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Started merely attempting to reintroduce the background layer.

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This commit is contained in:
Thomas Harte 2016-05-16 19:04:13 -04:00
parent 9d92ad659f
commit f19ed2e8f8
2 changed files with 29 additions and 48 deletions
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75
Machines/Atari2600/Atari2600.cpp
View File

@ -77,14 +77,15 @@ Machine::~Machine()
close_output();
}
void Machine::get_output_pixel(uint8_t *pixel, int offset)
uint8_t Machine::get_output_pixel()
{
// get the playfield pixel and hence a proposed colour
int offset = _horizontalTimer - (horizontalTimerPeriod - 160);
uint8_t playfieldPixel = _playfield[offset >> 2];
uint8_t playfieldColour = ((_playfieldControl&6) == 2) ? _playerColour[offset / 80] : _playfieldColour;
// get player and missile proposed pixels
uint8_t playerPixels[2] = {0, 0}, missilePixels[2] = {0, 0};
/* uint8_t playerPixels[2] = {0, 0}, missilePixels[2] = {0, 0};
for(int c = 0; c < 2; c++)
{
const uint8_t repeatMask = _playerAndMissileSize[c]&7;
@ -172,13 +173,10 @@ void Machine::get_output_pixel(uint8_t *pixel, int offset)
if(!(_playfieldControl&0x04) || !playfieldPixel) {
if(playerPixels[1] || missilePixels[1]) outputColour = _playerColour[1];
if(playerPixels[0] || missilePixels[0]) outputColour = _playerColour[0];
}
}*/
// store colour
// static int lc;
// if(_vSyncEnabled) lc = 0; else lc += (offset == 159) ? 1 : 0;
// *pixel = (uint8_t)(((offset / 10) << 4) | (((lc >> 4)&7) << 1));
*pixel = outputColour;
// return colour
return playfieldPixel ? playfieldColour : _backgroundColour;
}
// in imputing the knowledge that all we're dealing with is the rollover from 159 to 0,
@ -187,42 +185,21 @@ void Machine::get_output_pixel(uint8_t *pixel, int offset)
void Machine::output_pixels(unsigned int count)
{
/* const int32_t start_of_sync = 214;
const int32_t end_of_sync = 198;
const int32_t end_of_colour_burst = 188;*/
while(count--)
{
OutputState state;
switch(_horizontalTimer >> 2)
{
case 0: case 1: case 2: case 3:
state = OutputState::Blank;
break;
case 4: case 5: case 6: case 7:
state = OutputState::Sync;
break;
case 8: case 9: case 10: case 11:
state = OutputState::ColourBurst;
break;
case 12: case 13: case 14: case 15: case 16:
state = OutputState::Blank;
break;
case 17: case 18:
state = _vBlankExtend ? OutputState::Blank : OutputState::Pixel;
break;
default:
state = OutputState::Pixel;
break;
case 0: case 1: case 2: case 3: state = OutputState::Blank; break;
case 4: case 5: case 6: case 7: state = OutputState::Sync; break;
case 8: case 9: case 10: case 11: state = OutputState::ColourBurst; break;
case 12: case 13: case 14: case 15: case 16: state = OutputState::Blank; break;
case 17: case 18: state = _vBlankExtend ? OutputState::Blank : OutputState::Pixel; break;
default: state = OutputState::Pixel; break;
}
// logic: if vsync is enabled, output the opposite of the automatic hsync output
// if vsync is enabled, output the opposite of the automatic hsync output
if(_vSyncEnabled) {
state = (state = OutputState::Sync) ? OutputState::Blank : OutputState::Sync;
}
@ -258,12 +235,21 @@ void Machine::output_pixels(unsigned int count)
if(state == OutputState::Pixel) {
_outputBuffer = _crt->allocate_write_area(160);
if(_outputBuffer) for(int c = 0; c < 160; c++) _outputBuffer[c] = (uint8_t)rand();
} else {
_outputBuffer = nullptr;
}
}
if(state == OutputState::Pixel)
{
uint8_t colour = get_output_pixel();
if(_outputBuffer)
{
*_outputBuffer = colour;
_outputBuffer++;
}
}
/* if(_horizontalTimer < (_vBlankExtend ? 152 : 160)) {
uint8_t throwaway_pixel;
get_output_pixel(_outputBuffer ? &_outputBuffer[_lastOutputStateDuration] : &throwaway_pixel, 159 - _horizontalTimer);
@ -274,18 +260,13 @@ void Machine::output_pixels(unsigned int count)
increment_object_counter(2);
increment_object_counter(3);
increment_object_counter(4);
}
// assumption here: signed shifts right; otherwise it's just
// an attempt to avoid both the % operator and a conditional
_horizontalTimer--;
const int32_t sign_extension = _horizontalTimer >> 31;
_horizontalTimer = (_horizontalTimer&~sign_extension) | (sign_extension&horizontalTimerReload);
if(!_horizontalTimer)
_vBlankExtend = false;*/
}*/
_horizontalTimer = (_horizontalTimer + 1) % horizontalTimerPeriod;
if(!_horizontalTimer)
{
_vBlankExtend = false;
}
}
}

2
Machines/Atari2600/Atari2600.hpp
View File

@ -90,7 +90,7 @@ class Machine: public CPU6502::Processor<Machine> {
};
void output_pixels(unsigned int count);
void get_output_pixel(uint8_t *pixel, int offset);
uint8_t get_output_pixel();
Outputs::CRT::CRT *_crt;
// latched output state