[osg-users] EXTERNAL: Re: EXTERNAL: Re: EXTERNAL: Re: EXTERNAL: Re: Help on multitexturing..

Rowley, Marlin R marlin.r.rowley at lmco.com
Thu Apr 19 15:16:09 PDT 2018


Robert,

This problem has been solved.

Answer:


  1.  Passing strings to set a uniform name will NOT automatically convert numbers to strings (i.e. getOrCreateUniform(“some_string” + 4, … ) will not work.  It must be converted first. (i.e. getOrCreateUniform(“some_string” + std::to_string(4), … )
  2.  You can NOT index an array when setting a uniform’s value (i.e. uniform->set(num_array[0])).. It needs to be copied first (i.e. int x = num_array[0]; uniform->set(x);

Hope this helps others who are getting their feet wet with OSG.

Cheers,

-M

----------------------------------------
Marlin Rowley
Software Engineer, Staff
[cid:image002.jpg at 01D39374.DEC5A2E0]
Missiles and Fire Control
972-603-1931 (office)
214-926-0622 (mobile)
marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>

From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Rowley, Marlin R (US)
Sent: Thursday, April 19, 2018 3:54 PM
To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org>
Subject: EXTERNAL: Re: [osg-users] EXTERNAL: Re: EXTERNAL: Re: EXTERNAL: Re: Help on multitexturing..

Robert,

I’ve investigated further and believe I’ve found the problem but not sure how to fix it.

I have a constructor for a layered texture class where I pass it an image as the base layer.  I set the texture mode and create a texture in this constructor for the base class.  I also assign BASE_TEXTURE_UNIT to the sampler2D as an id to bind the texture to it for the shader (thanks for this..).

I run a function called updateShaders() (which I’ve sent snippets of code for) at the bottom of my constructor class.  If I access this base sampler texture in the shader, I get what I expect on the geometry.

Now, when I call a function to create a layer for this layered class (i.e. createLayer(some image, weight, etc..)) from the application, I create a texture from this function and I run the updateShaders() function again binding the BASE_TEXTURE_UNIT + 1 to my second sampler node and trying to bind it to the texture I just created.  THIS is what’s NOT working properly.  When I run GPUPerf debugger, I see that the texture unit is assigned the correct #2, but the BoundID isn’t equal to the unit number.  So when I sample from the texture in the shader, it’s just black because it can’t see this new binding (assume no blending in the shader just an overwrite).

To test this, I reconfigured my constructor to take 2 images instead of 1 image for the base and I forego the call to createLayer() in my application.  Sure enough, the binding is properly set.  Am I missing some kind of callback that should force a rebind when I call updateShaders()?

-M

----------------------------------------
Marlin Rowley
Software Engineer, Staff
[cid:image002.jpg at 01D39374.DEC5A2E0]
Missiles and Fire Control
972-603-1931 (office)
214-926-0622 (mobile)
marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>

From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Rowley, Marlin R (US)
Sent: Thursday, April 19, 2018 3:25 PM
To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org<mailto:osg-users at lists.openscenegraph.org>>
Subject: EXTERNAL: Re: [osg-users] EXTERNAL: Re: EXTERNAL: Re: Help on multitexturing..

Robert,

Changing the sampler_2d to an (int) doesn’t seem to fix the problem.  I still get a black texture in the scene.

Here is my updated code:

mGroupState->getOrCreateUniform("MySecondSampler", osg::Uniform::SAMPLER_2D)->set(BASE_TEXTURE_UNIT + 1);
            mGroupState->setTextureAttributeAndModes(BASE_TEXTURE_UNIT + 1, mSecondColor, osg::StateAttribute::OVERRIDE);

I want to write this second texture to unit 2.  (base_texture_unit = 1 + 1).  I still get a black object.

----------------------------------------
Marlin Rowley
Software Engineer, Staff
[cid:image002.jpg at 01D39374.DEC5A2E0]
Missiles and Fire Control
972-603-1931 (office)
214-926-0622 (mobile)
marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>

From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Rowley, Marlin R (US)
Sent: Thursday, April 19, 2018 2:30 PM
To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org<mailto:osg-users at lists.openscenegraph.org>>
Subject: EXTERNAL: Re: [osg-users] EXTERNAL: Re: Help on multitexturing..

