Bumpmap Shader

[Nemo Krad]

I have been working on a bumpmap shader from a book I got (Programming Vertex & Pixel Shaders by Wolfgan Engel) and got it working lovely with my engine. BUT to night I came on to start the next shader tutorial in the book and now my bumpmap shader is doing some odd stuff (see screen shot below)...

Any one got any ideas what is going on here or has any one had a similar experience and managed to find out what went wrong?

This is the shader:

Code:

float4x4 wvp;
float4x4 world;
float3 LightPosition;
float3 EyePosition;

struct VS_OUTPUT
{
float4 Pos : POSITION;
float2 Tex : TEXCOORD0;
float3 Light : TEXCOORD1;
float3 View : TEXCOORD2;
};

VS_OUTPUT VS(float4 Pos : POSITION,float2 Tex : TEXCOORD,float3 Normal : NORMAL,float3 Tangent : TANGENT)
{
VS_OUTPUT Out = (VS_OUTPUT)0;

Out.Pos = mul(Pos,wvp);

float3x3 worldToTangentSpace;
worldToTangentSpace[0] = mul(Tangent,world);
worldToTangentSpace[1] = mul(cross(Tangent,Normal),world);
worldToTangentSpace[2] = mul(Normal,world);

Out.Tex = Tex;

float4 PosWorld = mul(Pos,world);

Out.Light = mul(worldToTangentSpace,LightPosition);
Out.View = mul(worldToTangentSpace,-EyePosition - PosWorld);

return Out;
}

texture ColorMap;
sampler ColorMapSampler = sampler_state
{
Texture = <ColorMap>;
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};

texture BumpMap;
sampler BumpMapSampler = sampler_state
{
Texture = <BumpMap>;
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};

float4 PS(float2 Tex : TEXCOORD0,float3 Light : TEXCOORD1,float3 View : TEXCOORD2) : COLOR
{
float4 Color = tex2D(ColorMapSampler,Tex);
float3 Normal = (2 * (tex2D(BumpMapSampler,Tex))) - 1.0;

float3 LightDir = normalize(Light);
float3 ViewDir = normalize(View);

float Diffuse = saturate(dot(Normal,LightDir));
float Reflect = normalize(2 * Diffuse * Normal - LightDir);

float Specular = min(pow(saturate(dot(Reflect,ViewDir)),3),Color.w);

return 0.2 * Color + Color * Diffuse + Specular;
}

technique BumpMapShader
{
    pass P0
    {
        Sampler[0] = (ColorMapSampler);
        Sampler[1] = (BumpMapSampler);
   
        VertexShader = compile vs_2_0 VS();
        PixelShader  = compile ps_2_0 PS();
    }
}

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[Nemo Krad]

Now how odd is that?!?!?!?!?!??!?!!?

It's working again now. I have not altered the shader at all, all I have done is play around with the post processor a bit used it then switched it off again......

  WHAT IS GOING ON THERE THEN?!??! 

I know my PC is poop, but this is some strange stuff...

Anyone got any ideas?

[attachment deleted by admin]

[EclipsE]

lol

It's really wierd

[Nemo Krad]

Well it is starting to do my head in now! It has gone screwy again after I played with the old PP code, but I have put the code back as it was and now the thing is rendering it dead odd.....

The attached is the globe from the other side, the bumpmapping seems to be working but the lighting has now gone mental!

I have commented out the PP altogether and yet is it till playing up!! It's driving me mad 

[attachment deleted by admin]

[Nemo Krad]

This shader is still not playing ball, I will have another look tomorrow. I got a parallax bump map shader working in the mean time though.  small things pleas small minds I suppose 

[attachment deleted by admin]

[Tiago]

this would be a wild gess but are you shure your object has correct tangents and normals?

[EclipsE]

This shader is still not playing ball, I will have another look tomorrow. I got a parallax bump map shader working in the mean time though.  small things pleas small minds I suppose 

Share it with us 

[Nemo Krad]

Tiago,

I am using the same model that comes with the book that has the example shader in it so I am assuming it' tangents are all OK. If you can think of any other reason why the behavior of this shader should change when neither the shader the model or the assets have not altered I would appreciate it

I think I know why it is playing up now and that is down to the way i is currently calculating the Specular,  I think the next chapter holds the answer....

EclipsE,

The bumpmap shader is already here, but this is the parallax bumpmap.

