#include <SDL.h>
#include "log.h"
+// Useful defines
+
+//#define DEBUG
//#define SAMPLE_RATE (44100.0)
#define SAMPLE_RATE (48000.0)
#define SAMPLES_PER_FRAME (SAMPLE_RATE / 60.0)
-#define CYCLES_PER_SAMPLE (1024000.0 / SAMPLE_RATE)
-#define SOUND_BUFFER_SIZE (8192)
-//#define AMPLITUDE (16) // -32 - +32 seems to be plenty loud!
+// ~ 21
+//#define CYCLES_PER_SAMPLE (1024000.0 / SAMPLE_RATE)
+// ~ 17 (lower pitched than above...!)
+// Makes sense, as this is the divisor for # of cycles passed
+#define CYCLES_PER_SAMPLE (800000.0 / SAMPLE_RATE)
+//nope, too high #define CYCLES_PER_SAMPLE (960000.0 / SAMPLE_RATE)
+//#define SOUND_BUFFER_SIZE (8192)
+#define SOUND_BUFFER_SIZE (16384)
// Global variables
static SDL_cond * conditional = NULL;
static SDL_mutex * mutex = NULL;
static SDL_mutex * mutex2 = NULL;
-static uint8 ampPtr = 5;
+static int8 sample;
+static uint8 ampPtr = 5; // Start with -16 - +16
static uint16 amplitude[17] = { 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048,
4096, 8192, 16384, 32768 };
//
void SoundInit(void)
{
-#if 1
+#if 0
// To weed out problems for now...
return;
#endif
sampleBase = 0;
lastToggleCycles = 0;
samplePosition = 0;
+ sample = desired.silence; // ? wilwok ? yes
SDL_PauseAudio(false); // Start playback!
soundInitialized = true;
// (Actually, this should never happen since we fill the buffer beforehand.)
// (But, then again, if the sound hasn't been toggled for a while, then this
// makes perfect sense as the buffer won't have been filled at all!)
+ // (Should NOT starve now, now that we properly handle frame edges...)
// Let's try using a mutex for shared resource consumption...
SDL_mutexP(mutex2);
buffer[i] = soundBuffer[i];
// Fill buffer with last value
- memset(buffer + soundBufferPos, (uint8)(speakerState ? amplitude[ampPtr] : -amplitude[ampPtr]), length - soundBufferPos);
- soundBufferPos = 0; // Reset soundBufferPos to start of buffer...
+// memset(buffer + soundBufferPos, (uint8)(speakerState ? amplitude[ampPtr] : -amplitude[ampPtr]), length - soundBufferPos);
+ memset(buffer + soundBufferPos, (uint8)sample, length - soundBufferPos); soundBufferPos = 0; // Reset soundBufferPos to start of buffer...
sampleBase = 0; // & sampleBase...
//Ick. This should never happen!
//Actually, this probably happens a lot. (?)
Could add # of cycles in IRQ to lastToggleCycles, then currentPos will be guaranteed
to fall within acceptable limits.
+
+This *should* work, but if the IRQ isn't scheduled & etc, could screw timing up.
+Need to have a way to suspend IRQ thread as well as CPU thread when in the GUI,
+for example
+
+Another method would be to add to lastToggleCycles on every timeslice of the CPU,
+just like we used to.
+
+Or, run the CPU for CYCLES_PER_SAMPLE and take a sample, then copy the buffer over
+at the end of the timeslice. That way, we could just fill the buffer and let the
+IRQ handle draining it. No muss, no fuss.
*/
- if (currentPos > SOUND_BUFFER_SIZE - 1)
+ if ((soundBufferPos + currentPos) > (SOUND_BUFFER_SIZE - 1))
{
#if 0
WriteLog("ToggleSpeaker() about to go into spinlock at time: %08X (%u) (sampleBase=%u)!\n", time, time, sampleBase);
// SDL_CondWait(conditional, mutex);
// SDL_LockAudio();
// Hm.
+// This might not empty the buffer enough, causing hash and trash. !!! FIX !!!
SDL_mutexV(mutex2);//Release it so sound thread can get it,
SDL_CondWait(conditional, mutex);//Sleep/wait for the sound thread
SDL_mutexP(mutex2);//Re-lock it until we're done with it...
