Formalise a bit in each cell as an "IsActive()" bit

internal/conv/object.go

@@ -52,7 +52,7 @@ var transparent = color.RGBA{0, 0, 0, 0}
 func spriteToPic(name string, idx int, sprite *data.Sprite) *pixel.PictureData {
 	pic := pixel.MakePictureData(pixel.R(float64(0), float64(0), float64(sprite.Width), float64(sprite.Height)))
 
-	log.Printf("%v %v: width=%v height=%v", name, idx, sprite.Width, sprite.Height)
+	//log.Printf("%v %v: width=%v height=%v", name, idx, sprite.Width, sprite.Height)
 
 	for y := 0; y < int(sprite.Height); y++ {
 		// Start with all bytes transparent
@@ -61,7 +61,7 @@ func spriteToPic(name string, idx int, sprite *data.Sprite) *pixel.PictureData {
 		}
 
 		row := sprite.Rows[y]
-		log.Printf("%#v", row)
+		//log.Printf("%#v", row)
 		pixels := row[0 : len(row)-1] // Strip off the record separator (0x00)
 
 		// Not really clear on what this does yet. Aligned with sprite width in
@@ -79,7 +79,7 @@ func spriteToPic(name string, idx int, sprite *data.Sprite) *pixel.PictureData {
 
 		// Do nothing if we're out of pixels
 		if u0 == 0x80 {
-			log.Printf("Handling 0x80: %#v", pixels)
+			//log.Printf("Handling 0x80: %#v", pixels)
 			xOffset = int(pixels[0])
 			pixels = pixels[1:len(pixels)]
 
@@ -98,10 +98,10 @@ func spriteToPic(name string, idx int, sprite *data.Sprite) *pixel.PictureData {
 			}
 		}
 
-		log.Printf(
-			"%v %d: len(row)=%v, len(pixels)=%v sprWidth=%v u0=%v xOffset=%v",
-			name, idx, len(row), len(pixels), sprite.Width, u0, xOffset,
-		)
+		//log.Printf(
+		//	"%v %d: len(row)=%v, len(pixels)=%v sprWidth=%v u0=%v xOffset=%v",
+		//	name, idx, len(row), len(pixels), sprite.Width, u0, xOffset,
+		//)
 
 		for x, b := range pixels {
 			vec := pixel.V(float64(xOffset+x), float64(y))

internal/maps/maps.go

@@ -69,8 +69,8 @@ func (h Header) MapSetFilename() string {
 }
 
 type ObjRef struct {
-	AreaByte            byte
-	FrameAndUnknownByte byte
+	AreaByte          byte
+	SpriteAndFlagByte byte
 }
 
 // The index into a set palette to retrieve the object
@@ -78,8 +78,14 @@ func (o ObjRef) Index() int {
 	return int(o.AreaByte)
 }
 
-func (o ObjRef) Frame() int {
-	return int(o.FrameAndUnknownByte - 0x80)
+func (o ObjRef) Sprite() int {
+	// The top bit seems to be a flag of some kind
+	return int(o.SpriteAndFlagByte & 0x7f)
+}
+
+// The top bit seems to say whether we should draw or not.
+func (o ObjRef) IsActive() bool {
+	return (o.SpriteAndFlagByte & 0x80) == 0x80
 }
 
 type Cell struct {
@@ -108,19 +114,19 @@ func (c *Cell) At(n int) byte {
 	case 3:
 		return c.Surface.AreaByte
 	case 4:
-		return c.Surface.FrameAndUnknownByte
+		return c.Surface.SpriteAndFlagByte
 	case 5:
 		return c.Left.AreaByte
 	case 6:
-		return c.Left.FrameAndUnknownByte
+		return c.Left.SpriteAndFlagByte
 	case 7:
 		return c.Right.AreaByte
 	case 8:
-		return c.Right.FrameAndUnknownByte
+		return c.Right.SpriteAndFlagByte
 	case 9:
 		return c.Center.AreaByte
 	case 10:
-		return c.Center.FrameAndUnknownByte
+		return c.Center.SpriteAndFlagByte
 	case 11:
 		return c.Unknown11
 	case 12:
@@ -139,7 +145,6 @@ func (c *Cell) At(n int) byte {
 // Cells is always a fixed size; use At to get a cell according to x,y,z
 type Cells []Cell
 
-// FIXME: Ordering may be incorrect? I assume z,y,x for now...
 func (c Cells) At(x, y, z int) Cell {
 	return c[(z*MaxLength*MaxWidth)+(y*MaxWidth)+x]
 }