fish.cpp

#include "fish.h"

#include <algorithm>
#include <raymath.h>

#define ACCEL 200.0f
#define FRICTION 10.0f
#define MAX_SPEED 700.0f
#define RESET_SPEED 250.0f

Fish::Fish(const float width_limit, const float height_limit) {
    position = { static_cast<float>(GetRandomValue(20.0f, width_limit - 20.0f)), static_cast<float>(GetRandomValue(20.0f, height_limit - 20.0f))};
    velocity = { 0, 0 };
    acceleration = { 0, 0};
    rotation = 0.0f;
    this->width_limit = width_limit;
    this->height_limit = height_limit;
}

void Fish::Update(const float deltaTime) {
    GatherInstructions(); // Fish-specific behaviour
    ApplyPhysics(deltaTime); // Universal swimming physics
}

void Fish::ApplyPhysics(const float deltaTime) {
    // Applies acceleration based on input and friction
    if (acceleration.x != 0) {
        velocity.x += acceleration.x * ACCEL * deltaTime;
    } else {
        velocity.x -= velocity.x * FRICTION * deltaTime;
    }
    if (acceleration.y != 0) {
        velocity.y += acceleration.y * ACCEL * deltaTime;
    } else {
        velocity.y -= velocity.y * FRICTION * deltaTime;
    }

    // Limits max speed and staggers movement to simulate fish-ness
    if (Vector2Length(velocity) > MAX_SPEED) {
        velocity = Vector2Scale(Vector2Normalize(velocity), RESET_SPEED);
    }
    // Applies changes to current position
    position.x += velocity.x * deltaTime;
    position.y += velocity.y * deltaTime;

    // Check for collision
    if (position.x < 0 || position.x > width_limit) {
        position.x = std::clamp(position.x, 0.0f, width_limit);
        velocity.x = 0;
    }
    if (position.y < 0 || position.y > height_limit) {
        position.y = std::clamp(position.y, 0.0f, height_limit);
        velocity.y = 0;
    }

    // Updates sprite rotation
    if (Vector2Length(velocity) > 0.0001f) {
        rotation = atan2f(-velocity.y, -velocity.x) * (180.0f / PI);
    }
}

void Fish::Respawn(float width_limit, float height_limit) {
    position = { static_cast<float>(GetRandomValue(20.0f, width_limit - 20.0f)), static_cast<float>(GetRandomValue(20.0f, height_limit - 20.0f))},
    velocity = { 0, 0 },
    acceleration = { 0, 0};
    rotation = 0.0f;
}