Patch #902111: Change remaining random function calls to use RandomSource

svn-id: r13262

4 files changed, 12 insertions, 21 deletions

diff --git a/TODO b/TODO
index 1a71e3d65f..65db43a969 100644
--- a/TODO
+++ b/TODO
@@ -29,12 +29,6 @@ General
   of the subdirs). Better would be to introduce a somewhat higher level API,
   a replacement for File::open() which (optionally) takes a list of subdirs.
   E.g. for Scumm, only certain files are to be expected in the VIDEO subdir).
-* Use RandomSource for all random numbers. Right now there are a few places
-  where we don't:
-  - sound/fmopl.cpp uses rand() in one function
-  - backends/midi/adlib.cpp has its own random_nr() function.
-  Any others?
-  
 
 Build System
 ============
diff --git a/backends/midi/adlib.cpp b/backends/midi/adlib.cpp
index 7fb0de39b1..6b6ebb3528 100644
--- a/backends/midi/adlib.cpp
+++ b/backends/midi/adlib.cpp
@@ -573,6 +573,8 @@ private:
 	bool _isOpen;
 	bool _game_SmallHeader;
 
+	static Common::RandomSource _rnd;
+
 	FM_OPL *_opl;
 	byte *_adlib_reg_cache;
 	SoundMixer *_mixer;
@@ -624,7 +626,6 @@ private:
 	void struct10_init(Struct10 * s10, InstrumentExtra * ie);
 	static byte struct10_ontimer(Struct10 * s10, Struct11 * s11);
 	static void struct10_setup(Struct10 * s10);
-	static int random_nr(int a);
 	void mc_key_on(AdlibVoice *voice, AdlibInstrument *instr, byte note, byte velocity);
 
 	static void premix_proc(void *param, int16 *buf, uint len);
@@ -1230,7 +1231,7 @@ void MidiDriver_ADLIB::struct10_setup(Struct10 *s10) {
 	t = s10->table_a[f];
 	e = num_steps_table[lookup_table[t & 0x7F][b]];
 	if (t & 0x80) {
-		e = random_nr(e);
+		e = _rnd.getRandomNumber(e);
 	}
 	if (e == 0)
 		e++;
@@ -1243,7 +1244,7 @@ void MidiDriver_ADLIB::struct10_setup(Struct10 *s10) {
 		t = s10->table_b[f];
 		d = lookup_volume(c, (t & 0x7F) - 31);
 		if (t & 0x80) {
-			d = random_nr(d);
+			d = _rnd.getRandomNumber(d);
 		}
 		if (d + g > c) {
 			h = c - g;
@@ -1305,17 +1306,6 @@ void MidiDriver_ADLIB::adlib_playnote(int channel, int note) {
 	adlib_write(channel + 0xB0, oct | 0x20);
 }
 
-int MidiDriver_ADLIB::random_nr(int a) {
-	static byte _rand_seed = 1;
-	if (_rand_seed & 1) {
-		_rand_seed >>= 1;
-		_rand_seed ^= 0xB8;
-	} else {
-		_rand_seed >>= 1;
-	}
-	return _rand_seed * a >> 8;
-}
-
 void MidiDriver_ADLIB::part_key_off(AdlibPart *part, byte note) {
 	AdlibVoice *voice;
 
@@ -1564,3 +1554,5 @@ void MidiDriver_ADLIB::adlib_note_on(int chan, byte note, int mod) {
 	curnote_table[chan] = code;
 	adlib_playnote(chan, (int16) channel_table_2[chan] + code);
 }
+
+Common::RandomSource MidiDriver_ADLIB::_rnd;
diff --git a/sound/fmopl.cpp b/sound/fmopl.cpp
index 60dacbfc33..0b3c1664a9 100644
--- a/sound/fmopl.cpp
+++ b/sound/fmopl.cpp
@@ -471,7 +471,8 @@ inline void OPL_CALC_CH(OPL_CH *CH) {
 #define WHITE_NOISE_db 6.0
 inline void OPL_CALC_RH(OPL_CH *CH) {
 	uint env_tam, env_sd, env_top, env_hh;
-	int whitenoise = int((rand()&1) * (WHITE_NOISE_db / EG_STEP));
+	int whitenoise = int(oplRnd.getRandomNumber(1) * (WHITE_NOISE_db / EG_STEP));
+
 	int tone8;
 
 	OPL_SLOT *SLOT;
diff --git a/sound/fmopl.h b/sound/fmopl.h
index 509f0abc80..96db6196c1 100644
--- a/sound/fmopl.h
+++ b/sound/fmopl.h
@@ -27,6 +27,7 @@
 #define FMOPL_H_
 
 #include "common/scummsys.h"
+#include "common/util.h"
 
 enum {
 	FMOPL_ENV_BITS_HQ = 16,
@@ -158,6 +159,9 @@ unsigned char OPLRead(FM_OPL *OPL, int a);
 int OPLTimerOver(FM_OPL *OPL, int c);
 void OPLWriteReg(FM_OPL *OPL, int r, int v);
 void YM3812UpdateOne(FM_OPL *OPL, int16 *buffer, int length);
+
+static Common::RandomSource oplRnd;			/* OPL random number generator */
+
 #endif
 
 // Factory method