Hardware-accelerated country picking: 24-bit bijective RGB buffers

Evaluating point-in-polygon raycasts across 180+ TopoJSON country boundaries during real-time continuous projection morphing causes heavy CPU bottlenecks and dropped frames.

GeoGenesis replaces geometric hit-testing with an off-screen 24-bit bijective RGB color-picking buffer.

1. 24-Bit Bijective Integer Encoding

Each country feature index $k \in [0, N-1]$ is mapped to a unique 24-bit integer $C = k + 1$:

$R = C \pmod{256}, \quad G = \lfloor C / 256 \rfloor \pmod{256}, \quad B = \lfloor C / 65536 \rfloor \pmod{256}$

Decoding the pixel value read under the cursor:

$\text{Index } k = R + G \cdot 256 + B \cdot 65536 - 1$

If $R = G = B = 0$, the pointer is over ocean or void ($k = \text{null}$).

2. Zero-Stall Host Memory Pinning

The off-screen canvas context is initialized with { willReadFrequently: true }. This pins the backing buffer in host memory, eliminating GPU-to-CPU pipeline stalls during ctx.getImageData() calls. Pointer inspection executes in $< 0.05\text{ ms}$ ($O(1)$ constant time) regardless of polygon complexity.