ui: add simple hamburger style pile hint

1 files changed, 59 insertions, 0 deletions

diff --git a/go/ui/mapView.go b/go/ui/mapView.go
index 59e8f3a7..6a69ad5e 100644
--- a/go/ui/mapView.go
+++ b/go/ui/mapView.go
@@ -2,6 +2,7 @@ package ui
 
 import (
 	"fmt"
+	"image"
 	"image/color"
 	"log"
 	"math"
@@ -9,10 +10,25 @@ import (
 	"unicode"
 
 	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/vector"
 	"muhq.space/muhqs-game/go/assets"
 	"muhq.space/muhqs-game/go/game"
 )
 
+var (
+	// No idea why image.DrawTrianglesOptions needs this it is copied from
+	// the ebiten vector example.
+	whiteImage = ebiten.NewImage(3, 3)
+
+	// whiteSubImage is an internal sub image of whiteImage.
+	// Use whiteSubImage at DrawTriangles instead of whiteImage in order to avoid bleeding edges.
+	whiteSubImage = whiteImage.SubImage(image.Rect(1, 1, 2, 2)).(*ebiten.Image)
+)
+
+func init() {
+	whiteImage.Fill(color.White)
+}
+
 const (
 	PERMANENT_WIDTH  int = 40
 	PERMANENT_HEIGHT int = 40
@@ -183,12 +199,55 @@ func (vw *MapView) drawPermanentsLayer(screen *ebiten.Image) {
 			}
 
 			vw.permanentsLayer.DrawImage(permanentSymbol, op)
+
+			// Draw a pile hint
+			if len(p.Pile()) > 0 {
+				drawPileHint(permanentSymbol)
+			}
 		}
 	}
 
 	screen.DrawImage(vw.permanentsLayer, &ebiten.DrawImageOptions{})
 }
 
+const (
+	PILE_HINT_STARTX = 20
+	PILE_HINT_LENGTH = 15
+	PILE_HINT_STARTY = 25
+	PILE_HINT_WIDTH  = 2
+	PILE_HINT_SEP    = 2
+)
+
+func drawPileHint(screen *ebiten.Image) {
+	var path vector.Path
+	var i float32
+	for i = 1.0; i < 4; i++ {
+		y := PILE_HINT_STARTY + i*(PILE_HINT_WIDTH+PILE_HINT_SEP)
+		path.MoveTo(PILE_HINT_STARTX, y)
+		path.LineTo(PILE_HINT_STARTX+PILE_HINT_LENGTH, y)
+		path.Close()
+	}
+
+	var vs []ebiten.Vertex
+	var is []uint16
+	{
+		op := &vector.StrokeOptions{Width: PILE_HINT_WIDTH}
+		vs, is = path.AppendVerticesAndIndicesForStroke(nil, nil, op)
+	}
+
+	for i := range vs {
+		vs[i].SrcX = 1
+		vs[i].SrcY = 1
+		vs[i].ColorR = 0
+		vs[i].ColorG = 0
+		vs[i].ColorB = 0
+		vs[i].ColorA = 1
+	}
+
+	op := &ebiten.DrawTrianglesOptions{AntiAlias: true}
+	screen.DrawTriangles(vs, is, whiteSubImage, op)
+}
+
 func (vw *MapView) Draw(screen *ebiten.Image) {
 	vw.drawMapLayer(screen)
 	vw.drawPermanentsLayer(screen)