Move the palette code into internal/ so view-map can share it

internal/conv/object.go

@@ -0,0 +1,91 @@
+package conv
+
+import (
+	"bytes"
+	"image/color"
+	"log"
+
+	"github.com/faiface/pixel"
+
+	"ur.gs/chaos-gate/internal/data"
+)
+
+// Important conversions:
+//
+//   * Width & height now stored using int
+//   * Colour data is now 32-bit rather than using a palette
+type Sprite struct {
+	Width  int
+	Height int
+
+	Pic *pixel.PictureData
+}
+
+type Object struct {
+	Name    string
+	Sprites []Sprite
+}
+
+func ConvertObject(rawObj *data.Object, name string) *Object {
+	out := &Object{
+		Name:    name,
+		Sprites: make([]Sprite, len(rawObj.Sprites)),
+	}
+
+	for i, rawSpr := range rawObj.Sprites {
+		out.Sprites[i] = Sprite{
+			Width:  int(rawSpr.Width),
+			Height: int(rawSpr.Height),
+			Pic:    spriteToPic(rawSpr),
+		}
+	}
+
+	return out
+}
+
+// WIP. Try to convert the pixeldata into a picture.
+func spriteToPic(sprite *data.Sprite) *pixel.PictureData {
+	pic := pixel.MakePictureData(pixel.R(float64(0), float64(0), float64(sprite.Width), float64(sprite.Height)))
+
+	buf := bytes.NewBuffer(sprite.PixelData)
+
+	// The pixeldata seems to be formed of Y null-terminated records, with
+	// varying numbers of bytes in each row. Probably [type, *data] but ignore
+	// type for now.
+	//
+	// Theory: perhaps the data in each X is centered around the origin?
+	for y := 0; y < int(sprite.Height); y++ {
+		insn := buf.Next(1)[0] // Take the instruction byte, if that's what it is
+
+		switch insn {
+		case 0:
+			log.Printf("Reached the end of the sprite at y=%v (height=%v)", y, sprite.Height)
+		case 1, 0x80:
+			// Ignore these, as we know they exist and the logic below seems to handle them
+			// Although I suspect 0x80 means "centered run of bytes" while 0x1
+			// means "left-aligned run of bytes", since all 0x1 rows seem to be
+			// for 1x1 images, it makes no practical difference
+		default:
+			log.Printf("Record of unknown type %v", insn)
+		}
+
+		rowData, err := buf.ReadBytes(0)
+		if err != nil {
+			log.Printf("Error at y=%d: %v", y, err)
+			continue
+		}
+
+		// Ignore the record separator
+		rowData = rowData[0 : len(rowData)-1]
+
+		leftPad := (int(sprite.Width) - len(rowData)) / 2
+
+		for x, b := range rowData {
+			idx := pic.Index(pixel.V(float64(leftPad+x), float64(y)))
+			r, g, b, a := data.ColorPalette[int(b)].RGBA()
+			pic.Pix[idx] = color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)}
+		}
+	}
+
+	return pic
+}