Code:

float4x4 wvp;
float4x4 world;
float3 LightPosition;
float3 EyePosition;

struct VS_OUTPUT
{
float4 Pos : POSITION;
float2 Tex : TEXCOORD0;
float3 Light : TEXCOORD1;
float3 View : TEXCOORD2;
};

VS_OUTPUT VS(float4 Pos : POSITION,float2 Tex : TEXCOORD,float3 Normal : NORMAL,float3 Tangent : TANGENT)
{
VS_OUTPUT Out = (VS_OUTPUT)0;

Out.Pos = mul(Pos,wvp);

float3x3 worldToTangentSpace;
worldToTangentSpace[0] = mul(Tangent,world);
worldToTangentSpace[1] = mul(cross(Tangent,Normal),world);
worldToTangentSpace[2] = mul(Normal,world);

Out.Tex = Tex;

float4 PosWorld = mul(Pos,world);

Out.Light = mul(worldToTangentSpace,LightPosition);
Out.View = mul(worldToTangentSpace,EyePosition - PosWorld);

return Out;
}

texture ColorMap;
sampler ColorMapSampler = sampler_state
{
Texture = <ColorMap>;
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};

texture BumpMap;
sampler BumpMapSampler = sampler_state
{
Texture = <BumpMap>;
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};

texture HeightMap;
sampler HeightMapSampler = sampler_state
{
Texture = <HeightMap>;
MinFilter = Linear;
MagFilter = Linear;
MipFilter = Linear;
AddressU = Clamp;
AddressV = Clamp;
};

float4 PS(float2 Tex : TEXCOORD0,float3 Light : TEXCOORD1,float3 View : TEXCOORD2) : COLOR
{
const float scale = {0.04f};
const float bias = {0.02};
float3 LightDir = normalize(-Light);
float3 ViewDir = normalize(View);

float Height = scale * tex2D(HeightMapSampler,Tex) - bias;

float2 TexCorrected = Height * ViewDir + Tex;
float4 Color;
float3 Normal;


Color = tex2D(ColorMapSampler,TexCorrected);
Normal = (2 * (tex2D(BumpMapSampler,TexCorrected))) - 1.0;


float Diff = saturate(dot(Normal,LightDir));

return 0.2 * Color + Color * Diff;
}

technique BumpMapShader
{
    pass P0
    {
        Sampler[0] = (ColorMapSampler);
        Sampler[1] = (BumpMapSampler);
   
        VertexShader = compile vs_2_0 VS();
        PixelShader  = compile ps_2_0 PS();
    }
}

In both shaders, please forgive my lack of Semantics and comments, I am writing them then testing them as I go and will tidy them up later. Just thought, I just said I am writing them, I'm not, I am doing the examples from the book and then getting them to fit my engine... How my ego keeps trying to build me up   :

Also, your model needs the UV image of the ColorMap  for some reason, I will alter the shader at a later date so this can be passed to the shader rather than it relying on the model having it loaded.

Mike/Chr0n1x,

I think I should have put this thread in the code section now, any chance you guys can move it?  Unless you think it is OK here...

[Nemo Krad]

OK, this goes from bad to worse...

First run of the code today, no changes made to the code other than adding another shader and model to show it's effect. and my bump mapping is back to square one....

What on earth is going on?

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[Tiago]

the only reason i can think of to explain why it behaves diferently each time without you making any changes is that the shader is being passed data from an uninitialized point in memory.

its something like this, lets say you create an array[4][4] with but you never initialize the array, ussually you would get an error in C#, but its happened to me a lot of times in C++, and what you end up with is an array with so much garbage in it that when you try to read it it makes you think you just got a virus.

anyway, uninitialized memory is my theory. now, on how to fix it? not a clue really but hopefully this will help someone else help you with that

[mikeschuld]

Sounds like you are not setting device states correctly. You will probably have to do that explicitly in each shader to be what they need to be.

[Nemo Krad]

Ahhh, thats possible, I would have thought the book might have mentioned that, maybe it did and I skim read past it wanting to see the blighter working. I will take a look Mike.

Tiago,

I would accept that if the issue occurred on other shaders but it does not. I know exactly what you are talking about though, you don't play around with void **, malloc etc.. without coming across that sort of thing 

[Nemo Krad]

Mike,

I can't for the life of me see where it mentions required render states. In the C++ examples there are no states that I can see that get set and the shader example from the book is pretty much the same as the ones I have posted here.

I have tried having just the one model with the shader, disabled the pass to the light parameter (which left me with a model with a regular image on it but no bump mapping) I have tried all sorts and still to no avail (even a reboot lol). So, Mike, if you know of any states that should be set for a bump map shader then I would really appreciate it if you could tell me. It's driving me mad especially as I have had it working, I think that's what is most annoying the fact that it worked and I must have done something to break it, but for the life of me I don't know what....

Help 

[Nemo Krad]

OK, solved it...

I had some third party software on my PC that seemed to be interfering with my GCard when it came to bump maps, don't know why, but it did. All I know is I un-installed it and it all worked fine... .go figure...

Thanks to you all that had a look at this...

[EclipsE]

Wierd... btw, look at this

http://img231.imageshack.us/img231/7669/specialeffectsrf9.png