diff --git a/engine/Age.Engine.Tests/GfxStateTests.cs b/engine/Age.Engine.Tests/GfxStateTests.cs
index 802a785..fc7be97 100644
--- a/engine/Age.Engine.Tests/GfxStateTests.cs
+++ b/engine/Age.Engine.Tests/GfxStateTests.cs
@@ -59,4 +59,30 @@ public class GfxStateTests
Assert.Equal(-1, g.QuerySlot(0x10));
Assert.NotEqual(-1, g.QuerySlot(0x11));
}
+
+ [Fact]
+ public void LayersAppendInOrderAndUpdateInPlace()
+ {
+ var g = new GfxState();
+ g.AddOrUpdateLayer(new DrawLayer(0xA, 4, 0, 0, 800, 600, 0, 0));
+ g.AddOrUpdateLayer(new DrawLayer(0xB, 5, 0, 0, 200, 200, 100, 100));
+ g.AddOrUpdateLayer(new DrawLayer(0xA, 4, 0, 0, 800, 600, 0, 50)); // re-draw A -> update in place
+ var s = g.SnapshotLayers();
+ Assert.Equal(2, s.Count);
+ Assert.Equal(0xA, s[0].Handle); // order preserved (A still first)
+ Assert.Equal(50, s[0].DstY); // updated
+ Assert.Equal(0xB, s[1].Handle);
+ }
+
+ [Fact]
+ public void EraseRangeAlsoDropsLayers()
+ {
+ var g = new GfxState();
+ g.AddOrUpdateLayer(new DrawLayer(0x10, 4, 0, 0, 10, 10, 0, 0));
+ g.AddOrUpdateLayer(new DrawLayer(0x20, 5, 0, 0, 10, 10, 0, 0));
+ g.EraseRange(0x10, 1);
+ var s = g.SnapshotLayers();
+ Assert.Single(s);
+ Assert.Equal(0x20, s[0].Handle);
+ }
}
diff --git a/engine/Age.Engine/Model/GfxState.cs b/engine/Age.Engine/Model/GfxState.cs
index 65f9e0c..95bd83e 100644
--- a/engine/Age.Engine/Model/GfxState.cs
+++ b/engine/Age.Engine/Model/GfxState.cs
@@ -1,5 +1,10 @@
namespace Age.Engine.Model;
+/// A retained composite layer captured when the VM executes draw-texture — the host clears and
+/// re-composites the layer set each frame (replacing the immediate-mode permanent canvas). Keyed by the
+/// object so a re-draw updates in place and an erase (op 0x1f7) removes it.
+public readonly record struct DrawLayer(long Handle, int Slot, int SrcX, int SrcY, int W, int H, int DstX, int DstY);
+
/// Host-agnostic model of the AGE native gfx command-buffer (reversed in
/// docs/engine-re.md, gfx op-contract table). One registry maps an object handle to a GfxObject — the
/// native ctx+0x408 map that op 0x215 queries and the geometry get/set ops share. Each object carries a
@@ -59,10 +64,31 @@ public sealed class GfxState
/// NOT a create — objects are created lazily by the geometry SET ops (gfx_object_get_or_create).
public void EraseRange(long handle, long count)
{
- if (count > 1) for (long i = handle; i < handle + count; i++) Release(i);
- else Release(handle);
+ if (count > 1) for (long i = handle; i < handle + count; i++) { Release(i); RemoveLayers(i); }
+ else { Release(handle); RemoveLayers(handle); }
}
+ // ---- retained composite layers (mutated on the VM thread; snapshotted on the host render thread) ----
+ private readonly List _layers = new();
+ private readonly object _lock = new();
+
+ /// Record a draw: update the layer with this handle in place (preserving composite order), else
+ /// append. Order = execution order = paint order.
+ public void AddOrUpdateLayer(DrawLayer l)
+ {
+ lock (_lock)
+ {
+ for (int i = 0; i < _layers.Count; i++)
+ if (_layers[i].Handle == l.Handle) { _layers[i] = l; return; }
+ _layers.Add(l);
+ }
+ }
+
+ public void RemoveLayers(long handle) { lock (_lock) { _layers.RemoveAll(l => l.Handle == handle); } }
+
+ /// An immutable snapshot of the current layers, in composite order (for the host render loop).
+ public IReadOnlyList SnapshotLayers() { lock (_lock) { return _layers.ToArray(); } }
+
/// Pack (alpha, rgb) → 0xAARRGGBB, matching op 0x202/0x203's handler bit-manipulation for the
/// common (non-negative-sentinel) case. The alpha<0 / color<0 native-fetch path is deferred.
public static long PackColor(long alpha, long color)