System info & network

code/audio.cpp

@@ -0,0 +1,156 @@
+#include "audio.h"
+#include "enginestate.h"
+#include <string.h>
+
+
+void audio_cb(p_audio_buffer *buffer);
+
+
+void audio_init()
+{
+	audio_player *player = &engine.audio;
+
+	player->track_count    = 0;
+	player->track_capacity = 32;
+	player->tracks         = (audio_track *) p_alloc(player->track_capacity * sizeof(audio_track));
+	player->next_id        = 0;
+	player->sample_rate    = p_audio_sample_rate();
+
+	p_audio_register_data_callback(audio_cb);
+}
+
+track_id audio_add_track(p_audio_buffer *data, u32 flags)
+{
+	// @Correctness: fix track if it has a different sample rate
+	audio_player *player = &engine.audio;
+	audio_track track;
+
+	track.id = player->next_id;
+	player->next_id++;
+	track.data = *data;
+	track.progress = 0;
+	track.playing = !(flags & AUDIO_PAUSED);
+	track.loop = !!(flags & AUDIO_LOOP);
+	track.free_on_finish = !!(flags & AUDIO_FREE_ON_FINISH);
+	track.volume = 1.0;
+
+	if (player->track_count + 1 < player->track_capacity)
+	{
+		u64 index = player->track_count;
+		player->tracks[index] = track;
+		player->track_count++;
+	}
+	else
+	{
+		u32 replace_index = 0;
+		for(u32 i = 0; i < player->track_count; i++)
+		{
+			audio_track *current = &player->tracks[i];
+			if(track.loop == current->loop)
+			{
+				replace_index = i;
+				break;
+			}
+		}
+
+		player->tracks[replace_index] = track;
+	}
+
+	return track.id;
+}
+
+void audio_remove_track(track_id id)
+{
+	audio_player *player = &engine.audio;
+	for(int i = 0; i < player->track_count; i++)
+	{
+		audio_track *current = &player->tracks[i];
+		if(id == current->id)
+		{
+			u32 move_count = player->track_count - (i + 1);
+			if(current->free_on_finish)
+				p_free(current->data.samples);
+			memmove(current, current + 1, move_count * sizeof(audio_track));
+			player->track_count--;
+			break;
+		}
+	}
+}
+
+void audio_pause_track(track_id id)
+{
+	audio_track *track = audio_track_from_id(id);
+	if(track)
+		track->playing = false;
+}
+
+void audio_play_track(track_id id)
+{
+	audio_track *track = audio_track_from_id(id);
+	if(track)
+		track->playing = true;
+}
+
+void audio_change_track_volume(track_id id, f32 volume)
+{
+	audio_track *track = audio_track_from_id(id);
+	if(track)
+		track->volume = volume;
+}
+
+audio_track *audio_track_from_id(track_id id)
+{
+	audio_player *player = &engine.audio;
+	for(int i = 0; i < player->track_count; i++)
+	{
+		audio_track *current = &player->tracks[i];
+		if(id == current->id)
+			return current;
+	}
+	return NULL;
+}
+
+
+// @Correctness: audio cb modifies the array of tracks asynchronously. All r/w operations on tracks should be protected by a mutex.
+void audio_cb(p_audio_buffer *buffer)
+{
+	audio_player *player = &engine.audio;
+
+	buffer->size = minimum(buffer->size, 2048); // Low latency
+
+	for(u64 i = 0; i < buffer->size; i++)
+	{
+		buffer->samples[i].left  = 0;
+		buffer->samples[i].right = 0;
+	}
+
+	for(int track_i = 0; track_i < player->track_count; track_i++)
+	{
+		audio_track *current = &player->tracks[track_i];
+		if(current->playing)
+		{
+			u64 remaining = current->data.size - current->progress;
+			u64 copy_count = minimum(remaining, buffer->size);
+			if(current->loop)
+				copy_count = buffer->size;
+
+			for(u64 i = 0; i < copy_count; i++)
+			{
+				buffer->samples[i].left  += current->volume * current->data.samples[current->progress].left;
+				buffer->samples[i].right += current->volume * current->data.samples[current->progress].right;
+				current->progress = (current->progress + 1) % current->data.size;
+			}
+
+			if(!current->loop && current->progress == 0) // current->progress == 0 because we finished and then we looped around
+			{
+				// Finished playing. Remove track
+				u32 move_count = player->track_count - (track_i + 1);
+				if(current->free_on_finish)
+					p_free(current->data.samples); // @Bug: double free when the same sound is played 2 times. Find a way to signal we reached the end of the track so the user code can make its own free (if needed)
+				memmove(current, current + 1, move_count * sizeof(audio_track));
+				track_i--;
+				player->track_count--;
+			}
+		}
+	}
+}