Files
chameleon/Assets/Scripts/MeshPainter.cs
T
adminandClaude Opus 4.8 dcb1fc42a6 Add game mode manager with player-control and paint modes
Introduce an extensible game mode system toggled with Tab:
- Player Control: WASD movement with always-on mouse camera orbit
- Paint: player frozen, left-click paints, right-click holds to orbit

Add GameMode base class, GameModeManager, and the two concrete modes.
Refactor controlled scripts to expose clean state flags instead of
handling input themselves: ThirdPersonOrbitInput.LookMode,
PlayerCharacterController.ControlEnabled, MeshPainter.PaintingEnabled.

Also fix camera zoom: remove the obsolete /120 wheel normalization so
one scroll notch maps to one zoomSpeed step under the new Input System.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-22 15:13:46 +02:00

794 lines
30 KiB
C#

using System.Collections.Generic;
using UnityEngine;
#if ENABLE_INPUT_SYSTEM
using UnityEngine.InputSystem;
#endif
/// <summary>
/// Live mesh painting in Play mode.
/// Paints a fixed color (brush) onto the mesh's texture with the mouse.
///
/// TWO BACKENDS (switchable via <see cref="useGpu"/>, also live in Play mode):
///
/// * GPU (default): True shader painting into a RenderTexture. The brush is
/// drawn via a vertex/fragment shader - the mesh is unwrapped into the texture
/// layout using its UVs, and per texel the actual 3D position is tested against
/// the brush sphere. Edge padding against seams runs as a GPU blit.
/// Fast, because the GPU rasterizes all texels in parallel.
///
/// * CPU: Rasterization of the hit triangles on the CPU; per texel the 3D
/// position is computed barycentrically and tested against the brush sphere.
/// Edge padding via CPU dilation. Identical visual result, but more expensive.
///
/// BOTH backends paint seamlessly: a 3D sphere around the hit point captures
/// triangles on both sides of a UV seam at once (front/back share the same 3D
/// edge), no matter where they lie in the UV layout.
///
/// Simply attach to the GameObject you want to paint (e.g. paintman_UV/paintman_UV).
/// </summary>
[DisallowMultipleComponent]
public class MeshPainter : MonoBehaviour
{
/// <summary>
/// When false, mouse painting is ignored (the canvas/material stays as-is).
/// Toggled by the GameModeManager (painting is only enabled in paint mode).
/// </summary>
public bool PaintingEnabled { get; set; } = true;
[Header("Backend")]
[Tooltip("ON = GPU painting (shader/RenderTexture, fast). OFF = CPU painting. " +
"Can be toggled live in Play mode - the painted content is carried over.")]
public bool useGpu = true;
[Header("Brush")]
[Tooltip("Color used for painting.")]
public Color brushColor = Color.red;
[Tooltip("Brush radius in texels (visual size). Converted into a 3D radius per hit.")]
[Range(1, 256)]
public int brushSize = 16;
[Header("Canvas")]
[Tooltip("Resolution of the paint texture (square).")]
public int textureSize = 1024;
[Tooltip("Base color of the texture at startup (if none exists).")]
public Color baseColor = Color.white;
[Tooltip("Edge padding (texels) against visible UV seams. The color is 'bled' beyond the " +
"UV island edges so that bilinear sampling there does not pull in the unpainted " +
"base color. 0 = off.")]
[Range(0, 16)]
public int paddingTexels = 4;
[Header("Setup")]
[Tooltip("Camera for the mouse ray. Empty = Camera.main.")]
public Camera paintCamera;
[Tooltip("Only for animated meshes: re-bake the collider every frame (expensive!).")]
public bool updateColliderEveryFrame = false;
// --- shared references ---
private Renderer _renderer;
private SkinnedMeshRenderer _skinned;
private MeshCollider _collider;
private Mesh _bakedMesh;
private Material _materialInstance;
// Mesh caches (in the transform's local space = collider space).
