From 9b89462620d6c2f3a10ed40b5ba679ad029afab6 Mon Sep 17 00:00:00 2001
From: "Colin J. Brigato" <colin@brigato.fr>
Date: Fri, 4 Oct 2024 13:53:30 +0200
Subject: [PATCH 1/2] custom texture binding for Reflective to avoid double
 free, and race condition fix in appending draw commands for paint example

---
 ReflectiveBoundTexture.go | 13 ++++++++++---
 examples/paint/canvas.go  | 15 ++++++++++++---
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/ReflectiveBoundTexture.go b/ReflectiveBoundTexture.go
index a4750f3a..1c72841b 100644
--- a/ReflectiveBoundTexture.go
+++ b/ReflectiveBoundTexture.go
@@ -7,6 +7,7 @@ import (
 	"image/color"
 	"sync"
 
+	"github.com/AllenDang/cimgui-go/backend"
 	"github.com/AllenDang/cimgui-go/imgui"
 )
 
@@ -193,10 +194,16 @@ func (i *ReflectiveBoundTexture) unbind() {
 }
 
 // bind creates a new texture from the RGBA surface and assigns it to the ReflectiveBoundTexture.
+// note it bypasses normal texture management up to cimgui-go to avoid double free from finalizers.
 func (i *ReflectiveBoundTexture) bind() {
-	NewTextureFromRgba(i.Surface, func(tex *Texture) {
-		i.tex = tex
-	})
+	img := ImageToRgba(i.Surface)
+	i.tex = &Texture{
+		&backend.Texture{
+			ID:     backend.TextureManager(Context.backend).CreateTextureRgba(img, img.Bounds().Dx(), img.Bounds().Dy()),
+			Width:  img.Bounds().Dx(),
+			Height: img.Bounds().Dy(),
+		},
+	}
 }
 
 // GetSurfaceWidth returns the width of the RGBA surface.
diff --git a/examples/paint/canvas.go b/examples/paint/canvas.go
index beb32401..2651e3d2 100644
--- a/examples/paint/canvas.go
+++ b/examples/paint/canvas.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"image"
 	"image/color"
+	"sync"
 
 	"github.com/AllenDang/cimgui-go/imgui"
 
@@ -57,11 +58,13 @@ type Canvas struct {
 
 	// inited is a boolean flag indicating whether the canvas has been initialized.
 	inited bool
+
+	appendMu sync.Mutex
 }
 
-// GetDrawCommands returns a slice of drawCommand starting from the specified index.
+// getDrawCommands returns a slice of drawCommand starting from the specified index.
 // It allows retrieval of draw commands that have been added since a given point in time.
-func (c *Canvas) GetDrawCommands(sinceIndex int) []DrawCommand {
+func (c *Canvas) getDrawCommands(sinceIndex int) []DrawCommand {
 	return c.DrawCommands[sinceIndex:]
 }
 
@@ -79,6 +82,8 @@ func (c *Canvas) PushImageToBackend(commit bool) error {
 // AppendDrawCommands adds a slice of drawCommand to the canvas's existing draw commands.
 // It appends the provided commands to the DrawCommands slice.
 func (c *Canvas) AppendDrawCommands(cmds *[]DrawCommand) {
+	c.appendMu.Lock()
+	defer c.appendMu.Unlock()
 	c.DrawCommands = append(c.DrawCommands, *cmds...)
 }
 
@@ -104,6 +109,8 @@ func (c *Canvas) Compute() {
 		return
 	}
 
+	c.appendMu.Lock()
+
 	// Return if there are no draw commands to process
 	if len(c.DrawCommands) < 1 {
 		return
@@ -115,7 +122,9 @@ func (c *Canvas) Compute() {
 	}
 
 	// Get the new draw commands that need to be processed
-	draws := c.GetDrawCommands(c.LastComputedLen)
+	draws := c.getDrawCommands(c.LastComputedLen)
+	c.appendMu.Unlock()
+
 	for _, r := range draws {
 		switch r.Tool {
 		case 0:

From 7a2287175f06060a9eda24c34f4bfd1e2e00d78e Mon Sep 17 00:00:00 2001
From: "Colin J. Brigato" <colin@brigato.fr>
Date: Fri, 4 Oct 2024 14:06:36 +0200
Subject: [PATCH 2/2] fix unlock

---
 examples/paint/canvas.go | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/examples/paint/canvas.go b/examples/paint/canvas.go
index 2651e3d2..4416a08d 100644
--- a/examples/paint/canvas.go
+++ b/examples/paint/canvas.go
@@ -109,22 +109,29 @@ func (c *Canvas) Compute() {
 		return
 	}
 
-	c.appendMu.Lock()
+	var draws []DrawCommand
 
-	// Return if there are no draw commands to process
-	if len(c.DrawCommands) < 1 {
-		return
-	}
+	if func() bool {
+		c.appendMu.Lock()
+		defer c.appendMu.Unlock()
+
+		// Return if there are no draw commands to process
+		if len(c.DrawCommands) < 1 {
+			return true
+		}
+
+		// Return if all draw commands have already been processed
+		if len(c.DrawCommands) <= c.LastComputedLen {
+			return true
+		}
 
-	// Return if all draw commands have already been processed
-	if len(c.DrawCommands) <= c.LastComputedLen {
+		// Get the new draw commands that need to be processed
+		draws = c.getDrawCommands(c.LastComputedLen)
+		return false
+	}() {
 		return
 	}
 
-	// Get the new draw commands that need to be processed
-	draws := c.getDrawCommands(c.LastComputedLen)
-	c.appendMu.Unlock()
-
 	for _, r := range draws {
 		switch r.Tool {
 		case 0: