Sync audio listener with headset;

src/audio/audio.c

@@ -2,11 +2,18 @@
 #include "loaders/source.h"
 #include "util.h"
 #include <stdlib.h>
+#include <math.h>
 
 static AudioState state;
 
 static LPALCRESETDEVICESOFT alcResetDeviceSOFT;
 
+static void cross(float ux, float uy, float uz, float vx, float vy, float vz, float* x, float* y, float* z) {
+  *x = uy * vz - uz * vy;
+  *y = ux * vz - uz * vx;
+  *z = ux * vy - uy * vx;
+}
+
 void lovrAudioInit() {
   ALCdevice* device = alcOpenDevice(NULL);
   if (!device) {
@@ -65,15 +72,23 @@ void lovrAudioAdd(Source* source) {
   }
 }
 
-void lovrAudioGetOrientation(float* fx, float* fy, float* fz, float* ux, float* uy, float* uz) {
+void lovrAudioGetOrientation(float* angle, float* ax, float* ay, float* az) {
   float v[6];
   alGetListenerfv(AL_ORIENTATION, v);
-  *fx = v[0];
-  *fy = v[1];
-  *fz = v[2];
-  *ux = v[3];
-  *uy = v[4];
-  *uz = v[5];
+  float cx, cy, cz;
+  cross(v[0], v[1], v[2], v[3], v[4], v[5], &cx, &cy, &cz);
+  float w = 1 + v[0] * v[3] + v[1] * v[4] + v[2] * v[5];
+  *angle = 2 * acos(w);
+  float s = sqrt(1 - w * w);
+  if (w < .001) {
+    *ax = cx;
+    *ay = cy;
+    *az = cz;
+  } else {
+    *ax = cx / s;
+    *ay = cy / s;
+    *az = cz / s;
+  }
 }
 
 void lovrAudioGetPosition(float* x, float* y, float* z) {
@@ -113,7 +128,47 @@ void lovrAudioRewind() {
   }
 }
 
-void lovrAudioSetOrientation(float fx, float fy, float fz, float ux, float uy, float uz) {
+// Help
+void lovrAudioSetOrientation(float angle, float ax, float ay, float az) {
+
+  // Quaternion
+  float cos2 = cos(angle / 2.f);
+  float sin2 = sin(angle / 2.f);
+  float qx = sin2 * ax;
+  float qy = sin2 * ay;
+  float qz = sin2 * az;
+  float s = cos2;
+
+  float vx, vy, vz, qdotv, qdotq, a, b, c, cx, cy, cz;
+
+  // Forward
+  vx = 0;
+  vy = 0;
+  vz = -1;
+  qdotv = qx * vx + qy * vy + qz * vz;
+  qdotq = qx * qx + qy * qy + qz * qz;
+  a = 2 * qdotv;
+  b = s * s - qdotq;
+  c = 2 * s;
+  cross(qx, qy, qz, vx, vy, vz, &cx, &cy, &cz);
+  float fx = a * qx + b * vx + c * cx;
+  float fy = a * qy + b * vy + c * cy;
+  float fz = a * qz + b * vz + c * cz;
+
+  // Up
+  vx = 0;
+  vy = 1;
+  vz = 0;
+  qdotv = qx * vx + qy * vy + qz * vz;
+  qdotq = qx * qx + qy * qy + qz * qz;
+  a = 2 * qdotv;
+  b = s * s - qdotq;
+  c = 2 * s;
+  cross(qx, qy, qz, vx, vy, vz, &cx, &cy, &cz);
+  float ux = a * qx + b * vx + c * cx;
+  float uy = a * qy + b * vy + c * cy;
+  float uz = a * qz + b * vz + c * cz;
+
   ALfloat orientation[6] = { fx, fy, fz, ux, uy, uz };
   alListenerfv(AL_ORIENTATION, orientation);
 }

