Add claude docs

2026-06-16 10:15:59 -05:00
parent 8131bcd4d4
commit ed5c60ac30
32 changed files with 3781 additions and 13 deletions
@@ -0,0 +1,81 @@
+# Display -- Screen, Framebuffer, and Size Modes
+
+Source: `src/dusk/display/`
+
+See also: `.claude/display-texture.md`, `.claude/display-shader.md`
+
+---
+
+## Display size modes
+
+Two compile-time configurations exist:
+
+### Fixed size (`DUSK_DISPLAY_WIDTH` + `DUSK_DISPLAY_HEIGHT`)
+
+The render resolution is constant. Set both defines at CMake configure
+time. `SCREEN.width` and `SCREEN.height` are compile-time constants.
+
+### Dynamic size (`DUSK_DISPLAY_SIZE_DYNAMIC`)
+
+The window can be resized (desktop targets). Instead of fixed defines,
+set `DUSK_DISPLAY_WIDTH_DEFAULT` and `DUSK_DISPLAY_HEIGHT_DEFAULT`.
+The screen system renders to an internal framebuffer at a logical
+resolution and scales/letterboxes to the actual window.
+
+Screen modes available only with `DUSK_DISPLAY_SIZE_DYNAMIC`:
+
+| Mode | Behaviour |
+|------|-----------|
+| `SCREEN_MODE_BACKBUFFER` | Render directly to the window backbuffer |
+| `SCREEN_MODE_FIXED_SIZE` | Fixed pixel dimensions; letterboxed |
+| `SCREEN_MODE_ASPECT_RATIO` | Maintain aspect ratio at all cost |
+| `SCREEN_MODE_FIXED_HEIGHT` | Fixed height; width expands/contracts |
+| `SCREEN_MODE_FIXED_WIDTH` | Fixed width; height expands/contracts |
+| `SCREEN_MODE_FIXED_VIEWPORT_HEIGHT` | Fixed height at higher resolution |
+
+Configure via `SCREEN.mode` and the corresponding union field before
+calling `screenInit()`.
+
+---
+
+## Framebuffer (`framebuffer.h`)
+
+```c
+extern framebuffer_t FRAMEBUFFER_BACKBUFFER;
+extern const framebuffer_t *FRAMEBUFFER_BOUND;
+
+// Bind/unbind:
+frameBufferBind(fb);
+frameBufferUnbind();
+
+// Clear (pass flag combination):
+frameBufferClear(fb, FRAMEBUFFER_CLEAR_COLOR | FRAMEBUFFER_CLEAR_DEPTH);
+
+// Dimensions of the currently bound framebuffer:
+int32_t w = frameBufferGetWidth();
+int32_t h = frameBufferGetHeight();
+```
+
+`FRAMEBUFFER_BACKBUFFER` is the window surface. Off-screen framebuffers
+are used by the screen system when `DUSK_DISPLAY_SIZE_DYNAMIC` is on.
+
+---
+
+## Screen (`screen.h`)
+
+```c
+extern screen_t SCREEN;
+// SCREEN.width, SCREEN.height  -- logical render dimensions
+// SCREEN.aspect                -- width / height
+// SCREEN.background            -- clear colour
+
+errorret_t screenInit();
+errorret_t screenBind();    // call before rendering game content
+errorret_t screenUnbind();  // call after game content, before UI
+errorret_t screenRender();  // blit the internal framebuffer to the window
+errorret_t screenDispose();
+```
+
+`screenBind` / `screenUnbind` / `screenRender` are called by the scene
+system automatically each frame. Game code normally does not call them
+directly -- use the JS `render()` hook instead.