Add support for segment-shaped water contact patches

src/rendering/water-material.ts

@@ -28,7 +28,10 @@ export interface WaterContactTriangleMesh {
 
 export type WaterContactSource = WaterContactBounds | WaterContactOrientedBox | WaterContactTriangleMesh;
 
+export type WaterContactPatchShape = "box" | "segment";
+
 export interface WaterContactPatch {
+  shape: WaterContactPatchShape;
   x: number;
   z: number;
   halfWidth: number;
@@ -42,6 +45,7 @@ export interface WaterMaterialResult {
   animationUniform: { value: number } | null;
   contactPatchesUniform: { value: Vector4[] } | null;
   contactPatchAxesUniform: { value: Vector2[] } | null;
+  contactPatchShapesUniform: { value: number[] } | null;
 }
 
 interface WaterMaterialOptions {
@@ -66,7 +70,7 @@ interface OrientedWaterVolume {
   size: Vec3;
 }
 
-interface TriangleMeshPatchSample {
+interface TriangleMeshSegmentSample {
   patch: WaterContactPatch;
   normal: Vector3;
 }
@@ -389,6 +393,7 @@ function createPatchFromProjectedPoints(projectedPoints: Vector2[], preferredAxi
   const patchCenterSecondary = (minSecondary + maxSecondary) * 0.5;
 
   return {
+    shape: "box",
     x: primaryAxis.x * patchCenterPrimary + secondaryAxis.x * patchCenterSecondary,
     z: primaryAxis.y * patchCenterPrimary + secondaryAxis.y * patchCenterSecondary,
     halfWidth,
@@ -410,6 +415,28 @@ function computeTriangleNormal(pointA: Vector3, pointB: Vector3, pointC: Vector3
   return normal.normalize();
 }
 
+function createSegmentPatchFromEndpoints(startPoint: Vector2, endPoint: Vector2, radius: number): WaterContactPatch | null {
+  const axis = endPoint.clone().sub(startPoint);
+  const length = axis.length();
+
+  if (length <= WATER_CONTACT_EPSILON) {
+    return null;
+  }
+
+  axis.divideScalar(length);
+  const center = startPoint.clone().add(endPoint).multiplyScalar(0.5);
+
+  return {
+    shape: "segment",
+    x: center.x,
+    z: center.y,
+    halfWidth: length * 0.5,
+    halfDepth: Math.max(radius, WATER_CONTACT_EPSILON),
+    axisX: axis.x,
+    axisZ: axis.y
+  };
+}
+
 function addUniqueProjectedPoint(points: Vector2[], point: Vector2) {
   const alreadyExists = points.some(
     (candidate) => Math.abs(candidate.x - point.x) <= WATER_CONTACT_EPSILON && Math.abs(candidate.y - point.y) <= WATER_CONTACT_EPSILON
@@ -488,7 +515,7 @@ function createWaterlineSegmentFromPolygon(polygon: Vector3[], surfaceY: number)
   return [startPoint.clone(), endPoint.clone()] as const;
 }
 
-function createPatchCornerPoints(patch: WaterContactPatch) {
+function createSegmentEndpoints(patch: WaterContactPatch) {
   const axis = new Vector2(patch.axisX, patch.axisZ);
   if (axis.lengthSq() <= WATER_CONTACT_EPSILON) {
     axis.set(1, 0);
@@ -496,17 +523,13 @@ function createPatchCornerPoints(patch: WaterContactPatch) {
     axis.normalize();
   }
 
-  const perpendicularAxis = new Vector2(-axis.y, axis.x);
   const center = new Vector2(patch.x, patch.z);
-  return [
-    center.clone().add(axis.clone().multiplyScalar(patch.halfWidth)).add(perpendicularAxis.clone().multiplyScalar(patch.halfDepth)),
-    center.clone().add(axis.clone().multiplyScalar(patch.halfWidth)).add(perpendicularAxis.clone().multiplyScalar(-patch.halfDepth)),
-    center.clone().add(axis.clone().multiplyScalar(-patch.halfWidth)).add(perpendicularAxis.clone().multiplyScalar(patch.halfDepth)),
-    center.clone().add(axis.clone().multiplyScalar(-patch.halfWidth)).add(perpendicularAxis.clone().multiplyScalar(-patch.halfDepth))
-  ];
+  const offset = axis.clone().multiplyScalar(patch.halfWidth);
+
+  return [center.clone().sub(offset), center.clone().add(offset)] as const;
 }
 