private Vector3[] _verts;
private int[] _tris;
private Vector2[] _uvs;
private Vector3[] _triCenter; // centroid per triangle (for fast CPU culling)
private float[] _triRadius; // circumscribed radius per triangle (for fast CPU culling)
private float _avgUvToLocal = 1f; // average conversion: UV unit -> local unit
private bool _hasLastScreen;
private Vector2 _lastScreen;
private bool _gpuActive; // currently configured backend
private bool _setupValid;
// --- CPU backend ---
private Texture2D _paintTexture;
private Color32[] _pixels;
private bool[] _painted; // true = painted by the brush (persistent dilation source)
private int[] _fillStamp; // transient marker for padding texels per dilation call
private int _dilateStamp; // incremented per call -> padding from previous frames does not count as a source
private readonly List<int> _dilateScratch = new List<int>(512);
private readonly RaycastHit[] _rayHits = new RaycastHit[32]; // buffer so other colliders (player capsule, etc.) cannot block painting
private int _dx0, _dy0, _dx1, _dy1; // dirty rectangle (CPU upload)
// --- GPU backend ---
public Shader brushShader; // optional; otherwise Shader.Find("Hidden/MeshPaintBrush")
public Shader dilateShader; // optional; otherwise Shader.Find("Hidden/MeshPaintDilate")
private Material _brushMat;
private Material _dilateMat;
private RenderTexture _displayRT; // assigned to the material as _BaseMap
private RenderTexture _tempRT; // scratch for the dilation blit (ping-pong)
private bool _drewThisStroke;
private bool _prevSRGB;
// Step size (in screen pixels) for interpolation along the mouse movement.
private const float ScreenStepPixels = 5f;
// Upper bound of raycasts per frame (safeguard for very fast movements).
private const int MaxStepsPerFrame = 256;
private static readonly int BaseMapId = Shader.PropertyToID("_BaseMap");
private static readonly int MainTexId = Shader.PropertyToID("_MainTex");
private static readonly int BaseColorId = Shader.PropertyToID("_BaseColor");
private static readonly int ColorId = Shader.PropertyToID("_Color");
private static readonly int BrushColorId = Shader.PropertyToID("_BrushColor");
private static readonly int BrushCenterId = Shader.PropertyToID("_BrushCenter");
private static readonly int BrushRadiusId = Shader.PropertyToID("_BrushRadius");
private static readonly int PadId = Shader.PropertyToID("_Pad");
private void Start()
{
if (paintCamera == null) paintCamera = Camera.main;
_renderer = GetComponent<Renderer>();
_skinned = GetComponent<SkinnedMeshRenderer>();
if (_renderer == null)
{
Debug.LogError("[MeshPainter] No Renderer found on this GameObject.", this);
enabled = false;
return;
}
textureSize = Mathf.Clamp(textureSize, 32, 4096);
SetupCollider();
BuildMeshCaches();
if (_uvs == null || _uvs.Length == 0)
{
Debug.LogError("[MeshPainter] Mesh has no UVs - painting not possible.", this);
enabled = false;
return;
}
// Own material instance so the shared asset is not modified.
_materialInstance = _renderer.material; // automatically creates an instance
// Tint to white so the painted color appears unaltered.
if (_materialInstance.HasProperty(BaseColorId)) _materialInstance.SetColor(BaseColorId, Color.white);
else if (_materialInstance.HasProperty(ColorId)) _materialInstance.SetColor(ColorId, Color.white);
SetupBackend(useGpu, fromColor32: BuildBaseColors());
_setupValid = true;
Debug.Log($"[MeshPainter] Ready ({(_gpuActive ? "GPU" : "CPU")} painting, seamless). " +
"Hold the left mouse button and drag over the mesh.", this);
}
// ------------------------------------------------------------------
// Setup (shared)
// ------------------------------------------------------------------
private void SetupCollider()
{
_collider = GetComponent<MeshCollider>();
if (_collider == null) _collider = gameObject.AddComponent<MeshCollider>();
_collider.convex = false; // non-convex provides triangleIndex / textureCoord
_bakedMesh = new Mesh { name = "MeshPainter_Baked" };
BakeColliderMesh();
}
private void BakeColliderMesh()
{
if (_skinned != null)
{
// Static skinned mesh: bake into local coordinates (scale = 1).
