Better default coordinate constant

[brandonjpierce]

• Might be ideal to support something other than NaN https://github.com/visgl/deck.gl/pull/9174/files
• Export multiple variants, e.g. single value, array value, TypedArray value, etc

[brandonjpierce]

Super contrived port of GLSL function taken from: https://github.com/mattdesl/number-util/blob/master/index.js:

Reference: https://registry.khronos.org/OpenGL-Refpages/gl4/html/intBitsToFloat.xhtml

const int8 = new Int8Array(4);
const int32 = new Int32Array(int8.buffer, 0, 1);
const float32 = new Float32Array(int8.buffer, 0, 1);

function intBitsToFloat(value: number) {
  int32[0] = value;
  return float32[0];
}

[brandonjpierce]

Verified the above snippet, doing intBitsToFloat(-1) like how it is done in the deckgl shader correctly returns NaN. This calls into question another thought:

This "default coordinate" constant is primarily used as a fallback when no lon/lat is provided in the data. However, this is also a little contextualized to geojson data format specifically as other formats such as Arrow already give you a dict of null values for any given column. One could argue that if we needed to pass "empty" coordinates to a shader you may still run into this issue given that the return value of intBitsToFloat(-1) (in the function above, not in a shader) still returns NaN. Thus, you would still be passing NaN to the shader itself vs. deriving inside by checking if the attribute is falsy to begin with.