Sign in to follow this  

OpenGL rendering into a GL_LUMINANCE fbo

Recommended Posts

Hi, Does anybody know how if it is possible to create a 16 bits (or 8bits) fbo? Using GL_LUMINANCE16 doesn't work. float and integer format works but it doesn't fit my needs. The opengl registry says:
Although an early draft of the FBO specification permitted rendering into alpha, luminance, and intensity formats, this this capability was pulled when it was realized that it was under-specified exactly how rendering into these formats would work. (specifically, how R/G/B/A map to I/L/A) To resolve this we seem to have two options: A. Add new R and RG formats like NV_float_buffer did. B. For the existing one- and two- component formats, define the mapping from RGBA components to ILA components. The superbuffers group has informally decided that option A is preferable.
But I cannot find any "GL_RED16" anywhere :-( Any idea??

Share this post

Link to post
Share on other sites
Well, the paragraph just above the one you quoted says it all:

Presently none of the one- or two- component texture formats
defined in unextended OpenGL is color-renderable. The R
and RG float formats defined by the NV_float_buffer
extension are color-renderable.


Of course, all this is incredibly retarded. It introduces again a dependency on NV specific stuff. The ARB really needs to get their heads pulled out of their asses one of these days. "We can't define the RGB to ILA mappings, OMG OMG" is not an excuse to completely remove a vital feature such as rendering to a one or two component format. It's just pure stupidity. As usual, NV tries to save the day by adding the feature as a vendor dependent extension, but this doesn't really help a lot. IMO, all ARB members should be fired, and the control of the OpenGL standard handed over to Nvidia...

Share this post

Link to post
Share on other sites
I don't understand, both you and the gl spec actually... :-(
As I said, I don't want to use float texture...
So I guess the answer to my question is "no, you cannot do it".

Or maybe there's a strange mixture of type/format/internalformat that could do the trick?

Share this post

Link to post
Share on other sites
Ok, so the conclusion so far is that it is not possible to render into a GL_LUMINANCE8 or GL_LUMINANCE16, which almost looks surrealistic in 2008...

Oh well... Fair enough... Who needs to save bandwith anyway ;-)

Share this post

Link to post
Share on other sites
Original post by purpledog
Ok, so the conclusion so far is that it is not possible to render into a GL_LUMINANCE8 or GL_LUMINANCE16,

Yep, unfortunately that's correct. The only officially supported single or two component formats are GL_FLOAT_R_NV and GL_FLOAT_RG_NV (and derivatives). GL_LUMINANCE might work (and it does on certain NV cards / driver revisions), but that's completely unsupported from the official side (ie. ARB specs). Single/dual component integer texture formats might work (I never tried it, and the specs are unclear about this point).

So either you go floating point, or you waste space with an RGB(A) surface.

Original post by purpledog
which almost looks surrealistic in 2008...

See my rant above. The ARB is a joke.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  • Announcements

