TileSet internal data

[Chilly Willy]

The HV counters are at 0xC00008.

5.) HV Counter
The HV counter returns the vertical and horizontal position of the television's raster beam.
Reading the HV counter will return the following data:
VC7 VC6 VC5 VC4 VC3 VC2 VC1 VC0 (D15-D08)
HC8 HC7 HC6 HC5 HC4 HC3 HC2 HC1 (D07-D00)
VCx = Vertical position in lines.
HCx = Horizontal position in pixels.
According to the manual, VC0 is replaced with VC8 when in interlace mode 2.
For 8-bit reads, the even byte (e.g. C00008h) returns the V counter, and the odd byte (e.g. C00009h)
returns the H counter.
The V counter counts up from 00h to EAh, then it jumps back to E5h and continues counting up to
FFh. This allows it to cover the entire 262 line display.
The H counter counts up from 00h to E9h, then it jumps back to 93h and continues counting up to
FFh. This allows it to cover an entire 342 pixel line.
The H counter description is based upon known information about the SMS VDP's H counter. The
SMS has a 256x192 display, and each line consists of 342 pixels. (that includes blanking, retrace, etc.)
The description *could* be accurate for the Genesis' 32-cell display mode. This is not the case for the
40-cell display, where I would assume the H counter jumps back farther at a later point in the count-up.

[bioloid]

Great thanks, will try !

There a test without, hard to sync tried multiple things with map update... And tested just on/off each frame, but maybe I may just go with gameplay on/off later, will see.

https://youtu.be/O34y6uDcK0I

[bioloid]

Thanks it works, and no need bothering with counting back since just need parity : *(u8*)0xC00008) & 1

[bioloid]

https://youtu.be/F_MGJWloDJc

[bioloid]

Ok i have not enough free time but I started to work on the road graph : https://youtu.be/jUYF_CTGJ5I
Will add basic things like "stop" & "stop lights", but not sure where to go, could be cool to experiment this anyway.

[bioloid]

Just made an unity exporter, since i dont use "usual" 2/1 isometric, and spritessheets i found doesnt suit well.
https://youtu.be/Hpt6u3kYgaY
Next will be vehicles collisions

[bioloid]

oh and i will export multiple colors using the animation key, to got a car paint, but not sure what the game will be about.

[bioloid]

Today I got transparency working without bugs using 0XC00008, using vscroll in hinterrupt, and filling a single line when needed, but it was damn slow (the interrupt was just applying vscroll depending of the counter), so I switched to just baking transparent tiles and uploading transparent/not transparent when switching between floor & roof : https://www.youtube.com/watch?v=qXNJM_frTGs

[bioloid]

Oh and I passed the pipe to Highlight & Shadows, would like to have day/night cycle with car headlight & car shadows, not sure about priorities of sprites, i read those docs :
https://segaretro.org/Sega_Mega_Drive/S ... _highlight
https://segaretro.org/Sega_Mega_Drive/Priority

The first one states : "If sprite with a shadow/highlight pixel occludes another sprite, the plane will be visible through that pixel (with shadow/highlight applied)."

How Im supposed to sort sprites ?

[bioloid]

oh didnt saw this: SPR_setDepth

[bioloid]

Added highlight & shadows, only sega makes it possible
https://www.youtube.com/watch?v=D1FWgczm1us