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Amiga News and Community Announcements => Amiga News and Community Announcements => Amiga Programming and Development => Topic started by: EDanaII on November 03, 2012, 04:37:10 AM

Title: Amiga Screen Resolutions...
Post by: EDanaII on November 03, 2012, 04:37:10 AM
Greetings All,

Recently, I've been playing with various Amiga Frameworks. I've had various success with these getting to work. So, just for giggles, I decided to create my own. (Yea, I know, no small order, but... what the hell.) :)

So, among the classes I've been creating is, of course, a Display (Screen) class. Naturally, I ended up poking around in graphics/modeid.h header file and these declarations:
Code: [Select]
#define LORES_KEY 0x00000000
#define HIRES_KEY 0x00008000
#define SUPER_KEY 0x00008020
#define HAM_KEY 0x00000800
#define LORESLACE_KEY 0x00000004
#define HIRESLACE_KEY 0x00008004
#define SUPERLACE_KEY 0x00008024
#define HAMLACE_KEY 0x00000804
#define LORESDPF_KEY 0x00000400
#define HIRESDPF_KEY 0x00008400
#define SUPERDPF_KEY 0x00008420
#define LORESLACEDPF_KEY 0x00000404
#define HIRESLACEDPF_KEY 0x00008404
#define SUPERLACEDPF_KEY 0x00008424
#define LORESDPF2_KEY 0x00000440
#define HIRESDPF2_KEY 0x00008440
#define SUPERDPF2_KEY 0x00008460
#define LORESLACEDPF2_KEY 0x00000444
#define HIRESLACEDPF2_KEY 0x00008444
#define SUPERLACEDPF2_KEY 0x00008464
#define EXTRAHALFBRITE_KEY 0x00000080
#define EXTRAHALFBRITELACE_KEY 0x00000084
/* New for AA ChipSet (V39) */
#define HIRESHAM_KEY 0x00008800
#define SUPERHAM_KEY 0x00008820
#define HIRESEHB_KEY 0x00008080
#define SUPEREHB_KEY 0x000080a0
#define HIRESHAMLACE_KEY 0x00008804
#define SUPERHAMLACE_KEY 0x00008824
#define HIRESEHBLACE_KEY 0x00008084
#define SUPEREHBLACE_KEY 0x000080a4
/* Added for V40 - may be useful modes for some games or animations. */
#define LORESSDBL_KEY 0x00000008
#define LORESHAMSDBL_KEY 0x00000808
#define LORESEHBSDBL_KEY 0x00000088
#define HIRESHAMSDBL_KEY 0x00008808


Now, a question for anyone in the know... don't each of these effectively define a resolution?

For example, isn't a LORES_KEY effectively a 320x200 screen? And a HIRES_KEY effectively a a 640x200 screen while a HIRESLACE_KEY is 640x400 screen? And what's a DPF and DPF2 screen? Also, is there a map somewhere that indicates what these resolutions are?

Also, how does overscan affect these screen modes. Any suggestions there would also be appreciated.

Ed.