openGL draws it but DirectX not

jAyTeA · Post by **jAyTeA** » Thu Dec 07, 2006 8:27 pm

Hi,

i have a very basic custom scenenode, that draws a rectangle in front of the camera with some basic calculations. I use it to make a fast and basic bloom-effect (I have found the idea in this forum, but it just worked with FPS-cameras).

My problem is, that directX don't draws this rectangle, if the camerarotation is between two particular angles. When i render with openGL the rectangle is drawn always.
Here are 2 pictures of it:
first the one with the bloom:

and then the one without:

I hope you see the difference.

and some code of the scenenode:

Code: Select all

CQuadSceneNode::CQuadSceneNode(scene::ISceneNode* parent,scene::ISceneManager* mgr,s32 id): scene::ISceneNode(parent, mgr, id)
{
	Material.DiffuseColor = video::SColor(200,200,200,200);
	Material.EmissiveColor = video::SColor(200,200,200,200);
	Material.SpecularColor = video::SColor(200,200,200,200);
	Material.ZBuffer = false;
	Material.Wireframe = false;
	Material.PointCloud = false;
	Material.Lighting = false;
	Material.BackfaceCulling = false;
	Material.FogEnable = false;
	Material.GouraudShading = false;
	Material.NormalizeNormals = true;
	Material.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;

	irr::video::E_DRIVER_TYPE dr = mgr->getVideoDriver()->getDriverType();

	if (dr != video::EDT_OPENGL)
	{
		video::SColor Color = video::SColor(4,40,40,40);
		VertexQuad[0]=video::S3DVertex(-1,1,1,0,0,0,Color,0,0);
		VertexQuad[1]=video::S3DVertex(1,1,1,0,0,0,Color,1,0);
		VertexQuad[2]=video::S3DVertex(-1,-1,1,0,0,0,Color,0,1);
		VertexQuad[3]=video::S3DVertex(1,-1,1,0,0,0,Color,1,1);
	}
	else
	{
		video::SColor Color = video::SColor(4,34,34,34);
		VertexQuad[0]=video::S3DVertex(-1,1,0,0,0,0,Color,0,0);
		VertexQuad[1]=video::S3DVertex(1,1,0,0,0,0,Color,1,0);
		VertexQuad[2]=video::S3DVertex(-1,-1,0,0,0,0,Color,0,-1);
		VertexQuad[3]=video::S3DVertex(1,-1,0,0,0,0,Color,1,-1);
	}

	Box.reset(VertexQuad[0].Pos);

	for (s32 i=1; i<4; ++i)
	{
		Box.addInternalPoint(VertexQuad[i].Pos);
	}
}

void CQuadSceneNode::OnPreRender()
{
	if (IsVisible)
		SceneManager->registerNodeForRendering(this, ESNRP_TRANSPARENT);
	ISceneNode::OnPreRender();
}

void CQuadSceneNode::render()
{
	u16 indices[] = {	0,1,2, 3,2,1	};
	video::IVideoDriver* driver = SceneManager->getVideoDriver();

	vector3df vCamPos = SceneManager->getActiveCamera()->getPosition();
	vector3df vPlayerPos = SceneManager->getActiveCamera()->getTarget();
	vector3df vCamPlayer = (vPlayerPos-vCamPos);

	vector3df vNormal1 = vector3df(0,1,0).crossProduct( vCamPlayer ).normalize();
	vector3df vNormal2 = vNormal1.crossProduct( vCamPlayer ).normalize()*3/4;
	vector3df vTempPoint = vCamPos + (vCamPlayer.normalize())*1.01;

	VertexQuad[0].Pos = vTempPoint - vNormal1 - vNormal2;
	VertexQuad[1].Pos = vTempPoint + vNormal1 - vNormal2;
	VertexQuad[2].Pos = vTempPoint - vNormal1 + vNormal2;
	VertexQuad[3].Pos = vTempPoint + vNormal1 + vNormal2;

	driver->setMaterial(Material);
	driver->drawIndexedTriangleList(&VertexQuad[0], 4, &indices[0], 2);
}

I hope this is enough information.

omar shaaban · Post by **omar shaaban** » Thu Dec 07, 2006 9:17 pm

the 2 pictures for me are the same!!

jAyTeA · Post by **jAyTeA** » Thu Dec 07, 2006 9:45 pm

yes, its really hard to see, but the first one is brighter. you can see that at the sky.
I should try to make it brighter and replace the pictures. But the pictures are just to show, that at one point the rectangle is drawn correct but at another point nearby its not.

