In the process of analyzing this routine I ended up reaching the goal of modifying the camera behaviour. Now it is possible to move the camera using D-Pad. Enjoy! I provided the bps patch for the ROM in this folder: https://github.com/animaone/castlevania-64-camera-routine/raw/main/Castlevania%20(USA)%20(Rev%202).bps
The patch should be applied in the ROM named: Castlevania (USA) (Rev 2).z64
The ROM md5 is: 06b58673f7d31c56f8fe8186e86f6bd6
A few years ago I wanted to do a modding in this game. I couldn't remember why anymore, but after playing the game again for a while, I remembered.
There are 2 Castlevanias for Nintendo 64: Castlevania, also known as Castlevania64 and the other game is Castlevania Legacy of Darkness.
The fact is that the first game lacks some basic things like: manual camera control and pressing start to exit the menu (you can enter the menu with start but you cannot exit).
In Legacy of Darkness they added better camera control via the D-Pad. When we play both games the first thing that comes to mind is: "why isn't there better camera control in the first game?"
The automatic camera control is perfect, the problem is that when we are in a dungeon or climbing somewhere where we need precision, then the camera messes with the gameplay.
I think that's where the idea came from😆. I compared the automatic camera control routines of both games and there was no change from one game to another. In fact the two routines are exactly the same.
I could find the function that reads the joystick to generate the camera rotation values.
Here is the automatic camera routine for the curious:
But first... Now we have Castlevania Diagonal64!
I found a way to have more memory, and modify the routine and... here is the final video showing the camera mod: https://twitter.com/Anima_C13L/status/1486802837887664130
The next image shows the old first(buggy) mod.
Following is the original extracted camera control function(not all of them, they are a lot! :P)
void FUN_8000cc50(ushort *param_1)
{
undefined4 *puVar1;
ushort uVar2;
ushort *puVar3;
ushort *puVar4;
float fVar5;
undefined4 uVar6;
float fVar7;
undefined8 in_f4;
double dVar8;
uint uVar9;
undefined8 in_f6;
uint uVar10;
undefined8 in_f10;
float fVar11;
float fVar12;
float fVar13;
float fStack128;
undefined4 uStack104;
undefined4 uStack100;
undefined4 uStack96;
ushort *puStack92;
ushort *puStack88;
float fStack76;
float fStack72;
float fStack68;
undefined auStack64 [64];
uVar10 = (uint)((ulonglong)in_f10 >> 0x20);
uVar6 = (undefined4)((ulonglong)in_f4 >> 0x20);
uVar9 = (uint)((ulonglong)in_f6 >> 0x20);
if ((*param_1 & 0x100) == 0) {
puVar1 = *(undefined4 **)(param_1 + 0x1a);
guPerspectiveF(auStack64,param_1 + 0x12,*puVar1,puVar1[1],puVar1[2],puVar1[3],puVar1[4]);
uVar2 = param_1[1];
}
else {
puVar1 = *(undefined4 **)(param_1 + 0x1a);
guOrthoF(auStack64,*puVar1,puVar1[1],puVar1[2],puVar1[3],puVar1[4],puVar1[5],puVar1[6]);
uVar2 = param_1[1];
}
puVar3 = param_1 + 0x34;
if ((uVar2 & 0x60) == 0) {
FUN_80002da8(puVar3,param_1 + 0x26,param_1 + 0x20);
puVar4 = *(ushort **)(param_1 + 8);
if (puVar4 != (ushort *)0x0) {
if (puVar4 != (ushort *)0x0) {
uVar2 = *puVar4;
while (((uVar2 & 0x80) != 0 && (puVar4 = *(ushort **)(puVar4 + 8), puVar4 != (ushort *)0x0))
) {
uVar2 = *puVar4;
}
}
if (puVar4 != (ushort *)0x0) {
puStack92 = puVar4;
FUN_8000c800();
FUN_8000ca9c(puVar3,puStack92 + 0x34,puVar3);
}
}
uStack104 = DAT_80093360;