- currentPos = sampleBase + (uint32)((double)elapsedCycles / CYCLES_PER_SAMPLE);
+// currentPos = sampleBase + (uint32)((double)deltaCycles / CYCLES_PER_SAMPLE);
+ currentPos = (uint32)((double)deltaCycles / CYCLES_PER_SAMPLE);
#if 0
WriteLog("--> after spinlock (sampleBase=%u)...\n", sampleBase);
#endif
}
- int8 sample = (speakerState ? amplitude[ampPtr] : -amplitude[ampPtr]);
+ sample = (speakerState ? amplitude[ampPtr] : -amplitude[ampPtr]);
+
+ // currentPos is position from "zero" or soundBufferPos...
+ currentPos += soundBufferPos;
while (soundBufferPos < currentPos)
soundBuffer[soundBufferPos++] = (uint8)sample;
// This is done *after* in case the buffer had a long dead spot (I think...)
speakerState = !speakerState;
+ sample = (speakerState ? amplitude[ampPtr] : -amplitude[ampPtr]);
+ lastToggleCycles = elapsedCycles;
SDL_mutexV(mutex2);
// SDL_UnlockAudio();
}
// SDL_UnlockAudio();
}
+void AdjustLastToggleCycles(uint64 elapsedCycles)
+{
+#if 0
+ if (!soundInitialized)
+ return;
+
+ SDL_mutexP(mutex2);
+ lastToggleCycles += elapsedCycles;
+ SDL_mutexV(mutex2);
+
+// We should also fill the buffer here as well, even if the speaker
+// didn't toggle... !!! FIX !!!
+#else
+/*
+BOOKKEEPING
+
+We need to know the following:
+
+ o Where in the sound buffer the base or "zero" time is
+ o At what CPU timestamp the speaker was last toggled
+ NOTE: we keep things "right" by advancing this number every frame, even
+ if nothing happened! That way, we can keep track without having
+ to detect whether or not several frames have gone by without any
+ activity.
+
+How to do it:
+
+Every time the speaker is toggled, we move the base or "zero" time to the
+current spot in the buffer. We also backfill the buffer up to that point with
+the old toggle value. The next time the speaker is toggled, we measure the
+difference in time between the last time it was toggled (the "zero") and now,
+and repeat the cycle.
+
+We handle dead spots by backfilling the buffer with the current toggle value
+every frame--this way we don't have to worry about keeping current time and
+crap like that. So, we have to move the "zero" the right amount, just like
+in ToggleSpeaker(), and backfill only without toggling.
+*/
+#warning "This is VERY similar to ToggleSpeaker(); merge into common function. !!! FIX !!!"
+ if (!soundInitialized)
+ return;
+
+#ifdef DEBUG
+printf("SOUND: AdjustLastToggleCycles() start...\n");
+#endif
+ // Step 1: Calculate delta time
+ uint64 deltaCycles = elapsedCycles - lastToggleCycles;
+
+ // Step 2: Calculate new buffer position
+ uint32 currentPos = (uint32)((double)deltaCycles / CYCLES_PER_SAMPLE);
+
+ // Step 3: Make sure there's room for it
+ // We need to lock since we touch both soundBuffer and soundBufferPos
+ SDL_mutexP(mutex2);
+ while ((soundBufferPos + currentPos) > (SOUND_BUFFER_SIZE - 1))
+ {
+ // Hm.
+ // This might not empty the buffer enough, causing hash and trash. !!! FIX !!! [DONE]
+ SDL_mutexV(mutex2);//Release it so sound thread can get it,
+ SDL_CondWait(conditional, mutex);//Sleep/wait for the sound thread
+ SDL_mutexP(mutex2);//Re-lock it until we're done with it...
+
+//HMM, this doesn't need to lock or recalculate this value
+// currentPos = (uint32)((double)deltaCycles / CYCLES_PER_SAMPLE);
+ }
+
+ // Step 4: Backfill and adjust lastToggleCycles
+ // currentPos is position from "zero" or soundBufferPos...
+ currentPos += soundBufferPos;
+
+ // Backfill with current toggle state
+ while (soundBufferPos < currentPos)
+ soundBuffer[soundBufferPos++] = (uint8)sample;
+
+ SDL_mutexV(mutex2);
+ lastToggleCycles = elapsedCycles;
+#ifdef DEBUG
+printf("SOUND: AdjustLastToggleCycles() end...\n");
+#endif
+#endif
+}
+
void VolumeUp(void)
{
// Currently set for 8-bit samples
projects / apple2 / blobdiff