_skinned.BakeMesh(_bakedMesh);
_collider.sharedMesh = null;
_collider.sharedMesh = _bakedMesh;
}
else
{
var mf = GetComponent<MeshFilter>();
if (mf != null) _collider.sharedMesh = mf.sharedMesh;
}
}
/// <summary>Reads vertices/triangles/UVs of the collider mesh and computes culling data.</summary>
private void BuildMeshCaches()
{
Mesh m = _collider.sharedMesh;
if (m == null) return;
_verts = m.vertices;
_tris = m.triangles;
_uvs = m.uv;
// Fallback: UVs from the original mesh (BakeMesh usually keeps them, but better safe than sorry).
if ((_uvs == null || _uvs.Length != _verts.Length) && _skinned != null && _skinned.sharedMesh != null)
_uvs = _skinned.sharedMesh.uv;
if (_uvs == null || _uvs.Length != _verts.Length) return;
int triCount = _tris.Length / 3;
_triCenter = new Vector3[triCount];
_triRadius = new float[triCount];
double sumArea3D = 0.0, sumAreaUv = 0.0;
for (int t = 0; t < triCount; t++)
{
int i0 = _tris[t * 3], i1 = _tris[t * 3 + 1], i2 = _tris[t * 3 + 2];
Vector3 a = _verts[i0], b = _verts[i1], c = _verts[i2];
Vector3 center = (a + b + c) / 3f;
_triCenter[t] = center;
float ra = (a - center).sqrMagnitude;
float rb = (b - center).sqrMagnitude;
float rc = (c - center).sqrMagnitude;
_triRadius[t] = Mathf.Sqrt(Mathf.Max(ra, Mathf.Max(rb, rc)));
sumArea3D += 0.5 * Vector3.Cross(b - a, c - a).magnitude;
Vector2 ua = _uvs[i0], ub = _uvs[i1], uc = _uvs[i2];
sumAreaUv += 0.5 * Mathf.Abs(Cross2D(ub - ua, uc - ua));
}
if (sumAreaUv > 1e-9) _avgUvToLocal = (float)System.Math.Sqrt(sumArea3D / sumAreaUv);
}
/// <summary>Builds the base-color texels (copy of the existing material texture or baseColor).</summary>
private Color32[] BuildBaseColors()
{
var px = new Color32[textureSize * textureSize];
Texture sourceTex = null;
var shared = _renderer.sharedMaterial;
if (shared != null)
{
if (shared.HasProperty(BaseMapId)) sourceTex = shared.GetTexture(BaseMapId);
if (sourceTex == null && shared.HasProperty(MainTexId)) sourceTex = shared.GetTexture(MainTexId);
}
var src = sourceTex as Texture2D;
if (src != null)
{
try
{
if (src.width == textureSize && src.height == textureSize && src.isReadable)
return src.GetPixels32();
}
catch { /* not readable -> fall back to baseColor */ }
}
Color32 c = baseColor;
for (int i = 0; i < px.Length; i++) px[i] = c;
return px;
}
// ------------------------------------------------------------------
// Backend selection / switching
// ------------------------------------------------------------------
/// <summary>Sets up the desired backend and carries over the initial image content.</summary>
private void SetupBackend(bool gpu, Color32[] fromColor32)
{
if (gpu) SetupGpu(fromColor32);
else SetupCpu(fromColor32);
_gpuActive = gpu;
}
/// <summary>Switches the backend at runtime and carries over the currently painted content.</summary>
private void SwitchBackend(bool toGpu)
{
// save the current content as Color32
Color32[] current = (_gpuActive ? ReadGpuPixels() : (Color32[])_pixels.Clone());
if (_gpuActive) TeardownGpu();
else TeardownCpu();
SetupBackend(toGpu, current);
_hasLastScreen = false;
Debug.Log($"[MeshPainter] Backend switched -> {(toGpu ? "GPU" : "CPU")} painting.", this);
}
// ------------------------------------------------------------------
// CPU backend
// ------------------------------------------------------------------
private void SetupCpu(Color32[] initial)
{
_paintTexture = new Texture2D(textureSize, textureSize, TextureFormat.RGBA32, false, false)
{
name = "MeshPainter_Canvas",
wrapMode = TextureWrapMode.Clamp,
filterMode = FilterMode.Bilinear
};
_pixels = (initial != null && initial.Length == textureSize * textureSize)
? initial
: BuildBaseColors();
_painted = new bool[textureSize * textureSize];
_fillStamp = new int[textureSize * textureSize];
_dilateStamp = 0;
_paintTexture.SetPixels32(_pixels);
_paintTexture.Apply(false);
AssignTextureToMaterial(_paintTexture);
}
private void TeardownCpu()
{
if (_paintTexture != null) { Destroy(_paintTexture); _paintTexture = null; }
_pixels = null;
_painted = null;
_fillStamp = null;
}
// ------------------------------------------------------------------
// GPU backend
// ------------------------------------------------------------------
private void SetupGpu(Color32[] initial)
{
if (brushShader == null) brushShader = Shader.Find("Hidden/MeshPaintBrush");
if (dilateShader == null) dilateShader = Shader.Find("Hidden/MeshPaintDilate");
if (brushShader == null || dilateShader == null)
{
Debug.LogError("[MeshPainter] GPU shaders not found (Hidden/MeshPaintBrush or " +
"Hidden/MeshPaintDilate). Falling back to CPU painting.", this);
useGpu = false;
SetupCpu(initial);
_gpuActive = false;
return;
}
_brushMat = new Material(brushShader) { hideFlags = HideFlags.HideAndDontSave };
_dilateMat = new Material(dilateShader) { hideFlags = HideFlags.HideAndDontSave };
_displayRT = CreateRT("MeshPainter_DisplayRT");
_tempRT = CreateRT("MeshPainter_TempRT");
// Bring the initial image content into the display RT. Alpha = 0 marks "unpainted"
// (so the base color is not mistaken for a dilation source).
