fix #451: stabilize portal seam rendering

src/AcDream.App/Rendering/ParticleRenderer.Rhi.cs

@@ -71,10 +71,8 @@ public sealed unsafe partial class ParticleRenderer
 
     private const uint QuadStrideBytes = 4 * sizeof(float);
 
-    /// <summary>Floats per mesh-particle instance: a <c>mat4</c> plus an RGBA colour.</summary>
-    internal const int MeshInstanceFloats = 20;
-
-    private const uint MeshInstanceStrideBytes = MeshInstanceFloats * sizeof(float);
+    private static readonly uint MeshInstanceStrideBytes =
+        (uint)sizeof(MeshParticleGpuInstance);
 
     /// <summary>
     /// The billboard layout: the shared unit quad at vertex rate, and one
@@ -103,7 +101,8 @@ public sealed unsafe partial class ParticleRenderer
             // Location 6 is `in uint aTextureIndex` — an INTEGER shader input,
             // so R8G8B8A8's normalized cousin would be wrong in kind. It is one
             // 32-bit unsigned value; Float1 would reinterpret its bits.
-            new GpuVertexAttribute(6, GpuVertexFormat.UInt1, 64, Binding: 1)));
+            new GpuVertexAttribute(6, GpuVertexFormat.UInt1, 64, Binding: 1),
+            new GpuVertexAttribute(7, GpuVertexFormat.UInt1, 68, Binding: 1)));
 
     /// <summary>
     /// The mesh-particle layout: the shared world-mesh vertex at vertex rate,
@@ -126,7 +125,8 @@ public sealed unsafe partial class ParticleRenderer
             new GpuVertexAttribute(4, GpuVertexFormat.Float4, 16, Binding: 1),
             new GpuVertexAttribute(5, GpuVertexFormat.Float4, 32, Binding: 1),
             new GpuVertexAttribute(6, GpuVertexFormat.Float4, 48, Binding: 1),
-            new GpuVertexAttribute(7, GpuVertexFormat.Float4, 64, Binding: 1)));
+            new GpuVertexAttribute(7, GpuVertexFormat.Float4, 64, Binding: 1),
+            new GpuVertexAttribute(8, GpuVertexFormat.UInt1, 80, Binding: 1)));
 
     /// <summary>
     /// The RHI arm's constructor. No GL context, no <c>Shader</c>, no
@@ -340,22 +340,22 @@ public sealed unsafe partial class ParticleRenderer
             while (submission.Kind == ParticleSubmissionKind.Mesh
                 && _meshDrawListScratch[submission.DrawIndex].Key == meshKey);
 
-            int neededFloats = _meshRunScratch.Count * MeshInstanceFloats;
-            if (_meshInstanceScratch.Length < neededFloats)
-                _meshInstanceScratch = new float[neededFloats + 256 * MeshInstanceFloats];
+            int neededInstances = _meshRunScratch.Count;
+            if (_meshInstanceScratch.Length < neededInstances)
+                _meshInstanceScratch = new MeshParticleGpuInstance[neededInstances + 256];
             for (int instance = 0; instance < _meshRunScratch.Count; instance++)
             {
                 WriteMeshGpuInstance(
-                    _meshInstanceScratch,
-                    instance * MeshInstanceFloats,
+                    ref _meshInstanceScratch[instance],
                     _meshRunScratch[instance]);
             }
 
