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https://gitcode.com/gh_mirrors/le/LearnOpenGLProject.git
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73 lines
2.7 KiB
GLSL
73 lines
2.7 KiB
GLSL
#version 330 core
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out vec4 FragColor;
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struct Material {
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sampler2D diffuse; // 漫反射颜色分量从纹理采样
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sampler2D specular;// 镜面光照颜色分量从纹理采样
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float shininess;
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};
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// 聚光灯
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struct Light {
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vec3 position; // 需要位置
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vec3 direction;// 需要照射方向
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float cutOff;
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vec3 ambient;
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vec3 diffuse;
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vec3 specular;
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float constant; // 常数
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float linear; // 一次项
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float quadratic;// 二次项
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};
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in vec3 FragPos;
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in vec3 Normal;
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in vec2 TexCoords;// 纹理坐标
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uniform vec3 viewPos;
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uniform Material material;
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uniform Light light;
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void main()
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{
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// 光源的方向向量：像素点指向光源
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vec3 lightDir = normalize(light.position - FragPos);
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// 算出theta，dot(像素点指向光源，光源照射的方向取反）
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float theta = dot(lightDir, normalize(-light.direction));
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// float theta=dot(-lightDir, normalize(light.direction));// dot(光源指向像素点, 光源照射的方向)
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// 执行正常光照计算：由于theta是cos值，cutOff也是cos值，cos(0-90)递减，所以theta>，而不是<
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if(theta > light.cutOff){
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// 片段在切角内
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// 从漫反射纹理读取颜色分量
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vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
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// 漫反射光照分量
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vec3 norm = normalize(Normal);
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vec3 lightDir = normalize(light.position - FragPos); // 得到光源的方向,与一个点做光源一样
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float diff = max(dot(norm, lightDir), 0.0); // 得到光源对当前片段实际的漫反射影响
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vec3 diffuse = light.diffuse * diff * texture(material.diffuse, TexCoords).rgb;// 从漫反射纹理读取颜色分量
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// 镜面光照分量
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vec3 viewDir = normalize(viewPos - FragPos); // 是观察者方向，不是观察者看向的方向
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vec3 reflectDir = reflect(-lightDir, norm); // reflect要求第一个参数是光源指向像素点的向量
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float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);// 光源对当前片段的镜面光影响
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// 采样镜面光纹理颜色作为镜面光照颜色分量
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//vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords)); // 这句也行
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vec3 specular = light.specular * spec * texture(material.specular, TexCoords).rgb;
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// 计算衰减
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float distance = length(light.position - FragPos); // 得到光源到片段长度
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float attenuation = 1.0 / (light.constant + light.linear * distance // 根据公式
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+ light.quadratic * distance * distance);
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// 光照分量随距离衰减
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ambient *= attenuation;
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diffuse *= attenuation;
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specular *= attenuation;
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vec3 result = (ambient + diffuse + specular) ;
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FragColor = vec4(result, 1.0);
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}else{
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// 片段不在切角内：计算环境光，以免全黑
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FragColor = vec4(light.ambient * vec3(texture(material.diffuse, TexCoords)), 1.0) ;
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}
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} |