Bound GPU backbuffer layer retention

This commit is contained in:
gamer147
2026-07-30 11:49:14 -04:00
parent 2ba0870967
commit 499e72d4bb
5 changed files with 84 additions and 30 deletions

View File

@@ -17,6 +17,10 @@ public enum HostPresentationReason
DiscreteSourceCell = 16,
}
public readonly record struct BackbufferPublicationPolicy(
bool PreserveExistingPixels,
bool AppendGpuLayers);
public sealed class GodotAdvHost : IHost
{
private readonly Main _main;
@@ -99,7 +103,7 @@ public sealed class GodotAdvHost : IHost
private readonly Dictionary<int, IReadOnlyList<RenderObject>> _renderTargetSnapshots = new();
private readonly object _backbufferRangeLock = new();
private GfxHandleRange _backbufferRange = GfxHandleRange.All;
private bool _backbufferPublicationIsIncremental;
private bool _backbufferPublicationPreservesExistingPixels;
private bool _backbufferClearPending;
private LegacyScreenTransition? _screenTransition;
public volatile bool IsWaiting;
@@ -477,7 +481,7 @@ public sealed class GodotAdvHost : IHost
lock (_backbufferRangeLock)
{
_backbufferRange = new GfxHandleRange(firstHandle, count);
_backbufferPublicationIsIncremental = true;
_backbufferPublicationPreservesExistingPixels = true;
}
_timeline?.Event("present-object-range", new() { ["first"] = firstHandle, ["count"] = count });
// Native backbuffer 0x222 ends its D3D scene and calls Present before returning. Snapshot this
@@ -493,7 +497,8 @@ public sealed class GodotAdvHost : IHost
}
}
public bool SnapshotBackbufferObjects(GfxState gfx, long nowMs, List<RenderObject> snapshot)
public BackbufferPublicationPolicy SnapshotBackbufferObjects(
GfxState gfx, long nowMs, List<RenderObject> snapshot)
{
gfx.SnapshotVisibleObjects(nowMs, snapshot);
GfxHandleRange range;
@@ -501,14 +506,27 @@ public sealed class GodotAdvHost : IHost
lock (_backbufferRangeLock)
{
range = _backbufferRange;
preserveExistingPixels = _backbufferPublicationIsIncremental && !_backbufferClearPending;
preserveExistingPixels =
_backbufferPublicationPreservesExistingPixels && !_backbufferClearPending;
_backbufferClearPending = false;
}
int write = 0;
for (int read = 0; read < snapshot.Count; read++)
if (range.Contains(snapshot[read].Handle)) snapshot[write++] = snapshot[read];
if (write < snapshot.Count) snapshot.RemoveRange(write, snapshot.Count - write);
return preserveExistingPixels;
return ResolveBackbufferPublicationPolicy(
preserveExistingPixels, range, snapshot.Count);
}
internal static BackbufferPublicationPolicy ResolveBackbufferPublicationPolicy(
bool preserveExistingPixels, GfxHandleRange range, int visibleObjectCount)
{
// Native preservation is a pixel rule, not permission to retain an unbounded history of
// Godot Sprite2D nodes. Partial ranges must overlay. A nonempty full redraw compacts the GPU
// stage, while an empty full redraw leaves the preceding stage untouched.
bool appendGpuLayers = preserveExistingPixels
&& (range != GfxHandleRange.All || visibleObjectCount == 0);
return new BackbufferPublicationPolicy(preserveExistingPixels, appendGpuLayers);
}
public void ConfigureAdvWaitIndicator(AdvWaitIndicatorConfig config)
@@ -872,7 +890,9 @@ public sealed class GodotAdvHost : IHost
lock (_backbufferRangeLock)
{
_backbufferRange = GfxHandleRange.All;
_backbufferPublicationIsIncremental = false;
// Native gfx_render_frame draws every visible retained object over the current target.
// It does not clear first; backbuffer clearing is the separate explicit opcode 0x20e.
_backbufferPublicationPreservesExistingPixels = true;
}
int started = gfx.StartForegroundTransitions(_clock.NowMs);
int completed = gfx.CompleteForegroundTransitions(_clock.NowMs);
@@ -1062,7 +1082,7 @@ public sealed class GodotAdvHost : IHost
lock (_backbufferRangeLock)
{
_backbufferRange = GfxHandleRange.All;
_backbufferPublicationIsIncremental = false;
_backbufferPublicationPreservesExistingPixels = false;
_backbufferClearPending = false;
}
lock (_textLock)