From 2fae8a5012e99f87367152186a52de8e359dd127 Mon Sep 17 00:00:00 2001
From: Sander Schobers <sander@schobers.eu>
Date: Sat, 10 Feb 2018 09:12:42 +0100
Subject: [PATCH] Native Go image is now loaded directly as Allegro bitmap. -
 Previous implementation used a temporary file (PNG).

---
 allegro5/bitmap.go | 45 ++++++++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/allegro5/bitmap.go b/allegro5/bitmap.go
index eb1d0ee..f7aeebf 100644
--- a/allegro5/bitmap.go
+++ b/allegro5/bitmap.go
@@ -5,11 +5,10 @@ package allegro5
 import "C"
 
 import (
+	"errors"
 	"fmt"
 	"image"
-	"image/png"
-	"io/ioutil"
-	"os"
+	"image/color"
 	"unsafe"
 )
 
@@ -62,27 +61,35 @@ func NewBitmap(width, height int) (*Bitmap, error) {
 	return &Bitmap{b, width, height}, nil
 }
 
-func exportToPng(im image.Image) (string, error) {
-	tmp, err := ioutil.TempFile("", "galleg")
-	if nil != err {
-		return "", err
-	}
-	defer tmp.Close()
-	err = png.Encode(tmp, im)
-	if nil != err {
-		return "", err
-	}
-	return tmp.Name(), nil
-}
-
 // NewBitmapFromImage creates a new bitmap starting from a Go native image (image.Image)
 func NewBitmapFromImage(im image.Image) (*Bitmap, error) {
-	path, err := exportToPng(im)
+	var bnd = im.Bounds()
+	width, height := bnd.Dx(), bnd.Dy()
+	bmp, err := NewBitmap(width, height)
 	if nil != err {
 		return nil, err
 	}
-	defer os.Remove(path)
-	return LoadBitmap(path)
+	row := make([]uint8, width*4)
+	rgn := C.al_lock_bitmap(bmp.bitmap, C.ALLEGRO_PIXEL_FORMAT_ABGR_8888, C.ALLEGRO_LOCK_WRITEONLY)
+	if nil == rgn {
+		bmp.Destroy()
+		return nil, errors.New("unable to lock bitmap")
+	}
+	data := (*[1 << 30]uint8)(rgn.data)
+	offset := 0
+	for y := 0; y < height; y++ {
+		for x := 0; x < width; x++ {
+			pix := color.RGBAModel.Convert(im.At(x, y)).(color.RGBA)
+			row[x*4] = pix.R
+			row[x*4+1] = pix.G
+			row[x*4+2] = pix.B
+			row[x*4+3] = pix.A
+		}
+		copy(data[offset:], row)
+		offset += int(rgn.pitch)
+	}
+	C.al_unlock_bitmap(bmp.bitmap)
+	return bmp, nil
 }
 
 // LoadBitmap tries to load the image at the specified path as a bitmap