Deferred rendering issue

2013-04-01T20:01:55

Hello I have an issue in my deferred renderer (Dx9). As seen in the attached image between my meshes there is a small black line. This line becomes visible depending on the distance between the camera and the meshes. The problem seems to be in the point light shader. Since if i remove the light output and just draw color on the screenquad everything looks fine. GBuffer: VertexShaderOutput VertexShaderFunction(VertexShaderInput input) { VertexShaderOutput output; float4 worldPos = mul( float4(input.Position.xyz, 1.0f), World ); output.Position = mul( worldPos, ViewProjection ); output.UV = input.UV; output.Normal = mul( input.Normal, World ); output.Depth.x = output.Position.z; output.Depth.y = output.Position.w; return output; } PixelShaderOutput PixelShaderFunction(VertexShaderOutput input) : COLOR0 { PixelShaderOutput output; output.Color = tex2D( DiffuseMapSampler, input.UV ); output.Normal.xyz = ( input.Normal + 1.0f ) * 0.5f; output.Normal.a = 1.0f; float D = input.Depth.x / input.Depth.y; output.Depth = float4( D, D, D, 1.0f ); output.Glow = tex2D( GlowMapSampler, input.UV ); return output; } Point Light: VertexShaderOutput VertexShaderFunction(VertexShaderInput input) { VertexShaderOutput output; float4 worldPos = mul( float4(input.Position.xyz, 1.0f), World ); output.Position = mul( worldPos, ViewProjection ); output.ScreenPosition = output.Position; return output; } float4 PixelShaderFunction(VertexShaderOutput input) : COLOR0 { //obtain screen position input.ScreenPosition.xy /= input.ScreenPosition.w; //obtain textureCoordinates corresponding to the current pixel //the screen coordinates are in [-1,1]*[1,-1] //the texture coordinates need to be in [0,1]*[0,1] float2 uv = 0.5f * ( float2(input.ScreenPosition.x,-input.ScreenPosition.y) + 1.0f ); //allign texels to pixels uv += HalfPixel; //get normal data from the normalMap float4 normalData = tex2D( NormalMapSampler, uv ); //tranform normal back into [-1,1] range float3 normal = normalize( 2.0f * normalData.xyz - 1.0f ); //read depth float depth = tex2D( DepthMapSampler, uv ).r; //compute screen-space position float4 position; position.xy = input.ScreenPosition.xy; position.z = depth; position.w = 1.0f; //transform to world space position = mul( position, InversedViewProjection ); position /= position.w; //surface-to-light vector float3 lightVector = LightLocation - position; //compute attenuation based on distance - linear attenuation float attenuation = saturate( 1.0f - (length(lightVector) / LightRadius) ); //normalize light vector lightVector = normalize( lightVector ); //compute diffuse light float NdL = saturate( dot(normal, lightVector) ); float3 diffuseLight = NdL * Color.rgb * Intensity; return float4( diffuseLight, 1.0f ) * attenuation; } Any help is much appreciated!

Graphics and GPU Programming Programming

Started by Noxil March 30, 2013 08:33 AM

22 comments, last by Noxil 11 years ago

Noxil

792

Author

April 01, 2013 06:15 PM

The normals are exported from maya.

galop1n

1,046

April 01, 2013 06:45 PM

Strange you said that the gbuffer was ok and now the normal is wrong :)

The normal is world space as i can see in the point light shader (you should switch to view space but that's an other topic).

Do you just dump the mesh normal, or do you use some kind of tangent frame to use tangent space normal map ? If you use a tangent frame, do you have mirror in uv and you forget to split the vertex where the uv direction change ?

Spidey

766

April 01, 2013 07:59 PM

If you have pix, then you can output your corrupted g-buffer to the back buffer and run a single frame capture on it. Then run the "debug this pixel" feature on the black pixels by right clicking on them. That will let you step through the shader to see what is wrong.

Noxil

792

Author

April 01, 2013 08:01 PM

Thank you all for trying to help me.

Sadly i wont have time to look further into this for the coming week.

I will have to get back to this at a later time.

Deferred rendering issue

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Deferred rendering issue

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