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GBA: Fixed/improved window left/right behavior
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Fixes issue in speech bubbles in Megaman & Bass
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@SourMesen
SourMesen committed Apr 3, 2024
1 parent 7f4ba93 commit f862b0c
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Showing 2 changed files with 117 additions and 50 deletions.
149 changes: 105 additions & 44 deletions Core/GBA/GbaPpu.cpp
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Expand Up @@ -83,6 +83,7 @@ void GbaPpu::ProcessHBlank()
void GbaPpu::ProcessEndOfScanline()
{
ProcessSprites();
ProcessWindow();

if(!_skipRender && _emu->IsDebugging()) {
DebugProcessMemoryAccessView();
Expand All @@ -93,8 +94,9 @@ void GbaPpu::ProcessEndOfScanline()
_state.Cycle = 0;
_state.Scanline++;

//Reset renderer data for next scale
//Reset renderer data for next scanline
_lastRenderCycle = -1;
_lastWindowCycle = -1;
_oamLastCycle = -1;
std::fill(_layerOutput[0], _layerOutput[0] + 240, GbaPixelData {});
std::fill(_layerOutput[1], _layerOutput[1] + 240, GbaPixelData {});
Expand Down Expand Up @@ -165,23 +167,7 @@ void GbaPpu::ProcessEndOfScanline()
_console->GetMemoryManager()->SetIrqSource(GbaIrqSource::LcdScanlineMatch);
}

//Windows are enabled/disabled when the scanline reaches the start/end scanlines
//See window_midframe test - unsure about behavior when top==bottom
if(_state.Scanline == _state.Window[0].TopY) {
_window0Active = _state.Window0Enabled;
}
if(_state.Scanline == _state.Window[0].BottomY) {
_window0Active = false;
}

if(_state.Scanline == _state.Window[1].TopY) {
_window1Active = _state.Window1Enabled;
}
if(_state.Scanline == _state.Window[1].BottomY) {
_window1Active = false;
}

InitializeActiveWindows();
InitializeWindows();
}

void GbaPpu::SendFrame()
Expand Down Expand Up @@ -226,6 +212,7 @@ void GbaPpu::RenderScanline(bool forceRender)
}

ProcessSprites();
ProcessWindow();

if(_state.Scanline >= 160 || _lastRenderCycle >= 1006) {
return;
Expand Down Expand Up @@ -294,15 +281,16 @@ void GbaPpu::ProcessColorMath()
GbaPixelData sprPixel = {};

for(int x = start; x <= end; x++) {
wnd = _activeWindow[x];

if constexpr(windowEnabled) {
if(_state.WindowActiveLayers[_activeWindow[x]][GbaPpu::SpriteLayerIndex]) {
wnd = _activeWindow[x];
if(_state.WindowActiveLayers[wnd][GbaPpu::SpriteLayerIndex]) {
main = _oamReadOutput[x];
} else {
main = {};
}
} else {
wnd = GbaPpu::NoWindow;
main = _oamReadOutput[x];
}

Expand Down Expand Up @@ -391,37 +379,102 @@ void GbaPpu::BlendColors(uint16_t* dst, int x, uint16_t main, uint8_t aCoeff, ui
dst[x] = r | (g << 5) | (b << 10);
}

void GbaPpu::ApplyWindowBounds(uint8_t window)
void GbaPpu::InitializeWindows()
{
uint8_t x1 = _state.Window[window].LeftX;
uint8_t x2 = _state.Window[window].RightX;
if(x2 < x1 || x2 > 240) {
x2 = 240;
//Windows are enabled/disabled when the scanline reaches the start/end scanlines
//See window_midframe test - unsure about behavior when top==bottom
if(_state.Scanline == _state.Window[0].TopY) {
_window0ActiveY = _state.Window0Enabled;
}
if(_state.Scanline == _state.Window[0].BottomY) {
_window0ActiveY = false;
}

if(x1 < 240) {
memset(_activeWindow + x1, window, x2 - x1);
if(_state.Scanline == _state.Window[1].TopY) {
_window1ActiveY = _state.Window1Enabled;
}
if(_state.Scanline == _state.Window[1].BottomY) {
_window1ActiveY = false;
}

memset(_activeWindow, GbaPpu::OutsideWindow, sizeof(_activeWindow));
}

void GbaPpu::InitializeActiveWindows()
void GbaPpu::ProcessWindow()
{
//TODOGBA currently doesn't update mid-scanline, is this latched on the GBA?
if(!_state.Window0Enabled && !_state.Window1Enabled && !_state.ObjWindowEnabled) {
memset(_activeWindow, GbaPpu::NoWindow, sizeof(_activeWindow));
} else {
memset(_activeWindow, GbaPpu::OutsideWindow, sizeof(_activeWindow));
//Using the same logic as for window Y above, enable/disable windows when
//the current pixel matches the left/right X value for the window
//Some games set left > right, essentially making the window
//wrap around to the beginning of the next scanline.
//(MM&B does this for speech bubbles)
//TODOGBA is there any test rom for this (window x)?
int x = (_lastWindowCycle + 1) / 4;
int end = std::min(_state.Cycle / 4, 255) + 1;
if(x >= end) {
return;
}

if(_state.Window0Enabled || _state.Window1Enabled) {
for(int i = -1; i < 4; i++) {
uint16_t changePos = i < 0 ? 0 : _windowChangePos[i];
uint16_t nextChange = i < 3 ? _windowChangePos[i + 1] : 256;
if(nextChange == changePos || (changePos < x && nextChange < x)) {
continue;
}

