fish.cpp

#include "fish.h"

Fish::Fish() {}

Fish::Fish(glm::vec2* centers, float* distances, float* radii, int id){

    for(int i = 0; i < NUM_OF_JOINTS; i++){
        this->joints[i] = Joint(centers[i], distances[i], radii[i]);
    }

    this->tail_fin_joints[0] = this->joints[NUM_OF_JOINTS-1];
    this->tail_fin_joints[0].desiredDistance = 1.5f;
    this->tail_fin_joints[1] = this->tail_fin_joints[0];
    this->tail_fin_joints[1].desiredDistance = 1.5f;

    this->fishID = id;
    this->hit_checks_result = 0;

    this->hit_check_distance = 8.0f * radii[0];
    this->updateHitChecks();

    for(int i = 0; i < NUM_OF_JOINTS + 2; i++){
        this->tex_coords[i*4  ] = static_cast<float>(i)/static_cast<float>(NUM_OF_JOINTS);
        // this->tex_coords[i*4+1] = 0.1;
        this->tex_coords[i*4+1] = 0.1 + 0.1 * std::clamp(i-10, 0, 4);
        this->tex_coords[i*4+2] = static_cast<float>(i)/static_cast<float>(NUM_OF_JOINTS);
        // this->tex_coords[i*4+3] = 0.9;
        this->tex_coords[i*4+3] = 0.9 - 0.1 * std::clamp(i-10, 0, 4);
    }
}

Fish::~Fish(){
}

void Fish::updateMoveDir(glm::vec2 new_move_dir){
    this->next_move_dir = new_move_dir;
}

void Fish::Move(float delta_time){

    // moves the head of the fish in the direction passed into the function, then updates the position of the rest of the joints
    this->joints[0].moveDirection = glm::normalize(next_move_dir);
    this->joints[0].Center += this->joints[0].moveDirection * FISH_SPEED * delta_time;

    glm::vec2 head_point;
    head_point = Global::rotateVector(this->joints[0].moveDirection, -20) * this->joints[0].circleRadius * 1.3f;
    this->outline_vertices[0] = head_point.x;
    this->outline_vertices[1] = head_point.y;

    head_point = Global::rotateVector(this->joints[0].moveDirection,  20) * this->joints[0].circleRadius * 1.3f;
    this->outline_vertices[2] = head_point.x;
    this->outline_vertices[3] = head_point.y;

    head_point = Global::rotateVector(this->joints[0].moveDirection, -50) * this->joints[0].circleRadius;
    this->outline_vertices[4] = head_point.x;
    this->outline_vertices[5] = head_point.y;

    head_point = Global::rotateVector(this->joints[0].moveDirection,  50) * this->joints[0].circleRadius;
    this->outline_vertices[6] = head_point.x;
    this->outline_vertices[7] = head_point.y;

    // also calculates the vertices of the outline
    glm::vec2 point = Global::CalculateNormal(this->joints[0].moveDirection);
    this->outline_vertices[8] = point.x * this->joints[0].circleRadius;
    this->outline_vertices[9] = point.y * this->joints[0].circleRadius;

    point = -point;
    this->outline_vertices[10] = point.x * this->joints[0].circleRadius;
    this->outline_vertices[11] = point.y * this->joints[0].circleRadius;

    this->updateJoints();
    this->updateHitChecks();

    // print_outline_data();
}

void Fish::updateJoints(){

    // used to update the position of all of the joints (except the first one, which is updated by the move function) and updates the outline vertices
    for(int i = 1; i < NUM_OF_JOINTS; i++){
        float distance_between_joints = glm::distance(this->joints[i-1].Center, this->joints[i].Center);
        float desired_distance = this->joints[i].desiredDistance;
        this->joints[i].moveDirection = glm::normalize(this->joints[i-1].Center - this->joints[i].Center);
        if(distance_between_joints - desired_distance > 1e-2 || distance_between_joints - desired_distance< 1e-3){
            this->joints[i].Center += this->joints[i].moveDirection * (distance_between_joints - desired_distance);
        }

        // The outline vertex data is positioned in relation to the center of the head

        glm::vec2 pointOnCircle = Global::CalculateNormal(this->joints[i].moveDirection);
        glm::vec2 relativePosition = this->joints[i].Center - this->joints[0].Center;
        this->outline_vertices[4*i+8] = relativePosition.x + pointOnCircle.x * this->joints[i].circleRadius;
        this->outline_vertices[4*i+9] = relativePosition.y + pointOnCircle.y * this->joints[i].circleRadius;

        pointOnCircle = -pointOnCircle;
        this->outline_vertices[4*i+10] = relativePosition.x + pointOnCircle.x * this->joints[i].circleRadius;
        this->outline_vertices[4*i+11] = relativePosition.y + pointOnCircle.y * this->joints[i].circleRadius;
       
    }

    if(this->tail_fin_joints[0].desiredDistance - glm::distance(this->tail_fin_joints[0].Center, this->joints[NUM_OF_JOINTS-1].Center) < 1e-2){
        tail_fin_joints[0].moveDirection = glm::normalize(joints[NUM_OF_JOINTS-1].Center - tail_fin_joints[0].Center);
        tail_fin_joints[0].Center += tail_fin_joints[0].moveDirection * (glm::distance(tail_fin_joints[0].Center, joints[NUM_OF_JOINTS-1].Center) - tail_fin_joints[0].desiredDistance);
    }

    if(this->tail_fin_joints[1].desiredDistance - glm::distance(this->tail_fin_joints[0].Center, this->tail_fin_joints[1].Center) < 1e-2){
        tail_fin_joints[1].moveDirection = glm::normalize(tail_fin_joints[0].Center - tail_fin_joints[1].Center);
        tail_fin_joints[1].Center += tail_fin_joints[1].moveDirection * (glm::distance(tail_fin_joints[1].Center, tail_fin_joints[0].Center) - tail_fin_joints[1].desiredDistance);
    }
}

void Fish::updateHitChecks(){

    this->hit_checks_result = 0;

    float degreeChange = HIT_CHECK_ANGLE/(NUM_OF_HIT_CHECKS-1);

    for(int i = -(NUM_OF_HIT_CHECKS/2), j = 0; j < NUM_OF_HIT_CHECKS; j++, i++){

        this->hit_checks[j] = Global::rotateVector(this->joints[0].moveDirection, -degreeChange * i);
        
        glm::vec2 hit_check_world_pos = this->joints[0].Center + this->hit_checks[j] * hit_check_distance;

        // The if checks if the position of the hit check is outside a square with round corners, the exponent (4 in this case) determines the roundness (smaller exp -> rounder)
        // the result of 1.0 is just on the edge of the window, less than is inside, more than is on the outside
        if( powf(std::abs(hit_check_world_pos.x/FRUSTUM_HALF_WIDTH), 4) +
            powf(std::abs(hit_check_world_pos.y/(FRUSTUM_HALF_WIDTH*Global::aspect_ratio)), 4) >= 1.0){

                this->hit_checks_result += (i < 0) ? -1 : 1;
        }


    }
}