   question about lighting
  does diffuse and specular light the whole scene or is it only directional?   
Diffuse reflection and Specular reflection are two types of light reflection computed in the Blinn Phong shading model (and lots of other shading models).Every light produces diffuse/specular values for every surface that it affects, no matter what kind of light it is.   ;  so it lights the whole scene?   ;  That doesn't really make sense. Lighting is computed by determining the diffuse/specular contributions.If the whole scene is covered by lights, then yes?   ;  i mean if you use 1 light thats diffuse and specular , can you light the whole scene?   ;Quote:Original post by Anddosi mean if you use 1 light thats diffuse and specular , can you light the whole scene?If you have no shadows and every surface in your scene is pointing towards the light then yes. Any surface that is not pointing at the light will not get lit. Otherwise you will have to add some ambient to that light. There's no reason why you do need more than one light, after all some places are supposed to be dark sometimes.   ;  The amount of diffuse and specular you get on an object is down the the material properties, where the light hits depends on the light source.A directional light will hit the entire scene from a single point infinitely far away with no fall off.A point light will have a maximum range and fall off the further you get away from the source.A spot light will emit in a cone from a single point.;Quote:Original post by Anddosi mean if you use 1 light thats diffuse and specular , can you light the whole scene?Depends on what you mean by "light the whole scene."A single directional light will light every facing surface. A single point light will light every facing surface inside its attenuation range. A single spotlight will light every facing surface within its cone and inside its attenuation range.   ;  looking in effectedit i see the default shader as float3 lightDir<    string UIDirectional = "Light Direction";> = {0.577, -0.577, 0.577};so thats x,y,z on the left handed cord axis right?, why wouldnt the direction be something like 0.0f,0.0f,-5.0f because those cords above look strange   ;  length( float3(0.577, -0.577, 0.577) ) is approximately 1.0.length( float3(0.0f,0.0f,-5.0f) ) is 5.When representing a direction in a vector, it's normal to store a unit-length vector, AKA a normal vector (a vector who's length is 1.0).That default direction that you've shown is pointing 45º down/across/forwards.   