EDIT: I have uploaded a new bloom-picture with very exaggerated bloom, so now you should see a difference.

BastetFurry · Post by **BastetFurry** » Fri Dec 08, 2006 12:32 am

Please, mark what you want to show us with paint or something.
To me both pics are the same sans more brightness in the upper one.

goaty · Post by **goaty** » Fri Dec 08, 2006 8:11 am

I've illustrated this before with OpenGL rendering working, but not DirectX. I found it with using billboard colourisations, as in the OpenGL renderer coloured the billboards on command, but the DirectX didn't perform the same results to the command. See unresolved thread on billboard colourisation.

bgsteffens · Post by **bgsteffens** » Fri Dec 08, 2006 8:48 am

Bastet: The difference -is- the brightness. He's trying to simulate a rendering effect by alpha-blending an image over the entire doublebuffer before flipping it to the screen.

jAyTeA · Post by **jAyTeA** » Fri Dec 08, 2006 1:44 pm

@goaty: yes, i have seen this thread, but my problem is, that directX draws it in most cases but when the camara goes in a specific position behind the box it doesn't render.
The zone where it doesn't draw seems to be a (filled) circle (the camera can fly around the box in a specific distance).

@bgsteffens: yes, thats exactly what i want to do!

goaty · Post by **goaty** » Fri Dec 08, 2006 2:23 pm

jAyTeA : Ahhhhhh you're right. If I view it from the opposite direction using ths FPS camera, they are coloured as you would expect. So it must be the drawing direction of the create billboard node. How can the node be flipped the other way then?

jAyTeA · Post by **jAyTeA** » Fri Dec 08, 2006 4:30 pm

just deaktivate BackfaceCulling in the billboards material.

But i don't use billboards so there must be a problem with the renderer.

goaty · Post by **goaty** » Sat Dec 09, 2006 6:35 pm

And how is that done?

vitek · Post by **vitek** » Sat Dec 09, 2006 6:58 pm

At the very least you should probably be setting the world transformation matrix. If you are actually going to do a post processing effect [via render-to-texture], I don't think you want this thing to be a scene node in the graph, otherwise you need to hide when rendering the scene, and then you would manually render it later.

Travis

jAyTeA · Post by **jAyTeA** » Sat Dec 09, 2006 11:26 pm

@goaty: just call pSceneNode->getMaterial(0).BackfaceCulling = false;

@vitek: I don't know what you exactly mean. When should I set the transformation matrix? This scenenode is drawn after all other things.
Please explain what you would do.

goaty · Post by **goaty** » Mon Dec 11, 2006 11:54 am

thankz for the response, but I tried that and it still didnt work. But as I said previously, it still works on the reverse?!?!??!?

vitek · Post by **vitek** » Mon Dec 11, 2006 4:28 pm

When should I set the transformation matrix? This scenenode is drawn after all other things.

You should set the transformation matrices before you call drawIndexedTriangleList().

You can simplify your code a bit by setting the world, view and projection matrices to identity and just rendering a quad from (-1,-1) to (1,1). You still have to disable lighting, but that should simplify your render logic a bit.

Travis

jAyTeA · Post by **jAyTeA** » Mon Dec 11, 2006 5:23 pm

@goaty: hmm, then i really don't know. sorry!

@vitek: Thanks very much!! with the identitymatrices it looks much better!

But the problem with directX not drawing it correct is still there. This is really strange. I don't have any idea, where the problem could be. There must be a problem in the directX-piece of the engine. It works fine with openGL, but directX 9 and 8.1 have this problem.