Re: [stella] VCS.H standardization

Subject: Re: [stella] VCS.H standardization
From: "Erik J. Eid" <eeid@xxxxxxxxx>
Date: Mon, 26 Nov 2001 19:50:31 -0500
At 07:38 PM 11/25/01 -0800, Glenn Saunders wrote:
Here is the composite [stella.h]. Let's work on the constants. Anything missing here?

I'm looking at an old Microsoft Word version of the Stella Programmer's Guide for this...


; VARIOUS TIA REGISTER CONSTANTS
; NICK BENSEMA VCS.H MERGE

;VIDEO SYNC
VS_Enable           = 2

VS_Disable = 0. Setting bit 1 to 0 stops the vertical sync.


;PLAYERS
P_Reflect = $08

Should there be a P_NoReflect = 0? It might be overkill, but it could make code a little more clear if there's often switching between reflect and no reflect.


;MISSILES
M_Enable          = 2

Along the same lines, should there be M_Disable = 0 as well?


There's also the RESMP0 and RESMP1 registers which are used to lock the missile to the center of its player. These could be M_Lock = 2 and M_Unlock = 0.

There should also be similar constants for the ball (BL_Enable and BL_Disable).

;PLAYFIELD
PF_Reflect  = $01
PF_Score    = $02
PF_Priority = $04

Since these are for CTRLPF, how about these for the ball width:


BL_Single = $10
BL_Double = $20
BL_Quad   = $40
BL_Oct    = $80

;JOYSTICK 0
J0_Right = $80
J0_Left  = $40
J0_Down  = $20
J0_Up    = $10

It might be useful to have paddle trigger constants since these are read (I think) the same as some joystick movements. (P0_Trig = $80, P1_Trig = $40, P2_Trig = $08, P3_Trig = $04)


I'd also suggest adding constants for dealing with the keyboard controllers... provided anyone here knows how. :)

Also include constants for vertical delay (VR_Delay = 1, VR_NoDelay = 0).

The xxx_Disable constants may be a bit excessive, but I thought it might help make some code a little more clear. For example, if you set VDELP0 to VR_Delay, later on when you see VDELP0 set to VR_NoDelay, you'll know that the region between them is on a one-scanline delay.

All in all, this combined header file sounds like a good solution to our lack of standardization woes. Thanks for compiling it, Glenn!


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