Add lowpass filter

MacOSX/QuakeSpasm.xcodeproj/project.pbxproj

@@ -826,7 +826,10 @@
 				GCC_ENABLE_FIX_AND_CONTINUE = YES;
 				GCC_MODEL_TUNING = G5;
 				GCC_OPTIMIZATION_LEVEL = 0;
-				GCC_PREPROCESSOR_DEFINITIONS = SDL_FRAMEWORK;
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					SDL_FRAMEWORK,
+					USE_CODEC_VORBIS,
+				);
 				GCC_VERSION = com.apple.compilers.llvmgcc42;
 				HEADER_SEARCH_PATHS = (
 					codecs/include,
@@ -859,7 +862,7 @@
 					"$(FRAMEWORK_SEARCH_PATHS_QUOTED_FOR_TARGET_1)",
 				);
 				FRAMEWORK_SEARCH_PATHS_QUOTED_FOR_TARGET_1 = "\"$(SRCROOT)\"";
-				GCC_GENERATE_DEBUGGING_SYMBOLS = NO;
+				GCC_GENERATE_DEBUGGING_SYMBOLS = YES;
 				GCC_MODEL_TUNING = G5;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					USE_CODEC_MP3,
@@ -914,6 +917,7 @@
 					x86_64,
 					i386,
 				);
+				COPY_PHASE_STRIP = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					/Library/Frameworks,
 					"$(FRAMEWORK_SEARCH_PATHS)",
@@ -948,9 +952,9 @@
 				ARCHS = (
 					x86_64,
 					i386,
-					ppc,
 				);
-				DEPLOYMENT_POSTPROCESSING = YES;
+				COPY_PHASE_STRIP = NO;
+				DEPLOYMENT_POSTPROCESSING = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					/Library/Frameworks,
 					"$(FRAMEWORK_SEARCH_PATHS)",
@@ -1000,7 +1004,7 @@
 				"SDKROOT[arch=i386]" = "$(DEVELOPER_SDK_DIR)/MacOSX10.4u.sdk";
 				"SDKROOT[arch=ppc]" = "$(DEVELOPER_SDK_DIR)/MacOSX10.4u.sdk";
 				"SDKROOT[arch=x86_64]" = "$(DEVELOPER_SDK_DIR)/MacOSX10.6.sdk";
-				VALID_ARCHS = "i386 x86_64 ppc";
+				VALID_ARCHS = "i386 x86_64";
 			};
 			name = Release;
 		};

MacOSX/QuakeSpasm.xcodeproj/xcshareddata/xcschemes/QuakeSpasm.xcscheme

@@ -21,8 +21,8 @@
       </BuildActionEntries>
    </BuildAction>
    <TestAction
-      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.GDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.GDB"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
       buildConfiguration = "Debug">
       <Testables>
@@ -38,8 +38,8 @@
       </MacroExpansion>
    </TestAction>
    <LaunchAction
-      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.GDB"
-      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.GDB"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       displayScaleIsEnabled = "NO"
       displayScale = "1.00"
       launchStyle = "0"
@@ -59,9 +59,13 @@
       </BuildableProductRunnable>
       <CommandLineArguments>
          <CommandLineArgument
-            argument = "-basedir /Applications/Quake"
+            argument = "-basedir /Users/ericwa/Quake"
             isEnabled = "YES">
          </CommandLineArgument>
+         <CommandLineArgument
+            argument = "-sndspeed 44100"
+            isEnabled = "NO">
+         </CommandLineArgument>
          <CommandLineArgument
             argument = "-nolauncher"
             isEnabled = "NO">

Quake/q_sound.h

@@ -168,6 +168,7 @@ extern	vec3_t		listener_right;
 extern	vec3_t		listener_up;
 
 extern	cvar_t		sndspeed;
+extern	cvar_t		snd_mixspeed;
 extern	cvar_t		sfxvolume;
 extern	cvar_t		loadas8bit;
 