-function measurePatchExtentsInBasis(points: Vector2[], axis: Vector2) {
+function measureSegmentExtentsInBasis(points: Vector2[], radius: number, axis: Vector2) {
   const perpendicularAxis = new Vector2(-axis.y, axis.x);
   let minPrimary = Number.POSITIVE_INFINITY;
   let maxPrimary = Number.NEGATIVE_INFINITY;
@@ -525,8 +548,44 @@ function measurePatchExtentsInBasis(points: Vector2[], axis: Vector2) {
   return {
     minPrimary,
     maxPrimary,
-    minSecondary,
-    maxSecondary
+    minSecondary: minSecondary - radius,
+    maxSecondary: maxSecondary + radius
+  };
+}
+
+function createSegmentPatchFromCluster(cluster: {
+  axis: Vector2;
+  endpoints: Vector2[];
+  maxRadius: number;
+  extents: ReturnType<typeof measureSegmentExtentsInBasis>;
+}): WaterContactPatch | null {
+  const axis = cluster.axis.clone();
+
+  if (axis.lengthSq() <= WATER_CONTACT_EPSILON) {
+    axis.set(1, 0);
+  } else {
+    axis.normalize();
+  }
+
+  const perpendicularAxis = new Vector2(-axis.y, axis.x);
+  const halfWidth = (cluster.extents.maxPrimary - cluster.extents.minPrimary) * 0.5;
+  const halfDepth = Math.max(cluster.maxRadius, (cluster.extents.maxSecondary - cluster.extents.minSecondary) * 0.5);
+
+  if (halfWidth <= WATER_CONTACT_EPSILON || halfDepth <= WATER_CONTACT_EPSILON) {
+    return null;
+  }
+
+  const centerPrimary = (cluster.extents.minPrimary + cluster.extents.maxPrimary) * 0.5;
+  const centerSecondary = (cluster.extents.minSecondary + cluster.extents.maxSecondary) * 0.5;
+
+  return {
+    shape: "segment",
+    x: axis.x * centerPrimary + perpendicularAxis.x * centerSecondary,
+    z: axis.y * centerPrimary + perpendicularAxis.y * centerSecondary,
+    halfWidth,
+    halfDepth,
+    axisX: axis.x,
+    axisZ: axis.y
   };
 }
 
@@ -552,17 +611,17 @@ function getTriangleMeshMergeSettings(mergeProfile: WaterContactTriangleMesh["me
   };
 }
 
-function mergeTriangleMeshContactPatches(rawPatches: TriangleMeshPatchSample[], minimumThickness: number, mergeProfile: WaterContactTriangleMesh["mergeProfile"]) {
+function mergeTriangleMeshContactPatches(rawPatches: TriangleMeshSegmentSample[], minimumThickness: number, mergeProfile: WaterContactTriangleMesh["mergeProfile"]) {
   const mergeSettings = getTriangleMeshMergeSettings(mergeProfile, minimumThickness);
   const clusters: Array<{
     axis: Vector2;
     normal: Vector3;
-    points: Vector2[];
-    extents: ReturnType<typeof measurePatchExtentsInBasis>;
+    endpoints: Vector2[];
+    maxRadius: number;
+    extents: ReturnType<typeof measureSegmentExtentsInBasis>;
   }> = [];
 
   for (const rawPatch of rawPatches) {
-    const patchPoints = createPatchCornerPoints(rawPatch.patch);
     const patchAxis = new Vector2(rawPatch.patch.axisX, rawPatch.patch.axisZ);
     if (patchAxis.lengthSq() <= WATER_CONTACT_EPSILON) {
       patchAxis.set(1, 0);
@@ -570,6 +629,8 @@ function mergeTriangleMeshContactPatches(rawPatches: TriangleMeshPatchSample[],
       patchAxis.normalize();
     }
 
