62 lines
2.6 KiB
GLSL
62 lines
2.6 KiB
GLSL
// shaders/phong.frag
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#version 330 core
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// 从顶点着色器插值传入的变量
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in vec3 Position_worldspace;
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in vec3 Normal_cameraspace;
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in vec3 EyeDirection_cameraspace;
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in vec3 LightDirection_cameraspace;
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in vec2 UV;
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// 输出颜色
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out vec3 color;
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// Uniform 变量
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uniform sampler2D myTextureSampler; // 纹理采样器
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uniform vec3 lightColor; // 光源颜色
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uniform float lightPower; // 光照强度
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uniform vec3 viewPos_worldspace; // 观察者位置（世界空间）
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uniform vec3 lightPos_worldspace; // 光源位置（世界空间）
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// 材质属性 (可以作为uniform传入，这里为了简单硬编码)
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vec3 materialDiffuseColor = vec3(1.0, 1.0, 1.0); // 从纹理获取
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vec3 materialAmbientColor = vec3(0.1, 0.1, 0.1);
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vec3 materialSpecularColor = vec3(0.5, 0.5, 0.5);
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float materialShininess = 32.0;
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void main(){
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// 环境光
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vec3 AmbientLighting = materialAmbientColor * lightColor * 0.2; // 环境光强度通常较低
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// 漫反射光
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vec3 Normal_normalized = normalize(Normal_cameraspace);
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vec3 LightDirection_normalized = normalize(LightDirection_cameraspace);
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float cosTheta = clamp(dot(Normal_normalized, LightDirection_normalized), 0, 1); // clamp 避免负值
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vec3 DiffuseLighting = materialDiffuseColor * lightColor * cosTheta;
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// 镜面反射光
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vec3 EyeDirection_normalized = normalize(EyeDirection_cameraspace);
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vec3 ReflectionDirection = reflect(-LightDirection_normalized, Normal_normalized);
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float cosAlpha = clamp(dot(EyeDirection_normalized, ReflectionDirection), 0, 1);
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vec3 SpecularLighting = materialSpecularColor * lightColor * pow(cosAlpha, materialShininess);
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// 如果法线和光线方向相反（背面），则不应有镜面反射和漫反射
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if(dot(Normal_normalized, LightDirection_normalized) < 0.0){
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SpecularLighting = vec3(0,0,0);
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DiffuseLighting = vec3(0,0,0); // 可选，取决于是否做双面光照
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}
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// 从纹理采样颜色，并与漫反射材质颜色混合 (这里直接用纹理作为漫反射颜色)
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vec3 textureColor = texture(myTextureSampler, UV).rgb;
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DiffuseLighting = textureColor * lightColor * cosTheta;
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// 最终颜色 (光照强度衰减)
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float distance = length(lightPos_worldspace - Position_worldspace); // 实际光源与片元距离
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float attenuation = lightPower / (distance * distance); // 简单平方反比衰减
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color = AmbientLighting + (DiffuseLighting + SpecularLighting) * attenuation;
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// 不带衰减的简单版本（如果上面的衰减不工作，可以尝试这个）
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//color = AmbientLighting + DiffuseLighting + SpecularLighting;
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}
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