Quake/snd_dma.c

@@ -76,6 +76,7 @@ cvar_t		precache = {"precache", "1", CVAR_NONE};
 cvar_t		loadas8bit = {"loadas8bit", "0", CVAR_NONE};
 
 cvar_t		sndspeed = {"sndspeed", "11025", CVAR_NONE};
+cvar_t		snd_mixspeed = {"snd_mixspeed", "44100", CVAR_NONE};
 
 static	cvar_t	nosound = {"nosound", "0", CVAR_NONE};
 static	cvar_t	ambient_level = {"ambient_level", "0.3", CVAR_NONE};
@@ -161,6 +162,7 @@ void S_Init (void)
 	Cvar_RegisterVariable(&snd_show);
 	Cvar_RegisterVariable(&_snd_mixahead);
 	Cvar_RegisterVariable(&sndspeed);
+	Cvar_RegisterVariable(&snd_mixspeed);
 
 	if (safemode || COM_CheckParm("-nosound"))
 		return;
@@ -179,6 +181,12 @@ void S_Init (void)
 		Cvar_SetQuick (&sndspeed, com_argv[i+1]);
 	}
 	
+	i = COM_CheckParm("-mixspeed");
+	if (i && i < com_argc-1)
+	{
+		Cvar_SetQuick (&snd_mixspeed, com_argv[i+1]);
+	}
+
 	if (host_parms->memsize < 0x800000)
 	{
 		Cvar_SetQuick (&loadas8bit, "1");

Quake/snd_mix.c

@@ -149,6 +149,128 @@ static void S_TransferPaintBuffer (int endtime)
 	}
 }
 
+/*
+==============
+S_MakeBlackmanWindowKernel
+
+Based on equation 16-4 from
+"The Scientist and Engineer's Guide to Digital Signal Processing"
+
+kernel has room for M+1 floats,
+f_c is the filter cutoff frequency, as a fraction of the samplerate
+==============
+*/
+static void S_MakeBlackmanWindowKernel(float *kernel, int M, float f_c)
+{
+	int i;
+	for (i = 0; i <= M; i++)
+	{
+		if (i == M/2)
+		{
+			kernel[i] = 2 * M_PI * f_c;
+		}
+		else
+		{
+			kernel[i] = ( sin(2 * M_PI * f_c * (i - M/2.0)) / (i - (M/2.0)) )
+				* (0.42 - 0.5*cos(2 * M_PI * i / (double)M)
+				   + 0.08*cos(4 * M_PI * i / (double)M) );
+		}
+	}
+	
+// normalize the kernel so all of the values sum to 1
+	{
+		float sum = 0;
+		for (i = 0; i <= M; i++)
+		{
+			sum += kernel[i];
+		}
+		
+		for (i = 0; i <= M; i++)
+		{
+			kernel[i] /= sum;
+		}
+	}
+}
+
+// must be divisible by 4
+#define FILTER_KERNEL_SIZE 48
+
+/*
+==============
+S_LowpassFilter
+
+lowpass filters 24-bit integer samples in 'data' (stored in 32-bit ints).
+
+f_c is the filter cutoff frequency, as a fraction of the samplerate
+memory must be an array of FILTER_KERNEL_SIZE floats
+==============
+*/
+static void S_LowpassFilter(float f_c, int *data, int stride, int count,
+							float *memory)
+{
+	int i;
+	
+// M is the "kernel size" parameter for makekernel() - must be even.
+// FILTER_KERNEL_SIZE size is M+1, rounded up to be divisible by 4
+	const int M = FILTER_KERNEL_SIZE - 2;
+	
+	float input[FILTER_KERNEL_SIZE + count];
+	
+	static float kernel[FILTER_KERNEL_SIZE];
+	static float kernel_fc;
+	
+	if (f_c <= 0 || f_c > 0.5)
+		return;
+	
+	if (count < FILTER_KERNEL_SIZE)
+	{
+		Con_Warning("S_LowpassFilter: not enough samples");
+		return;
+	}
+
+// prepare the kernel
+	
+	if (kernel_fc != f_c)
+	{
+		S_MakeBlackmanWindowKernel(kernel, M, f_c);
+		kernel_fc = f_c;
+	}
+	
+// set up the input buffer
+// memory holds the previous FILTER_KERNEL_SIZE samples of input.
+
+	for (i=0; i<FILTER_KERNEL_SIZE; i++)
+	{
+		input[i] = memory[i];
+	}
+	for (i=0; i<count; i++)
+	{
+		input[FILTER_KERNEL_SIZE+i] = data[i * stride] / (32768.0 * 256.0);
+	}
+	
+// copy out the last FILTER_KERNEL_SIZE samples to 'memory' for next time
+	
+	memcpy(memory, input + count, FILTER_KERNEL_SIZE * sizeof(float));
+	
+// apply the filter
+	
+	for (i=0; i<count; i++)
+	{
+		float val[4] = {0, 0, 0, 0};
+		
+		int j;
+		for (j=0; j<=M; j+=4)
+		{
+			val[0] += kernel[j] * input[M + i - j];
+			val[1] += kernel[j+1] * input[M + i - (j+1)];
+			val[2] += kernel[j+2] * input[M + i - (j+2)];
+			val[3] += kernel[j+3] * input[M + i - (j+3)];
+		}
+		
+		data[i * stride] = (val[0] + val[1] + val[2] + val[3])
+		* (32768.0 * 256.0);
+	}
+}
 
