support for multi-pass shader

[Mancuso Raffaele]

is irrlicht able to process multi-pass shader?

[thespecial1]

not yet ;0)

[slavik262]

Render targets are your friends... It is possible.

[sio2]

not yet ;0)

Well, how do you think I implemented this fur multipass shader in Irrlicht, like three years ago?

[ACE247]

Render Targets...

[ent1ty]

Maybe show us some code how is this done?

[slavik262]

Without giving you code (I'm about to leave for somewhere at the moment), basically you render your object to a render target texture. Then you set that texture to the material of a quad (a pair of triangles), and you set your second pass shader to the material type of that quad. If you need additional passes, you just keep rendering to a render target texture and applying it to a quad, then re-rendering.

[ent1ty]

Isn't that how post-effect shaders are done?
What if I'd like to use 2 shaders: one for terrain rendering and another one for lighting? I assume you have to do at least 2 passes, one for every shader. But then, how do you combine the two resulting textures? Do you just take pixel[0,0] from first texture, then the same pixel from second texture and just * them? Or is this blending done in next, third shader pass?

[Lonesome Ducky]

I know with multipass lighting, one method is to render each lighting pass to a texture and then blend all the pass textures with additive blending. Worked like a charm for me.

[Kalango]

The only poblem is that this is slower thandefault multipassing or backbuffer acess.
Here is Sio2's examples:
http://sio2.g0dsoft.com/modules/wmpdown ... .php?cid=1
Some are open sourced, other are not.

[ent1ty]

OK, so I'm trying to do a very simple thing: draw entire scene onto a plane before the camera. But it somehow does not render the plane, or the plane is transparent. The plane is right before the camera, I checked.

Code: Select all

class CRenderer{
private:
  ISceneManager* smgr;
  IVideoDriver* video;
  IGPUProgrammingServices* gpu;

  ISceneNode* plane;
  ITexture* finalRender;

public:
  CRenderer(stringc folderPath, ISceneManager* nsmgr)
  {
    smgr= nsmgr;
    video= smgr->getVideoDriver();
    gpu= video->getGPUProgrammingServices();

    finalRender= video->addRenderTargetTexture(video->getCurrentRenderTargetSize());

    SMaterial* planeMat= new SMaterial;
    planeMat->setTexture(0, finalRender);

    IMesh* planeMesh= smgr->getGeometryCreator()->createPlaneMesh(dimension2d<f32>(1.94,1.94* (3.0/4.0)), dimension2d<u32>(1,1), planeMat, dimension2d<f32>(1,1));
    plane= smgr->addMeshSceneNode(planeMesh, smgr->getActiveCamera());
    plane->setMaterialFlag(EMF_LIGHTING, false);
    plane->setPosition(vector3df(0, 0, 1));
    plane->setRotation(vector3df(-90, 180, 0));
  }

  void render()
  {
    //array<ISceneNode*>nodes;
    //smgr->getSceneNodesFromType(ESNT_ANY, nodes);

    video->beginScene(true, true);


    video->setRenderTarget(finalRender, true, true, SColor(255,100,0,0));
    plane->setVisible(false);
    smgr->drawAll();

    video->setRenderTarget(0, true, true, SColor(255,0,0,100));
    plane->setVisible(true);
    plane->render();
    smgr->getGUIEnvironment()->drawAll();


    video->endScene();
  }

};

[ent1ty]

Could this be caused by 'Unsupported texture format' which is printed out when trying to do finalRender= video->addRenderTargetTexture(video->getCurrentRenderTargetSize());

[sio2]

Render Targets...

NO! I used a mulipass material. I even put it in bold!

NO RENDER TARGETS.

[Kalango]

Also, rtts ou can simulate post processing via software...its slow tho...

[slavik262]

Render Targets...

NO! I used a mulipass material. I even put it in bold!

NO RENDER TARGETS.

Can you explain what you mean by this? How did you go about it?

Also,

Also, rtts ou can simulate post processing via software...its slow tho...

What do you mean by this?