var seed = initial ?? BuildBaseColors();
UploadColorsToRT(seed, _displayRT, paintedAlpha: false);
AssignTextureToMaterial(_displayRT);
}
private void TeardownGpu()
{
if (_displayRT != null) { _displayRT.Release(); Destroy(_displayRT); _displayRT = null; }
if (_tempRT != null) { _tempRT.Release(); Destroy(_tempRT); _tempRT = null; }
if (_brushMat != null) { Destroy(_brushMat); _brushMat = null; }
if (_dilateMat != null) { Destroy(_dilateMat); _dilateMat = null; }
}
private RenderTexture CreateRT(string rtName)
{
var rt = new RenderTexture(textureSize, textureSize, 0, RenderTextureFormat.ARGB32, RenderTextureReadWrite.sRGB)
{
name = rtName,
wrapMode = TextureWrapMode.Clamp,
filterMode = FilterMode.Bilinear,
antiAliasing = 1,
useMipMap = false,
autoGenerateMips = false
};
rt.Create();
return rt;
}
/// <summary>Writes Color32 data into a RenderTexture via a temporary texture.</summary>
private void UploadColorsToRT(Color32[] colors, RenderTexture rt, bool paintedAlpha)
{
var tmp = new Texture2D(textureSize, textureSize, TextureFormat.RGBA32, false, false);
if (paintedAlpha)
{
// mark the entire content as "painted" (alpha = 255) -> no dilation needed.
for (int i = 0; i < colors.Length; i++) colors[i].a = 255;
}
else
{
// mark the base color as "unpainted" (alpha = 0).
for (int i = 0; i < colors.Length; i++) colors[i].a = 0;
}
tmp.SetPixels32(colors);
tmp.Apply(false);
Graphics.Blit(tmp, rt);
Destroy(tmp);
}
/// <summary>Reads the display RT back as Color32 (for the backend switch).</summary>
private Color32[] ReadGpuPixels()
{
var prev = RenderTexture.active;
RenderTexture.active = _displayRT;
var tex = new Texture2D(textureSize, textureSize, TextureFormat.RGBA32, false, false);
tex.ReadPixels(new Rect(0, 0, textureSize, textureSize), 0, 0, false);
tex.Apply(false);
RenderTexture.active = prev;
var px = tex.GetPixels32();
Destroy(tex);
return px;
}
// ------------------------------------------------------------------
// Material
// ------------------------------------------------------------------
private void AssignTextureToMaterial(Texture tex)
{
if (_materialInstance == null) return;
if (_materialInstance.HasProperty(BaseMapId)) _materialInstance.SetTexture(BaseMapId, tex);
if (_materialInstance.HasProperty(MainTexId)) _materialInstance.SetTexture(MainTexId, tex);
}
// ------------------------------------------------------------------
// Update / input
// ------------------------------------------------------------------
private void Update()
{
if (!_setupValid) return;
// Live backend switching.
if (useGpu != _gpuActive) SwitchBackend(useGpu);
// Painting disabled by the game mode (e.g. player-control mode): do nothing.
