平行光镜面反射模型

即Blinn-Phong 光照模型, 关于此模型的更多信息请google.

参照：http://www.lighthouse3d.com/tutorials/glsl-tutorial/directional-lights-ii/

源代码：http://download.csdn.net/detail/netrookie/4306817

主要看vertex shader:

struct MaterialParameters 
{
    vec4 emission;
    vec4 ambient;
    vec4 diffuse;
    vec4 specular;
    float shininess;
};

struct LightSourceParameters 
{
    vec4 ambient;
    vec4 diffuse;
    vec4 specular;
    vec4 position;
    vec4 halfVector;
    vec3 spotDirection;
    float spotExponent;
    float spotCutoff;
    float spotCosCutoff;
    float constantAttenuation;
    float linearAttenuation;
    float quadraticAttenuation;
};

uniform mat4 m_mvp_mat;
uniform mat4 m_mv_mat;
uniform mat4 m_model_it;

uniform MaterialParameters m_material_attr;
uniform LightSourceParameters m_light_attr;

attribute vec4 m_position;
attribute vec3 m_normal;

varying vec4 m_out_color;

void main()
{
    vec3 normal, light_dir;
    vec3 position_mv;
    vec3 view_dir;
    vec3 H;
    float NdotL,NdotHV;
    vec4 specular;

    light_dir = normalize(vec3(m_light_attr.position));
    normal = normalize(vec3(m_model_it * vec4(m_normal, 0.0)));

    NdotL = max(dot(normal, light_dir), 0.0);

    position_mv = vec3(m_mv_mat * m_position);
    view_dir = vec3(0, 0, 0) - position_mv;

    H = normalize(view_dir - light_dir);

    NdotHV = max(dot(normal, H), 0.0);
    
    specular = m_light_attr.ambient * m_material_attr.ambient + m_material_attr.specular * m_light_attr.specular * pow(NdotHV, m_material_attr.shininess);

    m_out_color = specular;
    
    gl_Position = m_mvp_mat * m_position;
}

截图：