Mercurial > almixer_isolated
changeset 74:c112e4576832
Fixed remaining fading bug for pause/resume.
My technique was wrong. I computed the amount of time remaining on pause and when I resumed, I grabbed the current time as the start and used the time remaining as the end. I think this is wrong because the volume curve may not be linear if I do this.
Instead, I will try saving the time remaining, but preserve the original fade duration. Then I will adjust the start time for the amount already played. So I don't need to create another variable, I will overwrite the fade start.
| author | Eric Wing <ewing . public |-at-| gmail . com> |
|---|---|
| date | Fri, 10 Aug 2012 23:38:56 -0700 |
| parents | 32757e494675 |
| children | 609d597b0dd9 |
| files | ALmixer.c |
| diffstat | 1 files changed, 48 insertions(+), 28 deletions(-) [+] |
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--- a/ALmixer.c Fri Aug 10 22:53:14 2012 -0700 +++ b/ALmixer.c Fri Aug 10 23:38:56 2012 -0700 @@ -2942,23 +2942,21 @@ if(ALmixer_Channel_List[channel].fade_enabled) { ALuint current_time = ALmixer_GetTicks(); - ALuint diff_time; - diff_time = current_time - + ALuint used_up_time; + used_up_time = current_time - ALmixer_Channel_List[channel].fade_start_time; /* When we unpause, we will want to reset * the start time so we can continue * to base calculations off GetTicks(). - * This means we need to subtract the amount - * of time already used up from expire_ticks. + * I originally did this wrong. I computed the amount of time remaining + * and when I resumed, I grabbed the current time as the start and used the time remaining as the end. + * I think this is wrong because the volume curve may not be linear. + * Instead, I will try saving the time remaining, but preserve the original fade duration. + * Then I will adjust the start time for the amount already played. + * So I don't need to create another variable, I will overwrite the start time with the remaining time. + * (Resume needs to know this implementation detail.) */ - ALmixer_Channel_List[channel].fade_expire_ticks = - ALmixer_Channel_List[channel].fade_expire_ticks - - diff_time; - /* Don't allow the time to go negative */ - if(ALmixer_Channel_List[channel].fade_expire_ticks < 0) - { - ALmixer_Channel_List[channel].fade_expire_ticks = 0; - } + ALmixer_Channel_List[channel].fade_start_time = used_up_time; } /* End fade check */ } /* End if PLAYING */ } /* End If in use */ @@ -3025,23 +3023,21 @@ if(ALmixer_Channel_List[i].fade_enabled) { ALuint current_time = ALmixer_GetTicks(); - ALuint diff_time; - diff_time = current_time - - ALmixer_Channel_List[i].fade_start_time; + ALuint used_up_time; + used_up_time = current_time - + ALmixer_Channel_List[i].fade_start_time; /* When we unpause, we will want to reset * the start time so we can continue * to base calculations off GetTicks(). - * This means we need to subtract the amount - * of time already used up from expire_ticks. + * I originally did this wrong. I computed the amount of time remaining + * and when I resumed, I grabbed the current time as the start and used the time remaining as the end. + * I think this is wrong because the volume curve may not be linear. + * Instead, I will try saving the time remaining, but preserve the original fade duration. + * Then I will adjust the start time for the amount already played. + * So I don't need to create another variable, I will overwrite the start time with the remaining time. + * (Resume needs to know this implementation detail.) */ - ALmixer_Channel_List[i].fade_expire_ticks = - ALmixer_Channel_List[i].fade_expire_ticks - - diff_time; - /* Don't allow the time to go negative */ - if(ALmixer_Channel_List[i].fade_expire_ticks < 0) - { - ALmixer_Channel_List[i].fade_expire_ticks = 0; - } + ALmixer_Channel_List[i].fade_start_time = used_up_time; } /* End fade check */ } /* End if PLAYING */ } /* End channel in use */ @@ -3123,8 +3119,20 @@ /* Do the same as expire time for fading */ if(ALmixer_Channel_List[channel].fade_enabled) { - ALmixer_Channel_List[channel].fade_start_time = ALmixer_GetTicks(); - } + /* I originally did this wrong. On pause, I computed the amount of time remaining + * and when I resumed, I grabbed the current time as the start and used the time remaining as the end. + * I think this is wrong because the volume curve may not be linear. + * Instead, I will try saving the time remaining, but preserve the original fade duration. + * Then I will adjust the start time for the amount already played. + * So I don't need to create another variable, I will overwrite the start time with the remaining time + * (Resume needs to know this implementation detail.) + */ + ALuint current_time = ALmixer_GetTicks(); + /* Recover the used_up_time from the overloaded fade_start_time variable */ + ALuint used_up_time = ALmixer_Channel_List[channel].fade_start_time; + /* So the adjusted start time is: */ + ALmixer_Channel_List[channel].fade_start_time = current_time - used_up_time; + } alSourcePlay(ALmixer_Channel_List[channel].alsource); if((error = alGetError()) != AL_NO_ERROR) @@ -3167,7 +3175,19 @@ /* Do the same as expire time for fading */ if(ALmixer_Channel_List[i].fade_enabled) { - ALmixer_Channel_List[i].fade_start_time = ALmixer_GetTicks(); + /* I originally did this wrong. On pause, I computed the amount of time remaining + * and when I resumed, I grabbed the current time as the start and used the time remaining as the end. + * I think this is wrong because the volume curve may not be linear. + * Instead, I will try saving the time remaining, but preserve the original fade duration. + * Then I will adjust the start time for the amount already played. + * So I don't need to create another variable, I will overwrite the start time with the remaining time + * (Resume needs to know this implementation detail.) + */ + ALuint current_time = ALmixer_GetTicks(); + /* Recover the used_up_time from the overloaded fade_start_time variable */ + ALuint used_up_time = ALmixer_Channel_List[i].fade_start_time; + /* So the adjusted start time is: */ + ALmixer_Channel_List[i].fade_start_time = current_time - used_up_time; } alSourcePlay(ALmixer_Channel_List[i].alsource);