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Convert float to float4

5ule1m4n Banned Member since: 9/7/2008 From: Sankt Gallen, Switzerland

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Posted - 11/7/2009 7:55:17 AM

Hi,

I'm trying to write the depth on to an offscreen surface, but all I get is white pixels. I tryed to do something like this:

float x;
return float4(floor(x) / 256, frac(x), frac(x), frac(x));

I don't know where I got this from but I found it on my notes, so I guess I must have seen this somewhere.

Could anyone give me a little hint how to do saving of depth in a color surface should be done? Was trolling the internet all day long. Thx a lot.

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Erik Rufelt Member since: 4/17/2002 From: Sweden

Posted - 11/7/2009 8:08:24 AM

Use a surface with a floating point format, and just return the depth from the pixel shader. Or do you actually want to view the depth in some color code?
What is this for?

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5ule1m4n Banned Member since: 9/7/2008 From: Sankt Gallen, Switzerland

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Posted - 11/7/2009 8:28:27 AM

I'm not sure how to do this in FX composer because I want to pass on the buffer to a pixel shader. And I can't give it on to the pixel shader as a depth buffer because I don't have access to the sampler.

DECLARE_QUAD_DEPTH_BUFFER(DepthBuffer, "D24S8")

[...]

float4 PointLightPS(uniform sampler2D norm, uniform sampler2D depth) {...}
PixelShader = compile ps_3_0 PointLightPS(NormalTextureSampler, DepthBuffer);

But on the other hand FX composer gives me an error when I'm trying to create an offscreen surface with a diffrent surface type:

DECLARE_QUAD_TEX(DepthBuffer, DepthBufferSampler, "D24S8")

You are probably right Erik, your appraoch is the right one but I can't get it to work. I only use the depth buffer to recreate the world position in a pixel shader. I do something like this:

1) Render normals, unlit color, and depth to offscreen surfaces.
2) Generate light map from these surfaces and output color.

EDIT: Got it working in XNA but not FX Composer, probably something i do wrong with the SAS stuff...

[Edited by - 5ule1m4n on November 7, 2009 5:28:38 PM]

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