 /*
 ===============================================================================
@@ -178,32 +300,7 @@ void S_PaintChannels (int endtime)
 			end = paintedtime + PAINTBUFFER_SIZE;
 
 	// clear the paint buffer
-		if (s_rawend < paintedtime)
-		{	// clear
 		memset(paintbuffer, 0, (end - paintedtime) * sizeof(portable_samplepair_t));
-		}
-		else
-		{	// copy from the streaming sound source
-			int		s;
-			int		stop;
-
-			stop = (end < s_rawend) ? end : s_rawend;
-
-			for (i = paintedtime; i < stop; i++)
-			{
-				s = i & (MAX_RAW_SAMPLES - 1);
-				paintbuffer[i - paintedtime] = s_rawsamples[s];
-			}
-		//	if (i != end)
-		//		Con_Printf ("partial stream\n");
-		//	else
-		//		Con_Printf ("full stream\n");
-			for ( ; i < end; i++)
-			{
-				paintbuffer[i - paintedtime].left =
-				paintbuffer[i - paintedtime].right = 0;
-			}
-		}
 
 	// paint in the channels.
 		ch = snd_channels;
@@ -255,6 +352,48 @@ void S_PaintChannels (int endtime)
 			}
 		}
 
+	// clip each sample to 0dB, then reduce by 6dB (to leave some headroom for
+	// the lowpass filter and the music). the lowpass will smooth out the
+	// clipping
+		for (i=0; i<end-paintedtime; i++)
+		{
+			paintbuffer[i].left = CLAMP(-32768 << 8, paintbuffer[i].left, 32767 << 8) >> 1;
+			paintbuffer[i].right = CLAMP(-32768 << 8, paintbuffer[i].right, 32767 << 8) >> 1;
+		}
+		
+	// apply a lowpass filter
+		if (sndspeed.value < shm->speed)
+		{
+			static float memory_l[FILTER_KERNEL_SIZE];
+			static float memory_r[FILTER_KERNEL_SIZE];
+			
+			const float cutoff_freq = (sndspeed.value * 0.45) / shm->speed;
+			
+			S_LowpassFilter(cutoff_freq, (int *)paintbuffer,       2, end - paintedtime, memory_l);
+			S_LowpassFilter(cutoff_freq, ((int *)paintbuffer) + 1, 2, end - paintedtime, memory_r);
+		}
+		
+	// paint in the music
+		if (s_rawend >= paintedtime)
+		{	// copy from the streaming sound source
+			int		s;
+			int		stop;
+			
+			stop = (end < s_rawend) ? end : s_rawend;
+			
+			for (i = paintedtime; i < stop; i++)
+			{
+				s = i & (MAX_RAW_SAMPLES - 1);
+			// lower music by 6db to match sfx
+				paintbuffer[i - paintedtime].left += s_rawsamples[s].left >> 1;
+				paintbuffer[i - paintedtime].right += s_rawsamples[s].right >> 1;
+			}
+			//	if (i != end)
+			//		Con_Printf ("partial stream\n");
+			//	else
+			//		Con_Printf ("full stream\n");
+		}
+		
 	// transfer out according to DMA format
 		S_TransferPaintBuffer(end);
 		paintedtime = end;

Quake/snd_sdl.c

@@ -86,7 +86,7 @@ qboolean SNDDMA_Init (dma_t *dma)
 	}
 
 	/* Set up the desired format */
-	desired.freq = tmp = sndspeed.value;
+	desired.freq = tmp = snd_mixspeed.value;
 	desired.format = (loadas8bit.value) ? AUDIO_U8 : AUDIO_S16SYS;
 	desired.channels = 2; /* = desired_channels; */
 	if (desired.freq <= 11025)