-            GpuRingAllocation instances = WriteVertexRing<float>(
+            GpuRingAllocation instances = WriteVertexRing<MeshParticleGpuInstance>(
                 frame,
-                _meshInstanceScratch.AsSpan(0, neededFloats));
+                _meshInstanceScratch.AsSpan(0, neededInstances));
             DrawMeshBatchRhi(
                 encoder,
+                frame,
                 global,
                 batch,
                 viewProjection,
@@ -384,7 +384,13 @@ public sealed unsafe partial class ParticleRenderer
         GpuRingAllocation ring = WriteVertexRing<BillboardGpuInstance>(
             frame,
             _instanceScratch.AsSpan(0, instances.Count));
-        BindBillboardPipeline(encoder, viewProjection, additive, ring.Buffer, ring.OffsetBytes);
+        BindBillboardPipeline(
+            encoder,
+            frame,
+            viewProjection,
+            additive,
+            ring.Buffer,
+            ring.OffsetBytes);
         encoder.DrawIndexed(
             (uint)QuadIndices.Length,
             (uint)instances.Count,
@@ -401,6 +407,7 @@ public sealed unsafe partial class ParticleRenderer
     /// </summary>
     private void BindBillboardPipeline(
         IGpuPassEncoder encoder,
+        IGpuFrame frame,
         Matrix4x4 viewProjection,
         bool additive,
         IGpuBuffer instanceBuffer,
@@ -426,10 +433,15 @@ public sealed unsafe partial class ParticleRenderer
         encoder.BindVertexBuffer(0, _quadVertexBuffer!, 0);
         encoder.BindVertexBuffer(1, instanceBuffer, instanceOffsetBytes);
         encoder.BindIndexBuffer(_quadIndexBuffer!, 0, GpuIndexType.UInt32);
+        WorldFrameSectionBinding.BindClipRegions(
+            encoder,
+            _scope!.Sections,
+            frame);
     }
 
     private void DrawMeshBatchRhi(
         IGpuPassEncoder encoder,
+        IGpuFrame frame,
         GlobalMeshBuffer global,
         ObjectRenderBatch batch,
         Matrix4x4 viewProjection,
@@ -472,6 +484,10 @@ public sealed unsafe partial class ParticleRenderer
                 "The shared mesh arena has no index store."),
             0,
             GpuIndexType.UInt16);
+        WorldFrameSectionBinding.BindClipRegions(
+            encoder,
+            _scope!.Sections,
+            frame);
         encoder.DrawIndexed(
             (uint)batch.IndexCount,
             instanceCount,
@@ -520,9 +536,8 @@ public sealed unsafe partial class ParticleRenderer
             Array.Resize(ref _preparedInstanceOffsets, count + 256);
         if (_instanceScratch.Length < count)
             Array.Resize(ref _instanceScratch, count + 256);
-        int neededMeshFloats = count * MeshInstanceFloats;
-        if (_meshInstanceScratch.Length < neededMeshFloats)
-            _meshInstanceScratch = new float[neededMeshFloats + 256 * MeshInstanceFloats];
+        if (_meshInstanceScratch.Length < count)
+            _meshInstanceScratch = new MeshParticleGpuInstance[count + 256];
 
         int billboardCount = 0;
         int meshCount = 0;
@@ -541,8 +556,7 @@ public sealed unsafe partial class ParticleRenderer
             {
                 _preparedInstanceOffsets[i] = (uint)meshCount;
                 WriteMeshGpuInstance(
-                    _meshInstanceScratch,
-                    meshCount++ * MeshInstanceFloats,
+                    ref _meshInstanceScratch[meshCount++],
                     deferred.Mesh.Instance);
             }
         }
@@ -553,9 +567,9 @@ public sealed unsafe partial class ParticleRenderer
                 _instanceScratch.AsSpan(0, billboardCount)))
             : default;
         _preparedMeshInstances = meshCount > 0
-            ? SectionOf(WriteVertexRing<float>(
+            ? SectionOf(WriteVertexRing<MeshParticleGpuInstance>(
                 frame,
-                _meshInstanceScratch.AsSpan(0, meshCount * MeshInstanceFloats)))
+                _meshInstanceScratch.AsSpan(0, meshCount)))
             : default;
         _preparedAlphaCount = count;
     }
@@ -591,6 +605,7 @@ public sealed unsafe partial class ParticleRenderer
                 {
                     BindBillboardPipeline(
                         encoder,
+                        RequireRhiFrame(),
                         viewProjection,
                         key.Additive,
                         billboards,
@@ -632,6 +647,7 @@ public sealed unsafe partial class ParticleRenderer
             {
                 DrawMeshBatchRhi(
                     encoder,
+                    RequireRhiFrame(),
                     global,
                     batch,
                     meshViewProjection,