diff options
Diffstat (limited to 'src/battle_transition.c')
| -rw-r--r-- | src/battle_transition.c | 56 |
1 files changed, 8 insertions, 48 deletions
diff --git a/src/battle_transition.c b/src/battle_transition.c index 08ae9e5b2..a5b6f369c 100644 --- a/src/battle_transition.c +++ b/src/battle_transition.c @@ -1599,12 +1599,7 @@ static void sub_80D1F64(s16 a1, s16 a2, u8 a3) } } } - // PROBLEM #3: We need (a2 << 16) & 0x30000 here. - // Is it because the programmer declared a s32 var to - // hold the value of a2 and then cast the result to s16? - // Currently I have to write it explicitly. - // (around line 460 in ASM) - if (!a3 || !((a2 << 16) & 0x30000)) + if (a3 == 0 || a2 % 4 == 0) { for (i = 0; i < 160; ++i) gScanlineEffectRegBuffers[1][i * 2 + a3] = (gScanlineEffectRegBuffers[1][i + 320] << 8) | gScanlineEffectRegBuffers[1][i + 480]; @@ -1618,49 +1613,14 @@ static void sub_80D1F64(s16 a1, s16 a2, u8 a3) case 0: if (res > 80) res = 80; - // PROBLEM #4: + // PROBLEM #3: // (around line 550 in ASM) - // Case 0-3 are very similar, so it's very likely - // that they have the same problem. - // The code is definitely functional equivalent, - // but the vanilla game used some extra shifts and - // used unsigned comparison. Another difference is - // that I can't figure out a way to make gUnknown_83FA444[a2] - // happen outside the loop body. - // It seems that sTransitionStructPtr->data[2] need - // to be used in the first statement so that the - // struct pointer sTransitionStructPtr will be loaded - // early enough. - // - // Logically the generated code is following if + do-while structure. - // But it seems that it can only make the situation even worse. - /* - i = res; - if (i > 0) - { - // This happens before loop body. - s16 unk = gUnknown_83FA444[a2]; - - do - { - sTransitionStructPtr->data[2] = ((i * unk) >> 8) + 120; - if (sTransitionStructPtr->data[2] <= 255) - { - sTransitionStructPtr->bg123HOfs = 400 - i; - sTransitionStructPtr->data[10] = gScanlineEffectRegBuffers[1][400 - i]; - if (gScanlineEffectRegBuffers[1][560 - i] < sTransitionStructPtr->data[2]) - gScanlineEffectRegBuffers[1][560 - i] = 120; - else if (gScanlineEffectRegBuffers[1][400 - i] < sTransitionStructPtr->data[2]) - gScanlineEffectRegBuffers[1][400 - i] = sTransitionStructPtr->data[2]; - } - } - while (--i > 0); - } - */ + // Case 0 ... 3 are very similar, so it's very likely that they have the same problem. + // Weird shifts around writing to sTransitionStructPtr->data[2], and the following comparison. for (i = res; i > 0; --i) { sTransitionStructPtr->data[2] = ((i * gUnknown_83FA444[a2]) >> 8) + 120; - if (sTransitionStructPtr->data[2] <= 255) + if (sTransitionStructPtr->data[2] <= 255u) // why is this unsigned? { sTransitionStructPtr->bg123HOfs = 400 - i; sTransitionStructPtr->data[10] = gScanlineEffectRegBuffers[1][400 - i]; @@ -1674,7 +1634,7 @@ static void sub_80D1F64(s16 a1, s16 a2, u8 a3) case 1: if (res > 80) res = 80; - // same as PROBLEM #4 + // same as PROBLEM #3 for (i = res; i > 0; --i) { s16 unkVal; @@ -1692,7 +1652,7 @@ static void sub_80D1F64(s16 a1, s16 a2, u8 a3) case 2: if (res < -79) res = -79; - // same as PROBLEM #4 + // same as PROBLEM #3 for (i = res; i <= 0; ++i) { sTransitionStructPtr->data[2] = ((i * gUnknown_83FA444[a2]) >> 8) + 120; @@ -1710,7 +1670,7 @@ static void sub_80D1F64(s16 a1, s16 a2, u8 a3) case 3: if (res < -79) res = -79; - // same as PROBLEM #4 + // same as PROBLEM #3 for (i = res; i <= 0; ++i) { sTransitionStructPtr->data[2] = ((i * gUnknown_83FA444[a2]) >> 8) + 120; |