diff options
Diffstat (limited to 'engines/sci/engine/kmath.cpp')
| -rw-r--r-- | engines/sci/engine/kmath.cpp | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/engines/sci/engine/kmath.cpp b/engines/sci/engine/kmath.cpp index 15bc24e0e3..ee5787af01 100644 --- a/engines/sci/engine/kmath.cpp +++ b/engines/sci/engine/kmath.cpp @@ -25,13 +25,22 @@ namespace Sci { +// Following variations existed: +// up until including 0.530 (Hoyle 1): will always get 2 parameters, even if 2 parameters were not passed +// it seems if range is 0, it will return the seed. +// 0.566 (Hero's Quest) to SCI1MID: check for 2 parameters, if not 2 parameters get seed. +// SCI1LATE+: 2 parameters -> get random number within range +// 1 parameter -> set seed +// any other amount of parameters -> get seed +// +// Right now, the weird SCI0 behavior (up until 0.530) for getting parameters and getting the seed is not implemented. +// We also do not let through more than 2 parameters to kRandom via signatures. In case there is a game doing this, +// a workaround should be added. reg_t kRandom(EngineState *s, int argc, reg_t *argv) { - switch (argc) { - case 1: // set seed to argv[0] - // SCI0/SCI01 just reset the seed to 0 instead of using argv[0] at all - return NULL_REG; + Common::RandomSource &rng = g_sci->getRNG(); - case 2: { // get random number + if (argc == 2) { + // get random number // numbers are definitely unsigned, for example lsl5 door code in k rap radio is random // and 5-digit - we get called kRandom(10000, 65000) // some codes in sq4 are also random and 5 digit (if i remember correctly) @@ -54,19 +63,25 @@ reg_t kRandom(EngineState *s, int argc, reg_t *argv) { if (range) range--; // the range value was never returned, our random generator gets 0->range, so fix it - const int randomNumber = fromNumber + (int)g_sci->getRNG().getRandomNumber(range); + const int randomNumber = fromNumber + (int)rng.getRandomNumber(range); return make_reg(0, randomNumber); } - case 3: // get seed - // SCI0/01 did not support this at all - // Actually we would have to return the previous seed - error("kRandom: scripts asked for previous seed"); - break; - - default: - error("kRandom: unsupported argc"); + // for other amounts of arguments + if (getSciVersion() >= SCI_VERSION_1_LATE) { + if (argc == 1) { + // 1 single argument is for setting the seed + // right now we do not change the Common RNG seed. + // It should never be required unless a game reuses the same seed to get the same combination of numbers multiple times. + // And in such a case, we would have to add code for such a feature (ScummVM RNG uses a UINT32 seed). + warning("kRandom: caller requested to set the RNG seed"); + return NULL_REG; + } } + + // treat anything else as if caller wants the seed + warning("kRandom: caller requested to get the RNG seed"); + return make_reg(0, rng.getSeed()); } reg_t kAbs(EngineState *s, int argc, reg_t *argv) { |