using skip frames properly (no audio)

README.md

@@ -8,7 +8,13 @@ quickerNES is an attempt to modernizing and improving the performance of quickNE
 - Add support for more mappers, controllers, and features supported by other emulators
 - Improve accuracy, if possible
 
-The main aim is to improve the exploration performance of my TASing bot, [JaffarPlus](https://github.com/SergioMartin86/jaffarPlus). However, if this work might help with homebrew emulation and other people having more fun, then much better!
+The main aim is to improve the performance of skip (non-rendering, no-audio) frame advances for brute force botting. (See: [JaffarPlus](https://github.com/SergioMartin86/jaffarPlus)). However, if this work might help with homebrew emulation and other people having more fun, then much better!
+
+Changes
+=========
+
+- Optimizations made in the CPU emulation core
+- Sound is no longer emulated during skip frames
 
 Credits
 =========

source/core/Nes_Core.cpp

@@ -38,7 +38,6 @@ Nes_Core::Nes_Core() : ppu( this )
 	mapper = NULL;
 	memset( &nes, 0, sizeof nes );
 	memset( &joypad, 0, sizeof joypad );
-    _doRendering = true;
 }
 
 const char * Nes_Core::init()
@@ -498,8 +497,11 @@ nes_time_t Nes_Core::emulate_frame_()
 	}
 }
 
-nes_time_t Nes_Core::emulate_frame()
+nes_time_t Nes_Core::emulate_frame(int joypad1, int joypad2)
 {
+	current_joypad [0] = (joypad1 |= ~0xFF);
+	current_joypad [1] = (joypad2 |= ~0xFF);
+
 	joypad_read_count = 0;
 	
 	cpu_time_offset = ppu.begin_frame( nes.timestamp ) - 1;
@@ -508,10 +510,10 @@ nes_time_t Nes_Core::emulate_frame()
 	
 	// TODO: clean this fucking mess up
 	auto t0 = emulate_frame_();
-	if (_doRendering == true) impl->apu.run_until_( t0 );
+	impl->apu.run_until_( t0 );
 	clock_ = cpu_time_offset;
 	auto t1 = cpu_time();
-	if (_doRendering == true) impl->apu.run_until_( t1 );
+	impl->apu.run_until_( t1 );
 	
 	nes_time_t ppu_frame_length = ppu.frame_length();
 	nes_time_t length = cpu_time();

source/core/Nes_Core.h

@@ -20,13 +20,10 @@ public:
 	Nes_Core();
 	~Nes_Core();
 	
-	// Flag to enable/disable rendering
-	bool _doRendering;
-
 	const char * init();
 	const char * open( Nes_Cart const* );
 	void reset( bool full_reset = true, bool erase_battery_ram = false );
-	blip_time_t emulate_frame();
+	blip_time_t emulate_frame(int joypad1, int joypad2);
 	void close();
 	
 	void save_state( Nes_State* ) const;

source/core/Nes_Emu.cpp

@@ -128,70 +128,59 @@ const char * Nes_Emu::emulate_skip_frame( int joypad1, int joypad2 )
 {
 	char *old_host_pixels = host_pixels;
 	host_pixels = NULL;
-	const char *result = emulate_frame(joypad1, joypad2);
+	emu.emulate_frame(joypad1, joypad2); 
 	host_pixels = old_host_pixels;
-	return result;
+	return 0;
 }
 
 const char * Nes_Emu::emulate_frame( int joypad1, int joypad2 )
 {
-	emu.current_joypad [0] = (joypad1 |= ~0xFF);
-	emu.current_joypad [1] = (joypad2 |= ~0xFF);
-
 	emu.ppu.host_pixels = NULL;
 
-	if (emu._doRendering == true)
+	unsigned changed_count = sound_buf->channels_changed_count();
+	bool new_enabled = (frame_ != NULL);
+
+	if ( sound_buf_changed_count != changed_count || sound_enabled != new_enabled )
 	{
-		unsigned changed_count = sound_buf->channels_changed_count();
-		bool new_enabled = (frame_ != NULL);
-		
-		if ( sound_buf_changed_count != changed_count || sound_enabled != new_enabled )
-		{
-			sound_buf_changed_count = changed_count;
-			sound_enabled = new_enabled;
-			enable_sound( sound_enabled );
-		}
+		sound_buf_changed_count = changed_count;
+		sound_enabled = new_enabled;
+		enable_sound( sound_enabled );
+	}
 
