How to make a gradient on the background color

arfgh · Post by **arfgh** » Fri Apr 18, 2008 11:29 pm

Is possible to produce a background gradient on the scene ?
I don`t know have any idea to do.

Kriolyth · Post by **Kriolyth** » Sat Apr 19, 2008 12:37 am

Draw a full-screen quad with vertex colors you need and lighting disabled. Turn off Z-buffer as well.

arfgh · Post by **arfgh** » Sat Apr 19, 2008 12:04 pm

can someone show some example ?

also, is not possible to create the gradient using only the background color ?

hybrid · Post by **hybrid** » Sat Apr 19, 2008 12:40 pm

Questions is what a gradient with just the background color would be. You know, gradients need at least two colors...
But no, there's no toehr way, and the suggested one is pretty simple.

arfgh · Post by **arfgh** » Sat Apr 19, 2008 1:22 pm

well hybird. Maybe is simple, but if we need to disable the z-buffer this will affect to the quality of the whole scene ?

hybrid · Post by **hybrid** » Sat Apr 19, 2008 2:02 pm

No, because you only disable it for rendering the quad (which is in the background anyway).

arfgh · Post by **arfgh** » Sat Apr 19, 2008 2:26 pm

ok hybrid, but can you show me n example of the use of this procedure ? i am very new at all this

kornwaretm · Post by **kornwaretm** » Mon Apr 21, 2008 5:27 am

make that background on adobe or what ever tools u have. use the

Code: Select all

virtual void irr::video::IVideoDriver::draw2DImage  (  const video::ITexture *  texture,  
  const core::rect< s32 > &  destRect,  
  const core::rect< s32 > &  sourceRect,  
  const core::rect< s32 > *  clipRect = 0,  
  video::SColor *  colors = 0,  
  bool  useAlphaChannelOfTexture = false 
 )  [pure virtual]

put this code before the smgr->drawAll();
ofcourse u cant use skydome or sky box for your scene, otherwise your background will covered.
can you please read the Irrlicht Engine 1.4 API documentation
it is located on \irrlicht-1.4\doc\irrlicht.chm , on your hardDrive.
there's also some (one may be...) example about drawing 2d image included with the engine.

arfgh · Post by **arfgh** » Mon Apr 21, 2008 12:50 pm

we are not talking about to put a texture on screen.
We are talking about to make a plane to show a gradient using the vertex colors.

JP · Post by JP » Mon Apr 21, 2008 1:40 pm

Look at the custom scene node example/tutorial and work from there. It shows you how to do gradient colours and it shows how to construct shapes, you should be able to figure out how to create just a plane instead of the pyramid type shape.

arfgh · Post by **arfgh** » Mon Apr 21, 2008 1:59 pm

yes but the problem is the fact i need this plane be on the background and covering the full irrlicht window.

JP · Post by JP » Mon Apr 21, 2008 2:16 pm

So you've got your plane with the gradient coded and working? If not then get that working first, then you can tackle the problem of making it fill the background.

You could draw it by parenting the node to the camera and making it large enough to fill the view (fairly small and close to the camera should do it). When it's actually rendered you'll want to make sure the z write is disabled, that can be done in the material setting of the custom scene node, check the API for the correct way of doing this.

arfgh · Post by **arfgh** » Mon Apr 21, 2008 6:47 pm

anyways JP what tutorial you mean ?

vitek · Post by **vitek** » Mon Apr 21, 2008 9:31 pm

Holy hell. The custom scene node example is included in the Irrlicht distribution in examples/03.CustomSceneNode/main.cpp. You already have the file on your machine, you just need to look at it.

Travis

JP · Post by JP » Tue Apr 22, 2008 7:50 am

Yeah... there's not much more you can say apart from the custom scene node tutorial.... That's as descriptive as it gets