Re: Wierd flashing when rendering simple diffuse lighting

Jman — Sat, 06 Jun 2009 23:39:05 GMT

I figured it out. I wasn't following the packing rules for some of my constant buffers.

Re: Wierd flashing when rendering simple diffuse lighting

Jman — Fri, 05 Jun 2009 18:14:32 GMT

I'm writing the whole thing in C++, using the Direct3D10 SDK. I'm not using the XNA Game Studio.

Re: Wierd flashing when rendering simple diffuse lighting

FortisVenaliter Productions — Fri, 05 Jun 2009 18:02:28 GMT

Check that you properly set the VertexDeclaration on the GraphicsDevice

Wierd flashing when rendering simple diffuse lighting

Jman — Fri, 05 Jun 2009 17:42:57 GMT

I have been trying to get a very simple pixel shader going that just applies diffuse lighting ( N dot L ) for a single directional light source. My pixel shader code is as follows:

cbuffer cb0 : register(b0)
{
   float4 vCameraPos;
   float4 vGlobalAmbient;
};

cbuffer cb1 : register(b1)
{
   float4 vAmbient;
   float4 vDiffuse;
   float4 vSpecular;
   int bDiffuseMap;
   int bGlossMap;
   int bNormalMap;
   int bBumpMap;
};

cbuffer cb2 : register(b2)
{
   float3 vLightColor;
   float3 vLightDir;
   int nLightType;
   float SomeOtherFloat;
};

struct PS_INPUT
{
   float4 vPosProj : SV_POSITION;
   float2 vTexUV   : TEXCOORD0;
   float3 vNormWorld : TEXCOORD1;
   float3 vPosWorld : TEXCOORD2;
};

// entry point
float4 main( PS_INPUT vert ) : SV_Target
{
   float4 color;
   color.a = vAmbient.a;

   float3 lightVec = normalize( vLightDir );
   float3 vectorToLight = normalize( vert.vPosWorld - lightVec );
   float fDiffuse = saturate( dot( vert.vNormWorld, vectorToLight ) );

   color.rgb = vLightColor * vAmbient.rgb;
   color.rgb += vDiffuse.rgb * fDiffuse * vLightColor;

   return color;
}

When I run this shader in my engine, the model it is rendering flashes between ambient-only and diffuse-lit very rapidly. I have determined that the problem is in the shader code, not my engine, and it is the statement that computes the fDiffuse variable. When I omit that line, and substitute a constant value for fDiffuse, the flashing goes away, but I am left with plain old ambient lighting.

Has anyone else seen this happening? Am I doing something wrong? plz help!

Direct3D 10

Re: Wierd flashing when rendering simple diffuse lighting

Re: Wierd flashing when rendering simple diffuse lighting

Re: Wierd flashing when rendering simple diffuse lighting

Wierd flashing when rendering simple diffuse lighting