#version 450

layout(location = 0) in vec4 frag_color;
layout(location = 1) in vec4 frag_mcolor;
layout(location = 2) in vec2 frag_texcoord;
layout(location = 3) in flat int frag_texindex;
layout(location = 4) in vec3 frag_pos;
layout(location = 5) in vec3 frag_normal;

layout(location = 0) out vec4 outColor;

layout(binding = 0) uniform GlobalVars {
    mat4 proj_view;
    vec3 light;
    vec3 eye;
} global;

layout(binding = 2) uniform sampler2D teximage[2];

void main() {
    // vec3 light_pos = vec3(5.0, 5.0, -5.0);
    // vec3 view_pos = vec3(3.0, 3.0, 3.0);
    
    float ambiant = 0.2;
    
    vec3 light_dir = normalize(global.light - frag_pos);
    float diff = max(dot(frag_normal, light_dir), 0.0);

    float specular_strength = 0.7;
    
    vec3 view_dir = normalize(global.eye - frag_pos);
    vec3 reflect_dir = reflect(-light_dir, frag_normal);
    float spec = pow(max(dot(view_dir, reflect_dir), 0.0), 64);
    float specular = specular_strength * spec;

    float factor = ambiant + diff + specular;
    vec4 pre_color = frag_color * texture(teximage[frag_texindex], frag_texcoord);
    pre_color = vec4(mix((factor * pre_color).rgb, frag_mcolor.rgb, frag_mcolor.a), pre_color.a);
    outColor = pre_color;
}