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Added something of the ball counter, but without yet a working HMOVE it's prone to error.

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This commit is contained in:
Thomas Harte 2016-05-17 07:18:14 -04:00
parent 7d3cf76576
commit 6a961c4d28
2 changed files with 23 additions and 15 deletions
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31
Machines/Atari2600/Atari2600.cpp
View File

@ -80,21 +80,26 @@ Machine::~Machine()
void Machine::update_upcoming_event()
{
unsigned int upcomingEventsPointerPlus4 = (_upcomingEventsPointer + 4)%number_of_upcoming_events;
// grab the background now, for display in four clocks
if(!(_horizontalTimer&3))
{
unsigned int offset = 4 + _horizontalTimer - (horizontalTimerPeriod - 160);
_upcomingEvents[(_upcomingEventsPointer + 4)%number_of_upcoming_events].updates |= Event::Action::Playfield;
_upcomingEvents[(_upcomingEventsPointer + 4)%number_of_upcoming_events].playfieldOutput = _playfield[(offset >> 2)%40];
_upcomingEvents[upcomingEventsPointerPlus4].updates |= Event::Action::Playfield;
_upcomingEvents[upcomingEventsPointerPlus4].playfieldOutput = _playfield[(offset >> 2)%40];
}
// the ball becomes visible whenever it hits zero, regardless of whether its status
// is the result of a counter rollover or a programmatic reset
if(!_objectCounter[4] && _ballGraphicsEnable&2)
if(!_objectCounter[4])
{
_upcomingEvents[upcomingEventsPointerPlus4].updates |= Event::Action::Ball;
}
_objectCounter[4] = (_objectCounter[4] + 1)%160;
// the players and missles become visible only upon overflow to zero
// the players and missles become visible only upon overflow to zero, so schedule for
// 5/6 clocks ahead from 159
}
uint8_t Machine::get_output_pixel()
@ -105,12 +110,12 @@ uint8_t Machine::get_output_pixel()
uint8_t playfieldColour = ((_playfieldControl&6) == 2) ? _playerColour[offset / 80] : _playfieldColour;
// get the ball proposed colour
// uint8_t ballPixel = 0;
// if(_ballGraphicsEnable&2) {
// int ballIndex = _objectCounter[4];
// int ballSize = 1 << ((_playfieldControl >> 4)&3);
// ballPixel = (ballIndex >= 0 && ballIndex < ballSize) ? 1 : 0;
// }
uint8_t ballPixel = 0;
if(_ballGraphicsEnable&2) {
int ballSize = 1 << ((_playfieldControl >> 4)&3);
ballPixel = (_pixelCounters.ball < ballSize) ? 1 : 0;
}
_pixelCounters.ball ++;
// get player and missile proposed pixels
/* uint8_t playerPixels[2] = {0, 0}, missilePixels[2] = {0, 0};
@ -196,7 +201,7 @@ uint8_t Machine::get_output_pixel()
}*/
// return colour
return _playfieldOutput ? playfieldColour : _backgroundColour;
return (_playfieldOutput | ballPixel) ? playfieldColour : _backgroundColour;
}
// in imputing the knowledge that all we're dealing with is the rollover from 159 to 0,
@ -236,9 +241,9 @@ void Machine::output_pixels(unsigned int count)
// apply any queued changes and flush the record
if(_upcomingEvents[_upcomingEventsPointer].updates & Event::Action::Playfield)
{
_playfieldOutput = _upcomingEvents[_upcomingEventsPointer].playfieldOutput;
}
if(_upcomingEvents[_upcomingEventsPointer].updates & Event::Action::Ball)
_pixelCounters.ball = 0;
_upcomingEvents[_upcomingEventsPointer].updates = 0;
// read that state

7
Machines/Atari2600/Atari2600.hpp
View File

@ -60,8 +60,8 @@ class Machine: public CPU6502::Processor<Machine> {
struct Event {
enum Action {
OutputSate = 1 << 0,
Playfield = 1 << 1,
Playfield = 1 << 0,
Ball = 1 << 1
};
unsigned int updates;
uint8_t playfieldOutput;
@ -70,6 +70,9 @@ class Machine: public CPU6502::Processor<Machine> {
unsigned int _upcomingEventsPointer;
uint8_t _playfieldOutput;
struct {
uint8_t ball;
} _pixelCounters;
// player registers
uint8_t _playerColour[2];