Public Access
twislaandClaude Opus 5.5
68d50b320f
The rules of the three Games (issue #101), with no screen and no keyboard in them: time and keys go in, the new state and what happened come out, and a seed decides the dice. With a player for a tune a note at a time, and Korobeiniki's notes. Host-tested. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0162FokPdvY2KsS4NBfwyWPk
93 lines
2.6 KiB
C++
93 lines
2.6 KiB
C++
#include "snake.h"
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#include <algorithm>
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namespace roro::games {
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namespace {
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bool opposite(Snake::Dir a, Snake::Dir b) { return (static_cast<int>(a) + 2) % 4 == static_cast<int>(b); }
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} // namespace
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void Snake::start() {
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body_.clear();
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taken_.fill(false);
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for (int i = 0; i < 3; i++) { // three cells in the middle, heading right
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Cell c{static_cast<int8_t>(kCols / 2 - i), static_cast<int8_t>(kRows / 2)};
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body_.push_back(c);
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mark(c, true);
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}
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dir_ = Dir::Right;
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turnCount_ = 0;
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score_ = 0;
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sinceMs_ = 0;
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alive_ = true;
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placeFood();
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}
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uint32_t Snake::intervalMs() const {
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uint32_t off = static_cast<uint32_t>(score_ / kFoodsAStep) * kFasterMs;
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return off >= kSlowestMs - kFastestMs ? kFastestMs : kSlowestMs - off;
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}
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void Snake::turn(Dir dir) {
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Dir last = turnCount_ ? turns_[turnCount_ - 1] : dir_;
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if (dir == last || opposite(dir, last) || turnCount_ >= 2) return;
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turns_[turnCount_++] = dir;
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}
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// On a free cell, each as likely as another.
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void Snake::placeFood() {
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int free = kCols * kRows - static_cast<int>(body_.size());
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if (free <= 0) return;
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int pick = rng_.below(free);
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for (int i = 0; i < kCols * kRows; i++) {
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if (taken_[static_cast<size_t>(i)]) continue;
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if (pick-- == 0) {
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food_ = {static_cast<int8_t>(i % kCols), static_cast<int8_t>(i / kCols)};
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return;
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}
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}
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}
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uint8_t Snake::step(uint32_t ms) {
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uint8_t events = 0;
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if (!alive_) return 0;
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sinceMs_ += std::min<uint32_t>(ms, 500);
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while (alive_ && sinceMs_ >= intervalMs()) {
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sinceMs_ -= intervalMs();
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events |= move();
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}
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return events;
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}
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uint8_t Snake::move() {
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if (turnCount_) {
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dir_ = turns_[0];
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turns_[0] = turns_[1];
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turnCount_--;
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}
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static const int8_t dc[4] = {0, 1, 0, -1}, dr[4] = {-1, 0, 1, 0};
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Cell head{static_cast<int8_t>(body_.front().col + dc[static_cast<int>(dir_)]),
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static_cast<int8_t>(body_.front().row + dr[static_cast<int>(dir_)])};
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bool eats = head == food_;
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// The tail moves on as the head arrives: the head may go where the tail was. A snake that
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// dies stays as it was, whole.
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bool ontoTail = !eats && head == body_.back();
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if (head.col < 0 || head.col >= kCols || head.row < 0 || head.row >= kRows || (taken(head) && !ontoTail)) {
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alive_ = false;
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return Died;
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}
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if (!eats) {
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mark(body_.back(), false);
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body_.pop_back();
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}
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body_.push_front(head);
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mark(head, true);
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if (!eats) return Moved;
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score_++;
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placeFood();
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return Moved | Ate;
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}
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} // namespace roro::games
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