I developped a small XNA games in 3D. I would like to add a "fog of war" on my models instantiated with an effect in my (.fx) file. The problem is, I do not know how to change the function "PixelShaderFunction".

File [.fx]

Here is the declaration of my variables in my effect file (.fx):

// InstancedModel.fx
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.

// Camera settings.
float4x4 World;
float4x4 View;
float4x4 Projection;

//Fog settings
float FogNear;
float FogFar;
float4 FogColor;

And my function "PixelShaderFunction" in my effect file (.fx):

// Both techniques share this same pixel shader.
float4 PixelShaderFunction(VertexShaderOutput input) : COLOR0
    return tex2D(Sampler, input.TextureCoordinate) * input.Color;
  • \$\begingroup\$ What do you mean "fog of war"? Is it about putting fog where there are no units in a strategy game? or about 3D fog where things get fainter as they get farther from the point of view? \$\endgroup\$ Mar 14, 2013 at 13:25
  • \$\begingroup\$ i think about the 3D fog where things get fainter as they get farther from the point of view \$\endgroup\$ Mar 14, 2013 at 13:52
  • \$\begingroup\$ You made the exact same question, and you even accepted it. If you got your question solved, why did you make a new one? gamedev.stackexchange.com/questions/50905 \$\endgroup\$ Mar 14, 2013 at 13:58
  • \$\begingroup\$ Because the old answer was correct! I asked how to apply a fog of war! Now I wonder how to create a function in my file PixelToShader. fx \$\endgroup\$ Mar 14, 2013 at 14:08
  • \$\begingroup\$ And anyway I can not delete because someone called attention to a moderator ...super \$\endgroup\$ Mar 14, 2013 at 14:10

1 Answer 1


You could take a look in XNA's BasicEffect shader source and see how they have implemented Fog support there.

The source code is available here.

  • \$\begingroup\$ Yes I know it is much easier to integrate a fog with class "BasicEffect". However, for other special reasons, I have to use the class "Effect" with a file. "Fx". Because I use an importer of special model for the technique "Model Instancing".And your link does not work for info ... ^ ^ \$\endgroup\$ Mar 14, 2013 at 12:58
  • \$\begingroup\$ I understand that there might be numerous reasons to use your own custom shader instead of BasicEffect. The link I provided contains a downloadable zip which contains all XNA stock effect files in their raw HLSL format. I suggested that it might be a good starting point to look how they have implemented Fog effect. I cannot help other than that as I am not that familiar with Fog effect principles myself. \$\endgroup\$ Mar 14, 2013 at 13:21
  • \$\begingroup\$ Ok thank you. It's already help me a lot. However I do not see where is your link .. The link mentioned above does not work. (dead link?) \$\endgroup\$ Mar 14, 2013 at 13:55
  • \$\begingroup\$ I wonder why the link didn't work ... anyway, I have changed it so it points to direct download link of the sample (hope it isn't against the rules). Let me know if there are still problems. \$\endgroup\$ Mar 14, 2013 at 14:02
  • \$\begingroup\$ Super. Thank you very much! Everything works perfectly now. Vai I take a look at these data. And I come back to keep you informed ;-). \$\endgroup\$ Mar 14, 2013 at 14:04

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