Function is_vision_block

plugins/reveal.cpp:169–191

identify blocks that have tiles within the box that contains the unit's 26 tile radius vision cylinder

// identify blocks that have tiles within the box that contains the unit's
// 26 tile radius vision cylinder
static bool is_vision_block(const df::coord & upos, const df::coord & bpos, int offset = 0) {
    const int radius = 27 + offset;

    int ux1, ux2, uy1, uy2;
    ux1 = upos.x - radius;
    ux2 = upos.x + radius;
    uy1 = upos.y - radius;
    uy2 = upos.y + radius;

    int bx1, bx2, by1, by2;
    bx1 = bpos.x;
    bx2 = bpos.x + 15;
    by1 = bpos.y;
    by2 = bpos.y + 15;

    int clip_x1, clip_x2, clip_y1, clip_y2;
    clip_x1 = std::max(ux1, bx1);
    clip_y1 = std::max(uy1, by1);
    clip_x2 = std::min(ux2, bx2);
    clip_y2 = std::min(uy2, by2);

    return clip_x1 <= clip_x2 && clip_y1 <= clip_y2;
}

static void do_reveal_adventure(color_ostream &out, bool no_hell, bool incremental = false) {
    df::coord pos;