GLSL halfvector?
vec3 halfVector = normalize(directionTowardsLight + directionTowardsEye);
Used by standart directional, point and spotlight sources. Directions are calculated from transformed position (excluding projection transform) in fragment shader. (In case of directional light it can be calculated outside the shader at all)
vec3 L = normalize(gl_LightSource[0].position.xyz); // directional
OR
vec3 worldPos = vec3(gl_ModelViewMatrix * gl_Vertex); // point
vec3 L = normalize(gl_LightSource[0].position.xyz - worldPos);
vec3 H = (L + V);
What version of OpenGL are you using? You shouldn't be using old OpenGL. Even "new" opengl will be old in a couple of years when Vulkan is in use.
I really wish OpenGL would just remove all the old documentation. It happens too many times that I'm reading documentation or the wiki only to see the "This is legacy code. Do no use!" warning in the middle of the document.
It is difficult when you are first learning this stuff, and you don't even realize you are learning old tech.
I have been compiling a list of modern OpenGL tutorials here: http://www.gamedev.net/topic/667482-modern-opengl-tutorials/
I just would like to know if gl_LightSource[0].halfVector.xyz is the same value as my calculated one.
I'm using directional lights.
OpenGL takes into account light type (I am not 100% sure, but it is easy to spot if its not)
Directional should have a light direction vector
gl_FragColor = vec4( gl_LightSource[0].halfVector.xyz, 1.0 );
It does not matter wheather the light is directional or not.
If it is directional light, only eye direction is a per pixel varying vector, if it is a position light, also light direction is per pixel varying vector. You should use explicit computations , even in old opengl, nothing should restrict you from that.
>>It does not matter wheather the light is directional or not.
Half vector is L+V. Are you saying Lpoint+V = Ldir+V? That doesn't make sense. They're two different light vectors.