src/audio/audio.h

@@ -19,14 +19,14 @@ void lovrAudioInit();
 void lovrAudioDestroy();
 void lovrAudioUpdate();
 void lovrAudioAdd(Source* source);
-void lovrAudioGetOrientation(float* fx, float* fy, float* fz, float* ux, float* uy, float* uz);
+void lovrAudioGetOrientation(float* angle, float* ax, float* ay, float* az);
 void lovrAudioGetPosition(float* x, float* y, float* z);
 float lovrAudioGetVolume();
 int lovrAudioHas(Source* source);
 void lovrAudioPause();
 void lovrAudioResume();
 void lovrAudioRewind();
-void lovrAudioSetOrientation(float fx, float fy, float fz, float ux, float uy, float uz);
+void lovrAudioSetOrientation(float angle, float ax, float ay, float az);
 void lovrAudioSetPosition(float x, float y, float z);
 void lovrAudioSetVolume(float volume);
 void lovrAudioStop();

src/lovr.c

@@ -65,7 +65,7 @@ void lovrInit(lua_State* L, int argc, char** argv) {
   luax_preloadmodule(L, "lovr.timer", l_lovrTimerInit);
 
   // Bootstrap
-  char buffer[2048];
+  char buffer[4096];
   snprintf(buffer, sizeof(buffer), "%s",
     "local conf = { "
     "  modules = { "
@@ -122,7 +122,13 @@ void lovrInit(lua_State* L, int argc, char** argv) {
     "      lovr.handlers[name](a, b, c, d) "
     "    end "
     "    local dt = lovr.timer.step() "
-    "    if lovr.audio then lovr.audio.update(dt) end "
+    "    if lovr.audio then "
+    "      lovr.audio.update() "
+    "      if lovr.headset and lovr.headset.isPresent() then "
+    "        lovr.audio.setPosition(lovr.headset.getPosition()) "
+    "        lovr.audio.setOrientation(lovr.headset.getOrientation()) "
+    "      end "
+    "    end "
     "    if lovr.update then lovr.update(dt) end "
     "    lovr.graphics.clear() "
     "    lovr.graphics.origin() "

src/lovr/audio.c

@@ -40,15 +40,13 @@ int l_lovrAudioUpdate(lua_State* L) {
 }
 
 int l_lovrAudioGetOrientation(lua_State* L) {
-  float fx, fy, fz, ux, uy, uz;
-  lovrAudioGetOrientation(&fx, &fy, &fz, &ux, &uy, &uz);
-  lua_pushnumber(L, fx);
-  lua_pushnumber(L, fy);
-  lua_pushnumber(L, fz);
-  lua_pushnumber(L, ux);
-  lua_pushnumber(L, uy);
-  lua_pushnumber(L, uz);
-  return 6;
+  float angle, ax, ay, az;
+  lovrAudioGetOrientation(&angle, &ax, &ay, &az);
+  lua_pushnumber(L, angle);
+  lua_pushnumber(L, ax);
+  lua_pushnumber(L, ay);
+  lua_pushnumber(L, az);
+  return 4;
 }
 
 int l_lovrAudioGetPosition(lua_State* L) {
@@ -98,13 +96,11 @@ int l_lovrAudioRewind(lua_State* L) {
 }
 
 int l_lovrAudioSetOrientation(lua_State* L) {
-  float fx = luaL_checknumber(L, 1);
-  float fy = luaL_checknumber(L, 2);
-  float fz = luaL_checknumber(L, 3);
-  float ux = luaL_checknumber(L, 4);
-  float uy = luaL_checknumber(L, 5);
-  float uz = luaL_checknumber(L, 6);
-  lovrAudioSetOrientation(fx, fy, fz, ux, uy, uz);
+  float angle = luaL_checknumber(L, 1);
+  float ax = luaL_checknumber(L, 2);
+  float ay = luaL_checknumber(L, 3);
+  float az = luaL_checknumber(L, 4);
+  lovrAudioSetOrientation(angle, ax, ay, az);
   return 0;
 }