OpenGL 4.0 GLSL 用多个光照模型

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在多个光照模型中，我们需要计算每个光照模型的颜色值，然后把这些颜色值相加得到最终物体表面的颜色值。

通常，我们会创建一个统一的数组来存储光源的位置和光照强度（密度）(见下文shader）

如图：一个5个光源的场景

顶点shader

#version 430layout (location = 0) in vec3 VertexPosition;layout (location = 1) in vec3 VertexNormal;out vec3 Color;struct LightInfo {  vec4 Position;  // Light position in eye coords.  vec3 Intensity; // Light intesity (amb., diff., and spec.)};uniform LightInfo lights[5];// Material parametersuniform vec3 Kd;            // Diffuse reflectivityuniform vec3 Ka;            // Ambient reflectivityuniform vec3 Ks;            // Specular reflectivityuniform float Shininess;    // Specular shininess factoruniform mat4 ModelViewMatrix;uniform mat3 NormalMatrix;uniform mat4 ProjectionMatrix;uniform mat4 MVP;vec3 ads( int lightIndex, vec4 position, vec3 norm ){    vec3 s = normalize( vec3(lights[lightIndex].Position - position) );    vec3 v = normalize(vec3(-position));    vec3 r = reflect( -s, norm );    vec3 I = lights[lightIndex].Intensity;    return I * ( Ka + Kd * max( dot(s, norm), 0.0 ) +Ks * pow( max( dot(r,v), 0.0 ), Shininess ) );}void main(){    vec3 eyeNorm = normalize( NormalMatrix * VertexNormal);    vec4 eyePosition = ModelViewMatrix * vec4(VertexPosition,1.0);    // Evaluate the lighting equation, for each light    Color = vec3(0.0);    for( int i = 0; i < 5; i++ )        Color += ads( i, eyePosition, eyeNorm );    gl_Position = MVP * vec4(VertexPosition,1.0);}

片元shader

#version 430in vec3 Color;layout( location = 0 ) out vec4 FragColor;void main() {    FragColor = vec4(Color, 1.0);}

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