#include "light_node.h"

//#define GL_COMPARE_REF_TO_TEXTURE 0x884E

BEGIN_NAMESPACE

light_node::light_node(light_type type_) {
    type = scene_node_type::light;
    light_type_ = type_;

    shadow_map_bias_matrix = glm::scale(glm::translate(glm::mat4(1.0f), glm::vec3(0.5f, 0.5f, 0.5f)),
                                        glm::vec3(0.5f, 0.5f, 0.5f));

    int textures_to_generate = light_type_ == light_type::point ? 6 : 1;
    for (int i = 0; i < textures_to_generate; i++) {
        GLuint shadow_map_texture_id;

        // setup the shadowmap texture
        glGenTextures(1, &shadow_map_texture_id);
        glBindTexture(GL_TEXTURE_2D, shadow_map_texture_id);

        // set texture parameters
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
        // TODO: see if we need
//        glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_INTENSITY);

        glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
                     shadow_map_width, shadow_map_width,
                     0,
                     GL_DEPTH_COMPONENT,
                     GL_UNSIGNED_BYTE,
                     nullptr);

        shadow_map[i] = std::make_shared<texture>(shadow_map_texture_id, shadow_map_width, shadow_map_width);
    }
}

void light_node::calculate_local_transform() {
    if (light_type_ == light_type::spot) {
        world_to_light_matrix[0] = glm::lookAt(position, spot_target, glm::vec3(0, 1, 0));
        light_projection_matrix[0] = glm::perspective(90.0f, 1.0f, 0.1f, 100.0f);
        glm::mat4 lightProjectionAndBiasMatrix = shadow_map_bias_matrix * light_projection_matrix[0];
        final_shadow_map_matrix[0] = lightProjectionAndBiasMatrix * world_to_light_matrix[0];
    }
}

END_NAMESPACE