openFrameworks | ofxImGui fbo + image + texture + clickable

ofApp.cpp

//.h
ofTexture tex;
ofFbo fbo;
void quantizerRefreshImage();

//.cpp

//setup
bool b = ofGetUsingArbTex();
ofDisableArbTex();

ofLoadImage(tex, getImagePath());
fbo.allocate(tex.getWidth(), tex.getHeight());
fbo.createAndAttachTexture(GL_RGB, 0); //Position
fbo.createAndAttachTexture(GL_RGBA32F, 1); //velocity
fbo.createAndAttachRenderbuffer(GL_DEPTH_COMPONENT, GL_DEPTH_ATTACHMENT);
fbo.checkStatus();

fbo.begin();
ofClear(0);
fbo.end();

if (b) ofEnableArbTex();

fbo.begin();//draw once only
ofClear(0, 0, 0, 0);
tex.draw(0, 0);
fbo.end();

//-

//draw image preview

if (tex.isAllocated())
{
  float w = tex.getWidth();
  float h = tex.getHeight();
  float ratio = h / w;

  if (ImGui::ImageButton((ImTextureID)(uintptr_t)fbo.getTexture(0).getTextureData().textureID, ImVec2(_w, _w * ratio)))
  {
    ofLogNotice(__FUNCTION__) << "Image Pressed";
  }
}
ImGui::Text(currentImage_name.get().c_str());

//----

//other examples

// https://forum.openframeworks.cc/t/ofximgui-cant-display-more-than-one-image-in-a-window/36677/4
// https://forum.openframeworks.cc/t/how-to-draw-an-offbo-in-ofximgui-window/33174

//I’ve found it works with this kind of FBO:

ofFbo::Settings fboSettings ;
fboSettings.width = width ;
fboSettings.height = height ;
fboSettings.internalformat = GL_RGBA ;
fboSettings.textureTarget = GL_TEXTURE_2D ;
previewFbo.allocate( fboSettings ) ;

//then

previewFbo.begin() ;
cam->draw( 0.f, 0.f ) ;
previewFbo.end() ;
ImTextureID textureID = ( ImTextureID )( uintptr_t )previewFbo.getTexture().getTextureData().textureID ;
auto size = ImGui::GetContentRegionAvail() ; // for example
ImGui::Image( textureID, size ) ;

--
  
ofFbo::Settings fboSettings ;
fboSettings.width = image1.getWidth() ;
fboSettings.height = image1.getHeight() ;
fboSettings.internalformat = GL_RGBA ;
fboSettings.textureTarget = GL_TEXTURE_2D ;
fbo1.allocate( fboSettings ) ;

ofFbo::Settings fboSettings2;
fboSettings.width = image2.getWidth() ; //Note that I wrote fboSettings instead of fboSettings2, my mistake
fboSettings.height = image2.getHeight() ;
fboSettings.internalformat = GL_RGBA ;
fboSettings.textureTarget = GL_TEXTURE_2D ;
fbo2.allocate(fboSettings2);