Web: add panning, move mixing to wasm

web/Constants.js

@@ -75,10 +75,6 @@ let Constants = {
         BREAK_FRAME: 1,
         BREAK_POINT: 2,
 
-        // Extra properties
-        EXT_PIXELS : 0,
-        EXT_SAMPLES: 1,
-
         // Anaglyph colors
         STEREO_CYAN   : 0x00C6F0,
         STEREO_GREEN  : 0x00B400,

web/Core.js

@@ -82,23 +82,20 @@ new class Core {
             let sim = {
                 canvas  : null,
                 keys    : Constants.VB.SGN,
-                pointer : sims[x] = this.CreateSim(),
+                pointer : sims[x] = this.CreateSim()
-                volume  : 1
             };
             this.sims.set(sim.pointer, sim);
 
             // Video
-            this.SetAnaglyph(sim.pointer,
-                Constants.web.STEREO_RED, Constants.web.STEREO_CYAN);
             sim.pixels = this.#noalloc(
-                this.GetExt(sim.pointer, Constants.web.EXT_PIXELS),
+                this.GetExtPixels(sim.pointer),
                 384*224*4, sim, "pixels", Uint8ClampedArray
             );
             sim.image = new ImageData(sim.pixels, 384, 224);
 
             // Audio
             sim.samples = this.#noalloc(
-                this.GetExt(sim.pointer, Constants.web.EXT_SAMPLES),
+                this.GetExtSamples(sim.pointer),
                 41700 / 50 * 2, sim, "samples", Float32Array
             );
 
@@ -296,6 +293,12 @@ new class Core {
         this.dom.postMessage({ promised: true });
     }
 
+    // Specify audio panning
+    setPanning(message) {
+        this.SetPanning(message.sim, message.panning);
+        this.dom.postMessage({ promised: true });
+    }
+
     // Specify a new communication peer
     setPeer(message) {
         let orphaned = [];
@@ -318,7 +321,7 @@ new class Core {
 
     // Specify audio volume
     setVolume(message) {
-        this.sims.get(message.sim).volume = message.volume;
+        this.SetVolume(message.sim, message.volume);
         this.dom.postMessage({ promised: true });
     }
 
@@ -408,19 +411,13 @@ new class Core {
 
             // Mix and output audio samples
             let buffer = this.audio.buffers.shift();
-            if (this.automatic.sims.length > 1) {
+            this.Mix(
+                this.audio.samples.pointer,
+                this.automatic.pointers.pointer,
+                this.automatic.sims.length
+            );
             for (let x = 0; x < buffer.length; x++)
-                    buffer[x] = 0;
+                buffer[x] = this.audio.samples[x];
-                for (let sim of this.automatic.sims)
-                for (let x = 0; x < buffer.length; x++)
-                    buffer[x] += sim.samples[x] * sim.volume;
-                for (let x = 0; x < buffer.length; x++)
-                    buffer[x] = Math.min(Math.max(-1, buffer[x]), +1);
-            } else {
-                let sim = this.automatic.sims[0];
-                for (let x = 0; x < buffer.length; x++)
-                    buffer[x] = sim.samples[x] * sim.volume;
-            }
             this.audio.postMessage(buffer.buffer, [ buffer.buffer ]);
 
             // Output staged images if there's one audio buffer to go

web/VB.js

@@ -285,6 +285,7 @@ class Sim extends HTMLElement {
     #core;      // Core proxy
     #emulating; // Current emulation status
     #keys;      // Controller state
+    #panning;   // Audio stereo balance
     #peer;      // Communication peer
     #pointer;   // Pointer in core memory
     #volume;    // Audio output volume
@@ -313,9 +314,10 @@ class Sim extends HTMLElement {
         this.#core      = core;
         this.#emulating = false;
         this.#keys      = Constants.VB.SGN;
+        this.#panning   = 0.0;
         this.#peer      = null;
         this.#pointer   = pointer;
-        this.#volume    = 1;
+        this.#volume    = 1.0;
         delete this.proxy;
 
         // Create a <canvas> for the video image
@@ -360,6 +362,7 @@ class Sim extends HTMLElement {
     get anaglyph() { return this.#anaglyph.slice(); }
     get core    () { return this.#core.core       ; }
     get keys    () { return this.#keys            ; }
+    get panning () { return this.#panning         ; }
     get peer    () { return this.#peer            ; }
     get volume  () { return this.#volume          ; }
 