uStack100 = DAT_80093364;
uStack96 = DAT_80093368;
FUN_80002a98(&uStack104,puVar3,0xffffffff80387b30);
fVar5 = *(float *)(param_1 + 0x4e);
fVar13 = *(float *)(param_1 + 0x4c);
fStack72 = DAT_80387b64 - fVar5;
fStack68 = DAT_80387b60 - fVar13;
fVar7 = *(float *)(param_1 + 0x50);
fStack76 = DAT_80387b68 - fVar7;
dVar8 = (double)CONCAT44(uVar6,fStack76);
if ((double)((ulonglong)uVar9 << 0x20) == (double)fStack68) {
DAT_80387b60 = (float)((double)DAT_80387b60 + DAT_800a2798);
fVar7 = *(float *)(param_1 + 0x50);
fVar5 = *(float *)(param_1 + 0x4e);
fVar13 = *(float *)(param_1 + 0x4c);
dVar8 = DAT_800a2798;
}
uVar9 = (uint)((ulonglong)dVar8 >> 0x20);
guLookAtF(0xffffffff80387b30,fVar13,fVar5,fVar7,DAT_80387b60,DAT_80387b64,DAT_80387b68,0,
0x3f800000,0);
uVar6 = sqrtf(fStack68 * fStack68 + fStack76 * fStack76);
uVar2 = FUN_80004394(fStack72,uVar6);
param_1[0x29] = uVar2;
dVar8 = (double)DAT_80387b58;
fVar13 = DAT_80387b58;
if (dVar8 < (double)((ulonglong)uVar9 << 0x20)) {
fVar13 = -DAT_80387b58;
}
uVar2 = FUN_80004394(fVar13,DAT_80387b38);
param_1[0x2a] = uVar2;
if ((double)fStack76 < (double)((ulonglong)dVar8 & 0xffffffff00000000)) {
param_1[0x2a] = -param_1[0x2a];
uVar2 = param_1[0x2a];
}
else {
uVar2 = param_1[0x2a];
}
param_1[0x2b] = 0;
param_1[0x2a] = uVar2 + 0x4000;
FUN_8000ca9c(0xffffffff80387b30,auStack64);
}
else {
puVar4 = param_1 + 0x34;
FUN_80002da8(puVar4,param_1 + 0x26,param_1 + 0x20);
puVar3 = *(ushort **)(param_1 + 8);
if (puVar3 == (ushort *)0x0) {
fVar13 = *(float *)(param_1 + 0x2e);
}
else {
if (puVar3 != (ushort *)0x0) {
uVar2 = *puVar3;
while (((uVar2 & 0x80) != 0 && (puVar3 = *(ushort **)(puVar3 + 8), puVar3 != (ushort *)0x0))
) {
uVar2 = *puVar3;
}
}
if (puVar3 != (ushort *)0x0) {
puStack88 = puVar3;
FUN_8000c800(puVar3);
FUN_8000ca9c(puVar4,puStack88 + 0x34,puVar4);
}
fVar13 = *(float *)(param_1 + 0x2e);
}
fVar7 = *(float *)(param_1 + 0x4e);
fVar12 = *(float *)(param_1 + 0x2c);
fVar5 = *(float *)(param_1 + 0x4c);
fStack72 = fVar13 - fVar7;
fStack68 = fVar12 - fVar5;
fStack128 = *(float *)(param_1 + 0x30);
fVar11 = *(float *)(param_1 + 0x50);
fStack76 = fStack128 - fVar11;
if ((double)((ulonglong)uVar10 << 0x20) == (double)fStack68) {
fVar5 = *(float *)(param_1 + 0x4c);
fStack128 = *(float *)(param_1 + 0x30);
uVar9 = (uint)((ulonglong)(double)fVar12 >> 0x20);
fVar13 = *(float *)(param_1 + 0x2e);
fVar7 = *(float *)(param_1 + 0x4e);
*(float *)(param_1 + 0x2c) = (float)((double)fVar12 + DAT_800a2790);
fVar12 = *(float *)(param_1 + 0x2c);
fVar11 = *(float *)(param_1 + 0x50);
}
guLookAtF(0xffffffff80387b30,fVar5,fVar7,fVar11,fVar12,fVar13,fStack128,0,0x3f800000,0);
if (param_1 == DAT_8009b438) {
FUN_800008d0(0xffffffff80387b30,0xffffffff80389e8c,0x40);
}
uVar6 = sqrtf(fStack68 * fStack68 + fStack76 * fStack76);
uVar2 = FUN_80004394(fStack72,uVar6);
param_1[0x29] = uVar2;
dVar8 = (double)DAT_80387b58;
fVar13 = DAT_80387b58;
if (dVar8 < (double)((ulonglong)uVar9 << 0x20)) {
fVar13 = -DAT_80387b58;
}
uVar2 = FUN_80004394(fVar13,DAT_80387b38);
param_1[0x2a] = uVar2;
if ((double)fStack76 < (double)((ulonglong)dVar8 & 0xffffffff00000000)) {
param_1[0x2a] = -param_1[0x2a];
uVar2 = param_1[0x2a];
}
else {
uVar2 = param_1[0x2a];
}
param_1[0x2b] = 0;
param_1[0x2a] = uVar2 + 0x4000;
FUN_8000ca9c(0xffffffff80387b30,auStack64,0xffffffff80387b30);
}
guMtxF2L(0xffffffff80387b30,((int)(param_1 + 0x3fe58aa4) / 0xa8) * 0x40 + DAT_80387ae8);
return;
}