I thought the sampler value was a pointer to a texture?

I set the texture unit to 1 because we’ll need the base texture unit 0 later on.  My goal is to turn on up to 10 texture units and blend them all together.

To be more clear, he is some more code:

mGroupState = mBoundGeometry->getOrCreateStateSet();
      mGroupState->getOrCreateUniform("BaseTexSampler", osg::Uniform::SAMPLER_2D)->set(mBaseColor.get());
      mGroupState->getOrCreateUniform("BaseWeight", osg::Uniform::FLOAT)->set(mBaseWeight);
      mGroupState->setTextureAttributeAndModes(BASE_TEXTURE_UNIT, mBaseColor, osg::StateAttribute::ON);

This sets the base texture unit 1 to be bound to the mBaseColor (which is a osg::ref_ptr<osg::Texture2D>) created before the function call.

Then, I do this right afterwards:

if (mNumLayers)
      {
            int indx = 0;
      osg::ref_ptr<osg::Texture2D> tex = mTextureMap[indx];// iter->second;
            mGroupState->getOrCreateUniform("TexLayerSampler0", osg::Uniform::SAMPLER_2D)->set(tex.get());
            mGroupState->setTextureAttributeAndModes(BASE_TEXTURE_UNIT + 1, tex, osg::StateAttribute::OVERRIDE);
      }

Here I get the texture from a std::map.  And then I set the sampler to be bound to the texture.  I then bind the texture unit 2 to the texture.

-M

----------------------------------------
Marlin Rowley
Software Engineer, Staff
[cid:image002.jpg at 01D39374.DEC5A2E0]
Missiles and Fire Control
972-603-1931 (office)
214-926-0622 (mobile)
marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>

From: osg-users [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of Robert Osfield
Sent: Thursday, April 19, 2018 2:05 PM
To: OpenSceneGraph Users <osg-users at lists.openscenegraph.org<mailto:osg-users at lists.openscenegraph.org>>
Subject: EXTERNAL: Re: [osg-users] Help on multitexturing..

Hi Marlin,
The sampler value should be an int, so you shouldn't pass a texture pointer to your setting of the TexLayerSampler0 second sampler.  Perhaps this was just a copy and paste error.
As a general note, normally one would assign a base texture on texture unit 0 rather than 1.

Robert.


On 19 April 2018 at 19:06, Rowley, Marlin R <marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>> wrote:
Hello,

I’ve been wracking my brain all day on trying to figure out how to do this with no clear examples found online.

I have this set of calls in my C++:

mGroupState = mBoundGeometry->getOrCreateStateSet();
      mGroupState->getOrCreateUniform("BaseTexSampler", osg::Uniform::SAMPLER_2D)->set(mBaseColor);
      mGroupState->getOrCreateUniform("BaseWeight", osg::Uniform::FLOAT)->set(mBaseWeight);
      mGroupState->setTextureAttributeAndModes(BASE_TEXTURE_UNIT, mBaseColor, osg::StateAttribute::ON);

I’ve bound this base texture to texture unit (BASE_TEXTURE_UNIT = 1).

Later in the code, I have this in another function if I create another layer with another texture:


mGroupState->getOrCreateUniform("TexLayerSampler0", osg::Uniform::SAMPLER_2D)->set(tex);

            mGroupState->setTextureAttribute(BASE_TEXTURE_UNIT + 1, tex, osg::StateAttribute::ON);

Where I’ve created a second texture and want it to reside in texture unit 2.

However, in my shader code when indexing the TexLayerSampler0, I only get base texture.

finalColor = texture(TexLayerSampler0, LayeredTexCoords[0].st);

Which is wrong.  I’m stil trying to figure out OpenGL and how it works along with OSG so sorry for the inexperience.

-M

----------------------------------------
Marlin Rowley
Software Engineer, Staff
[cid:image002.jpg at 01D39374.DEC5A2E0]
Missiles and Fire Control
972-603-1931 (office)
214-926-0622 (mobile)
marlin.r.rowley at lmco.com<mailto:marlin.r.rowley at lmco.com>


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