Better common fake mic, #3320744

This is the preliminary patch that adds different
behaviour to the comon fake mic implementation to better
match desmume feature set.

This patch adds the code for the missing feature before
changing the mic API.

From rogerman, #3320744

desmume/src/mic.cpp

@@ -1,6 +1,6 @@
 /* mic.cpp - this file is part of DeSmuME
  *
- * Copyright (C) 2009 DeSmuME Team
+ * Copyright (C) 2009-2011 DeSmuME Team
  *
  * This file is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,37 +20,178 @@
 
 #ifndef WIN32
 
-#include "types.h"
+#include <stdlib.h>
 #include "mic.h"
+#include "NDSSystem.h"
 #include "readwrite.h"
-#include "emufile.h"
 
-static BOOL silence = TRUE;
+#define MIC_NULL_SAMPLE_VALUE 0
+#define MIC_MAX_BUFFER_SAMPLES 320
+#define MIC_BUFFER_SIZE (sizeof(u8) * MIC_MAX_BUFFER_SAMPLES)
+#define NUM_INTERNAL_NOISE_SAMPLES 32
 
-BOOL Mic_Init()
+static u8 *micSampleBuffer = NULL; // Pointer to the internal sample buffer.
+static u8 *micReadPosition = NULL; // Pointer to the read position of the internal sample buffer.
+static u8 *micWritePosition = NULL; // Pointer to the write position of the internal sample buffer.
+static unsigned int micBufferFillCount; // The number of readable samples in the internal sample buffer.
+
+static void Mic_BufferClear(void)
 {
-	return TRUE;
+	if (micSampleBuffer == NULL) {
+		return;
+	}
+
+	memset(micSampleBuffer, MIC_NULL_SAMPLE_VALUE, MIC_BUFFER_SIZE);
+	micReadPosition = micSampleBuffer;
+	micWritePosition = micSampleBuffer;
+	micBufferFillCount = 0;
 }
 
-void Mic_Reset()
+BOOL Mic_Init(void)
 {
+	BOOL result = FALSE;
+
+	u8 *newBuffer = (u8 *)malloc(MIC_BUFFER_SIZE);
+	if (newBuffer == NULL) {
+		return result;
+	}
+
+	micSampleBuffer = newBuffer;
+	Mic_BufferClear();
+	result = TRUE;
+
+	return result;
 }
 
-void Mic_DeInit()
+void Mic_DeInit(void)
 {
+	free(micSampleBuffer);
+	micSampleBuffer = NULL;
 }
 
-u8 Mic_ReadSample()
+void Mic_Reset(void)
 {
-	if (silence)
-		return 0;
+	*micReadPosition = MIC_NULL_SAMPLE_VALUE;
+	micWritePosition = micReadPosition;
+	micBufferFillCount = 0;
+}
 
-	return 150;
+static bool Mic_GetActivate(void)
+{
+	return NDS_getFinalUserInput().mic.micButtonPressed;
+}
+
+static bool Mic_IsBufferFull(void)
+{
+	return (micBufferFillCount >= MIC_MAX_BUFFER_SAMPLES);
+}
+
+static bool Mic_IsBufferEmpty(void)
+{
+	return (micBufferFillCount == 0);
+}
+
+static u8 Mic_DefaultBufferRead(void)
+{
+	u8 theSample = MIC_NULL_SAMPLE_VALUE;
+
+	if (micSampleBuffer == NULL) {
+		return theSample;
+	}
+
+	theSample = *micReadPosition;
+
+	if (Mic_IsBufferEmpty()) {
+		return theSample;
+	}
+
+	micReadPosition++;
+	micBufferFillCount--;
+
+	// Move the pointer back to start if we reach the end of the memory block.
+	if (micReadPosition >= (micSampleBuffer + MIC_BUFFER_SIZE)) {
+		micReadPosition = micSampleBuffer;
+	}
+
+	return theSample;
+}
+
+u8 Mic_ReadSample(void)
+{
+	// All mic modes other than Physical must have the mic hotkey pressed in order
+	// to work.
+	if (CommonSettings.micMode != TCommonSettings::Physical && !Mic_GetActivate()) {
+		return MIC_NULL_SAMPLE_VALUE;
+	}
+
+	return Mic_DefaultBufferRead();
+}
+
+static void Mic_DefaultBufferWrite(u8 theSample)
+{
+	if (micSampleBuffer == NULL || Mic_IsBufferFull()) {
+		return;
+	}
+
+	*micWritePosition = theSample;
+	micWritePosition++;
+	micBufferFillCount++;
+
+	// Move the pointer back to start if we reach the end of the memory block.
+	if (micWritePosition >= (micSampleBuffer + MIC_BUFFER_SIZE)) {
+		micWritePosition = micSampleBuffer;
+	}
+}
+
+static u8 Mic_GenerateInternalNoiseSample(void)
+{
+	const u8 noiseSample[NUM_INTERNAL_NOISE_SAMPLES] =
+	{
+		0xFC, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF5, 0xFF, 0xFF, 0xFF, 0xFF, 0x8E, 0xFF, 
+		0xF4, 0xE1, 0xBF, 0x9A, 0x71, 0x58, 0x5B, 0x5F, 0x62, 0xC2, 0x25, 0x05, 0x01, 0x01, 0x01, 0x01
+	};
+	static unsigned int i = 0;
+
+	if (++i >= NUM_INTERNAL_NOISE_SAMPLES) {
+		i = 0;
+	}
+
+	return noiseSample[i];
+}
+
+static u8 Mic_GenerateWhiteNoiseSample(void)
+{
+	return (u8)(rand() & 0xFF);
+}
+
+static u8 Mic_GenerateNullSample(void)
+{
+	return MIC_NULL_SAMPLE_VALUE;
 }
 
 void Mic_DoNoise(BOOL noise)
 {
-	silence = !noise;
+	u8 (*generator) (void) = NULL;
+
+	if (micSampleBuffer == NULL) {
+		return;
+	}
+
+	if (!noise) {
+		generator = &Mic_GenerateNullSample;
+	} else if (CommonSettings.micMode == TCommonSettings::InternalNoise) {
+		generator = &Mic_GenerateInternalNoiseSample;
+	} else if (CommonSettings.micMode == TCommonSettings::Random) {
+		generator = &Mic_GenerateWhiteNoiseSample;
+	}
+
+	if (generator == NULL) {
+		return;
+	}
+
+	while (micBufferFillCount < MIC_MAX_BUFFER_SAMPLES) {
+		Mic_DefaultBufferWrite(generator());
+	}
 }
 
 void mic_savestate(EMUFILE* os)

desmume/src/mic.h

@@ -1,6 +1,6 @@
 /* mic.h - this file is part of DeSmuME
  *
- * Copyright (C) 2009 DeSmuME Team
+ * Copyright (C) 2009-2011 DeSmuME Team
  *
  * This file is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,8 +20,10 @@
 
 #ifndef MIC_H
 #define MIC_H
+
 #include <iostream>
 #include "emufile.h"
+#include "types.h"
 
 #ifdef WIN32
 static char MicSampleName[256];
@@ -34,12 +36,12 @@ extern int MicDisplay;
 void Mic_DoNoise(BOOL);
 #endif
 
-BOOL Mic_Init();
-void Mic_Reset();
-void Mic_DeInit();
-u8 Mic_ReadSample();
+BOOL Mic_Init(void);
+void Mic_Reset(void);
+void Mic_DeInit(void);
+u8 Mic_ReadSample(void);
 
 void mic_savestate(EMUFILE* os);
 bool mic_loadstate(EMUFILE* is, int size);
 
-#endif
+#endif // MIC_H