I've just got my deferred shader pipeline to a point where I start getting some images out, but I got a problem I can't figure out: When I light my scene with a spotlight I get a pixel-thin outline around objects.
Here is a slightly more complex scene with the same problem:
All the geometry get a thin edge of lighter pixels.
Here is the pixel shader I use in the lighting pass of the deferred shader:
float4x4 SpotLightTransform;
float3 light_position;
float3 light_direction;
struct VS_Output {
float4 position : POSITION;
float2 uv : TEXCOORD0;
};
float4 PS_Spot( VS_Output IN ) : COLOR0 {
float3 view_pos = tex2D( texture_position_sampler, IN.uv ).rgb;
float3 normal = normalize( tex2D( texture_normal_sampler, IN.uv ).rgb );
float3 albedo = tex2D( texture_albedo_sampler, IN.uv );
float4 spot_pos = mul( float4( view_pos, 1 ), SpotLightTransform );
float u = ( spot_pos.x / spot_pos.w ) / 2.0f + 0.5f;
float v = ( spot_pos.y / spot_pos.w ) / 2.0f + 0.5f;
// Clamp light contribution to spotlight texture
float4 spot_light =
u >= 0 && u <= 1 && v >= 0 && v <= 1 ?
tex2D( texture_spot_sampler, float2( u, 1 - v ) ) :
float4( 0, 0, 0, 0 );
float3 L = normalize( light_position - view_pos );
float NL = max( dot( normal, L ), 0 );
return float4( albedo * NL * spot_light.rgb * spot_light.a, 1 );
}
(I have removed texture samplers and the trivial vertex shader to make it more readable.)
My G buffers are D3DFMT_A16B16G16R16F. Can anyone help me track down this bug?
/Promethium
Here is a slightly more complex scene with the same problem:
All the geometry get a thin edge of lighter pixels.
Here is the pixel shader I use in the lighting pass of the deferred shader:
