#pragma once

#include "cgp/cgp.hpp"

struct perlin_noise_parameters
{
	float persistency = 0.35f;
	float frequency_gain = 2.0f;
	int octave = 6;
	float terrain_height = 0.5f;
};

float evaluate_terrain_height(float x, float y, float terrain_length);

/** Compute a terrain mesh 
	The (x,y) coordinates of the terrain are set in [-length/2, length/2].
	The z coordinates of the vertices are computed using evaluate_terrain_height(x,y).
	The vertices are sampled along a regular grid structure in (x,y) directions. 
	The total number of vertices is N*N (N along each direction x/y) 	*/
cgp::mesh create_terrain_mesh(int N, float length);

std::vector<cgp::vec3> generate_positions_on_terrain(int N, float terrain_length);