Orkuncakilkaya
6a83c28e05
The #78 investigation rejected hardware f32/f64 for the coordinate types (they would desync lockstep/replay/save) and identified camera zoom as the one genuinely-missing render feature. Ship it: Camera.zoom(scale) scales the whole view about the screen centre by a Q16.16 factor, threaded through the same two framebuffer chokepoints (rt_put_px/rt_fill_rect) that carry the camera offset, so it composes with Camera.set/follow/shake. Gated by an internal rt_cam_zoomed flag so a game that never zooms renders byte-for-byte identically (golden renders unchanged); Camera.zoom(1.0) turns it back off. The world coordinate types stay integer px + Q16.16 velocity, so it's a pure render-time transform and itself deterministic. Example examples/library/camera_zoom.ludic (pixel-readback verified), docs page, RFC updated (docs/RFC-POSITION-TYPES.md). Full suite 105/0, fixpoint holds. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
31 lines
1.4 KiB
Markdown
31 lines
1.4 KiB
Markdown
---
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id: camera-zoom
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name: Camera.zoom
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category: camera
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kind: namespace-method
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tokens: Camera.zoom
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sig: Camera.zoom(scale)
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tip: Scale the whole view about the screen centre by a Q16.16 factor (1.0 = none).
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order: 4
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ns: Camera
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member: zoom
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---
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Sets a render-time zoom: every draw is scaled about the screen centre by <code>scale</code>, a Q16.16 <code>fixed</code> factor. <code>1.0</code> is no zoom (and turns the zoom path back off, restoring the byte-identical un-zoomed blit); <code>2.0</code> is 2x in; <code>0.5</code> is 2x out. It composes with <a href="camera-set"><code>Camera.set</code></a> / <a href="camera-follow"><code>Camera.follow</code></a> (which move the view) and <a href="camera-shake"><code>Camera.shake</code></a>.
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Zoom is a *render-time transform*, not a change to the world coordinate types — those stay integer pixels + Q16.16 velocity so lockstep, replay and <code>world_save</code> hold (see the position-types RFC, #78). Because it rides on fixed-point, the zoom is itself deterministic: the same <code>scale</code> produces the same pixels on every machine and headless.
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Parameters:
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- `scale` — the zoom factor (`fixed`); `1.0` = no zoom, `>1` zooms in, `<1` zooms out
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```ludic
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program Demo {
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property Cam { z: fixed = 1.0 }
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model View { Cam }
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handler DrawWorld phase Render {
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Camera.zoom(2.0)
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Screen.fill_rectangle(150, 110, 20, 20, 0xffcc00)
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Screen.show()
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}
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}
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```
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