Alpha Problem

[spike314]

Hi all

Ive been trying to setup a alpha mesh using EMT_TRANSPARENT_ADD_COLOR and EMT_TRANSPARENT_VERTEX_ALPHA which looks great from 1 place. but if i move the camera closer to 0,0,0 the alpha channel changes.



if i set my alpha to 0 it still has the same effect but the node goes black.

here is how im setting up the alpha

Code: Select all

        MyAlpha = 0.5;
	int IntAlpha = (int)(MyAlpha*255);
	int swpAlpha = IntAlpha-255;


	int MaterialCount =  node->getMaterialCount();
	for(int i=0; i<MaterialCount; i++)
	{		
		video::SMaterial &mat = node->getMaterial(i);
		mat.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;//video::EMT_TRANSPARENT_ADD_COLOR;
		mat.Lighting = false;
		mat.DiffuseColor.setAlpha(IntAlpha);
		mat.AmbientColor.setAlpha(IntAlpha);
	}

			 Anode = (scene::IAnimatedMeshSceneNode*)node;
			 Amesh = Anode->getMesh();
			for(u32 i=0; i<Amesh->getMeshBufferCount(); i++)
			{
				scene::IMeshBuffer* buffer = Amesh->getMeshBuffer(i);
				video::S3DVertex* vertex = (video::S3DVertex*)buffer->getVertices();
				for(u32 j=0; j<buffer->getVertexCount(); j++)
				{					
					vertex[j].Color = video::SColor(IntAlpha,IntAlpha,IntAlpha,IntAlpha);
				}
			}	

any would be great Thanks

[hybrid]

Better use the MeshManipulator method to set the alpha value. At least it does not change the vertex colors and hence does not corrupt the proper texturing.

[spike314]

Ive just tryed that but still has the same effect.

[Acki]

if i set my alpha to 0 it still has the same effect but the node goes black.

Code: Select all

vertex[j].Color = video::SColor(IntAlpha,IntAlpha,IntAlpha,IntAlpha);

that's because you set the vertex colors to black then !!!
try this:

Code: Select all

vertex[j].Color = video::SColor(IntAlpha,255,255,255);

remember only the 1st parameter is the alpha channel !!!

because of the transparency I'm not sure, but I had a similar problem when I used transparent textures...
after I used makeColorKeyTexture I forgot to recalculate the mipmap levels...
well, you don't use makeColorKeyTexture here, so I'm not sure about that...

EDIT: I just tested your code and the Ninja stays transparent, regardless of the distance to the camera...

[spike314]

So could that be a problem with my camera settings you think?

[Acki]

So could that be a problem with my camera settings you think?

I doubt...
maybe you can make a small, full working example that shows the problem ???
bc with the posted snippet I can't reproduce this...

[spike314]

I did have driver->setAllowZWriteOnTransparent(true); which was making the node black if disabled the node just disapears. it seems to be a Zorder problem bc if i remove the room i can see the node from every side. I am using irrlicht 1.6 but ive made that many changes to it, it will be very hard to convert.

[Acki]

sorry, can't reproduce it, neither with setAllowZWriteOnTransparent(true); nor with Irrlicht 1.6 !!!
and such informations like Irrlicht version and using functions like setAllowZWriteOnTransparent can be very important so you always should mention them...

you realy should make a minimalistic test program, at least for yourself for testing !!!
for testing I used the quake map from the sdk, maybe try this too to see if the error depends on your level mesh...

I am using irrlicht 1.6 but ive made that many changes to it, it will be very hard to convert.

yeah, I know this problem, that's the reason why I created my IrrExtensions so I can make all changes with a few mouse klicks and a little bit of patience while compiling...

[feelthat]

//follow code test good in b3d obj 3ds
//demo here
https://plus.google.com/photos/10618554 ... 8774360364

////////////////////////////////////////////////////////////////
IAnimatedMesh* mesh;
IAnimatedMeshSceneNode* node;
.
.
.
mesh = smgr->getMesh( memfile );
node = smgr->addAnimatedMeshSceneNode( mesh );
node->setMaterialFlag(EMF_LIGHTING, true); // use light is ok~~~
node->setMaterialFlag(EMF_NORMALIZE_NORMALS, true);

u32 MyAlpha = 150; //0~255
u32 MaterialCount = node->getMaterialCount();
for(u32 i=0; i<MaterialCount; i++)
{
video::SMaterial& tex_mat = node->getMaterial(i);
tex_mat.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;
tex_mat.AmbientColor.setAlpha(MyAlpha);
tex_mat.DiffuseColor.setAlpha(MyAlpha);
tex_mat.SpecularColor.setAlpha(MyAlpha);
tex_mat.EmissiveColor.setAlpha(MyAlpha);
}


//this can do or not by ur choice
for(u32 i=0; i<mesh->getMeshBufferCount(); i++)
{
scene::IMeshBuffer* buffer = mesh->getMeshBuffer(i);
video::S3DVertex* vertex = (video::S3DVertex*)buffer->getVertices();
for(u32 j=0; j<buffer->getVertexCount(); j++)
{
vertex[j].Color.setAlpha(MyAlpha);
}
}

So could that be a problem with my camera settings you think?