miaoda-game-mode7-core

Engine-independent Mode 7 coordinate math for retro racers, low-altitude flight, rotating maps, water/ground planes, and arena views. It returns map sampling coordinates; image data, shaders, filtering, and sprites remain renderer-owned.

pnpm add miaoda-game-mode7-core

const camera = {position: {x: 100, y: 200}, heading: Math.PI / 4, height: 1, fieldOfView: Math.PI / 2, horizonY: 180};
const viewport = {width: 640, height: 360};
for (let y = 181; y < viewport.height; y += 1) {
  const row = buildMode7PerspectiveScanline(camera, viewport, y);
  if (row) sampleRow(row.start, row.step);
}
const carAnchor = projectMode7GroundPoint(camera, viewport, car.position);

Angles are radians and positions are continuous map units. Each perspective scanline supplies one start coordinate and one constant per-pixel world step. buildMode7PerspectiveScanlines can skip rows for a low-resolution effect.

For raw rotation/scale/shear, use mapMode7Texel or buildMode7AffineScanline with an explicit 2x2 transform, pivot, and scroll. The package models one flat plane; use segmented roads for hills or a terrain package for height fields.