+    const patchEndpoints = createSegmentEndpoints(rawPatch.patch);
+
     let merged = false;
 
     for (const cluster of clusters) {
@@ -583,7 +644,7 @@ function mergeTriangleMeshContactPatches(rawPatches: TriangleMeshPatchSample[],
         continue;
       }
 
-      const patchExtents = measurePatchExtentsInBasis(patchPoints, cluster.axis);
+      const patchExtents = measureSegmentExtentsInBasis(patchEndpoints, rawPatch.patch.halfDepth, cluster.axis);
       const primaryGap = Math.max(0, Math.max(cluster.extents.minPrimary - patchExtents.maxPrimary, patchExtents.minPrimary - cluster.extents.maxPrimary));
       const secondaryGap = Math.max(0, Math.max(cluster.extents.minSecondary - patchExtents.maxSecondary, patchExtents.minSecondary - cluster.extents.maxSecondary));
       const clusterPrimarySpan = cluster.extents.maxPrimary - cluster.extents.minPrimary;
@@ -601,8 +662,9 @@ function mergeTriangleMeshContactPatches(rawPatches: TriangleMeshPatchSample[],
         continue;
       }
 
-      cluster.points.push(...patchPoints.map((point) => point.clone()));
-      cluster.extents = measurePatchExtentsInBasis(cluster.points, cluster.axis);
+      cluster.endpoints.push(...patchEndpoints.map((point) => point.clone()));
+      cluster.maxRadius = Math.max(cluster.maxRadius, rawPatch.patch.halfDepth);
+      cluster.extents = measureSegmentExtentsInBasis(cluster.endpoints, cluster.maxRadius, cluster.axis);
       merged = true;
       break;
     }
@@ -611,14 +673,15 @@ function mergeTriangleMeshContactPatches(rawPatches: TriangleMeshPatchSample[],
       clusters.push({
         axis: patchAxis,
         normal: rawPatch.normal.clone(),
-        points: patchPoints.map((point) => point.clone()),
-        extents: measurePatchExtentsInBasis(patchPoints, patchAxis)
+        endpoints: patchEndpoints.map((point) => point.clone()),
+        maxRadius: rawPatch.patch.halfDepth,
+        extents: measureSegmentExtentsInBasis(patchEndpoints, rawPatch.patch.halfDepth, patchAxis)
       });
     }
   }
 
   return clusters
-    .map((cluster) => createPatchFromProjectedPoints(cluster.points, cluster.axis, minimumThickness))
+    .map((cluster) => createSegmentPatchFromCluster(cluster))
     .filter((patch): patch is WaterContactPatch => patch !== null);
 }
 
@@ -645,7 +708,7 @@ function appendTriangleMeshContactPatches(
   );
   const bandMinimumThickness = Math.max(0.08, Math.min(0.22, surfaceBand * 0.45));
   const triangleVertices = [new Vector3(), new Vector3(), new Vector3()];
-  const rawPatches: TriangleMeshPatchSample[] = [];
+  const rawPatches: TriangleMeshSegmentSample[] = [];
 
   for (let indexOffset = 0; indexOffset <= source.indices.length - 3; indexOffset += 3) {
     const polygon: Vector3[] = [];
@@ -683,11 +746,7 @@ function appendTriangleMeshContactPatches(
       continue;
     }
 
-    const patch = createPatchFromProjectedPoints(
-      [waterlineSegment[0], waterlineSegment[1]],
-      preferredAxis,
-      bandMinimumThickness
-    );
+    const patch = createSegmentPatchFromEndpoints(waterlineSegment[0], waterlineSegment[1], bandMinimumThickness);
 
     if (patch !== null) {
       rawPatches.push({
@@ -811,6 +870,13 @@ export function createWaterContactPatchAxisUniformValue(contactPatches?: WaterCo
   });
 }
 
+export function createWaterContactPatchShapeUniformValue(contactPatches?: WaterContactPatch[]): number[] {
+  return Array.from({ length: MAX_WATER_CONTACT_PATCHES }, (_, index) => {
+    const patch = contactPatches?.[index];
+    return patch?.shape === "segment" ? 1 : 0;
+  });
+}
+
 export function createWaterMaterial(options: WaterMaterialOptions): WaterMaterialResult {
   if (options.wireframe) {
     return {
@@ -823,7 +889,8 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
       }),
       animationUniform: null,
       contactPatchesUniform: null,
-      contactPatchAxesUniform: null
+      contactPatchAxesUniform: null,
+      contactPatchShapesUniform: null
     };
   }
 
