// luma.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

export const lightingUniformsGLSL = /* glsl */ `\
precision highp int;

// #if (defined(SHADER_TYPE_FRAGMENT) && defined(LIGHTING_FRAGMENT)) || (defined(SHADER_TYPE_VERTEX) && defined(LIGHTING_VERTEX))
struct AmbientLight {
  vec3 color;
};

struct PointLight {
  vec3 color;
  vec3 position;
  vec3 attenuation; // 2nd order x:Constant-y:Linear-z:Exponential
};

struct DirectionalLight {
  vec3 color;
  vec3 direction;
};

uniform lightingUniforms {
  int enabled;
  int lightType;

  int directionalLightCount;
  int pointLightCount;

  vec3 ambientColor;

  vec3 lightColor0;
  vec3 lightPosition0;
  vec3 lightDirection0;
  vec3 lightAttenuation0;

  vec3 lightColor1;
  vec3 lightPosition1;
  vec3 lightDirection1;
  vec3 lightAttenuation1;

  vec3 lightColor2;
  vec3 lightPosition2;
  vec3 lightDirection2;
  vec3 lightAttenuation2;
} lighting;

PointLight lighting_getPointLight(int index) {
  switch (index) {
    case 0:
      return PointLight(lighting.lightColor0, lighting.lightPosition0, lighting.lightAttenuation0);
    case 1:
      return PointLight(lighting.lightColor1, lighting.lightPosition1, lighting.lightAttenuation1);
    case 2:
    default:  
      return PointLight(lighting.lightColor2, lighting.lightPosition2, lighting.lightAttenuation2);
  }
}

DirectionalLight lighting_getDirectionalLight(int index) {
  switch (index) {
    case 0:
      return DirectionalLight(lighting.lightColor0, lighting.lightDirection0);
    case 1:
      return DirectionalLight(lighting.lightColor1, lighting.lightDirection1);
    case 2:
    default:   
      return DirectionalLight(lighting.lightColor2, lighting.lightDirection2);
  }
} 

float getPointLightAttenuation(PointLight pointLight, float distance) {
  return pointLight.attenuation.x
       + pointLight.attenuation.y * distance
       + pointLight.attenuation.z * distance * distance;
}

// #endif
`;