From 7d7bc43a80ba9606625f9ffd00ba39b1b63d3a3b Mon Sep 17 00:00:00 2001
From: Sander Schobers <sander@schobers.eu>
Date: Thu, 15 Feb 2018 20:17:27 +0100
Subject: [PATCH] Added flag to NewBitmapFromImage. Bitmap is now created as a
 memory bitmap and converted to a video bitmap if the user requested that
 explicitly.

---
 allegro5/bitmap.go  | 50 +++++++++++++++++++++++++++++++++++++--------
 allegro5/flagmut.go | 18 ++++++++++++++++
 2 files changed, 60 insertions(+), 8 deletions(-)
 create mode 100644 allegro5/flagmut.go

diff --git a/allegro5/bitmap.go b/allegro5/bitmap.go
index 9d7a9af..ebb4af2 100644
--- a/allegro5/bitmap.go
+++ b/allegro5/bitmap.go
@@ -60,18 +60,44 @@ func NewBitmap(width, height int) (*Bitmap, error) {
 	return &Bitmap{b, width, height}, nil
 }
 
+type newBmpFlagsCapture struct {
+	cap C.int
+}
+
+func captureNewBmpFlags() *newBmpFlagsCapture {
+	var cap = C.al_get_new_bitmap_flags()
+	return &newBmpFlagsCapture{cap}
+}
+
+func (c *newBmpFlagsCapture) Mut(mut func(*flagMut)) {
+	var m = &flagMut{c.cap}
+	mut(m)
+	C.al_set_new_bitmap_flags(m.flg)
+}
+
+func (c *newBmpFlagsCapture) Revert() {
+	C.al_set_new_bitmap_flags(c.cap)
+}
+
 // NewBitmapFromImage creates a new bitmap starting from a Go native image (image.Image)
-func NewBitmapFromImage(im image.Image) (*Bitmap, error) {
+func NewBitmapFromImage(im image.Image, video bool) (*Bitmap, error) {
+	var newBmpFlags = captureNewBmpFlags()
+	defer newBmpFlags.Revert()
+	newBmpFlags.Mut(func(m *flagMut) {
+		m.Unset(C.ALLEGRO_VIDEO_BITMAP)
+		m.Set(C.ALLEGRO_MEMORY_BITMAP)
+		m.Set(C.ALLEGRO_MIN_LINEAR)
+	})
 	var bnd = im.Bounds()
 	width, height := bnd.Dx(), bnd.Dy()
-	bmp, err := NewBitmap(width, height)
-	if nil != err {
-		return nil, err
+	var b = C.al_create_bitmap(C.int(width), C.int(height))
+	if nil == b {
+		return nil, errors.New("error creating memory bitmap")
 	}
 	row := make([]uint8, width*4)
-	rgn := C.al_lock_bitmap(bmp.bitmap, C.ALLEGRO_PIXEL_FORMAT_ABGR_8888, C.ALLEGRO_LOCK_WRITEONLY)
+	rgn := C.al_lock_bitmap(b, C.ALLEGRO_PIXEL_FORMAT_ABGR_8888, C.ALLEGRO_LOCK_WRITEONLY)
 	if nil == rgn {
-		bmp.Destroy()
+		C.al_destroy_bitmap(b)
 		return nil, errors.New("unable to lock bitmap")
 	}
 	data := (*[1 << 30]uint8)(rgn.data)
@@ -87,8 +113,16 @@ func NewBitmapFromImage(im image.Image) (*Bitmap, error) {
 		copy(data[offset:], row)
 		offset += int(rgn.pitch)
 	}
-	C.al_unlock_bitmap(bmp.bitmap)
-	return bmp, nil
+	C.al_unlock_bitmap(b)
+	if video {
+		newBmpFlags.Mut(func(m *flagMut) {
+			m.Unset(C.ALLEGRO_MEMORY_BITMAP)
+			m.Set(C.ALLEGRO_VIDEO_BITMAP)
+			m.Set(C.ALLEGRO_MIN_LINEAR)
+		})
+		C.al_convert_bitmap(b)
+	}
+	return &Bitmap{b, width, height}, nil
 }
 
 // LoadBitmap tries to load the image at the specified path as a bitmap
diff --git a/allegro5/flagmut.go b/allegro5/flagmut.go
new file mode 100644
index 0000000..b4113c3
--- /dev/null
+++ b/allegro5/flagmut.go
@@ -0,0 +1,18 @@
+package allegro5
+
+// #include <stdlib.h>
+import "C"
+
+type flagMut struct {
+	flg C.int
+}
+
+func (m *flagMut) Set(f C.int) {
+	m.flg |= f
+}
+
+func (m *flagMut) Unset(f C.int) {
+	if m.flg&f == f {
+		m.flg ^= f
+	}
+}