@@ -837,7 +904,8 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
       }),
       animationUniform: null,
       contactPatchesUniform: null,
-      contactPatchAxesUniform: null
+      contactPatchAxesUniform: null,
+      contactPatchShapesUniform: null
     };
   }
 
@@ -845,6 +913,7 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
   const halfSize = new Vector2(Math.max(options.halfSize.x, WATER_CONTACT_EPSILON), Math.max(options.halfSize.z, WATER_CONTACT_EPSILON));
   const contactPatchesUniform = { value: createWaterContactPatchUniformValue(options.contactPatches) };
   const contactPatchAxesUniform = { value: createWaterContactPatchAxisUniformValue(options.contactPatches) };
+  const contactPatchShapesUniform = { value: createWaterContactPatchShapeUniformValue(options.contactPatches) };
   const waveStrength = Math.max(0, options.waveStrength);
   const waveAmplitude = 0.016 + Math.min(0.12, waveStrength * 0.06);
   const clampedOpacity = Math.max(0.14, Math.min(1, options.opacity));
@@ -864,6 +933,7 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
     varying vec3 vWaveNormal;
     varying vec3 vWorldPos;
     varying vec3 vViewDir;
+    #include <fog_pars_vertex>
 
     void main() {
       vec3 transformedPosition = position;
@@ -891,9 +961,11 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
       }
 
       vec4 worldPos = modelMatrix * vec4(transformedPosition, 1.0);
+      vec4 mvPosition = viewMatrix * worldPos;
       vWorldPos = worldPos.xyz;
       vViewDir = normalize(cameraPosition - worldPos.xyz);
-      gl_Position = projectionMatrix * viewMatrix * worldPos;
+      gl_Position = projectionMatrix * mvPosition;
+      #include <fog_vertex>
     }
   `;
 
@@ -908,11 +980,13 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
     uniform vec2 halfSize;
     uniform vec4 contactPatches[${MAX_WATER_CONTACT_PATCHES}];
     uniform vec2 contactPatchAxes[${MAX_WATER_CONTACT_PATCHES}];
+    uniform float contactPatchShapes[${MAX_WATER_CONTACT_PATCHES}];
 
     varying vec2 vLocalSurfaceUv;
     varying vec3 vWaveNormal;
     varying vec3 vWorldPos;
     varying vec3 vViewDir;
+    #include <fog_pars_fragment>
 
     float hash(vec2 p) {
       return fract(sin(dot(p, vec2(127.1, 311.7))) * 43758.5453123);
@@ -943,6 +1017,22 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
       return value;
     }
 
+    float signedDistanceToRegion(vec2 point, vec2 center, vec2 axis, vec2 halfExtents) {
+      vec2 patchPerpendicular = vec2(-axis.y, axis.x);
+      vec2 patchLocalUv = vec2(dot(point - center, axis), dot(point - center, patchPerpendicular));
+      vec2 regionDelta = abs(patchLocalUv) - halfExtents;
+      vec2 outsideDelta = max(regionDelta, 0.0);
+      float outsideDistance = length(outsideDelta);
+      float insideDistance = min(max(regionDelta.x, regionDelta.y), 0.0);
+      return outsideDistance + insideDistance;
+    }
+
+    float distanceToSegmentBand(vec2 point, vec2 center, vec2 axis, float halfLength) {
+      float along = clamp(dot(point - center, axis), -halfLength, halfLength);
+      vec2 closestPoint = center + axis * along;
+      return distance(point, closestPoint);
+    }
+
     void main() {
       vec3 normal = normalize(vWaveNormal);
       vec3 viewDir = normalize(vViewDir);
@@ -972,19 +1062,34 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
           }
 
