duuqnd/cave-story-solaris
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix an occational invalid memory read

Browse source 
Stupid floating-point rounding errors. Had to undo a fancy
optimisation to avoid it.
This commit is contained in:
Clownacy 2020-01-09 09:10:24 +00:00
parent c831031ba4
commit 449a09b09e
1 changed files with 10 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

29
src/Backends/Audio/SDL2.cpp
View file

@ -75,28 +75,21 @@ static void MixSounds(float *stream, unsigned int frames_total)
{
float *steam_pointer = stream;
unsigned int frames_done = 0;
while (frames_done != frames_total)
for (unsigned int frames_done = 0; frames_done < frames_total; ++frames_done)
{
const unsigned int frames_to_do = MIN((unsigned int)ceil((sound->frames - sound->position) / sound->advance_delta), frames_total - frames_done);
// Get two samples, and normalise them to 0-1
const float sample1 = (sound->samples[(size_t)sound->position] - 128.0f) / 128.0f;
const float sample2 = (sound->samples[(size_t)sound->position + 1] - 128.0f) / 128.0f;
for (unsigned int i = 0; i < frames_to_do; ++i)
{
// Get two samples, and normalise them to 0-1
const float sample1 = (sound->samples[(size_t)sound->position] - 128.0f) / 128.0f;
const float sample2 = (sound->samples[(size_t)sound->position + 1] - 128.0f) / 128.0f;
// Perform linear interpolation
const float interpolated_sample = sample1 + ((sample2 - sample1) * (float)fmod(sound->position, 1.0));
// Perform linear interpolation
const float interpolated_sample = sample1 + ((sample2 - sample1) * (float)fmod(sound->position, 1.0));
*steam_pointer++ += interpolated_sample * sound->volume_l;
*steam_pointer++ += interpolated_sample * sound->volume_r;
*steam_pointer++ += interpolated_sample * sound->volume_l;
*steam_pointer++ += interpolated_sample * sound->volume_r;
sound->position += sound->advance_delta;
sound->position += sound->advance_delta;
}
if ((size_t)sound->position >= sound->frames)
if (sound->position >= sound->frames)
{
if (sound->looping)
{
@ -109,8 +102,6 @@ static void MixSounds(float *stream, unsigned int frames_total)
break;
}
}
frames_done += frames_to_do;
}
}
}