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Atari 2600: Double and quad size players are now correctly delayed an extra pixel.

This commit is contained in:
pjgat09 2016-02-16 15:45:48 -05:00
parent 8a9e8c8671
commit 194905763a
1 changed files with 74 additions and 46 deletions
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120
BizHawk.Emulation.Cores/Consoles/Atari/2600/Tia/Tia.PlayerData.cs
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@ -13,7 +13,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
public byte Color;
public byte HPosCnt;
public byte ScanCnt;
public byte ScanStrchCnt;
public bool ScanCntInit;
public byte HM;
public bool Reflect;
public bool Delay;
@ -27,77 +27,105 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
var result = false;
if (ScanCnt < 8)
{
// Make the mask to check the graphic
byte playerMask = (byte)(1 << (8 - 1 - ScanCnt));
// Reflect it if needed
if (Reflect)
if (!ScanCntInit)
{
playerMask = (byte)ReverseBits(playerMask, 8);
}
// Make the mask to check the graphic
byte playerMask = (byte)(1 << (8 - 1 - ScanCnt));
// Check the graphic (depending on delay)
if (!Delay)
{
if ((Grp & playerMask) != 0)
// Reflect it if needed
if (Reflect)
{
result = true;
playerMask = (byte)ReverseBits(playerMask, 8);
}
}
else
{
if ((Dgrp & playerMask) != 0)
// Check the graphic (depending on delay)
if (!Delay)
{
result = true;
if ((Grp & playerMask) != 0)
{
result = true;
}
}
else
{
if ((Dgrp & playerMask) != 0)
{
result = true;
}
}
// Reset missile, if desired
if (ScanCnt == 0x04 && HPosCnt <= 16 && Missile.ResetToPlayer)
{
Missile.HPosCnt = 0;
}
}
// Reset missile, if desired
if (ScanCnt == 0x04 && HPosCnt <= 16 && Missile.ResetToPlayer)
{
Missile.HPosCnt = 0;
}
// Increment counter
// When this reaches 8, we've run out of pixel
// Increment the Player Graphics Scan Counter
// If we're drawing a stretched player, only incrememnt the
// counter every 2 or 4 clocks
// This counter advances once per clock for single sized players,
// once every 2 clocks for double sized players (Nusiz == 0x05),
// and once every 4 clocks for quad sizes players (Nusize == 0x07)
// The ticks for starting and advancing this counter are tied to the div4 clocking phase.
// The first tick for single sized players happens immediately.
// The first tick for double and quad sized players is delayed one clock cycle,
// and then happen every 2 or 4 clocks
// Double size player
if ((Nusiz & 0x07) == 0x05)
{
ScanStrchCnt++;
ScanStrchCnt %= 2;
if ((HPosCnt + 3) % 2 == 0)
{
if (ScanCntInit)
{
ScanCntInit = false;
ScanCnt = 0;
}
else
{
ScanCnt++;
}
}
}
// Quad size player
else if ((Nusiz & 0x07) == 0x07)
{
ScanStrchCnt++;
ScanStrchCnt %= 4;
if ((HPosCnt + 3) % 4 == 0)
{
if (ScanCntInit)
{
ScanCntInit = false;
ScanCnt = 0;
}
else
{
ScanCnt++;
}
}
}
// Single size player
else
{
ScanStrchCnt = 0;
}
if (ScanStrchCnt == 0)
{
ScanCntInit = false;
ScanCnt++;
}
}
// At counter position 0 we should start drawing, a pixel late
// Set the scan counter at 0, and at the next pixel the graphic will start drawing
// At counter position 0 we should initalize the scan counter.
// Note that for double and quad sized players that the scan counter is not started immediately.
if (HPosCnt == 0 && !Reset)
{
ScanCnt = 0;
if ((Nusiz & 0x07) == 0x05 || (Nusiz & 0x07) == 0x07)
if ((Nusiz & 0x07) == 0x05)
{
ScanStrchCnt = 0;
ScanCntInit = true;
}
else if ((Nusiz & 0x07) == 0x07)
{
ScanCntInit = true;
}
else
{
ScanCntInit = false;
}
}
@ -148,7 +176,7 @@ namespace BizHawk.Emulation.Cores.Atari.Atari2600
ser.Sync("color", ref Color);
ser.Sync("hPosCnt", ref HPosCnt);
ser.Sync("scanCnt", ref ScanCnt);
ser.Sync("scanStrchCnt", ref ScanStrchCnt);
ser.Sync("scanCntInit", ref ScanCntInit);
ser.Sync("HM", ref HM);
ser.Sync("reflect", ref Reflect);
ser.Sync("delay", ref Delay);