VertexShader.txt

attribute vec3 aPosition;
attribute vec2 aTextureCoord;
varying vec2 vTextureCoord;
uniform mat4 uModelView;
uniform mat4 uProj;

attribute vec3 aVertexNormal;

uniform mat4 uNormalMatrix;
uniform vec3 uAmbientColor;
uniform vec3 uLightDirection;
uniform vec3 uDirectionalColor;
uniform bool uUseAmbientLight;
uniform bool uUseParallelLlight;

varying vec3 vLightWeighting;

void main()
{
    gl_Position = uProj * uModelView * vec4(aPosition,1.0);
    vTextureCoord = aTextureCoord;

    if(uUseAmbientLight||uUseParallelLlight)
	{
        if(uUseAmbientLight)
        {
            vLightWeighting += uAmbientColor;
        }

        if(uUseParallelLlight)
        {
           vec3 transformedNormal = (uNormalMatrix * vec4(aVertexNormal, 1.0)).xyz;
           float directionalLightWeighting = max(dot(transformedNormal,-uLightDirection), 0.0);
           vLightWeighting += uDirectionalColor * directionalLightWeighting;
        }
    }
    else
    {
        vLightWeighting = vec3(1.0, 1.0, 1.0);
    }
}