@@ -479,6 +482,27 @@ class Sim extends HTMLElement {
         });
     }
 
+    // Specify audio panning
+    async setPanning(panning) {
+
+        // Error checking
+        if (!Number.isFinite(panning) ||panning < -1 || panning > +1) {
+            throw new RangeError(
+                "Panning must be a number from -1 to +1.");
+        }
+
+        // Configure instance fields
+        this.#panning = panning;
+
+        // Send the panning to the core
+        await this.#core.toCore({
+            command : "setPanning",
+            promised: true,
+            sim     : this.#pointer,
+            panning : panning
+        });
+    }
+
     // Specify a new communication peer
     async setPeer(peer = null) {
 

web/wasm.c

@@ -12,9 +12,14 @@
 #define BREAK_FRAME 1
 #define BREAK_POINT 2
 
-// Extra properties
+// Anaglyph colors
-#define EXT_PIXELS  0
+#define STEREO_CYAN    0x00C6F0
-#define EXT_SAMPLES 1
+#define STEREO_GREEN   0x00B400
+#define STEREO_MAGENTA 0xC800FF
+#define STEREO_RED     0xFF0000
+
+// Element counts
+#define NUM_SAMPLES (41700 / 50 * 2)
 
 
 
@@ -24,9 +29,11 @@
 typedef struct {
     int32_t  breaks;
     uint32_t left[256];
+    float    panning;
     uint8_t  pixels[384 * 224 * 4];
     uint32_t right[256];
-    float    samples[41700 * 2];
+    float    samples[NUM_SAMPLES];
+    float    volume;
 } Ext;
 
 
@@ -43,6 +50,36 @@ int wasmOnFrame(VB *sim) {
 
 /////////////////////////////// Module Exports ////////////////////////////////
 
+// Specify anaglyph colors
+EMSCRIPTEN_KEEPALIVE void SetAnaglyph(VB *sim, uint32_t left, uint32_t right) {
+    Ext *ext = (Ext *) vbGetUserData(sim);
+
+    // Erase all RGB values
+    for (int x = 0; x < 256; x++)
+        ext->left[x] = ext->right[x] = 0xFF000000;
+
+    // Process all RGB channels
+    for (int c = 0, shift = 16; c < 3; c++, shift -= 8) {
+        double    max;  // Magnitude of channel value
+        uint32_t *dest; // Lookup data
+
+        // Select the magnitude and lookup channel
+        dest = ext->left;
+        max  = (left >> shift & 0xFF) / 255.0;
+        if (max == 0) {
+            dest = ext->right;
+            max  = (right >> shift & 0xFF) / 255.0;
+            if (max == 0)
+                continue;
+        }
+
+        // Compute the resulting RGB values
+        for (int x = 0; x < 256; x++)
+            *dest++ |= (uint32_t) (x * max + 0.5) << (16 - shift);
+    }
+
+}
+
 // Instantiate a simulation
 EMSCRIPTEN_KEEPALIVE void* CreateSim() {
     size_t   sizeOfSim = vbSizeOf();
@@ -56,7 +93,10 @@ EMSCRIPTEN_KEEPALIVE void* CreateSim() {
     // Configure extra
     Ext *ext = (Ext *) (pointer + sizeOfSim);
     ext->breaks  = 0;
+    ext->panning = 0.0f;
+    ext->volume  = 1.0f;
     vbSetUserData(sim, ext);
+    SetAnaglyph(sim, STEREO_RED, STEREO_CYAN);
 
     // Initialize pixels with opaque black
     for (unsigned x = 0; x < 384 * 224; x++)
@@ -99,6 +139,16 @@ EMSCRIPTEN_KEEPALIVE int Emulate(VB **sims, unsigned count, uint32_t *clocks) {
     return vbEmulateEx(sims, count, clocks);
 }
 
+// Retrieve a sim's pixel pointer
+EMSCRIPTEN_KEEPALIVE void* GetExtPixels(VB *sim) {
+    return ((Ext *) vbGetUserData(sim))->pixels;
+}
+
+// Retrieve a sim's sample pointer
+EMSCRIPTEN_KEEPALIVE void* GetExtSamples(VB *sim) {
+    return ((Ext *) vbGetUserData(sim))->samples;
+}
+
 // Retrieve the break condition flags for a sim
 EMSCRIPTEN_KEEPALIVE int32_t GetBreaks(VB *sim) {
     return ((Ext *) vbGetUserData(sim))->breaks;
@@ -127,16 +177,6 @@ EMSCRIPTEN_KEEPALIVE void GetDasm(uint32_t *buffer, void *dasm, int count) {
     }
 }
 
-// Retrieve an extra property
-EMSCRIPTEN_KEEPALIVE void* GetExt(VB *sim, int id) {
-    Ext *ext = (Ext *) vbGetUserData(sim);
-    switch (id) {
-        case EXT_PIXELS : return ext->pixels;
-        case EXT_SAMPLES: return ext->samples;
-    }
-    return NULL;
-}
-
 // Retrieve anaglyph-tinted pixels from a sim
 EMSCRIPTEN_KEEPALIVE void GetPixels(VB *sim) {
     Ext     *ext    = (Ext *) vbGetUserData(sim);
@@ -146,6 +186,71 @@ EMSCRIPTEN_KEEPALIVE void GetPixels(VB *sim) {
         *(uint32_t *) pixels = ext->left[pixels[0]] | ext->right[pixels[1]];
 }
 
