panda3d/samples/fireflies/light.sha

//Cg
//
//Cg profile arbvp1 arbfp1

void vshader(float4 vtx_position : POSITION,
             out float4 l_position : POSITION,
             out float4 l_pos : TEXCOORD0,
             uniform float4x4 mat_modelproj,
             uniform float4x4 trans_model_to_clip)
{
  l_position=mul(mat_modelproj, vtx_position);
  l_pos=mul(trans_model_to_clip, vtx_position);
  l_pos.z = l_pos.w;
}

void fshader(float4 l_pos: TEXCOORD0,
             uniform sampler2D k_texnormal : TEXUNIT0,
             uniform sampler2D k_texalbedo : TEXUNIT1,
             uniform sampler2D k_texdepth  : TEXUNIT2,
             uniform float4 texpad_texnormal,
             uniform float4 k_proj,
             uniform float4 vspos_model,
             uniform float4 k_lightcolor,
             uniform float4 row0_model_to_view,
             out float4 o_color: COLOR)
{
  float3 screen = l_pos.xyz / l_pos.w;
  float2 texcoords = float2(screen.xy) * texpad_texnormal.xy + texpad_texnormal.xy;

  float4 albedo = tex2D(k_texalbedo, texcoords);
  float4 normal = tex2D(k_texnormal, texcoords);
  float  depth = tex2D(k_texdepth, texcoords);

  float3 view = (screen.xzy * k_proj.xyz) / (depth + k_proj.w);

  float3 lightvec = float3(vspos_model) - view;
  float  lightdist = length(lightvec);
  float3 lightdir = lightvec / lightdist;
  float  scaledist = (lightdist / row0_model_to_view.x);
  float  falloff = saturate(1.0 - scaledist);
  float  brite = falloff * falloff * dot(lightdir, float3(normal));
  o_color = albedo * k_lightcolor * brite;
  o_color.a = 1;
}