU readback * No per-frame uploads --- # Phase 6 — GPU particle spawn pass ### Goal Spawn particles from the text mask **on the GPU**. ### What you add * Compute shader: * Reads text texture * Allocates particles * Fixed max particle count ### Success criteria * Particle count matches glyph density * No CPU involvement * Deterministic layout --- # Phase 7 — Vector field + failure animation ### Goal Wrong password triggers chaos. ### What you add * Vector field function * State uniform (`locked / failed`) * Forces applied only when failed ### Success criteria * Visual response is immediate * Reset does not require regeneration --- # Phase 8 — Input + PAM ### Goal Make it real. ### What you add * `wl_keyboard` * `xkbcommon` * PAM worker thread * Unlock signal to Hyprland Render loop **never blocks**. --- # Phase 9 — Hardening You handle: * Output hotplug * Suspend/resume * VT switch * Compositor restart * GL context loss This is what separates demos from lockscreens.

marsultor added the

labels 2025-12-21 15:26:01 -06:00

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