+// Mix audio samples for output
+EMSCRIPTEN_KEEPALIVE void Mix(float *buffer, VB **sims, int count) {
+
+    // Process all sims
+    for (int x = 0; x < count; x++) {
+        Ext   *ext     = (Ext *) vbGetUserData(sims[x]);
+        float *samples = ext->samples;
+        float  v       = ext->volume;
+
+        // First sim initializes buffer
+        if (x == 0) {
+            if (ext->panning < 0) {
+                float l = -ext->panning * v;
+                float r = (1.0f + ext->panning) * v;
+                for (unsigned y = 0; y < NUM_SAMPLES; y += 2) {
+                    buffer[y    ] = samples[y] * v + samples[y + 1] * l;
+                    buffer[y + 1] = samples[y + 1] * r;
+                }
+            } else if (ext->panning > 0) {
+                float r = ext->panning * v;
+                float l = (1.0f - ext->panning) * v;
+                for (unsigned y = 0; y < NUM_SAMPLES; y += 2) {
+                    buffer[y    ] = samples[y] * l;
+                    buffer[y + 1] = samples[y + 1] * v + samples[y] * r;
+                }
+            } else {
+                for (unsigned y = 0; y < NUM_SAMPLES; y++)
+                    buffer[y] = samples[y] * v;
+            }
+        }
+
+        // Subsequent sims add to buffer
+        else {
+            if (ext->panning < 0) {
+                float l = -ext->panning * v;
+                float r = (1.0f + ext->panning) * v;
+                for (unsigned y = 0; y < NUM_SAMPLES; y += 2) {
+                    buffer[y    ] += samples[y] * v + samples[y + 1] * l;
+                    buffer[y + 1] += samples[y + 1] * r;
+                }
+            } else if (ext->panning > 0) {
+                float r = ext->panning * v;
+                float l = (1.0f - ext->panning) * v;
+                for (unsigned y = 0; y < NUM_SAMPLES; y += 2) {
+                    buffer[y    ] += samples[y] * l;
+                    buffer[y + 1] += samples[y + 1] * v + samples[y] * r;
+                }
+            } else {
+                for (unsigned y = 0; y < NUM_SAMPLES; y++)
+                    buffer[y] += samples[y] * v;
+            }
+        }
+
+    }
+
+    // Clipping
+    for (unsigned y = 0; y < NUM_SAMPLES; y++) {
+        if (buffer[y] < -1.0f)
+            buffer[y] = -1.0f;
+        else if (buffer[y] > +1.0f)
+            buffer[y] = +1.0f;
+    }
+
+}
+
 // Determine the size in bytes of a pointer
 EMSCRIPTEN_KEEPALIVE int PointerSize() {
     return sizeof (void *);
@@ -156,32 +261,12 @@ EMSCRIPTEN_KEEPALIVE void* Realloc(void *data, size_t size) {
     return realloc(data, size);
 }
 
-// Specify anaglyph colors
+// Specify audio panning
-EMSCRIPTEN_KEEPALIVE void SetAnaglyph(VB *sim, uint32_t left, uint32_t right) {
+EMSCRIPTEN_KEEPALIVE void SetPanning(VB *sim, float panning) {
-    Ext *ext = (Ext *) vbGetUserData(sim);
+    ((Ext *) vbGetUserData(sim))->panning = panning;
-
-    // Erase all RGB values
-    for (int x = 0; x < 256; x++)
-        ext->left[x] = ext->right[x] = 0xFF000000;
-
-    // Process all RGB channels
-    for (int c = 0, shift = 16; c < 3; c++, shift -= 8) {
-        double    max;  // Magnitude of channel value
-        uint32_t *dest; // Lookup data
-
-        // Select the magnitude and lookup channel
-        dest = ext->left;
-        max  = (left >> shift & 0xFF) / 255.0;
-        if (max == 0) {
-            dest = ext->right;
-            max  = (right >> shift & 0xFF) / 255.0;
-            if (max == 0)
-                continue;
-        }
-
-        // Compute the resulting RGB values
-        for (int x = 0; x < 256; x++)
-            *dest++ |= (uint32_t) (x * max + 0.5) << (16 - shift);
 }
 
+// Specify audio volume
+EMSCRIPTEN_KEEPALIVE void SetVolume(VB *sim, float volume) {
+    ((Ext *) vbGetUserData(sim))->volume = volume;
 }