# Display Refactor Progress

## Immediate Goal
Render a 32x32 white square through the new render opcode stack on Linux.

## Architecture (summary)
See `.claude/display-refactor.md` for the full design.

- `src/dusk/render/` -- opcode format + buffer + submission API (the *contract*).
- Platform backends (e.g. `src/duskgl/`) consume the buffer and translate to native API calls.
- `src/dusk/display/` -- orchestration shell only: `displayInit`, `displayUpdate`, `displayDispose`.
- Scenes call `renderSprite(...)`, `renderClear(...)`. The backend executes the intent.

## Opcode format (32 bytes)
Every command starts with a 4-byte `ropheader_t` (opcode, flags, depth). Two commands defined:
- `ROP_CLEAR` (32 bytes) -- clear with a color.
- `ROP_DRAW_SPRITE` (32 bytes) -- screen-space int16 x/y/w/h + tint color.

## Milestone 1 -- Archive + strip existing display deps ✓
- [x] Old `src/dusk/display/` archived (now deleted from working tree via git).
- [x] Old `src/duskgl/display/` removed (new GL renderer replaces it).
- [x] `engine.c` stripped to minimal subsystems, set to `SCENE_TYPE_TEST`.
- [x] `scene.c` stripped of old display/shader/screen references.
- [x] `console.c` stripped of display deps.
- [x] `ui/CMakeLists.txt` gutted (re-implementation deferred).
- [x] `asset/loader/CMakeLists.txt` -- display loaders disabled.
- [x] `asset/loader/assetloader.h` -- display loader types removed.
- [x] `rpg/overworld/chunk.h` -- mesh_t / meshvertex_t removed.
- [x] `rpg/overworld/map.c` -- mesh/spritebatch calls removed.
- [x] `scene/overworld/sceneoverworld.c` -- stubbed to empty callbacks.
- [x] Test suite display tests disabled.

## Milestone 2 -- Render opcode system ✓
- [x] `src/dusk/render/rop.h` -- `ropheader_t`, `ropclear_t`, `ropsprite_t`.
- [x] `src/dusk/render/ropbuffer.h/.c` -- `ROPBUFFER` global, reset, alloc.
- [x] `src/dusk/render/render.h/.c` -- `renderClear()`, `renderSprite()`.
- [x] `src/dusk/render/CMakeLists.txt`.

## Milestone 3 -- New minimal display shell ✓
- [x] `src/dusk/display/display.h/.c` -- init/update/dispose, calls platform hooks.
- [x] `src/dusk/display/displaystate.h` -- cull/depth/blend flags.
- [x] `src/dusk/display/color.csv` + `CMakeLists.txt` -- color generation kept.

## Milestone 4 -- GL backend ✓
- [x] `src/duskgl/render/rendergl.h/.c`:
  - GL 3.3 core shader (ortho projection, solid color, no texture yet).
  - `renderGLInit` -- creates VAO/VBO/shader.
  - `renderGLFlush(buf, w, h)` -- walks ROPBUFFER, GL calls per opcode.
  - `ROP_CLEAR` → `glClearColor` + `glClear`.
  - `ROP_DRAW_SPRITE` → 6-vertex quad, `glDrawArrays`.
- [x] `src/duskgl/error/errorgl.h/.c` -- `errorGLCheck`.
- [x] `src/duskgl/CMakeLists.txt`.
- [x] `src/dusksdl2/display/displaysdl2.h/.c` updated:
  - `displaySDL2Init` -- SDL2 window + GL 3.3 context + `renderGLInit`.
  - `displaySDL2Flush(ropbuffer_t *)` -- MakeCurrent + `renderGLFlush`.
  - `displaySDL2Swap` -- SDL_GL_SwapWindow.
- [x] `src/dusklinux/display/displayplatform.h` updated with new macros.

## Milestone 5 -- Test scene ✓
- [x] `SCENE_TYPE_TEST` added to `scenetype.h/.c`.
- [x] `src/dusk/scene/test/scenetest.h/.c`:
  - `renderClear(color(32, 32, 48, 255))` -- dark blue-grey background.
  - `renderSprite(100, 100, 32, 32, COLOR_WHITE)` -- 32x32 white square.
- [x] `engine.c` starts with `SCENE_TYPE_TEST`.

## Milestone 6 -- Verified ✓
- [x] Build succeeds with no errors (2026-06-18).
- [x] Engine initializes: SDL window + GL context + shader + test scene.
- [x] No crashes running for 5+ seconds.
- [ ] 32x32 white square visually confirmed on screen.

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## Status: BUILD PASSING -- awaiting visual confirmation

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## Decisions log

**2026-06-18** -- `color_t = color4b_t` (from generated `display/color.h`). The color generation pipeline (color.csv + Python tool) is kept in the new minimal `src/dusk/display/CMakeLists.txt`.

**2026-06-18** -- `ROP_SIZE = 32`. All opcodes fixed 32 bytes. 3D quads will be 64 bytes when added later.

**2026-06-18** -- Depth sort deferred. Buffer stores unsorted commands; painter platforms sort on flush. GL uses Z-buffer.

**2026-06-18** -- Texture system not yet wired into the opcode pipeline. `ROP_DRAW_SPRITE` with `texture=0` uses solid tint color only (no sampler). Texture handle system comes next.

**2026-06-18** -- GL backend uses GL 3.3 Core profile. Shader takes screen-space pixel coordinates and converts to clip space using window size queried from SDL each frame.

**2026-06-18** -- `ROPBUFFER` is a global (4096 slots × 32 bytes = 128 KB). Reset at start of each frame in `displayUpdate`.

**2026-06-18** -- `ui/`, `rpg/overworld` display code, asset display loaders all temporarily stubbed/disabled. Will be rewritten against the new render API.