if (!PaintingEnabled)
{
_hasLastScreen = false;
return;
}
if (updateColliderEveryFrame && _skinned != null)
{
BakeColliderMesh();
BuildMeshCaches();
}
if (!TryGetMouse(out bool pressed, out Vector2 screenPos))
return;
if (!pressed)
{
_hasLastScreen = false;
return;
}
if (paintCamera == null) return;
if (_gpuActive) BeginGpuStroke();
else { _dx0 = textureSize; _dy0 = textureSize; _dx1 = -1; _dy1 = -1; }
if (_hasLastScreen)
{
// Interpolate along the mouse movement in screen space and re-raycast at
// each step -> the stroke follows the mesh surface.
float dist = Vector2.Distance(_lastScreen, screenPos);
int steps = Mathf.Clamp(Mathf.CeilToInt(dist / ScreenStepPixels), 1, MaxStepsPerFrame);
for (int s = 1; s <= steps; s++)
PaintAtScreen(Vector2.Lerp(_lastScreen, screenPos, s / (float)steps));
}
else
{
PaintAtScreen(screenPos);
}
if (_gpuActive) EndGpuStroke();
else
{
if (paddingTexels > 0) DilatePadding(paddingTexels);
FlushDirty();
}
_lastScreen = screenPos;
_hasLastScreen = true;
}
/// <summary>
/// Raycast at a screen position. If the ray hits the mesh, a 3D sphere is painted
/// around the hit point (seamless) - via GPU or CPU depending on the backend.
/// </summary>
private void PaintAtScreen(Vector2 screenPos)
{
Ray ray = paintCamera.ScreenPointToRay(screenPos);
// Collect all hits and pick the nearest one that belongs to the paint mesh.
// A plain Physics.Raycast returns only the closest collider, so anything in
// front of the mesh (the player's CharacterController capsule, future props,
// the camera-collision proxy) would block painting. Filtering by collider
// keeps painting working from every camera angle.
int hitCount = Physics.RaycastNonAlloc(ray, _rayHits, 1000f, ~0, QueryTriggerInteraction.Ignore);
RaycastHit hit = default;
float nearest = float.MaxValue;
bool found = false;
for (int i = 0; i < hitCount; i++)
{
if (_rayHits[i].collider != _collider) continue;
if (_rayHits[i].distance < nearest)
{
nearest = _rayHits[i].distance;
hit = _rayHits[i];
found = true;
}
}
if (!found) return;
if (_verts == null || hit.triangleIndex < 0) return;
// Bring the hit point into local mesh space (= collider/vertex space).
Vector3 pLocal = transform.InverseTransformPoint(hit.point);
// Convert the brush radius (texels) into a local 3D radius using the UV
// density of the hit triangle -> the brush stays visually the same size.
float scale = _avgUvToLocal;
int t = hit.triangleIndex;
if (t * 3 + 2 < _tris.Length)
{
int i0 = _tris[t * 3], i1 = _tris[t * 3 + 1], i2 = _tris[t * 3 + 2];
float area3D = 0.5f * Vector3.Cross(_verts[i1] - _verts[i0], _verts[i2] - _verts[i0]).magnitude;
float areaUv = 0.5f * Mathf.Abs(Cross2D(_uvs[i1] - _uvs[i0], _uvs[i2] - _uvs[i0]));
if (areaUv > 1e-9f)
{
float s = Mathf.Sqrt(area3D / areaUv);
// guard against degenerate UVs: keep close to the average.
scale = Mathf.Clamp(s, _avgUvToLocal * 0.25f, _avgUvToLocal * 4f);
}
}
float radiusLocal = (brushSize / (float)textureSize) * scale;
if (radiusLocal <= 0f) return;
if (_gpuActive) DrawBrushGpu(pLocal, radiusLocal);
else PaintSphere3D(pLocal, radiusLocal);
}
// ------------------------------------------------------------------
// GPU painting
// ------------------------------------------------------------------
private void BeginGpuStroke()
{
_drewThisStroke = false;
_prevSRGB = GL.sRGBWrite;
GL.sRGBWrite = true; // correct sRGB encoding when writing into the sRGB RT (linear project)
Graphics.SetRenderTarget(_displayRT);
_brushMat.SetColor(BrushColorId, brushColor);
}
private void DrawBrushGpu(Vector3 pLocal, float radiusLocal)
{
_brushMat.SetVector(BrushCenterId, pLocal);
_brushMat.SetFloat(BrushRadiusId, radiusLocal);
if (!_brushMat.SetPass(0)) return;
int sub = _bakedMesh.subMeshCount;
for (int i = 0; i < sub; i++)
Graphics.DrawMeshNow(_bakedMesh, Matrix4x4.identity, i);
_drewThisStroke = true;
}
private void EndGpuStroke()
{
Graphics.SetRenderTarget(null);
// Edge padding against UV seams: blit the display RT through the dilation
// shader into _tempRT and then swap (the result ends up in _displayRT again).
