5.4.light_casters.fs

#version 330 core
out vec4 FragColor;


struct Material {
    sampler2D diffuse;
    sampler2D specular;    
    float shininess;
}; 

struct Light {
    vec3 position;  
    vec3 direction;
    float cutOff;
    float outerCutOff;
  
    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
	
    float constant;
    float linear;
    float quadratic;
};

struct PointLight{
    vec3 position;

    float constant;
    float linear;
    float quadratic;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};
struct DirLight{
    vec3 position;

    vec3 ambient;
    vec3 diffuse;
    vec3 specular;
};


in vec3 FragPos;  
in vec3 Normal;  
in vec2 TexCoords;
  
uniform vec3 viewPos;
uniform Material material;
uniform Light light;
uniform DirLight dirLight;
uniform PointLight pointLight;



vec3 CalcDirLight(DirLight light, vec3 normal, vec3 viewDir )
{
    vec3 lightDir = normalize(-light.position);

    float diff = max(dot(normal, lightDir), 0.0);

    vec3 reflectDir =reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);

    vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, TexCoords));  
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    
    return (ambient + diffuse + specular);
}

vec3 CalcPointLight(PointLight light, vec3 normal, vec3 fragPos, vec3 viewDir)
{
    vec3 lightDir = normalize(viewPos - fragPos);
     float diff = max(dot(normal, lightDir), 0.0);

    vec3 reflectDir =reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);

    float distance = length(light.position - fragPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + light.quadratic * (distance * distance));  
    vec3 ambient = light.ambient * vec3(texture(material.diffuse, TexCoords));
    vec3 diffuse = light.diffuse * diff * vec3(texture(material.diffuse, TexCoords));  
    vec3 specular = light.specular * spec * vec3(texture(material.specular, TexCoords));
    ambient  *= attenuation; 
    diffuse   *= attenuation;
    specular *= attenuation;   
    return (ambient + diffuse + specular);
}

void main()
{
    // ambient
    vec3 ambient = light.ambient * texture(material.diffuse, TexCoords).rgb;
    
    // diffuse 
    vec3 norm = normalize(Normal);
    vec3 lightDir = normalize(light.position - FragPos);
    float diff = max(dot(norm, lightDir), 0.0);
    vec3 diffuse = light.diffuse * diff * texture(material.diffuse, TexCoords).rgb;  
    
    // specular
    vec3 viewDir = normalize(viewPos - FragPos);
    vec3 reflectDir = reflect(-lightDir, norm);  
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), material.shininess);
    vec3 specular = light.specular * spec * texture(material.specular, TexCoords).rgb;  
    
    // spotlight (soft edges)
    float theta = dot(lightDir, normalize(-light.direction)); 
    float epsilon = (light.cutOff - light.outerCutOff);
    float intensity = clamp((theta - light.outerCutOff) / epsilon, 0.0, 1.0);
    diffuse  *= intensity;
    specular *= intensity;
    
    // attenuation
    float distance    = length(light.position - FragPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + light.quadratic * (distance * distance));    
    ambient  *= attenuation; 
    diffuse   *= attenuation;
    specular *= attenuation;   
        
    vec3 result = ambient + diffuse + specular;
    result+= CalcDirLight(dirLight, norm, viewDir);
    result+=CalcPointLight(pointLight, norm, FragPos, viewDir);

    

    FragColor = vec4(result, 1.0);
}