7.5 KiB
7.5 KiB
Modify the Terrain heightmap
The example code below tells Unity to use the built-in painting Material to modify the Terrain's heightmap, and render a Brush preview in the Scene view.
using UnityEngine;
using UnityEditor;
using UnityEditor.TerrainTools;
class CustomTerrainTool : TerrainPaintToolWithOverlays<CustomTerrainTool>
{
private float m_BrushOpacity = 1f;
private float m_BrushSize = 25f;
private float m_BrushRotation = 0f;
// Name of the Terrain Tool. This appears in the tool UI.
public override string GetName()
{
return "Examples/Custom Terrain Tool";
}
// Description for the Terrain Tool. This appears in the tool UI.
public override string GetDescription()
{
return "This is a custom Terrain Tool that modifies the Terrain heightmap.";
}
// Override this function to add UI elements to the tool settings
public override void OnToolSettingsGUI(Terrain terrain, IOnInspectorGUI editContext)
{
m_BrushOpacity = EditorGUILayout.Slider("Opacity", m_BrushOpacity, 0, 1);
m_BrushSize = EditorGUILayout.Slider("Size", m_BrushSize, .001f, 100f);
m_BrushRotation = EditorGUILayout.Slider("Rotation", m_BrushRotation, 0, 360);
}
// Override this function to add UI elements to the inspector UI. If the UI is the same between the Inspector
// and Tool Settings overlay, you can call one from the other.
public override void OnInspectorGUI(Terrain terrain, IOnInspectorGUI editContext)
{
OnToolSettingsGUI(terrain, editContext);
}
// Ease of use function for rendering modified Terrain Texture data into a PaintContext. This is used in both OnRenderBrushPreview and OnPaint.
private void RenderIntoPaintContext(UnityEngine.TerrainTools.PaintContext paintContext, Texture brushTexture, UnityEngine.TerrainTools.BrushTransform brushXform)
{
// Get the built-in painting Material reference
Material mat = UnityEngine.TerrainTools.TerrainPaintUtility.GetBuiltinPaintMaterial();
// Bind the current brush texture
mat.SetTexture("_BrushTex", brushTexture);
// Bind the tool-specific shader properties
var opacity = Event.current.control ? -m_BrushOpacity : m_BrushOpacity;
mat.SetVector("_BrushParams", new Vector4(opacity, 0.0f, 0.0f, 0.0f));
// Setup the material for reading from/writing into the PaintContext texture data. This is a necessary step to setup the correct shader properties for appropriately transforming UVs and sampling textures within the shader
UnityEngine.TerrainTools.TerrainPaintUtility.SetupTerrainToolMaterialProperties(paintContext, brushXform, mat);
// Render into the PaintContext's destinationRenderTexture using the built-in painting Material - the id for the Raise/Lower pass is 0.
Graphics.Blit(paintContext.sourceRenderTexture, paintContext.destinationRenderTexture, mat, 0);
}
// Render Tool previews in the SceneView
public override void OnRenderBrushPreview(Terrain terrain, IOnSceneGUI editContext)
{
// Dont render preview if this isnt a Repaint
if (Event.current.type != EventType.Repaint) return;
// Only do the rest if user mouse hits valid terrain
if (!editContext.hitValidTerrain) return;
// Get the current BrushTransform under the mouse position relative to the Terrain
UnityEngine.TerrainTools.BrushTransform brushXform = UnityEngine.TerrainTools.TerrainPaintUtility.CalculateBrushTransform(terrain, editContext.raycastHit.textureCoord, m_BrushSize, m_BrushRotation);
// Get the PaintContext for the current BrushTransform. This has a sourceRenderTexture from which to read existing Terrain texture data.
UnityEngine.TerrainTools.PaintContext paintContext = UnityEngine.TerrainTools.TerrainPaintUtility.BeginPaintHeightmap(terrain, brushXform.GetBrushXYBounds(), 1);
// Get the built-in Material for rendering Brush Previews
Material previewMaterial = TerrainPaintUtilityEditor.GetDefaultBrushPreviewMaterial();
// Render the brush preview for the sourceRenderTexture. This will show up as a projected brush mesh rendered on top of the Terrain
TerrainPaintUtilityEditor.DrawBrushPreview(paintContext, TerrainBrushPreviewMode.SourceRenderTexture, editContext.brushTexture, brushXform, previewMaterial, 0);
// Render changes into the PaintContext destinationRenderTexture
RenderIntoPaintContext(paintContext, editContext.brushTexture, brushXform);
// Restore old render target.
RenderTexture.active = paintContext.oldRenderTexture;
// Bind the sourceRenderTexture to the preview Material. This is used to compute deltas in height
previewMaterial.SetTexture("_HeightmapOrig", paintContext.sourceRenderTexture);
// Render a procedural mesh displaying the delta/displacement in height from the source Terrain texture data. When modifying Terrain height, this shows how much the next paint operation will alter the Terrain height
TerrainPaintUtilityEditor.DrawBrushPreview(paintContext, TerrainBrushPreviewMode.DestinationRenderTexture, editContext.brushTexture, brushXform, previewMaterial, 1);
// Cleanup resources
UnityEngine.TerrainTools.TerrainPaintUtility.ReleaseContextResources(paintContext);
}
// Perform painting operations that modify the Terrain texture data
public override bool OnPaint(Terrain terrain, IOnPaint editContext)
{
// Get the current BrushTransform under the mouse position relative to the Terrain
UnityEngine.TerrainTools.BrushTransform brushXform = UnityEngine.TerrainTools.TerrainPaintUtility.CalculateBrushTransform(terrain, editContext.uv, m_BrushSize, m_BrushRotation);
// Get the PaintContext for the current BrushTransform. This has a sourceRenderTexture from which to read existing Terrain texture data
// and a destinationRenderTexture into which to write new Terrain texture data
UnityEngine.TerrainTools.PaintContext paintContext = UnityEngine.TerrainTools.TerrainPaintUtility.BeginPaintHeightmap(terrain, brushXform.GetBrushXYBounds());
// Call the common rendering function used by OnRenderBrushPreview and OnPaint
RenderIntoPaintContext(paintContext, editContext.brushTexture, brushXform);
// Commit the modified PaintContext with a provided string for tracking Undo operations. This function handles Undo and resource cleanup for you
UnityEngine.TerrainTools.TerrainPaintUtility.EndPaintHeightmap(paintContext, "Terrain Paint - Raise or Lower Height");
// Return whether or not Trees and Details should be hidden while painting with this Terrain Tool
return true;
}
// Return true for this property to display the brush attributes overlay
public override bool HasBrushAttributes => true;
// Return true for this property to display the brush selector overlay
public override bool HasBrushMask => true;
// Return true for this property to display the tool settings overlay
public override bool HasToolSettings => true;
// File names of the light theme icons - prepend d_ to the file name to generate dark theme variants.
// Override these to specify your own icon.
// public override string OnIcon => "Assets/Icon_on.png";
// public override string OffIcon => "Assets/Icon_off.png";
// The toolbar category the icon appears under.
public override TerrainCategory Category => TerrainCategory.CustomBrushes;
// Where in the icon list the icon appears.
public override int IconIndex => 100;
}