if (_drewThisStroke && paddingTexels > 0)
{
_dilateMat.SetInt(PadId, paddingTexels);
Graphics.Blit(_displayRT, _tempRT, _dilateMat, 0);
var swap = _displayRT; _displayRT = _tempRT; _tempRT = swap;
AssignTextureToMaterial(_displayRT);
}
GL.sRGBWrite = _prevSRGB;
}
// ------------------------------------------------------------------
// CPU painting (rasterization + dilation)
// ------------------------------------------------------------------
/// <summary>
/// Paints a sphere in local 3D space: rasterizes all triangles in range into
/// the texture and colors every texel whose 3D position lies inside the sphere.
/// </summary>
private void PaintSphere3D(Vector3 pLocal, float radiusLocal)
{
Color32 col = brushColor;
float r2 = radiusLocal * radiusLocal;
int triCount = _tris.Length / 3;
float ts = textureSize;
for (int t = 0; t < triCount; t++)
{
// Fast culling: sphere against the triangle's circumscribed circle.
float reach = radiusLocal + _triRadius[t];
if ((_triCenter[t] - pLocal).sqrMagnitude > reach * reach) continue;
int i0 = _tris[t * 3], i1 = _tris[t * 3 + 1], i2 = _tris[t * 3 + 2];
Vector3 v0 = _verts[i0], v1 = _verts[i1], v2 = _verts[i2];
Vector2 uv0 = _uvs[i0], uv1 = _uvs[i1], uv2 = _uvs[i2];
// UV -> pixel.
float p0x = uv0.x * ts, p0y = uv0.y * ts;
float p1x = uv1.x * ts, p1y = uv1.y * ts;
float p2x = uv2.x * ts, p2y = uv2.y * ts;
// Bounding box in pixel space.
int minX = Mathf.Clamp(Mathf.FloorToInt(Mathf.Min(p0x, Mathf.Min(p1x, p2x))), 0, textureSize - 1);
int maxX = Mathf.Clamp(Mathf.CeilToInt(Mathf.Max(p0x, Mathf.Max(p1x, p2x))), 0, textureSize - 1);
int minY = Mathf.Clamp(Mathf.FloorToInt(Mathf.Min(p0y, Mathf.Min(p1y, p2y))), 0, textureSize - 1);
int maxY = Mathf.Clamp(Mathf.CeilToInt(Mathf.Max(p0y, Mathf.Max(p1y, p2y))), 0, textureSize - 1);
if (maxX < minX || maxY < minY) continue;
// Barycentric denominator.
float d = (p1y - p2y) * (p0x - p2x) + (p2x - p1x) * (p0y - p2y);
if (Mathf.Abs(d) < 1e-7f) continue;
float invD = 1f / d;
const float eps = -1e-4f; // small tolerance against 1px cracks between triangles
for (int y = minY; y <= maxY; y++)
{
float py = y + 0.5f;
int rowStart = y * textureSize;
for (int x = minX; x <= maxX; x++)
{
float px = x + 0.5f;
float a = ((p1y - p2y) * (px - p2x) + (p2x - p1x) * (py - p2y)) * invD;
if (a < eps) continue;
float b = ((p2y - p0y) * (px - p2x) + (p0x - p2x) * (py - p2y)) * invD;
if (b < eps) continue;
float c = 1f - a - b;
if (c < eps) continue;
// 3D position of the texel via barycentric interpolation.
float wx = a * v0.x + b * v1.x + c * v2.x;
float wy = a * v0.y + b * v1.y + c * v2.y;
float wz = a * v0.z + b * v1.z + c * v2.z;
float ddx = wx - pLocal.x, ddy = wy - pLocal.y, ddz = wz - pLocal.z;
if (ddx * ddx + ddy * ddy + ddz * ddz > r2) continue;
_pixels[rowStart + x] = col;
_painted[rowStart + x] = true;
if (x < _dx0) _dx0 = x;
if (x > _dx1) _dx1 = x;
if (y < _dy0) _dy0 = y;
if (y > _dy1) _dy1 = y;
}
}
}
}
/// <summary>
/// Edge padding / texture dilation against visible UV seams (CPU).