-		frame_t* f = frame_;
-		if ( f )
-		{
-			emu.ppu.max_palette_size = host_palette_size;
-			emu.ppu.host_palette = f->palette + emu.ppu.palette_begin;
-			// add black and white for emulator to use (unless emulator uses entire
-			// palette for frame)
-			f->palette [252] = 0x0F;
-			f->palette [254] = 0x30;
-			f->palette [255] = 0x0F;
-			if ( host_pixels )
-				emu.ppu.host_pixels = (uint8_t*) host_pixels +
-				emu.ppu.host_row_bytes * f->top;
+	frame_t* f = frame_;
+	if ( f )
+	{
+		emu.ppu.max_palette_size = host_palette_size;
+		emu.ppu.host_palette = f->palette + emu.ppu.palette_begin;
+		// add black and white for emulator to use (unless emulator uses entire
+		// palette for frame)
+		f->palette [252] = 0x0F;
+		f->palette [254] = 0x30;
+		f->palette [255] = 0x0F;
+		if ( host_pixels )
+			emu.ppu.host_pixels = (uint8_t*) host_pixels +
+			emu.ppu.host_row_bytes * f->top;
 
-			if ( sound_buf->samples_avail() )
-				clear_sound_buf();
+		if ( sound_buf->samples_avail() )
+			clear_sound_buf();
 
-			nes_time_t frame_len = emu.emulate_frame();
-			sound_buf->end_frame( frame_len, false );
+		nes_time_t frame_len = emu.emulate_frame(joypad1, joypad2);
+		sound_buf->end_frame( frame_len, false );
 
-			f = frame_;
-			f->sample_count      = sound_buf->samples_avail();
-			f->chan_count        = sound_buf->samples_per_frame();
-			f->palette_begin     = emu.ppu.palette_begin;
-			f->palette_size      = emu.ppu.palette_size;
-			f->joypad_read_count = emu.joypad_read_count;
-			f->burst_phase       = emu.ppu.burst_phase;
-			f->pitch             = emu.ppu.host_row_bytes;
-			f->pixels            = emu.ppu.host_pixels + f->left;
-		}
-		else
-		{
-			emu.ppu.max_palette_size = 0;
-			emu.emulate_frame();
-		}
+		f = frame_;
+		f->sample_count      = sound_buf->samples_avail();
+		f->chan_count        = sound_buf->samples_per_frame();
+		f->palette_begin     = emu.ppu.palette_begin;
+		f->palette_size      = emu.ppu.palette_size;
+		f->joypad_read_count = emu.joypad_read_count;
+		f->burst_phase       = emu.ppu.burst_phase;
+		f->pitch             = emu.ppu.host_row_bytes;
+		f->pixels            = emu.ppu.host_pixels + f->left;
 	}
 	else
 	{
 		emu.ppu.max_palette_size = 0;
-		emu.emulate_frame();
+		emu.emulate_frame(joypad1, joypad2);
 	}
 
 	return 0;

source/core/Nes_Emu.h

@@ -40,11 +40,8 @@ public:
 	static const uint16_t image_width   = 256;
 	static const uint16_t image_height  = 240;
 
-    const uint8_t* getHostPixels () const { return emu.ppu.host_pixels; }
+   const uint8_t* getHostPixels () const { return emu.ppu.host_pixels; }
     
-    void enableRendering() { emu._doRendering = true; }
-	void disableRendering() { emu._doRendering = false; }
- 
 // Basic emulation
 
 	// Emulate one video frame using joypad1 and joypad2 as input. Afterwards, image

source/emuInstance.hpp

@@ -171,6 +171,9 @@ class EmuInstance
   return moveString;
  }
 
+ void enableRendering()  { _doRendering = true; }
+ void disableRendering() { _doRendering = false; }
+
  void advanceState(const std::string& move)
  {
   if (move.find("r") != std::string::npos) _nes->reset(false); 
@@ -180,13 +183,17 @@ class EmuInstance
 
  void advanceState(const inputType controller1, const inputType controller2) 
  {
-  _nes->emulate_frame(controller1, controller2);
+  if (_doRendering == true)  _nes->emulate_frame(controller1, controller2);
+  if (_doRendering == false) _nes->emulate_skip_frame(controller1, controller2);
  }
 
  Nes_Emu* getInternalEmulator() const { return _nes; }
 
  private:
 
+ // Flag to determine whether to enable/disable rendering
+ bool _doRendering = true;
+
  inline size_t getStateSizeImpl() const
  {
   // Using dry writer to just obtain the state size

source/tester.cpp

@@ -58,7 +58,7 @@ int main(int argc, char *argv[])
   auto e = EmuInstance(romFilePath, initialStateFilePath);
   
   // Disable rendering
-  e.getInternalEmulator()->disableRendering();
+  e.disableRendering();
 
   // Getting initial hash
   auto initialHash = e.getStateHash();