I'm trying to make a multi-sample scene a texture, here is the code I'm using. I get a black screen. I check the completeness of fbo at the end of init, and they report that both fbo are complete.
void init_rendered_FBO() { glGenFramebuffers(1,&fbo); glBindFramebuffer(GL_FRAMEBUFFER, fbo); glGenTextures(1,&fbo_tex); glBindTexture(GL_TEXTURE_2D, fbo_tex); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); // glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width_screen, height_screen, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, width_screen, height_screen); glBindTexture (GL_TEXTURE_2D, 0); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, fbo_tex, 0); int objectType; glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE,&objectType); ASSERT(objectType == GL_TEXTURE); int objectName; glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME,&objectName); ASSERT(glIsTexture(objectName) == GL_TRUE); int wid, hei, fmt; glBindTexture(GL_TEXTURE_2D, objectName); glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &wid); glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &hei); glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_INTERNAL_FORMAT, &fmt); glBindTexture(GL_TEXTURE_2D, 0); std::string format = convertInternalFormatToString(fmt); std::cout << "Color attachment 0: " << objectName << " " << wid << "x" << hei << ", " << format << std::endl; ASSERT(checkFramebufferStatus()); glBindFramebuffer(GL_FRAMEBUFFER, 0); } // this is the init function that gets called. void init_rendered_multisample_FBO() { init_rendered_FBO(); // now I'm going to set up the additional component necessary to perform multisampling which is a new fbo // that has a multisampled color buffer attached. I won't need a multisample depth buffer. glGenFramebuffers(1,&multi_fbo); glBindFramebuffer(GL_FRAMEBUFFER,multi_fbo); glGenRenderbuffers(1,&renderbuffer_multi); glBindRenderbuffer(GL_RENDERBUFFER,renderbuffer_multi); glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_RGBA, width_screen,height_screen); glBindRenderbuffer(GL_RENDERBUFFER,0); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer_multi); int objectType; glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE,&objectType); ASSERT(objectType == GL_RENDERBUFFER); int objectName; glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME,&objectName); ASSERT(glIsRenderbuffer(objectName) == GL_TRUE); glBindRenderbuffer(GL_RENDERBUFFER,objectName); int wid,hei,fmt,sam; glGetRenderbufferParameteriv(GL_RENDERBUFFER,GL_RENDERBUFFER_WIDTH,&wid); glGetRenderbufferParameteriv(GL_RENDERBUFFER,GL_RENDERBUFFER_HEIGHT,&hei); glGetRenderbufferParameteriv(GL_RENDERBUFFER,GL_RENDERBUFFER_INTERNAL_FORMAT,&fmt); glGetRenderbufferParameteriv(GL_RENDERBUFFER,GL_RENDERBUFFER_SAMPLES,&sam); glBindRenderbuffer(GL_RENDERBUFFER,0); printf("Renderbuffer: %dx%d, fmt=%d, samples=%d\n",wid,hei,fmt,sam); ASSERT(checkFramebufferStatus()); glBindFramebuffer(GL_FRAMEBUFFER, 0); } // this is called after rendering to multi_fbo void resolve_multisample_FBO() { glBindFramebuffer(GL_READ_FRAMEBUFFER, multi_fbo); glReadBuffer(GL_COLOR_ATTACHMENT0); glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo); GLenum drawbuf = GL_COLOR_ATTACHMENT0; glDrawBuffers(1,&drawbuf); glBlitFramebuffer(0,0,width_screen,height_screen,0,0,width_screen,height_screen,GL_COLOR_BUFFER_BIT,GL_NEAREST); }
Can you notice everything that I forgot? I think the problem might be with calling glFramebufferRenderbuffer . I tried switching the first arg to GL_READ_FRAMEBUFFER , but it did not fix it.
I check glGetError and there are no errors. If I set something up incorrectly, something will probably fail and give me INVALID_ENUM or INVALID_OPERATION to help me narrow down the problem.
The way I use this code is that to enable multisampling, all I need to change is to bind multi_fbo when drawing, and then call the resolution function, which will bind and blit. After that, my fbo texture (which works fine when I show directly to it) should now contain a multisample. But it's just black. I also called glEnable(GL_MULTISAMPLE) in another part of the initialization code.
Now I will try to split the texture without multisampling into another texture to make sure that it works. Hope this helps me narrow down where I squinted.
Update: Thus, it turns out that the regular FBO is copied to another identical FBO (both have textures attached to the color 0 attachment), it produces the same black screen. Blyth just doesn't work.
What is also strange is that as soon as I try to flare up, then draw a SOURCE fbo texture, it is still black. It is like an attempt at bliss, it just destroys everything.
Does anyone know or have any FBO bit code? I can’t find anyone, but I know that people got a multi-sample FBO job.
Here you can help: If you have code that calls glBlitFramebuffer at any time, I would like to see other calls to configure this operation. I can't seem to get anything but black buffers and textures when I call it.
Update: Blit to backbuffer works, even with multisampling! This, of course, absolutely does not require installation, since I just bind the framebuffer 0. Therefore, the problem is that the problem is to create an FBO that has a texture binding that needs to be involved.