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audio: Added a postmix callback to logical devices.

Browse Source 
You can see it in action in testaudio by mousing over a logical device; it
will show a visualizer for the current PCM (whatever is currently being
recorded on a capture device, or whatever is being mixed for output on
playback devices).

Fixes #8122.
This commit is contained in:
Ryan C. Gordon
2023-09-07 10:56:09 -04:00
parent 7207bdce5d
commit 3a992af446
7 changed files with 316 additions and 9 deletions
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167
test/testaudio.c
View File

@@ -10,6 +10,8 @@
#include "testutils.h"
#define POOF_LIFETIME 250
#define VISUALIZER_WIDTH 100
#define VISUALIZER_HEIGHT 50
typedef struct Texture
{
@@ -50,6 +52,15 @@ struct Thing
SDL_bool iscapture;
SDL_AudioSpec spec;
Thing *physdev;
SDL_bool visualizer_enabled;
SDL_bool visualizer_updated;
SDL_Texture *visualizer;
SDL_Mutex *postmix_lock;
float *postmix_buffer;
int postmix_buflen;
int postmix_allocated;
SDL_AudioSpec postmix_spec;
SDL_AtomicInt postmix_updated;
} logdev;
struct {
SDL_AudioSpec spec;
@@ -98,6 +109,7 @@ static SDLTest_CommonState *state = NULL;
static Thing *things = NULL;
static char *current_titlebar = NULL;
static Thing *mouseover_thing = NULL;
static Thing *droppable_highlighted_thing = NULL;
static Thing *dragging_thing = NULL;
static int dragging_button = -1;
@@ -279,21 +291,40 @@ static void DestroyThing(Thing *thing)
return;
}
if (mouseover_thing == thing) {
mouseover_thing = NULL;
}
if (droppable_highlighted_thing == thing) {
droppable_highlighted_thing = NULL;
}
if (dragging_thing == thing) {
dragging_thing = NULL;
}
switch (thing->what) {
case THING_POOF: break;
case THING_NULL: break;
case THING_TRASHCAN: break;
case THING_LOGDEV:
case THING_LOGDEV_CAPTURE:
SDL_CloseAudioDevice(thing->data.logdev.devid);
SDL_DestroyTexture(thing->data.logdev.visualizer);
SDL_DestroyMutex(thing->data.logdev.postmix_lock);
SDL_free(thing->data.logdev.postmix_buffer);
break;
case THING_PHYSDEV:
case THING_PHYSDEV_CAPTURE:
SDL_free(thing->data.physdev.name);
break;
case THING_WAV:
SDL_free(thing->data.wav.buf);
break;
case THING_STREAM:
SDL_DestroyAudioStream(thing->data.stream.stream);
break;
@@ -748,6 +779,135 @@ static void LogicalDeviceThing_ondrop(Thing *thing, int button, float x, float y
}
}
static void SDLCALL PostmixCallback(void *userdata, const SDL_AudioSpec *spec, float *buffer, int buflen)
{
Thing *thing = (Thing *) userdata;
SDL_LockMutex(thing->data.logdev.postmix_lock);
if (thing->data.logdev.postmix_allocated < buflen) {
void *ptr = SDL_realloc(thing->data.logdev.postmix_buffer, buflen);
if (!ptr) {
SDL_UnlockMutex(thing->data.logdev.postmix_lock);
return; /* oh well. */
}
thing->data.logdev.postmix_buffer = (float *) ptr;
thing->data.logdev.postmix_allocated = buflen;
}
SDL_copyp(&thing->data.logdev.postmix_spec, spec);
SDL_memcpy(thing->data.logdev.postmix_buffer, buffer, buflen);
thing->data.logdev.postmix_buflen = buflen;
SDL_AtomicSet(&thing->data.logdev.postmix_updated, 1);
SDL_UnlockMutex(thing->data.logdev.postmix_lock);
}
static void UpdateVisualizer(SDL_Renderer *renderer, SDL_Texture *visualizer, const int channels, const float *buffer, const int buflen)
{
static const SDL_Color channel_colors[8] = {
{ 255, 255, 255, 255 },
{ 255, 0, 0, 255 },
{ 0, 255, 0, 255 },
{ 0, 0, 255, 255 },
{ 255, 255, 0, 255 },
{ 0, 255, 255, 255 },
{ 255, 0, 255, 255 },
{ 127, 127, 127, 255 }
};
SDL_SetRenderTarget(renderer, visualizer);
SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
SDL_RenderClear(renderer);
if (buffer && buflen) {
const int frames = (buflen / sizeof (float)) / channels;
