[SOLVED]Re: Odd HLSL Normal mapping issue

Zazu Yen — Fri, 19 Jun 2009 20:28:33 GMT

Well, the shader is fine. The meshes I was using had no TBN data so the normals were not getting translated into model space correctly. I don't know why I didn't recognize the default data in the tangent, normal, binormal input registers in PIX.

Let this be a hard lesson learned, always check the validity of your starting data when things appear to be going wrong for no reason! At least my shaders were, in fact, fine all along.

[SOLVED]Odd HLSL Normal mapping issue

Zazu Yen — Fri, 19 Jun 2009 00:22:17 GMT

Maybe someone here can help me with this, it's driving me nuts.

I've been working on a fairly simple HLSL shader and everything is working pretty well except for one problem, I've spent hours tinkering with the code and stepping through disassembly in PIX with no luck. The normal map looks fine from the 'front' of the sample sphere, but it appears to slowly invert as it wraps around the sphere, so that in the 'back' of the sphere what should be sticking out is sticking in and vice-versa. Here is a sample image:

On the left is the front of the sphere and is the way it's supposed to look, on the right the sphere has been turned about 180 degrees. You can see that the grout on the right image is actually looking higher than the bricks.
http://www.twilightfair.com/otherstuff/images/NormalExamples.jpg

This would seem to be a simple problem, a missing transition or an out of order matrix multiplication, but I've had no luck finding it. I need some experienced eyes to take a look at the code and point out my fallacy. Here is the HLSL shader with all the extras pulled out (spectral mapping, spectral highlights, environment mapping, etc. etc.) It still has the same problem.

Relevant C# code:

                                    Matrix marbleWorld = Matrix.CreateFromYawPitchRoll(ballRotation.Y, ballRotation.X, ballRotation.Z);         
                    effect.Parameters["WorldTransform"].SetValue(marbleWorld);         
                    effect.Parameters["CameraTransform"].SetValue(marbleWorld * camera.View * camera.Projection);         
                    effect.Parameters["DirectionalLightDirection"].SetValue(new Vector3(1.0f, -1.0f, 0.5f));         
                    effect.Parameters["DirectionalLightColor"].SetValue(new Vector4(0.5f, 0.5f, 0.5f, 1.0f));         

HLSL code:

                            //////////////////////////////////////////////////         
            //  Normal debugging shader         
            //////////////////////////////////////////////////         
                     
            struct VertexIn         
            {         
                float4 position  : POSITION0;         
                float2 texCoords : TEXCOORD0;         
                float3 normal    : NORMAL0;             
                float3 tangent   : TANGENT0;         
                float3 binormal  : BINORMAL0;         
            };         
                     
            struct VertexToPixelBuggedNormal         
            {         
                float4 position      : POSITION;             
                float2 texCoords     : TEXCOORD0;         
                float3 viewVector    : TEXCOORD1;         
                float3 normal        : TEXCOORD2;         
                         
                float3x3 tangentToWorld : TEXCOORD3;         
            };         
                     
            VertexToPixelBuggedNormal BuggedNormalVertexShader(VertexIn input)         
            {         
                VertexToPixelBuggedNormal output = (VertexToPixelBuggedNormal)0;         
                     
                output.position = mul(input.position, CameraTransform);         
                         
                output.texCoords = input.texCoords;         
                         
                output.normal = normalize(mul(float4(input.normal,1.0f), WorldTransform));         
                         
                output.viewVector = -(DirectionalLightDirection.xyz*50) - mul(input.position, WorldTransform);         
                         
                output.tangentToWorld[0] = mul(float4(input.tangent,1.0f),WorldTransform).xyz;         
                output.tangentToWorld[1] = mul(float4(input.binormal,1.0f),WorldTransform).xyz;         
                output.tangentToWorld[2] = mul(float4(input.normal,1.0f), WorldTransform).xyz;         
                                 
                return output;         
            }         
                     
            PixelToFrame BuggedNormalPixelShader(VertexToPixelBuggedNormal input)         
            {         
                PixelToFrame output = (PixelToFrame)0;                 
                     
                // clean up our inputs a bit         
                input.viewVector = normalize(input.viewVector);         
                     
                // bump map         
                float3 bumpNorm = (2 * (tex2D(BumpSampler, input.texCoords).rgb-0.5f));         
                bumpNorm = normalize(mul(bumpNorm,input.tangentToWorld));         
                             
                // directional light         
                float4 DirectionalLighting = (dot(bumpNorm, input.viewVector)) * DirectionalLightColor;         
                     
                // base color             
                float4 baseColor = tex2D(TextureSampler, input.texCoords);         
                     
                // adjust for lighting         
                baseColor.xyz *= saturate(DirectionalLighting + AmbientColor).xyz;         
                         
                output.Color = baseColor;         
                     
                return output;          
            }         
                     
            technique BuggedNormal         
            {         
                pass Pass0         
                {         
                     VertexShader = compile vs_2_0 BuggedNormalVertexShader();         
                     PixelShader = compile ps_2_0 BuggedNormalPixelShader();         
                }         
            }         
                     

Thanks for any help you can offer!

Direct3D

[SOLVED]Re: Odd HLSL Normal mapping issue

[SOLVED]Odd HLSL Normal mapping issue