  • Forum Statistics

    • Total Topics
    • Total Posts
  • Similar Content

    • By test opty
      Hi all,
      I'm starting OpenGL using a tut on the Web. But at this point I would like to know the primitives needed for creating a window using OpenGL. So on Windows and using MS VS 2017, what is the simplest code required to render a window with the title of "First Rectangle", please?
    • By DejayHextrix
      Hi, New here. 
      I need some help. My fiance and I like to play this mobile game online that goes by real time. Her and I are always working but when we have free time we like to play this game. We don't always got time throughout the day to Queue Buildings, troops, Upgrades....etc.... 
      I was told to look into DLL Injection and OpenGL/DirectX Hooking. Is this true? Is this what I need to learn? 
      How do I read the Android files, or modify the files, or get the in-game tags/variables for the game I want? 
      Any assistance on this would be most appreciated. I been everywhere and seems no one knows or is to lazy to help me out. It would be nice to have assistance for once. I don't know what I need to learn. 
      So links of topics I need to learn within the comment section would be SOOOOO.....Helpful. Anything to just get me started. 
      Dejay Hextrix 
    • By mellinoe
      Hi all,
      First time poster here, although I've been reading posts here for quite a while. This place has been invaluable for learning graphics programming -- thanks for a great resource!
      Right now, I'm working on a graphics abstraction layer for .NET which supports D3D11, Vulkan, and OpenGL at the moment. I have implemented most of my planned features already, and things are working well. Some remaining features that I am planning are Compute Shaders, and some flavor of read-write shader resources. At the moment, my shaders can just get simple read-only access to a uniform (or constant) buffer, a texture, or a sampler. Unfortunately, I'm having a tough time grasping the distinctions between all of the different kinds of read-write resources that are available. In D3D alone, there seem to be 5 or 6 different kinds of resources with similar but different characteristics. On top of that, I get the impression that some of them are more or less "obsoleted" by the newer kinds, and don't have much of a place in modern code. There seem to be a few pivots:
      The data source/destination (buffer or texture) Read-write or read-only Structured or unstructured (?) Ordered vs unordered (?) These are just my observations based on a lot of MSDN and OpenGL doc reading. For my library, I'm not interested in exposing every possibility to the user -- just trying to find a good "middle-ground" that can be represented cleanly across API's which is good enough for common scenarios.
      Can anyone give a sort of "overview" of the different options, and perhaps compare/contrast the concepts between Direct3D, OpenGL, and Vulkan? I'd also be very interested in hearing how other folks have abstracted these concepts in their libraries.
    • By aejt
      I recently started getting into graphics programming (2nd try, first try was many years ago) and I'm working on a 3d rendering engine which I hope to be able to make a 3D game with sooner or later. I have plenty of C++ experience, but not a lot when it comes to graphics, and while it's definitely going much better this time, I'm having trouble figuring out how assets are usually handled by engines.
      I'm not having trouble with handling the GPU resources, but more so with how the resources should be defined and used in the system (materials, models, etc).
      This is my plan now, I've implemented most of it except for the XML parts and factories and those are the ones I'm not sure of at all:
      I have these classes:
      For GPU resources:
      Geometry: holds and manages everything needed to render a geometry: VAO, VBO, EBO. Texture: holds and manages a texture which is loaded into the GPU. Shader: holds and manages a shader which is loaded into the GPU. For assets relying on GPU resources:
      Material: holds a shader resource, multiple texture resources, as well as uniform settings. Mesh: holds a geometry and a material. Model: holds multiple meshes, possibly in a tree structure to more easily support skinning later on? For handling GPU resources:
      ResourceCache<T>: T can be any resource loaded into the GPU. It owns these resources and only hands out handles to them on request (currently string identifiers are used when requesting handles, but all resources are stored in a vector and each handle only contains resource's index in that vector) Resource<T>: The handles given out from ResourceCache. The handles are reference counted and to get the underlying resource you simply deference like with pointers (*handle).  
      And my plan is to define everything into these XML documents to abstract away files:
      Resources.xml for ref-counted GPU resources (geometry, shaders, textures) Resources are assigned names/ids and resource files, and possibly some attributes (what vertex attributes does this geometry have? what vertex attributes does this shader expect? what uniforms does this shader use? and so on) Are reference counted using ResourceCache<T> Assets.xml for assets using the GPU resources (materials, meshes, models) Assets are not reference counted, but they hold handles to ref-counted resources. References the resources defined in Resources.xml by names/ids. The XMLs are loaded into some structure in memory which is then used for loading the resources/assets using factory classes:
      Factory classes for resources:
      For example, a texture factory could contain the texture definitions from the XML containing data about textures in the game, as well as a cache containing all loaded textures. This means it has mappings from each name/id to a file and when asked to load a texture with a name/id, it can look up its path and use a "BinaryLoader" to either load the file and create the resource directly, or asynchronously load the file's data into a queue which then can be read from later to create the resources synchronously in the GL context. These factories only return handles.
      Factory classes for assets:
      Much like for resources, these classes contain the definitions for the assets they can load. For example, with the definition the MaterialFactory will know which shader, textures and possibly uniform a certain material has, and with the help of TextureFactory and ShaderFactory, it can retrieve handles to the resources it needs (Shader + Textures), setup itself from XML data (uniform values), and return a created instance of requested material. These factories return actual instances, not handles (but the instances contain handles).
      Is this a good or commonly used approach? Is this going to bite me in the ass later on? Are there other more preferable approaches? Is this outside of the scope of a 3d renderer and should be on the engine side? I'd love to receive and kind of advice or suggestions!
    • By nedondev
      I 'm learning how to create game by using opengl with c/c++ coding, so here is my fist game. In video description also have game contain in Dropbox. May be I will make it better in future.
  • Popular Now