Hi Yolo!
Well, I’m convinced after much testing Airborne’s steering re-centering is entirely different to hard/race/street drivin’. The centering encoder signals are completely ignored. For Airborne, when your car re-spawns after crashing, whatever the wheel position your steering wheel is in at that time becomes the new center (regardless of angle). The center position can also self adjust during play should you oversteer (Say that you rotate the wheel 3 times clockwise to go round a tight turn. You’ll only need to do roughly one anit-clockwise rotation for the car to go in a straight line again).
I came to the conclusion that this game can only really be enjoyed with a mouse/spinner. Even then it would need force feedback so you had a feeling of where the steering center is.
Then I had a thought which was followed by a hack which might help...
I modified hdc68k_wheel_r() for airborne. I took out the steering latching stuff. I’ve added a key ‘S’ that can hold to adjust your steering wheel back to center during play. Here’s how it works:
Say that you are playing the game, you want the car to go straight, your steering wheel is in its central position but the car is pulling to the right. To fix this you need to turn your steering wheel left (Until the car is moving in a straight line), then press and hold the ‘S’ key, then turn your steering wheel to its central position, and release the ‘S’ key. That’s it.
I know its not really an ideal solution, but it might improve the game experience and help us get better laps times
In hardriv.cpp, in the "static INPUT_PORTS_START( hdrivair )" section, I've changed this line:-
PORT_BIT(0xfff, 0x200, IPT_PADDLE) PORT_MINMAX(0x000, 0x3ff) PORT_SENSITIVITY(100) PORT_KEYDELTA(5) PORT_REVERSE PORT_NAME("Steering Wheel")
to this...
PORT_BIT( 0xfff, 0x000, IPT_POSITIONAL ) PORT_POSITIONS(0xfff) PORT_WRAPS PORT_SENSITIVITY(50) PORT_KEYDELTA(1) PORT_REVERSE PORT_NAME("Steering Wheel")
Then in harddriv_m.cpp, replace the hdc68k_wheel_r() function with this...
uint16_t harddriv_state::hdc68k_wheel_r()
{
// grab the new wheel value
uint16_t new_wheel, raw_wheel = m_12badc[0].read_safe(0xffff);
int wheel_diff = 0;
bool is_wheel_increasing = false;
static uint8_t wheel_snapshot = 0;
static uint8_t wheel_offset = 0;
static bool steering_enabled = true;
if (machine().input().code_pressed(KEYCODE_S))
{
if (steering_enabled)
{
popmessage("Steering disabled (Re-center your wheel now...)");
steering_enabled = false;
wheel_snapshot = (m_hdc68k_last_wheel+wheel_offset)&0xff;
}
return ((wheel_snapshot << 8) | 0xff);
}
else
{
if (!steering_enabled)
{
popmessage("Steering enabled");
steering_enabled = true;
wheel_offset = (wheel_snapshot - raw_wheel)&0xff;
m_hdc68k_last_wheel = raw_wheel;
}
}
// Work out which way the wheel is spinning
if((m_hdc68k_last_wheel < 0x400) && (raw_wheel > 0xC00)) is_wheel_increasing = false; //Wrapped from bottom to top
else if ((m_hdc68k_last_wheel > 0xC00) && (raw_wheel < 0x400)) is_wheel_increasing = true; //Wrapped from top to bottom
else if(m_hdc68k_last_wheel > raw_wheel) is_wheel_increasing = false;
else if(m_hdc68k_last_wheel < raw_wheel) is_wheel_increasing = true;
//Steering damping:
//Ensure we don't jump from one encoder value to another too quickly confusing the game
//The game is aware only of changes to m_12badc's lower byte. This means the game can get easily confused if you where to move
//the wheel very quickly from say position 0x800 to 0xC12 in one cycle (Which was perhaps physically impossible using the
//actual arcade encoder). The game would be under the impression the wheel has moved only 0x12 values, rather than 0x412 values.
//If we detect a large change, slowly feed that information back to the game in managemtble amounts.
new_wheel = m_hdc68k_last_wheel;
while(new_wheel != raw_wheel)
{
if (is_wheel_increasing)
{
if (new_wheel >= 0xFFF) new_wheel = 0x000;
else new_wheel++;
}
else
{
if (new_wheel <= 0x000) new_wheel = 0xFFF;
else new_wheel--;
}
//Lets say the encoder can't move more that 32 teeth per cycle...
if (wheel_diff++ > 0x10) break;
}
if (machine().input().code_pressed(KEYCODE_LSHIFT))
{
popmessage("wheel=0x%04X", new_wheel);
}
m_hdc68k_last_wheel = new_wheel;
return ((new_wheel+wheel_offset) << 8) | 0xff;
}
Hi Geecab,that is a really good solution for the Hard Drivin' Airborne off center bug. I'll need to try it out and see! I'm thinking it would be more responsive when turning the wheel compared to the EMA buffering code I'm currently using to stop it going off center because it adds a very slight latency to the wheel.
Just thought I'd mention this because you seem to be confused about Street Drivin's steering wheel behaviour. Street Drivin's steering is different from Race Drivin' Compact, Hard Drivin' Compact, the cockpit versions AND different from Airborne.
Street Drivin' doesn't have the "steering going off-center bug" when you crash or when you go offroad or even if you turn the wheel too fast etc, it never goes out of alignment. Only the compact versions have that and Airborne. The only reason it seemed to be happening in Street Drivin' before is because the steering range was the same as the others (0x010, 0xff0), when it was changed it to 0x000, 0x3ff it completely fixed the steering, it stops the bug that happens when you steer to the maximum left or right. The change of the PORT_MINMAX to (0x000, 0x3ff) fixed that bug for Airborne too but Airborne has the same bugs that the compact versions have but unfortunately your solution for the compact versions doesn't fix it for Airborne.
BTW I'm now sure that Street Drivin's ROM is actually a cockpit version and I'm even more certain of that now because if you look at the ROM's that get loaded into the main program memory it shares ROM's with Race Drivin' Panorama which on MAME is a cockpit ROM and not a compact. None of the cockpit ROMs are compatible with the compact except the sound ROM's and Jed Margolin even mentions that fact on his website. You can try it for yourself, Street Drivin' already plays perfectly!
Just thought I'd mention it because it could help narrow down the problem Airborne is having because they both have the same steering wheel range in common but Street Drivin' doesn't do the wheel edge/centering stuff the same as any of the others and that is why it doesn't have the bug you were experiencing on the compact versions or Airborne.
I noticed the first set of ROM's in the main program seem to be the ones that contain the test menu code. I was able to load up the Race Drivin Panorama version of the test menu in Street Drivin' by swapping the ROM's over but it made the screen garbled too. It was all readable and seemed to work but had strange values and the writing just looked weird like the resolution is set wrong or something.
I've gave up on my mission of trying to make Street Drivin' have gears by fiddling with the ROM's because today I found out that the Race Drivin' Panorama has the extra stock car track and even has the drone cars from Street Drivin' on it. The only problem i noticed with it was the frame rate even when using my overclock. I fixed this by loading up only the main PCB ROM's and not the left and right PCB ROM's using the Race Drivin' cockpit machine configuration and now the game plays smooth. I think it's because there is a hack in the MAME source code that's used to get the 3 screens in sync and even when you choose 1 screen only in the MAME video options it still seems to be using that hack and using the side PCB's.