opengl es 2.0镜面照明

Question

这是我在这里的第一篇文章，但我正在试图解决这个问题的墙壁撞我的头。下面的代码是我的一个令人难以置信的简单的Opengl ES 2.0应用程序的片段着色器。顶点着色器完成所有常见业务。问题在于高光反射，它正在对每个顶点的基础上执行计算，而不是每个片段。如果有人能向我解释为什么会发生这种情况，我将不胜感激。谢谢。

顺便说一句，对于效率低下的代码感到抱歉，我只是回到照明的基础知识来试图跟踪这个问题。

precision highp float; 

struct DirectionLight 
{ 
    vec4 Ambient; 
    vec4 Diffuse; 
    vec4 Specular; 
}; 

struct Material 
{ 
    vec4 Ambient; 
    vec4 Diffuse; 
    vec4 Specular; 
    float SpecularExponent; 
}; 

const float c_zero = 0.0; 
const float c_one = 1.0; 

uniform DirectionLight u_directionLight; 
uniform Material   u_material; 
uniform sampler2D  u_texture; 
uniform vec3    u_lightPosition; 
uniform vec3    u_eyePosition; 

varying vec3    v_position; 
varying vec3    v_normal; 
varying vec2    v_texCoord; 

void main() 
{ 
    vec4 totalLight = vec4(c_zero, c_zero, c_zero, c_zero); 
    vec4 ambient = vec4(c_zero, c_zero, c_zero, c_zero); 
    vec4 diffuse = vec4(c_zero, c_zero, c_zero, c_zero); 
    vec4 specular = vec4(c_zero, c_zero, c_zero, c_zero); 
    vec3 halfPlane = vec3(c_zero, c_zero, c_zero); 

    halfPlane = normalize(u_eyePosition + u_lightPosition); 

    float distance = length(u_lightPosition - v_position); 
    float attenuation = c_one/(c_one + (0.1 * distance) + (0.01 * distance * distance)); 

    vec3 lightVector = normalize(u_lightPosition - v_position); 

    float ndotl = max(dot(v_normal, lightVector), 0.1); 
    float ndoth = max(dot(v_normal, halfPlane), 0.1); 

    ambient = u_directionLight.Ambient * u_material.Ambient; 
    diffuse = ndotl * u_directionLight.Diffuse * u_material.Diffuse; 

    if(ndoth > c_zero) 
    { 
     specular = pow(ndoth, u_material.SpecularExponent) * u_directionLight.Specular * u_material.Specular; 
    } 

    totalLight = ambient + ((diffuse + specular) * attenuation); 

    gl_FragColor = totalLight;// * (texture2D(u_texture, v_texCoord)); 
} 

Answer 1

我认为这可以帮助您与漫射照明http://www.learnopengles.com/android-lesson-two-ambient-and-diffuse-lighting/