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Steve2
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- Adjustable edge curve 

- Better speaker flip-flop simulation
This commit is contained in:
tudnai 2020-05-24 13:07:34 -07:00
parent ab120dc459
commit 7758fe3c33
2 changed files with 34 additions and 10 deletions
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3
A2Mac.xcodeproj/project.xcworkspace/xcuserdata/trudnai.xcuserdatad/xcdebugger/Expressions.xcexplist
View File

@ -439,6 +439,9 @@
<PersistentString
value = "(int16_t)28000 + (int16_t)-32768">
</PersistentString>
<PersistentString
value = "28000 + fadeLevel">
</PersistentString>
</PersistentStrings>
</ContextState>
<ContextState

41
src/dev/audio/speaker.c
View File

@ -136,6 +136,8 @@ void spkr_exit() {
}
char spkr_state = 0;
void spkr_toggle() {
// TODO: This is very slow!
// printf("io_KBDSTRB\n");
@ -146,22 +148,42 @@ void spkr_toggle() {
// (we will play the entire buffer at the end of the frame)
spkr_sample_idx = (clkfrm / (default_MHz_6502 / spkr_sample_rate)) * 2;
if ( spkr_level > SPKR_LEVEL_ZERO ) {
if ( spkr_state ) {
// down edge
while( (spkr_level = (spkr_level + SPKR_LEVEL_MIN) / 2 ) > SPKR_LEVEL_MIN + 1 ) {
spkr_samples[ spkr_sample_idx++ ] = spkr_level;
spkr_samples[ spkr_sample_idx++ ] = spkr_level;
spkr_state = 0;
float fadeLevel = spkr_level - SPKR_LEVEL_MIN;
while ( fadeLevel > +1 ) {
spkr_samples[ spkr_sample_idx++ ] = SPKR_LEVEL_MIN + fadeLevel;
spkr_samples[ spkr_sample_idx++ ] = SPKR_LEVEL_MIN + fadeLevel;
// how smooth we want the speeker to decay, so we will hear no pops and crackles
// 0.9 gives you a kind of saw wave at 1KHz (beep)
// 0.7 is better, but Xonix gives you a bit distorted speech and Donkey Kong does not sound the same
fadeLevel *= 0.64;
}
spkr_level = SPKR_LEVEL_MIN;
}
else {
// up edge
while( (spkr_level = (spkr_level + SPKR_LEVEL_MAX) / 2 ) < SPKR_LEVEL_MAX - 1 ) {
spkr_samples[ spkr_sample_idx++ ] = spkr_level;
spkr_samples[ spkr_sample_idx++ ] = spkr_level;
spkr_state = 1;
float fadeLevel = spkr_level - SPKR_LEVEL_MAX;
while ( fadeLevel < -1 ) {
spkr_samples[ spkr_sample_idx++ ] = SPKR_LEVEL_MAX + fadeLevel;
spkr_samples[ spkr_sample_idx++ ] = SPKR_LEVEL_MAX + fadeLevel;
// how smooth we want the speeker to decay, so we will hear no pops and crackles
// 0.9 gives you a kind of saw wave at 1KHz (beep)
// 0.7 is better, but Xonix gives you a bit distorted speech and Donkey Kong does not sound the same
fadeLevel *= 0.64;
}
spkr_level = SPKR_LEVEL_MAX;
}
//spkr_samples[sample_idx] = spkr_level;
for ( int i = spkr_sample_idx; i < spkr_buf_size + spkr_extra_buf; i++ ) {
spkr_samples[i] = spkr_level;
@ -209,10 +231,9 @@ void spkr_update() {
// simple linear mute
const int steepness = 64;
float step = (SPKR_LEVEL_ZERO - (float)spkr_level) / steepness;
float fadeLevel = spkr_level - SPKR_LEVEL_ZERO;
if ( step != 0 ) {
if ( spkr_level != SPKR_LEVEL_ZERO ) {
spkr_sample_idx = 0;
while ( ( fadeLevel < -1 ) || ( fadeLevel > 1 ) ) {
@ -222,7 +243,7 @@ void spkr_update() {
// how smooth we want the speeker to decay, so we will hear no pops and crackles
fadeLevel *= 0.999;
}
spkr_level = SPKR_LEVEL_ZERO + fadeLevel;
spkr_level = SPKR_LEVEL_ZERO;
//spkr_samples[sample_idx] = spkr_level;
memset(spkr_samples + spkr_sample_idx, SPKR_LEVEL_ZERO, spkr_extra_buf * sizeof(spkr_samples[0]));