/// Colors a thin border (pad texels) around the freshly painted areas with their
/// color. The dilation source is exclusively brush-painted texels (_painted).
/// </summary>
private void DilatePadding(int pad)
{
if (_dx1 < _dx0 || _dy1 < _dy0) return; // nothing painted
int x0 = Mathf.Max(0, _dx0 - pad);
int y0 = Mathf.Max(0, _dy0 - pad);
int x1 = Mathf.Min(textureSize - 1, _dx1 + pad);
int y1 = Mathf.Min(textureSize - 1, _dy1 + pad);
_dilateStamp++; // unique per call -> padding from previous frames does not count as a source
for (int iter = 0; iter < pad; iter++)
{
_dilateScratch.Clear();
for (int y = y0; y <= y1; y++)
{
int row = y * textureSize;
for (int x = x0; x <= x1; x++)
{
int idx = row + x;
if (_painted[idx] || _fillStamp[idx] == _dilateStamp) continue;
if (TryFindPaddingSource(x, y, out Color32 c))
{
_pixels[idx] = c;
_dilateScratch.Add(idx);
if (x < _dx0) _dx0 = x;
if (x > _dx1) _dx1 = x;
if (y < _dy0) _dy0 = y;
if (y > _dy1) _dy1 = y;
}
}
}
for (int k = 0; k < _dilateScratch.Count; k++)
_fillStamp[_dilateScratch[k]] = _dilateStamp;
if (_dilateScratch.Count == 0) break;
}
}
/// <summary>Searches the 8-neighborhood for a source texel (painted or already padded) and returns its color.</summary>
private bool TryFindPaddingSource(int x, int y, out Color32 col)
{
for (int oy = -1; oy <= 1; oy++)
{
int ny = y + oy;
if (ny < 0 || ny >= textureSize) continue;
int nrow = ny * textureSize;
for (int ox = -1; ox <= 1; ox++)
{
if (ox == 0 && oy == 0) continue;
int nx = x + ox;
if (nx < 0 || nx >= textureSize) continue;
int nidx = nrow + nx;
if (_painted[nidx] || _fillStamp[nidx] == _dilateStamp)
{
col = _pixels[nidx];
return true;
}
}
}
col = default;
return false;
}
/// <summary>Uploads only the region changed this frame to the GPU once (CPU backend).</summary>
private void FlushDirty()
{
if (_dx1 < _dx0 || _dy1 < _dy0) return; // nothing painted
int bw = _dx1 - _dx0 + 1;
int bh = _dy1 - _dy0 + 1;
var block = new Color32[bw * bh];
for (int y = 0; y < bh; y++)
System.Array.Copy(_pixels, (_dy0 + y) * textureSize + _dx0, block, y * bw, bw);
_paintTexture.SetPixels32(_dx0, _dy0, bw, bh, block);
_paintTexture.Apply(false);
}
// ------------------------------------------------------------------
// Helpers
// ------------------------------------------------------------------
private static float Cross2D(Vector2 a, Vector2 b) => a.x * b.y - a.y * b.x;
private bool TryGetMouse(out bool pressed, out Vector2 screenPos)
{
pressed = false;
screenPos = Vector2.zero;
#if ENABLE_INPUT_SYSTEM
var mouse = Mouse.current;
if (mouse != null)
{
pressed = mouse.leftButton.isPressed;
screenPos = mouse.position.ReadValue();
return true;
}
#endif
#if ENABLE_LEGACY_INPUT_MANAGER
pressed = Input.GetMouseButton(0);
screenPos = Input.mousePosition;
return true;
#else
return false;
#endif
}
private void OnDestroy()
{
if (_bakedMesh != null) Destroy(_bakedMesh);
if (_materialInstance != null) Destroy(_materialInstance);
TeardownCpu();
TeardownGpu();
}
}