           vec2 patchAxis = contactPatchAxes[patchIndex];
-          vec2 patchPerpendicular = vec2(-patchAxis.y, patchAxis.x);
-          vec2 patchLocalUv = vec2(dot(vLocalSurfaceUv - patchData.xy, patchAxis), dot(vLocalSurfaceUv - patchData.xy, patchPerpendicular));
-          vec2 regionDelta = abs(patchLocalUv) - patchData.zw;
-          vec2 outsideDelta = max(regionDelta, 0.0);
-          float outsideDistance = length(outsideDelta);
-          float insideDistance = min(max(regionDelta.x, regionDelta.y), 0.0);
-          float signedDistance = outsideDistance + insideDistance;
-          float boundaryScale = max(min(patchData.z, patchData.w), 0.18);
-          float normalizedDistance = abs(signedDistance) / boundaryScale;
-          float contactBody = 1.0 - smoothstep(0.0, 0.65, max(signedDistance, 0.0) / boundaryScale);
-          float ripple = (sin(normalizedDistance * 13.0 - time * 3.2) * 0.5 + 0.5) * exp(-normalizedDistance * 2.6);
+          if (dot(patchAxis, patchAxis) <= 0.0) {
+            patchAxis = vec2(1.0, 0.0);
+          } else {
+            patchAxis = normalize(patchAxis);
+          }
+
+          float alongDistance = dot(vLocalSurfaceUv - patchData.xy, patchAxis);
+          float contactBody = 0.0;
+          float ripple = 0.0;
+          float normalizedDistance = 1.0;
+          float tangentNoise = noise(vec2(alongDistance * 0.45 + float(patchIndex) * 7.13, time * 0.12));
+
+          if (contactPatchShapes[patchIndex] > 0.5) {
+            float segmentRadius = max(patchData.w * mix(0.82, 1.18, tangentNoise), 0.05);
+            float segmentDistance = distanceToSegmentBand(vLocalSurfaceUv, patchData.xy, patchAxis, patchData.z);
+            normalizedDistance = segmentDistance / segmentRadius;
+            contactBody = 1.0 - smoothstep(0.0, 1.0, normalizedDistance);
+            ripple = (sin(normalizedDistance * 11.0 - time * 3.2 + alongDistance * 0.48) * 0.5 + 0.5) * exp(-normalizedDistance * 1.9);
+          } else {
+            float boundaryScale = max(min(patchData.z, patchData.w), 0.18) * mix(0.86, 1.14, tangentNoise);
+            float signedDistance = signedDistanceToRegion(vLocalSurfaceUv, patchData.xy, patchAxis, patchData.zw);
+            normalizedDistance = abs(signedDistance) / max(boundaryScale, 0.05);
+            contactBody = 1.0 - smoothstep(0.0, 1.0, normalizedDistance);
+            ripple = (sin(normalizedDistance * 13.0 - time * 3.2 + alongDistance * 0.35) * 0.5 + 0.5) * exp(-normalizedDistance * 2.6);
+          }
+
           float wakeNoise = noise(vLocalSurfaceUv * 3.4 + vec2(time * 0.34, -time * 0.28));
-          float foamField = max(contactBody * 0.42, ripple * (0.72 + wakeNoise * 0.28));
+          float foamField = max(contactBody * 0.48, ripple * (0.68 + wakeNoise * 0.32));
           contactFoam = max(contactFoam, foamField);
           contactRipple = max(contactRipple, ripple);
           contactSheen = max(contactSheen, contactBody);
@@ -1007,6 +1112,7 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
         : clamp(surfaceOpacity * 0.72 + refraction * 0.08 + caustics * 0.04, 0.16, 0.7);
 
       gl_FragColor = vec4(color, alpha);
+      #include <fog_fragment>
     }
   `;
 
@@ -1022,10 +1128,12 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
       isTopFace: { value: topFaceFlag },
       halfSize: { value: halfSize },
       contactPatches: contactPatchesUniform,
-      contactPatchAxes: contactPatchAxesUniform
+      contactPatchAxes: contactPatchAxesUniform,
+      contactPatchShapes: contactPatchShapesUniform
     },
     transparent: true,
     depthWrite: false,
+    fog: true,
     side: DoubleSide
   });
 
@@ -1033,6 +1141,7 @@ export function createWaterMaterial(options: WaterMaterialOptions): WaterMateria
     material,
     animationUniform,
     contactPatchesUniform,
-    contactPatchAxesUniform
+    contactPatchAxesUniform,
+    contactPatchShapesUniform
   };
 }