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Dylan
01-31-2007, 10:43 PM
What does this warning mean?

VERTEX INFO:

warning: no vertex attribute is explicitly assigned to vertex attribute zero

sqrt[-1]
01-31-2007, 10:57 PM
Vetex attribute zero is special, so you always have to have it active with an attribute when using shaders. (more for legacy reasons)

Hampel
01-31-2007, 11:57 PM
Have a look at this thread (http://www.opengl.org/discussion_boards/ubb/ultimatebb.php?ubb=get_topic;f=11;t=001319) .

Dylan
02-01-2007, 05:30 AM
I'm sorry but I do still not understand what I have to do to get rid of that warning...

al I am doing is draw a bunch of vertices and manipulate their position using a texture fetch

Flavious
02-01-2007, 07:06 AM
Have you tried explicitly assigning an attribute to vertex attribute 0? That seems to be what everyone is suggesting.

Hope it helps...

Cheers

Dylan
02-01-2007, 10:37 AM
ok, I was a bit confused by the terms used. I understand now, something like
a = gl_Vertex.x;does the trick.

sqrt[-1]
02-01-2007, 07:07 PM
Uh, That may fix is as you are now requiring the shader to read from the vertex position, but it may be a bit hacky. (Ie may break in future)

I assume you pass some vertex attributes to the shader? Just make sure one of them is using attribute 0.

Also, post your vertex shader and set up code and we may be able to point out the mistake.

Dylan
02-01-2007, 10:29 PM
ok my very simple vertex shader looks as follows:

uniform sampler2D texUnit;

void main()
{
vec2 texCoord = vec2(gl_MultiTexCoord0);
vec4 c = texture2D(texUnit, texCoord);
gl_Position = gl_ModelViewProjectionMatrix * c;
}I have put a number of vertex positions into a texture and have sent it to GPU memory. Then I use drawarrays using a vertexpointer and a texcoordpointer. The vertices are displayed correctly on screen.

sqrt[-1]
02-01-2007, 10:56 PM
Arr, ok I see now.

If you wanted to fix this, you would have to replace gl_MultiTexCoord0 with a vertex attribute and set the attribute number to zero.