OpenGL中的镜面光照问题

Question

我的镜面光线有一些问题，我有环境和漫反射但我现在正在寻找镜面反射来尝试做一个漂亮的模型。

我的vertexShader中有以下内容：

#version 330

layout (location = 0) in vec3 Position;
layout (location = 1) in vec3 Normal;

out vec4 Colour0;

// Transforms
uniform mat4 gModelToWorldTransform;
uniform mat4 gWorldToViewToProjectionTransform;

// Ambient light parameters
uniform vec3 gAmbientLightIntensity;

// Directional light parameters
uniform vec3 gDirectionalLightIntensity;
uniform vec3 gDirectionalLightDirection;

// Material constants
uniform float gKa;
uniform float gKd;
uniform float gKs;
uniform float gKsStrength;


void main()
{  
    // Transform the vertex from local space to homogeneous clip space 
    vec4 vertexPositionInModelSpace = vec4(Position, 1);
    vec4 vertexInWorldSpace = gModelToWorldTransform * vertexPositionInModelSpace;
    vec4 vertexInHomogeneousClipSpace = gWorldToViewToProjectionTransform * vertexInWorldSpace;
    gl_Position = vertexInHomogeneousClipSpace;

    // Calculate the directional light intensity at the vertex
    // Find the normal in world space and normalise it
    vec3 normalInWorldSpace = (gModelToWorldTransform * vec4(Normal, 0.0)).xyz;
    normalInWorldSpace = normalize(normalInWorldSpace);

    // Calculate the ambient light intensity at the vertex
    // Ia = Ka * ambientLightIntensity
    vec4 ambientLightIntensity = gKa * vec4(gAmbientLightIntensity, 1.0);

    // Setup the light direction and normalise it
    vec3 lightDirection = normalize(-gDirectionalLightDirection);

    //lightDirection = normalize(gDirectionalLightDirection);
    // Id = kd * lightItensity * N.L
    // Calculate N.L
    float diffuseFactor = dot(normalInWorldSpace, lightDirection);
    diffuseFactor = clamp(diffuseFactor, 0.0, 1.0);

    // N.L * light source colour * intensity
    vec4 diffuseLightIntensity = gKd * vec4(gDirectionalLightIntensity, 1.0f) * diffuseFactor;

    vec3 lightReflect = normalize(reflect(gDirectionalLightDirection, Normal));

    //Calculate the specular light intensity at the vertex
    float specularFactor = dot(normalInWorldSpace, lightReflect);
    specularFactor = pow(specularFactor, gKsStrength);
    vec4 specularLightIntensity = gKs * vec4(gDirectionalLightIntensity, 1.0f) * specularFactor;

    // Final vertex colour is the product of the vertex colour
    // and the total light intensity at the vertex 

    vec4 colour = vec4(0.0, 1.0, 0.0, 1.0);
    Colour0 = colour * (ambientLightIntensity + diffuseLightIntensity + specularLightIntensity);
}

然后在我的main.cpp中我有一些代码试着让它一起工作，镜面光肯定是做某事，只是，而不是让模型看起来有光泽，它似乎加强了光到点我看不到任何细节。

我创建了以下变量：

// Lighting uniforms location

GLuint gAmbientLightIntensityLoc;
GLuint gDirectionalLightIntensityLoc;
GLuint gDirectionalLightDirectionLoc;
GLuint gSpecularLightIntensityLoc;

// Materials uniform location
GLuint gKaLoc;
GLuint gKdLoc;
GLuint gKsLoc;
GLuint gKsStrengthLoc;

然后我在renderSceneCallBack()函数中设置我的变量，在main：

中调用

// Set the material properties
glUniform1f(gKaLoc, 0.2f); 
glUniform1f(gKdLoc, 0.9f);
glUniform1f(gKsLoc, 0.5f);
glUniform1f(gKsStrengthLoc, 0.5f);

然后我创建了一个initLights()函数，我想处理所有光照，这也在主要调用：

static void initLights()
{
    // Setup the ambient light
    vec3 ambientLightIntensity = vec3(0.2f, 0.2f, 0.2f);
    glUniform3fv(gAmbientLightIntensityLoc, 1, &ambientLightIntensity[0]);

    // Setup the direactional light
    vec3 directionalLightDirection = vec3(0.0f, 0.0f, -1.0f);
    normalize(directionalLightDirection);
    glUniform3fv(gDirectionalLightDirectionLoc, 1, &directionalLightDirection[0]);

    vec3 directionalLightIntensity = vec3(0.8f, 0.8f, 0.8f);
    glUniform3fv(gDirectionalLightIntensityLoc, 1, &directionalLightIntensity[0]);

    //Setup the specular Light
    vec3 specularLightIntensity = vec3(0.5f, 0.5f, 0.5f);
    glUniform3fv(gSpecularLightIntensityLoc, 1, &specularLightIntensity[0]);
}

任何人都可以看到我可能做错了什么，我可能会有一些错误的计算器，我只是没有看到它。环境/漫反射照明都正常工作。这张照片说明了目前正在发生的事情，左边的环境，中间的漫反射和右边的强度设置为30的镜面反射。

答案

我忘了把这个值传递给主要的：

gKsStrengthLoc = glGetUniformLocation(shaderProgram, "gKsStrength");
    //assert(gDirectionalLightDirectionLoc != 0xFFFFFFFF);

现在使用所选答案

一切正常

Answer 1

gKsStrength的价值看起来太小了：

glUniform1f(gKsStrengthLoc, 0.5f);

此值控制对象的闪亮程度，值越高，对象越有光泽。如果您在着色器中查看计算，这是有道理的：

specularFactor = pow(specularFactor, gKsStrength);

指数越大，值越快下降，这意味着镜面反射高光越来越窄。

典型值可能类似于10.0f，适用于中等光泽，30.0f适用于相当光泽，甚至更高适用于非常光亮的材料。

当你的值为0.5f时，你得到一个非常宽的镜面“亮点”。您的镜面反射强度值也相当高（0.5），因此高光部分将覆盖大部分物体，并使大部分颜色饱和。