NV40 and vertex textures

How do I set these up? From reading the NVIDIA GPU Programming Guide the only texture formats able to be used are R32F and A32FB32FG32FR32F, which I presume correspond to FLOAT_R_NV and FLOAT_RGBA_NV (or FLOAT_R32_NV and FLOAT_RGBA32_NV maybe?) respectively in OpenGL. The NV_float_buffer extension says “… FLOAT_R_NV, FLOAT_RG_NV, FLOAT_RGB_NV, and FLOAT_RGBA_NV are known as floating-point textures. Floating-point textures are only supported for the TEXTURE_RECTANGLE_NV target.” So I need to do e.g.

glTexImage2D(GL_TEXTURE_RECTANGLE_NV, 0, GL_FLOAT_RGBA_NV, 2, 2, 0, GL_RGBA, GL_FLOAT, (const GLvoid *)pNodeTex);

to create my texture (plus the other standard texture setup code)? Then I should be able to access it in my vertex shader? At the moment I’ve got something like

	uniform sampler2D tex;

	void main()
		vec4 disp = texture2D(tex, gl_Vertex.xy);
		gl_Position = ftransform();

where I’m using the vertex position to index the texture. This is just a do-nothing line at the moment to get texture access working. My info log gives me:

‘error C1115: unable to find compatible overloaded function “tex2D”’
‘error C1016: expression type incompatible with function return type’

Am I doing something obviously wrong that would cause this to happen? Forgetting to set anything up? I am providing the texture to the shader correctly AFAIK. E.g. I can take the same line and put it in the fragment shader and all works fine (with a plain TEXTURE_2D format - this is my first time messing with float textures). My texture at this stage is a simple 2x2 GLfloat texture that I just wanted to use to displace a quad’s vertices to get a feeling for vertex textures. Do I have to have a particular floating point color buffer to get this to work maybe? The NVSDK simple vertex texture demo doesn’t AFAIK. It uses GLUT_RGB. I’m using NeHe base code.

I’m embarrassed to say I’m using 65.62 drivers that have appeared on the net in the last couple of days, and I was under the impression that 65 series would support vertex textures in GLSL. Card is a 6800GT.

Thanks in advance.

It’s a GLSL compiler error. This mean it is not yet supported.
IMHO, we have to wait for official Cg 1.3 with SM3.0 support. Next nv step will be GLSL SM3.0 support.

About 65.xx drivers… NVidia says that GLSL SM3.0 features will be in Forceware Release 65. Right now, there is no any 65.xx drivers on nv dev page. Your drivers might be fake!


I sort of gathered it was due to no driver support. You’re probably right about the drivers being dodgy. I’m just fairly desperate for vertex textures so I was happy to see these “65” drivers. Sigh I guess I’ll keep waiting.

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