//============================================================================== // Script: TerrainPainter // Author: Victor NP // Date Created: [2023-07-22] // Description: This script controls a terrain painting tool in Unity. It // allows the user to 'paint' onto the terrain using a brush. The size and shape of the // brush is controlled by a decal projector and a 2D texture. // // © [2023] Vairondor. All rights reserved. //============================================================================== using UnityEngine; using UnityEngine.Rendering.HighDefinition;
using UnityEngine;
using UnityEngine.Rendering.HighDefinition;
namespace WorldForge { ///
/// Enum for different types of terrain modification. ///
public enum TerrainModificationMode { RaiseLower, Flatten, Smooth, Paint }
public class TerrainPainter : MonoBehaviour
{
public Terrain terrain;
public Texture2D brushTexture;
public DecalProjector brushDecalProjector; // Reference to a DecalProjector component
public float brushScale = 1f; // Adjust this to change the size of the brush
public TerrainModificationMode mode = TerrainModificationMode.RaiseLower;
public int layerIndex = -1;
private TerrainData terrainData;
// Add a dictionary to store the modified coordinates and their strengths
private Dictionary<Vector2Int, float> selectedCoordinates = new Dictionary<Vector2Int, float>();
void Start()
{
terrain = GameManager.Instance.terrain.current;
terrainData = terrain.terrainData;
}
private void Update()
{
// Clear the dictionary at the beginning of each frame
selectedCoordinates.Clear();
// Check if the user is clicking the left mouse button (button index 0)
if (Input.GetMouseButton(0))
{
HandleTerrainModification();
}
}
/// <summary>
/// Handles terrain modification when the left mouse button is clicked.
/// Raycasts from the camera to the mouse position to determine if the mouse is hitting the terrain.
/// If so, it calculates the brush strength and updates the selected coordinates for modification.
/// Finally, applies the modifications to the terrain's heightmap based on the selected coordinates.
/// </summary>
private void HandleTerrainModification()
{
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
RaycastHit hit;
if (Physics.Raycast(ray, out hit))
{
Terrain terrain = hit.collider.GetComponent<Terrain>();
if (terrain != null)
{
float brushStrength = 1f;
UpdateSelectedCoordinates(hit.point, brushStrength);
}
}
}
/// <summary>
/// Update the dictionary with the modified coordinates and strengths based on the brush position and strength.
/// </summary>
/// <param name = "brushPosition">The position of the brush in world space.</param>
/// <param name = "brushStrength">The strength of the brush.</param>
private void UpdateSelectedCoordinates(Vector3 brushPosition, float brushStrength)
{
Vector2Int startIndices = GetHeightmapStartIndices(brushPosition);
Vector2Int brushAreaSize = GetBrushAreaSize();
startIndices = ClampHeightmapIndices(startIndices, brushAreaSize);
// Loop through the brush area and update the dictionary with the modified coordinates and strengths
for (int x = startIndices.x; x < startIndices.x + brushAreaSize.x; x++)
{
for (int y = startIndices.y; y < startIndices.y + brushAreaSize.y; y++)
{
Vector2Int coordinate = new Vector2Int(x, y);
float strength = GetBrushStrength(x - startIndices.x, y - startIndices.y) * brushStrength;
if (selectedCoordinates.ContainsKey(coordinate))
{
// If the coordinate is already in the dictionary, add the new strength to the existing one
selectedCoordinates[coordinate] += strength;
}
else
{
// If the coordinate is not in the dictionary, add it with the strength
selectedCoordinates.Add(coordinate, strength);
}
}
}
}
/// <summary>
/// Converts a point in world space to a position on the heightmap.
/// </summary>
/// <param name = "point">A point in world space.</param>
/// <returns>The corresponding position on the heightmap.</returns>
private Vector2Int GetHeightmapStartIndices(Vector3 point)
{
// Convert the hit position from world space to terrain-local space
Vector3 terrainLocalPos = terrain.transform.InverseTransformPoint(point);
// Calculate which part of the heightmap we want to modify
int heightmapX = (int)((terrainLocalPos.x / terrainData.size.x * terrainData.heightmapResolution) - (brushTexture.width * brushScale / 2f));
int heightmapZ = (int)((terrainLocalPos.z / terrainData.size.z * terrainData.heightmapResolution) - (brushTexture.height * brushScale / 2f));
return new Vector2Int(heightmapX, heightmapZ);
}
/// <summary>
/// Calculates the size of the brush in heightmap coordinates.
/// </summary>
/// <returns>The size of the brush in heightmap coordinates.</returns>
private Vector2Int GetBrushAreaSize()
{
// Define the width and height of the area around the hit point we want to modify
int width = (int)(brushTexture.width * brushScale);
int height = (int)(brushTexture.height * brushScale);
return new Vector2Int(width, height);
}
/// <summary>
/// Ensures the start indices don't exceed the heightmap boundaries and handles edge cases.
/// </summary>
/// <param name = "startIndices">The start indices of the brush on the heightmap.</param>
/// <param name = "brushAreaSize">The size of the brush in heightmap coordinates.</param>
/// <returns>The clamped start indices.</returns>
private Vector2Int ClampHeightmapIndices(Vector2Int startIndices, Vector2Int brushAreaSize)
{
// Calculate the end indices of the brush area
Vector2Int endIndices = startIndices + brushAreaSize;
// Ensure we don't exceed the heightmap boundaries
startIndices.x = Mathf.Clamp(startIndices.x, 0, terrainData.heightmapResolution - brushAreaSize.x);
startIndices.y = Mathf.Clamp(startIndices.y, 0, terrainData.heightmapResolution - brushAreaSize.y);
// Check if the end indices go beyond the terrain's edge
if (endIndices.x > terrainData.heightmapResolution)
{
// Calculate the excess amount beyond the terrain's edge
int excessX = endIndices.x - terrainData.heightmapResolution;
// Adjust the start index to clip the brush
startIndices.x -= excessX;
}
if (endIndices.y > terrainData.heightmapResolution)
{
// Calculate the excess amount beyond the terrain's edge
int excessY = endIndices.y - terrainData.heightmapResolution;
// Adjust the start index to clip the brush
startIndices.y -= excessY;
}
return startIndices;
}
/// <summary>
/// Calculates the strength of the brush at a specific point within the brush texture.
/// </summary>
/// <param name = "x">The x coordinate within the brush texture.</param>
/// <param name = "y">The y coordinate within the brush texture.</param>
/// <returns>The strength of the brush at the specified point.</returns>
private float GetBrushStrength(int x, int y)
{
// Get the color of the pixel at this point in the brush texture
Color pixelColor = brushTexture.GetPixel(x, y);
// The strength of the brush is determined by the alpha value of the pixel
return pixelColor.a;
}
}
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