if(_window1Active) {
ApplyWindowBounds(GbaPpu::Window1);
}
if(x == _state.Window[0].LeftX) {
_window0ActiveX = _state.Window0Enabled;
}
if(x == _state.Window[0].RightX) {
_window0ActiveX = false;
}

if(x == _state.Window[1].LeftX) {
_window1ActiveX = _state.Window1Enabled;
}
if(x == _state.Window[1].RightX) {
_window1ActiveX = false;
}

int length = std::min(nextChange - x, end - x);
if(_window0ActiveX && _window0ActiveY) {
memset(_activeWindow + x, GbaPpu::Window0, length);
} else if(_window1ActiveX && _window1ActiveY) {
memset(_activeWindow + x, GbaPpu::Window1, length);
}

if(_window0Active) {
ApplyWindowBounds(GbaPpu::Window0);
x += length;
if(x >= end) {
break;
}
}
} else {
_window0ActiveX = false;
_window1ActiveX = false;
}

_lastWindowCycle = _state.Cycle;
}

void GbaPpu::SetWindowX(uint8_t& regValue, uint8_t newValue)
{
if(regValue != newValue) {
regValue = newValue;
UpdateWindowChangePoints();
}
}

void GbaPpu::UpdateWindowChangePoints()
{
//Generate a sorted list of the positions where the windows start/end
//Used in ProcessWindow to process the changes in chunks
_windowChangePos[0] = _state.Window[0].LeftX;
_windowChangePos[1] = _state.Window[0].RightX;
_windowChangePos[2] = _state.Window[1].LeftX;
_windowChangePos[3] = _state.Window[1].RightX;
std::sort(_windowChangePos, _windowChangePos + 4);
}

void GbaPpu::SetPixelData(GbaPixelData& pixel, uint16_t color, uint8_t priority, uint8_t layer)
{
pixel.Color = color;
Expand Down Expand Up @@ -1247,10 +1300,10 @@ void GbaPpu::WriteRegister(uint32_t addr, uint8_t value)
case 0x2E: case 0x3E: SetTransformOrigin<16>((addr & 0x10) >> 4, value, true); break;
case 0x2F: case 0x3F: SetTransformOrigin<24>((addr & 0x10) >> 4, value & 0x0F, true); break;

case 0x40: _state.Window[0].RightX = value; break;
case 0x41: _state.Window[0].LeftX = value; break;
case 0x42: _state.Window[1].RightX = value; break;
case 0x43: _state.Window[1].LeftX = value; break;
case 0x40: SetWindowX(_state.Window[0].RightX, value); break;
case 0x41: SetWindowX(_state.Window[0].LeftX, value); break;
case 0x42: SetWindowX(_state.Window[1].RightX, value); break;
case 0x43: SetWindowX(_state.Window[1].LeftX, value); break;

case 0x44: _state.Window[0].BottomY = value; break;
case 0x45: _state.Window[0].TopY = value; break;
Expand Down Expand Up @@ -1479,8 +1532,12 @@ void GbaPpu::Serialize(Serializer& s)
SVArray(_memoryAccess, 308 * 4);

SV(_triggerSpecialDma);
SV(_window0Active);
SV(_window1Active);

SV(_lastWindowCycle);
SV(_window0ActiveY);
SV(_window1ActiveY);
SV(_window0ActiveX);
SV(_window1ActiveX);

SV(_lastRenderCycle);
SV(_evalOamIndex);
Expand Down Expand Up @@ -1549,4 +1606,8 @@ void GbaPpu::Serialize(Serializer& s)
SVI(_objData[i].Height);
}
}

if(!s.IsSaving()) {
UpdateWindowChangePoints();
}
}
18 changes: 12 additions & 6 deletions Core/GBA/GbaPpu.h
View file
Expand Up @@ -116,14 +116,19 @@ class GbaPpu final : public ISerializable
GbaPixelData _layerOutput[4][GbaConstants::ScreenWidth] = {};

uint8_t _oamWindow[GbaConstants::ScreenWidth] = {};
uint8_t _activeWindow[GbaConstants::ScreenWidth] = {};
uint8_t _activeWindow[256] = {};

Timer _frameSkipTimer;
bool _skipRender = false;

bool _triggerSpecialDma = false;
bool _window0Active = false;
bool _window1Active = false;

int16_t _lastWindowCycle = -1;
bool _window0ActiveY = false;
bool _window1ActiveY = false;
bool _window0ActiveX = false;
bool _window1ActiveX = false;
uint8_t _windowChangePos[4] = {};

int16_t _lastRenderCycle = -1;
GbaLayerRendererData _layerData[4] = {};
Expand Down Expand Up @@ -166,11 +171,12 @@ class GbaPpu final : public ISerializable
template<GbaPpuBlendEffect effect, bool bg0Enabled, bool bg1Enabled, bool bg2Enabled, bool bg3Enabled, bool windowEnabled> void ProcessColorMath();

void BlendColors(uint16_t* dst, int x, uint16_t a, uint8_t aCoeff, uint16_t b, uint8_t bCoeff);
void ApplyWindowBounds(uint8_t window);
void InitializeActiveWindows();

template<bool isSubColor> uint16_t ReadColor(int x, uint16_t addr);

void InitializeWindows();
void ProcessWindow();
void SetWindowX(uint8_t& regValue, uint8_t newValue);
void UpdateWindowChangePoints();
void SetWindowActiveLayers(int window, uint8_t cfg);

void SendFrame();
Expand Down

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