const int skip = frames / (VISUALIZER_WIDTH * 2);
int i, j;
for (i = channels - 1; i >= 0; i--) {
const SDL_Color *color = &channel_colors[i % SDL_arraysize(channel_colors)];
SDL_FPoint points[VISUALIZER_WIDTH + 2];
float prevx = 0.0f;
int pointidx = 1;
points[0].x = 0.0f;
points[0].y = VISUALIZER_HEIGHT * 0.5f;
for (j = 0; j < (SDL_arraysize(points)-1); j++) {
const float val = buffer[((j * skip) * channels) + i];
const float x = prevx + 2;
const float y = (VISUALIZER_HEIGHT * 0.5f) - (VISUALIZER_HEIGHT * (val * 0.5f));
SDL_assert(pointidx < SDL_arraysize(points));
points[pointidx].x = x;
points[pointidx].y = y;
pointidx++;
prevx = x;
}
SDL_SetRenderDrawColor(renderer, color->r, color->g, color->b, 255);
SDL_RenderLines(renderer, points, pointidx);
}
}
SDL_SetRenderTarget(renderer, NULL);
}
static void LogicalDeviceThing_ontick(Thing *thing, Uint64 now)
{
const SDL_bool ismousedover = (thing == mouseover_thing) ? SDL_TRUE : SDL_FALSE;
if (!thing->data.logdev.visualizer || !thing->data.logdev.postmix_lock) { /* need these to work, skip if they failed. */
return;
}
if (thing->data.logdev.visualizer_enabled != ismousedover) {
thing->data.logdev.visualizer_enabled = ismousedover;
if (!ismousedover) {
SDL_SetAudioPostmixCallback(thing->data.logdev.devid, NULL, NULL);
} else {
if (thing->data.logdev.postmix_buffer) {
SDL_memset(thing->data.logdev.postmix_buffer, '\0', thing->data.logdev.postmix_buflen);
}
SDL_AtomicSet(&thing->data.logdev.postmix_updated, 1); /* so this will at least clear the texture later. */
SDL_SetAudioPostmixCallback(thing->data.logdev.devid, PostmixCallback, thing);
}
}
}
static void LogicalDeviceThing_ondraw(Thing *thing, SDL_Renderer *renderer)
{
if (thing->data.logdev.visualizer_enabled) {
SDL_FRect dst;
dst.w = thing->rect.w;
dst.h = thing->rect.h;
dst.x = thing->rect.x + ((thing->rect.w - dst.w) / 2);
dst.y = thing->rect.y + ((thing->rect.h - dst.h) / 2);
if (SDL_AtomicGet(&thing->data.logdev.postmix_updated)) {
float *buffer;
int channels;
int buflen;
SDL_LockMutex(thing->data.logdev.postmix_lock);
channels = thing->data.logdev.postmix_spec.channels;
buflen = thing->data.logdev.postmix_buflen;
buffer = (float *) SDL_malloc(thing->data.logdev.postmix_buflen);
if (buffer) {
SDL_memcpy(buffer, thing->data.logdev.postmix_buffer, thing->data.logdev.postmix_buflen);
SDL_AtomicSet(&thing->data.logdev.postmix_updated, 0);
}
SDL_UnlockMutex(thing->data.logdev.postmix_lock);
UpdateVisualizer(renderer, thing->data.logdev.visualizer, channels, buffer, buflen);
SDL_free(buffer);
}
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 30);
SDL_RenderTexture(renderer, thing->data.logdev.visualizer, NULL, &dst);
}
}
static Thing *CreateLogicalDeviceThing(Thing *parent, const SDL_AudioDeviceID which, const float x, const float y)
{
static const ThingType can_be_dropped_onto[] = { THING_TRASHCAN, THING_NULL };
@@ -760,9 +920,16 @@ static Thing *CreateLogicalDeviceThing(Thing *parent, const SDL_AudioDeviceID wh
thing->data.logdev.devid = which;
thing->data.logdev.iscapture = iscapture;
thing->data.logdev.physdev = physthing;
thing->data.logdev.visualizer = SDL_CreateTexture(state->renderers[0], SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, VISUALIZER_WIDTH, VISUALIZER_HEIGHT);
thing->data.logdev.postmix_lock = SDL_CreateMutex();
if (thing->data.logdev.visualizer) {
SDL_SetTextureBlendMode(thing->data.logdev.visualizer, SDL_BLENDMODE_BLEND);
}
thing->line_connected_to = physthing;
thing->ontick = LogicalDeviceThing_ontick;
thing->ondrag = DeviceThing_ondrag;
thing->ondrop = LogicalDeviceThing_ondrop;
thing->ondraw = LogicalDeviceThing_ondraw;
thing->can_be_dropped_onto = can_be_dropped_onto;
SetLogicalDeviceTitlebar(thing);