mirror of
https://github.com/cellos51/balatro-gba.git
synced 2026-09-07 16:36:10 -05:00
0eb7042468
* Implement our own Xorshift32 RNG algo to manage independent number sequences * Fix issues with seed 0 * adress @MeirGavish's review * Apply suggestions from @MeirGavish's code review Co-authored-by: MeirGavish <meir.gavish@gmail.com> * adress the rest of @MeirGavish's review * adress @MeirGavish's review * Fix last issues --------- Co-authored-by: MathisMartin31 <mathis.martin31@gmail.com> Co-authored-by: MeirGavish <meir.gavish@gmail.com> Co-authored-by: MonteCrysto <monte.crysto31@gmail.com>
101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/**
|
|
* @file random.h
|
|
*
|
|
* @brief Common functions to handle RNG manipulation. Using this interface has three goals:
|
|
* 1. Make RNG repeatable so that people can share seeds and saves, and end up with the same run
|
|
* 2. Prevent the players from engaging in save-scumming since the pseudo-RNG is deterministic
|
|
* 3. Accomodate for base-36 seeds, so that we can freely chose one with alpha-numeric characters in
|
|
* the seed screen input
|
|
*/
|
|
#ifndef RANDOM_H
|
|
#define RANDOM_H
|
|
|
|
#include <tonc.h>
|
|
|
|
/**
|
|
* @brief Keys to different independent RNG sequences
|
|
*/
|
|
enum RngSequence
|
|
{
|
|
RNG_SEQ_CARD_SHUFFLE,
|
|
RNG_SEQ_BLIND,
|
|
RNG_SEQ_SHOP_ITEMS,
|
|
RNG_SEQ_SKIP_TAGS,
|
|
|
|
// Each Joker with a random effect has its own independent RNG sequence
|
|
RNG_SEQ_JOKER_MISPRINT,
|
|
RNG_SEQ_JOKER_RESERVED_PARKING,
|
|
RNG_SEQ_JOKER_BUSINESS_CARD,
|
|
|
|
// For non-gameplay related things such as sound effects or visual effects, so as to not
|
|
// interfere with important stuff like Shop rolls or Joker effects.
|
|
RNG_SEQ_MISC,
|
|
|
|
RNG_SEQ_MAX
|
|
};
|
|
|
|
/**
|
|
* @brief Information to track and restore RNG state
|
|
*/
|
|
typedef struct
|
|
{
|
|
/** Initial seed */
|
|
u32 seed;
|
|
/** Individual states for independent rng sequences */
|
|
u32 states[RNG_SEQ_MAX];
|
|
} RngInfo;
|
|
|
|
/**
|
|
* @brief Starts counting CPU cycles, which will be used by rng_shuffle_seed to
|
|
* generate a more random seed. To be called once on game start.
|
|
*/
|
|
void rng_init(void);
|
|
|
|
/**
|
|
* @brief Accumulates CPU cycles for RNG seed generation, call exaclty once per frame.
|
|
*/
|
|
void rng_update(void);
|
|
|
|
/**
|
|
* @brief Set the rng seed to the chosen value, and reset the step counter to 0.
|
|
* The seed will be capped at `MAX_BASE36` for compatibility with the Seed Input screen
|
|
* used to choose a seed for seeded runs.
|
|
*
|
|
* @param seed the new RNG seed
|
|
*/
|
|
void rng_set_seed(u32 seed);
|
|
|
|
/**
|
|
* @brief Sets a new randomized seed for the RNG using a source of entropy.
|
|
*
|
|
* This needs to be called at least once before generating anything random but not on the very
|
|
* first cycle because it uses a CPU timer for entropy.
|
|
*
|
|
* This would also be used to generate the new seed when starting a new non-player-seeded run
|
|
*
|
|
* @note `rng_init` needs to have been called, so that the CPU profiling can provide entropy.
|
|
* @sa rng_init
|
|
*/
|
|
void rng_shuffle_seed(void);
|
|
|
|
/**
|
|
* @brief Get the next "randomly" generated number in the sequence corresponding to the given type.
|
|
*
|
|
* @param key key to the RNG sequence we need to pull a random number from
|
|
*
|
|
* @return u32
|
|
*/
|
|
u32 rng_get_u32(enum RngSequence key);
|
|
|
|
/**
|
|
* @brief Restore RNG info struct in the GameVariables. Sets the `seed` and restores the state for
|
|
* each independent sequence
|
|
*
|
|
* @param info RngInfo struct applied
|
|
*
|
|
* @note Consistency of the RNG after reloading the RngInfo struct has yet to be tested properly
|
|
*/
|
|
void rng_restore(RngInfo info);
|
|
|
|
#endif // RANDOM_H
|