Stereo streaming accepts side-by-side images as input

This is useful for applications like Brayns which render natively in
side-by-side format. Splitting the image into a left and right part
during the tiling process is more optimal and user-friendly than
asking the application to do it and make two send() calls.

apps/SimpleStreamer/main.cpp

@@ -59,6 +59,7 @@ bool deflectInteraction = false;
 bool deflectCompressImage = true;
 bool deflectStereoStreamLeft = false;
 bool deflectStereoStreamRight = false;
+bool deflectStereoSideBySide = false;
 unsigned int deflectCompressionQuality = 75;
 std::string deflectHost;
 std::string deflectStreamId = "SimpleStreamer";
@@ -115,6 +116,8 @@ void syntax(const int exitStatus)
  std::cout << " -r enable stereo streaming, right image "
  "only (default: OFF)"
  << std::endl;
+ std::cout << " -2 enable side-by-side stereo (default: OFF)"
+ << std::endl;
  exit(exitStatus);
 }
 
@@ -152,6 +155,9 @@ void readCommandLineArguments(int argc, char** argv)
  case 'r':
  deflectStereoStreamRight = true;
  break;
+ case '2':
+ deflectStereoSideBySide = true;
+ break;
  case 'h':
  syntax(EXIT_SUCCESS);
  default:
@@ -253,6 +259,28 @@ struct Image
  image.height, 4);
  return image;
  }
+
+ static Image sideBySide(const Image& left, const Image& right)
+ {
+ Image image;
+ image.width = left.width + right.width;
+ image.height = std::max(left.height, right.height);
+ image.data.resize(image.width * image.height * 4);
+ for (uint j = 0; j < left.height; ++j)
+ {
+ const auto lineBegin = left.data.data() + 4 * j * left.width;
+ const auto lineOut = image.data.data() + 4 * j * image.width;
+ std::copy(lineBegin, lineBegin + 4 * left.width, lineOut);
+ }
+ for (uint j = 0; j < right.height; ++j)
+ {
+ const auto lineBegin = right.data.data() + 4 * j * right.width;
+ const auto lineOut =
+ image.data.data() + 4 * j * image.width + 4 * left.width;
+ std::copy(lineBegin, lineBegin + 4 * right.width, lineOut);
+ }
+ return image;
+ }
 };
 
 bool send(const Image& image, const deflect::View view)
@@ -274,6 +302,27 @@ bool timeout(const float sec)
  return std::chrono::duration<float>{clock::now() - start}.count() > sec;
 }
 
+void drawLeft()
+{
+ glClearColor(0.7, 0.3, 0.3, 1.0);
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ glutSolidTeapot(1.f);
+}
+
+void drawRight()
+{
+ glClearColor(0.3, 0.7, 0.3, 1.0);
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ glutSolidTeapot(1.f);
+}
+
+void drawMono()
+{
+ glClearColor(0.5, 0.5, 0.5, 1.0);
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ glutSolidTeapot(1.f);
+}
+
 void display()
 {
  static Camera camera;
@@ -282,7 +331,16 @@ void display()
  bool success = false;
  bool waitToStart = false;
  static bool deflectFirstEventReceived = false;
- if (deflectStereoStreamLeft || deflectStereoStreamRight)
+ if (deflectStereoSideBySide)
+ {
+ drawLeft();
+ const auto leftImage = Image::readGlBuffer();
+ drawRight();
+ const auto rightImage = Image::readGlBuffer();
+ const auto sideBySideImage = Image::sideBySide(leftImage, rightImage);
+ success = send(sideBySideImage, deflect::View::side_by_side);
+ }
+ else if (deflectStereoStreamLeft || deflectStereoStreamRight)
  {
  // Poor man's attempt to synchronise the start of separate stereo
  // streams (waiting on first event from server or 5 sec. timeout).
@@ -294,27 +352,21 @@ void display()
 
  if (deflectStereoStreamLeft && !waitToStart)
  {
- glClearColor(0.7, 0.3, 0.3, 1.0);
- glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
- glutSolidTeapot(1.f);
+ drawLeft();
  const auto leftImage = Image::readGlBuffer();
  success = send(leftImage, deflect::View::left_eye);
  }
  if (deflectStereoStreamRight && !waitToStart)
  {
- glClearColor(0.3, 0.7, 0.3, 1.0);
- glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
- glutSolidTeapot(1.f);
+ drawRight();
  const auto rightImage = Image::readGlBuffer();
  success = (!deflectStereoStreamLeft || success) &&
  send(rightImage, deflect::View::right_eye);
  }
  }
  else
  {
- glClearColor(0.5, 0.5, 0.5, 1.0);
- glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
- glutSolidTeapot(1.f);
+ drawMono();
  success = send(Image::readGlBuffer(), deflect::View::mono);
  }