From ddef7351c11da779a9233bed2a1b1d7cf12b4cc8 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 19 Jun 2022 17:18:13 +0900
Subject: [PATCH] internal/graphicsdriver/directx: bug fix: clear constant
 buffers at the end of DrawTriangles

Constant buffers should not be reset while a stencil buffer is used.

Closes #2138
---
 .../directx/graphics_windows.go               | 18 ++--
 internal/processtest/testdata/issue2138.go    | 94 +++++++++++++++++++
 2 files changed, 103 insertions(+), 9 deletions(-)
 create mode 100644 internal/processtest/testdata/issue2138.go

diff --git a/internal/graphicsdriver/directx/graphics_windows.go b/internal/graphicsdriver/directx/graphics_windows.go
index 598cdc7c2..94f4d26f0 100644
--- a/internal/graphicsdriver/directx/graphics_windows.go
+++ b/internal/graphicsdriver/directx/graphics_windows.go
@@ -1156,6 +1156,15 @@ func (g *Graphics) DrawTriangles(dstID graphicsdriver.ImageID, srcs [graphics.Sh
 		}
 	}
 
+	// Release constant buffers when too many ones were created.
+	// This is needed espciallly for testings, where present is always false.
+	if len(g.pipelineStates.constantBuffers[g.frameIndex]) >= 16 {
+		if err := g.flushCommandList(g.drawCommandList); err != nil {
+			return err
+		}
+		g.pipelineStates.releaseConstantBuffers(g.frameIndex)
+	}
+
 	return nil
 }
 
@@ -1166,15 +1175,6 @@ func (g *Graphics) drawTriangles(pipelineState *iD3D12PipelineState, srcs [graph
 
 	g.drawCommandList.DrawIndexedInstanced(uint32(indexLen), 1, uint32(indexOffset), 0, 0)
 
-	// Release constant buffers when too many ones were created.
-	// This is needed espciallly for testings, where present is always false.
-	if len(g.pipelineStates.constantBuffers[g.frameIndex]) >= 16 {
-		if err := g.flushCommandList(g.drawCommandList); err != nil {
-			return err
-		}
-		g.pipelineStates.releaseConstantBuffers(g.frameIndex)
-	}
-
 	return nil
 }
 
diff --git a/internal/processtest/testdata/issue2138.go b/internal/processtest/testdata/issue2138.go
new file mode 100644
index 000000000..6358e4473
--- /dev/null
+++ b/internal/processtest/testdata/issue2138.go
@@ -0,0 +1,94 @@
+// Copyright 2022 The Ebitengine Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"errors"
+	"image"
+	"image/color"
+	"math"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/text"
+	"github.com/hajimehoshi/ebiten/v2/vector"
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/gofont/goregular"
+	"golang.org/x/image/font/opentype"
+)
+
+var regularTermination = errors.New("regular termination")
+
+var (
+	emptyImage        = ebiten.NewImage(3, 3)
+	debugCircleImage  *ebiten.Image
+	emptyTextureImage = emptyImage.SubImage(image.Rect(1, 1, 2, 2)).(*ebiten.Image)
+	face              font.Face
+)
+
+func init() {
+	emptyImage.Fill(color.White)
+
+	img := image.NewRGBA(image.Rect(0, 0, 20, 20))
+	debugCircleImage = ebiten.NewImageFromImage(img)
+
+	emptyImage.Fill(color.Black)
+
+	f, _ := opentype.Parse(goregular.TTF)
+	face, _ = opentype.NewFace(f, &opentype.FaceOptions{
+		Size: 12,
+		DPI:  72,
+	})
+}
+
+type Game struct {
+	counter int
+}
+
+func (g *Game) Update() error {
+	g.counter++
+	if g.counter > 16 {
+		return regularTermination
+	}
+	return nil
+}
+
+func (g *Game) Draw(screen *ebiten.Image) {
+	// Before the fix, some complex renderings with EvenOdd might cause a DirectX error like this (#2138):
+	//     panic: directx: IDXGISwapChain4::Present failed: HRESULT(2289696773)
+
+	screen.DrawImage(debugCircleImage, nil)
+	text.Draw(screen, "014678.,", face, 100, 100, color.White)
+
+	p := vector.Path{}
+	p.Arc(100, 100, 6, 0, 2*math.Pi, vector.Clockwise)
+	filling, indicies := p.AppendVerticesAndIndicesForFilling(nil, nil)
+	screen.DrawTriangles(filling, indicies, emptyTextureImage, &ebiten.DrawTrianglesOptions{
+		FillRule: ebiten.EvenOdd,
+	})
+}
+
+func (g *Game) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
+	return 800, 600
+}
+
+func main() {
+	if err := ebiten.RunGame(&Game{}); err != nil && !errors.Is(err, regularTermination) {
+		panic(err)
+	}
+
+}