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Qt OpenGL 光照实现

backend 2025/7/15 2:22:42

Qt 中使用 OpenGL 实现光照效果主要基于 OpenGL 的光照模型和着色器编程。以下是 Qt OpenGL 光照实现的核心原理：

一. 光照模型基础

OpenGL 使用 Phong 光照模型，包含三个主要光照分量：

环境光(Ambient)：场景中的基础光照，没有方向性
漫反射光(Diffuse)：与表面法线和光线方向相关的散射光
镜面光(Specular)：在特定角度可见的高光反射

二. Qt 中的实现方式

2.1 传统固定管线方式 (已过时但简单)

cpp

// 启用光照
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0); // 启用0号光源// 设置光源属性
GLfloat lightPosition[] = {1.0f, 1.0f, 1.0f, 1.0f};
GLfloat lightAmbient[] = {0.2f, 0.2f, 0.2f, 1.0f};
GLfloat lightDiffuse[] = {0.8f, 0.8f, 0.8f, 1.0f};
GLfloat lightSpecular[] = {1.0f, 1.0f, 1.0f, 1.0f};glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, lightSpecular);// 设置材质属性
GLfloat materialAmbient[] = {0.7f, 0.7f, 0.7f, 1.0f};
GLfloat materialDiffuse[] = {0.8f, 0.8f, 0.8f, 1.0f};
GLfloat materialSpecular[] = {1.0f, 1.0f, 1.0f, 1.0f};
GLfloat materialShininess = 100.0f;glMaterialfv(GL_FRONT, GL_AMBIENT, materialAmbient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, materialDiffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, materialSpecular);
glMaterialf(GL_FRONT, GL_SHININESS, materialShininess);

2.2 现代可编程管线方式 (推荐)

使用着色器实现光照效果：

顶点着色器示例

glsl

#version 330 corelayout(location = 0) in vec3 position;
layout(location = 1) in vec3 normal;out vec3 FragPos;
out vec3 Normal;uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;void main()
{FragPos = vec3(model * vec4(position, 1.0));Normal = mat3(transpose(inverse(model))) * normal;gl_Position = projection * view * vec4(FragPos, 1.0);
}

片段着色器示例 (Phong光照)

glsl

#version 330 corein vec3 FragPos;
in vec3 Normal;out vec4 FragColor;uniform vec3 lightPos;
uniform vec3 viewPos;
uniform vec3 lightColor;
uniform vec3 objectColor;void main()
{// 环境光float ambientStrength = 0.1;vec3 ambient = ambientStrength * lightColor;// 漫反射vec3 norm = normalize(Normal);vec3 lightDir = normalize(lightPos - FragPos);float diff = max(dot(norm, lightDir), 0.0);vec3 diffuse = diff * lightColor;// 镜面光float specularStrength = 0.5;vec3 viewDir = normalize(viewPos - FragPos);vec3 reflectDir = reflect(-lightDir, norm);float spec = pow(max(dot(viewDir, reflectDir), 0.0), 32);vec3 specular = specularStrength * spec * lightColor;vec3 result = (ambient + diffuse + specular) * objectColor;FragColor = vec4(result, 1.0);
}