@woosh/meep-engine/src/engine/graphics/ecs/light/shadow/setShadowCameraDimensionsDiscrete.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 *
 * @param {Vector2} mapSize
 * @param camera
 * @param {number} x0
 * @param {number} y0
 * @param {number} z0
 * @param {number} x1
 * @param {number} y1
 * @param {number} z1
 */
export function setShadowCameraDimensionsDiscrete(
    mapSize,
    camera,
    x0,
    y0,
    z0,
    x1,
    y1,
    z1
) {
    const dX = x1 - x0;
    const dY = y1 - y0;

    const shadow_map_width = mapSize.x;
    const shadow_map_height = mapSize.y;

    const rX = dX / shadow_map_width;
    const rY = dY / shadow_map_height;

    //set start coordinate to pixel-snapped position
    const x0_d = x0 - x0 % rX - rX / 2;
    const y0_d = y0 - y0 % rY - rY / 2;

    const x1_d = x0_d + (dX) * ((shadow_map_width + 1) / shadow_map_width);
    const y1_d = y0_d + (dY) * ((shadow_map_height + 1) / shadow_map_height);

    camera.left = x0_d;
    camera.right = x1_d;

    camera.bottom = y0_d;
    camera.top = y1_d;
}