ssao - error on results. hidden parts are showing up

Hi,

I'm not sure what causes this problem. Maybe it has something to do with your alpha and cullMode? I think you need to post some more code so everyone can understand your process better.

I'm sure you overwrite depth values everywhere. Drop more code.

ok, this is my texture and Render Target creation:


// this texture is 32bit float. CLAMP_TO_EDGE and filter set to NEAREST
_sceneNormalTex = new Texture( GL.GL_TEXTURE_2D );
_sceneNormalTex.createGLFloat( GL.GL_RGBA_FLOAT32_ATI, GL.GL_RGBA, sizeX, sizeY );

// this is the render target. i create a RT with color+depth components. and attach the above texture to it.
_sceneNormalRT = new FBO( _sceneNormalTex, GL.GL_TEXTURE_2D, GL.GL_COLOR_ATTACHMENT0_EXT, GL.GL_DEPTH_COMPONENT );




this is the shader used to render the scene normals and linear depth to the Texture above



------------------------
vertexDepthOutput VS_DepthMap( in vertexDepthInput IN )
{
vertexDepthOutput OUT = (vertexDepthOutput)0;

float4 pos = float4( IN.position, 1.0 );
OUT.position = mul( worldViewProj, pos );

OUT.viewPos = mul( matModelView, float4(IN.position,1.0) );

OUT.normal = mul( worldViewProj, float4(IN.normal, 1) ).xyz;

return OUT;
}

float4 PS_NormalMap( in vertexDepthOutput IN ) : COLOR
{
//float depth = -IN.viewPos.z / farPlane;
//float depth = (-IN.viewPos.z * IN.viewPos.w) / farPlane;
float depth = length(IN.viewPos) / farPlane;

//float3 norm = normalize( IN.normal );
float3 norm = 0.5f * (normalize(IN.normal) + 1.0f);

return float4( norm.x, norm.y, norm.z, depth );
}

technique Technique_NormalMap
{
pass P0
{
VertexProgram = compile arbvp1 VS_DepthMap();
FragmentProgram = compile arbfp1 PS_NormalMap();
}
}

-----------------------


after i get this texture with normals and depth i pass it to the SSAO shader.

the SSAO shader comes from GAMERENDERING

its said to pass the normals in screen space and to pass a noise texture which i got from the website aswell.. well the results are what you can see above..

hope this is enough information..

thanks in advance for your help.

It looks like this is a problem with your render state. Double check that your depth test state is setup correctly.

Yep, looks like either you have depth test and/or write turned off

hi, i also thought so, but i have enabled depthtest and depthwrite when i render to the texture (this is the only time where i need z-buffer)

it shouldn't be the depth testing, coz when i set the texture alpha to 1.0 everything renders just fine. This problems seem related to the depth in the alpha channel. seems like for some weird reason it is using the texture's A channel (depth) for alpha.. if you look at the code you'll see i don't do that at all, anywhere.


i have found one weird thing.

i was using one texture for Normals+Depth in the example above. Just for testing, i have created 2 different textures, NormalTexture and DepthTexture and rendered seperately to each of them.

i have found that by doing this i actually got it to work without the problems above, BUT it only works right if i set the Alpha channel of the NormalTexture with the depth value anyway. If i set it to 1.0 as to make it competely opaque (since i shouldn't need the A-channel anymore) the results of the SSAO are different. looks more like omni-lighting effect other than ambient occlusion.

it's really weird effect and the changes needed to get it to look right have no sense..

Quote:

Original post by murderv when i set the texture alpha to 1.0 everything renders just fine.

Oh, in that case then maybe you accidentally have alpha blend or test enabled?

eesh. that was correct. i had blending enabled when rendering to texture :/
thanks for your help..


one other thing, i get some wrapping problems with AO. it seems in the top and right borders of the screen it gets darker or whiter. seems like it fetches from the side of the texture with normals na depth.

how do you guys usually handle this problem ?

Set texture addressing mode to CLAMP.

hi, yes i thought of that and tried it. did not work that well. i get the same problems

Hi,

I think you have to set all textures that you sample from to CLAMP as long as they are involved in the SSAO calculation process.

yes, i have tried that.
i have set every rendertarget to clamp and even clamp_to_edge, i have set the random noise texture to clamp aswell, but the errors on image caused by this last change are very strange. i don't think noise texture should be clamped. i still get the problems with closed ambients like the sponza model. the lighting moves around, seems like it wraps. i'm not sure.

everything seems just like everyone does and still i've been having alot of problems..

thanks everyone for your help. i'll see what i can do from here