Mapping PMG coords to screen resolution

[damosan]

I'm working with PMG on a gr.8 screen.  Has anyone come up with a quick way of mapping PM graphics coords to the underlying screen resolution?

 

Thanks.

[Wrathchild]

what do you mean? they appear at the same co-ords regardless of the screen resolution

[damosan]

2 minutes ago, Wrathchild said:

what do you mean? they appear at the same co-ords regardless of the screen resolution

 

Left margin is like 47 and the right is 206ish?  I need to map that to 0 - 319.

[Wrathchild]

PM pixels are a colour clock wide and so would 'align' every 2 pixels in hirez mode

so effectively you just want (x/2)+xmargin then

Edited January 31, 2021 by Wrathchild

[phaeron]

P/M horizontal coordinates are 48-208 for a normal width screen. 48 aligns the left edge of a player or missile with the left edge of the playfield, at any P/M width. 208 aligns the left edge of P/M with the right edge of the playfield.

[TGB1718]

I'm currently writing a utility that uses Graphics 3 screen, I know the top left corner positions and set these to their

base values, then horizontal position is calculated as follows to move P0 one pixel left (or right) with joystick movement.

POKE(HPOSP0,HP0+x-6+((x-10)*3));  

 

Vertical is calculated to move 4 lines UP or DOWN to maintain one pixel movement

mycorsor is pointing at PMBASE + base position of P0 + offset into P0

 

                    for(i=4;i<8;i++)
                        POKE(mycursor+i,0); // clear old cursor
                    for(i=0;i<4;i++)
                        POKE(mycursor+i,cursor_data); // write new cursor