nx_framebuffer.nx

nx_framebuffer.nx -- u32 pixel buffer + z-buffer foundation. Per gap roadmap Phase 1: substrate needs a framebuffer for the software rasterizer to write into. This primitive provides: - u32 packed-RGBA framebuffer (w x h i64 cells) - Q14 depth buffer (parallel array) - Clear / set-pixel / set-depth primitives - Tile-clear for chunked updates PIXEL FORMAT: 0xRRGGBBAA packed in low 32 bits of i64. DEPTH FORMAT: Q14 metres signed. Initial depth = MAX (far plane). Caller allocates the buffer; primitive just provides accessors. To compose with the canvas blit, the JS shim reads the buffer's low 32 bits and writes RGBA8. PUBLIC APIs: nx_fb_alloc(w, h) -> *i64 framebuffer (w * h cells) nx_fb_depth_alloc(w, h) -> *i64 depth buffer nx_fb_clear(fb, w, h, color) fill with solid color nx_fb_clear_depth(zb, w, h) reset depth to far plane nx_fb_set(fb, w, h, x, y, color) nx_fb_get(fb, w, h, x, y) -> i64 nx_fb_depth_test_set(fb, zb, w, h, x, y, z, color) -> 0/1 Returns 1 if pixel written (z < existing); 0 otherwise. nx_fb_pack_rgba(r, g, b, a) -> i64 packed color helper genealogy_id: software_rasterizer_canon + frame_buffer_canon lineage_id: nx_framebuffer_q14_v1