up3

server/player/skin/cape.go

@@ -0,0 +1,52 @@
+package skin
+
+import (
+	"image"
+	"image/color"
+)
+
+// Cape represents the cape that a skin may additionally have. A skin is of a fixed size (always 32x64 bytes)
+// and may be either empty or of that size.
+type Cape struct {
+	w, h int
+
+	// Pix holds the colour data of the cape in an RGBA byte array, similarly to the way that the pixels of
+	// a Skin are stored.
+	// The size of Pix is always 32 * 64 * 4 bytes.
+	Pix []uint8
+}
+
+// NewCape initialises a new Cape using the width and height passed. The pixels are pre-allocated so that the
+// Cape may be used immediately.
+func NewCape(width, height int) Cape {
+	return Cape{w: width, h: height, Pix: make([]uint8, width*height*4)}
+}
+
+// ColorModel ...
+func (c Cape) ColorModel() color.Model {
+	return color.RGBAModel
+}
+
+// Bounds returns the bounds of the cape, which is always 32x64 or 0x0, depending on if the cape has any data
+// in it.
+func (c Cape) Bounds() image.Rectangle {
+	return image.Rectangle{
+		Max: image.Point{X: c.w, Y: c.h},
+	}
+}
+
+// At returns the colour at a given position in the cape, provided the X and Y are within the bounds of the
+// cape passed during construction.
+// The concrete type returned by At is a color.RGBA value.
+func (c Cape) At(x, y int) color.Color {
+	if x < 0 || y < 0 || x >= c.w || y >= c.h {
+		panic("pixel coordinates out of bounds")
+	}
+	offset := x*4 + c.w*y*4
+	return color.RGBA{
+		R: c.Pix[offset],
+		G: c.Pix[offset+1],
+		B: c.Pix[offset+2],
+		A: c.Pix[offset+3],
+	}
+}