Orkuncakilkaya
31cfbc2465
Completes the transform/state-based rendering #23 tracked as blocked on new renderer state. All of it threads through the two framebuffer chokepoints every draw primitive already funnels through (rt_put_px / rt_fill_rect), so one place gives the whole draw API a camera, a clip rect, and a blend mode. Defaults are neutral — camera (0,0), clip = full screen, blend = replace — so every existing golden render is byte-identical (the 60+ render tests still pass unchanged). New renderer state (runtime/native/core.ludic): - Screen.camera(x, y) / Camera.set(x, y) world-space draw offset; a world point draws at (wx-x, wy-y). Moves everything — reset to (0,0) for a HUD. - Camera.follow(x, y, lerp) ease the offset toward centring a target (fixed lerp 0..1) - Camera.shake(amount) +/- amount jitter from the seeded RNG (replay shakes identically); 0 clears - Screen.clip(x,y,w,h) / clip_reset() screen-space clip rectangle - Screen.blend_mode(m) 0 = replace, 1 = additive (clamped) New primitives: - Screen.oval(x, y, rx, ry, color) axis-aligned ellipse outline (midpoint) - Screen.measure_text(text) -> int advance width in the 5x7 font - Screen.pixel(x, y) -> int read a framebuffer pixel (0x00RRGGBB) Everything stays integer and deterministic (the camera, shake, and blend all reproduce exactly under identical inputs), so headless renders remain diffable. Camera.follow interpolates in the fixed domain (fixed*fixed then floor) to avoid the int*fixed coercion trap. Screen.pixel makes the whole surface testable by reading rendered pixels back: examples/library/render.ludic asserts 18 cases — pixel round-trip, camera and Camera.set/follow offsets, clip in/out + reset, additive blend with 255 clamp, oval extremes vs hollow centre, and text measurement — all verified against the actual framebuffer, not just that the call compiled. Wired into x test (now 65 passed). Docs: 7 new Screen pages + a Camera section with 3 pages, inventory/coverage green. Seed reseeded; the C-free bootstrap fixpoint holds. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
28 lines
1.1 KiB
Markdown
28 lines
1.1 KiB
Markdown
---
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id: screen-camera
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name: Screen.camera
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category: screen
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kind: namespace-method
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tokens: Screen.camera
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sig: Screen.camera(x, y)
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tip: Set the world-space camera offset for the draw path.
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order: 18
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ns: Screen
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member: camera
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---
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Sets a camera offset applied to every draw: a world point <code>(wx, wy)</code> lands on screen at <code>(wx - x, wy - y)</code>. Move it to scroll the world under a fixed viewport. The camera moves <em>everything</em> drawn, so reset it to <code>(0, 0)</code> before drawing a fixed HUD. Same control as <a href="camera-set"><code>Camera.set</code></a>. Deterministic.
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```ludic
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program Demo {
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property Position { x: int = 0, y: int = 0 }
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model Player { Position }
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handler DrawWorld phase Render {
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Screen.camera(Position.x - 160, Position.y - 120) # centre on the player
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Screen.fill_rectangle(x: 0, y: 0, width: 16, height: 16, color: Color.Red)
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Screen.camera(0, 0) # HUD in screen space
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Screen.draw_text(x: 4, y: 4, text: "SCORE", color: Color.White, scale: 1)
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Screen.show()
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}
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}
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```
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