History: PerPixel Lighting

//The simplest (EXACT, see remarks) perpixel lighting I could do is:
 //(though it still supports ambient and specular terms, so it could still be simpler :)
 
 //Note: lighting is done in object-space, in the frag shader
 
 void Simple_Perpixel_Vert(
                        //ADDED BY EUGEN - support for texture with the per pixel lighting
                        float2 uv : TEXCOORD0,
                         float4 position : POSITION, 
                         float3 normal   : NORMAL,
                 //vert shader input
 
                         uniform float4 lightPosition,
             uniform float3 eyePosition,
                 //both in object space
 
                         uniform float4x4 worldviewproj, 
             
                         out float4 oClipPos    : POSITION,
                 //pass to clipping
 
             out float4 oPos    : TEXCOORD0,
             out float3 oNorm    : TEXCOORD1,
                         out float4 oLightPos    : TEXCOORD2,            
             out float3 oEyePos    : TEXCOORD3,
                        //ADDED BY EUGEN - support for texture with the per pixel lighting
                        out float2 oUv       : TEXCOORD4
                 //pass to frag shader
              ) 
 { 
     oClipPos = mul(worldviewproj, position); 
 
     oPos = position;
     oNorm     = normal; 
     oLightPos = lightPosition;
     oEyePos = eyePosition;
        //ADDED BY EUGEN - support for texture with the per pixel lighting
        oUv = uv;
 
         //Remarks:
 
         //since we want exact calculations in every case,
         //calculate light and eye directions in frag shader,
         //don't let the rasterizer interpolate them from here
 
         //more costy than doing directions here, per-vertex, but
         //produces accurate lighting in VERY low tessellation cases,
         //light close to surface (for.ex. closer than poly size)
 } 
 
 
 void Simple_PerPixel_Frag(
 
                  float4 pos         : TEXCOORD0,
             float3 normal        : TEXCOORD1, 
              float4 lightpos        : TEXCOORD2,
             float3 eyepos        : TEXCOORD3,
                        //ADDED BY EUGEN - support for texture with the per pixel lighting
                        float2 uv        : TEXCOORD4,
 
             uniform float4 lightDiffuse,
             uniform float4 lightSpecular,
             uniform float exponent,
 
             uniform float4 ambient,
             uniform sampler2D texture,
 
                         out float4 oColor : COLOR 
 ) 
 {
     float3 N = normalize(normal);
 
         //Remarks: 
 
         //we could do this normalize() in vert shader, or skip it
         //see some info at lighthouse3d GLSL explanations    
 
     float3 EyeDir = normalize(eyepos - pos.xyz);
     float3 LightDir = normalize(lightpos.xyz -  (pos * lightpos.w));
     float3 HalfAngle = normalize(LightDir + EyeDir);
 
     float NdotL = dot(LightDir, N);
     float NdotH = dot(HalfAngle, N);
     float4 Lit = lit(NdotL,NdotH,exponent);
 
     //cg docs say using their lit function is the fastest
 
        //ADDED BY EUGEN - support for texture with the per pixel lighting
        float3 textColour = expand(tex2D(texture, uv).xyz);
 
        //ADDED BY EUGEN - support for texture with the per pixel lighting
        oColor = lightDiffuse * Lit.y + lightSpecular * Lit.z + ambient + float4(textColour, 1);
 }

vertex_program Simple_Perpixel_Vert cg 
 { 
       source ARNOLD.cg 
 
       default_params 
       { 
                  param_named_auto lightPosition light_position_object_space 0
         param_named_auto eyePosition camera_position_object_space
 
                  param_named_auto worldviewproj worldviewproj_matrix
       } 
 
       entry_point Simple_Perpixel_Vert 
       profiles vs_1_1 arbvp1 
 } 
 
 fragment_program Simple_PerPixel_Frag cg 
 { 
       source ARNOLD.cg 
 
       default_params 
       {
                  param_named_auto lightDiffuse light_diffuse_colour 0
         param_named_auto lightSpecular light_specular_colour 0
 
         param_named exponent float 127
             //VERY high value, to produce large highlights
 
         param_named ambient float4 0.0 0.0 0.0 1.0
             //faint environment lighting
       } 
 
       entry_point Simple_PerPixel_Frag
       profiles ps_2_0 arbfp1
 }
 
 material Simple_Perpixel 
 { 
       technique 
       {
         // Base ambient pass, needing to avoid transparent artifacts
         // at for.ex. knot mesh
 //        pass
 //        {    
 //            vertex_program_ref Ambient
 //            {
 //            }
 //        }
         pass 
         { 
             // do this for each light
 //            iteration once_per_light
 //            scene_blend add
 
                     vertex_program_ref Simple_Perpixel_Vert
                     { 
                     } 
 
                     fragment_program_ref Simple_PerPixel_Frag
                     { 
                     } 
                        //EUGEN - support for textures with the perpixel lighting
                        texture_unit
                        {
                                //use your own texture here, this is just an example
                                texture totem.dds
                        }
              } 
       } 
 }
 
 //(uncomment lines to add multipass multilight support: plus you need Ambient vert shader  
 // from below, plus take out the ”+ambient” part of final color line in Simple_PerPixel_Frag)
 // And perhaps the file parser will complain if perpixel material is listed before ambient stuff
 // so you might list ambient things in the start of this file.
 
 void Ambient_vp(
         float4 position : POSITION,
 
           out float4 oPosition : POSITION,
           out float4 colour    : COLOR,
 
           uniform float4x4 worldViewProj,
           uniform float4 ambient)
 {
     oPosition = mul(worldViewProj, position);
     colour = ambient;
 }
 
 vertex_program Ambient cg
 {
     source ARNOLD.cg
 
     default_params
     {
         param_named_auto worldViewProj worldviewproj_matrix
         param_named ambient float4 0.2 0.2 0.2 1.0
     }
 
     entry_point Ambient_vp
     profiles vs_1_1 arbvp1
 }