From b6dcfafb6d49734e435c1754349e5f47356752a6 Mon Sep 17 00:00:00 2001
From: Nick Thomas <me@ur.gs>
Date: Sun, 25 Mar 2018 12:49:36 +0100
Subject: [PATCH] Remove a dodgy optimization and allow mouse clicks to output
 cell position

---
 cmd/view-map/main.go | 50 ++++++++++++++++++++++++++++++--------------
 1 file changed, 34 insertions(+), 16 deletions(-)

diff --git a/cmd/view-map/main.go b/cmd/view-map/main.go
index f29ab09..934ba89 100644
--- a/cmd/view-map/main.go
+++ b/cmd/view-map/main.go
@@ -134,11 +134,6 @@ func (e *env) getSprite(palette []string, ref maps.ObjRef) *conv.Sprite {
 	return &obj.Sprites[ref.Frame()]
 }
 
-var (
-	cellWidth  = 64.0 // I think, anyway
-	cellLength = 64.0
-)
-
 // TODO: build all the sprites in the set into a single spritesheet so we can
 // use pixel.Batch
 func (s *state) present(pWin *pixelgl.Window) {
@@ -176,10 +171,7 @@ func (s *state) renderCell(x, y, z int, pWin *pixelgl.Window) {
 
 	cell := s.env.gameMap.Cells.At(x, y, z)
 
-	// Try optimizing zero surfaces out, they tend to be? all-transparent
-	if cell.Surface.Index() != 0 {
-		sprites = append(sprites, s.env.getSprite(s.env.set.Palette, cell.Surface))
-	}
+	sprites = append(sprites, s.env.getSprite(s.env.set.Palette, cell.Surface))
 
 	sprites = append(
 		sprites,
@@ -193,13 +185,7 @@ func (s *state) renderCell(x, y, z int, pWin *pixelgl.Window) {
 	fX := float64(x - z)
 	fY := float64(y - z)
 
-	xPos := fX * cellWidth
-	yPos := fY * cellLength
-
-	// The rotation translates the rectangular coordinates to diamond
-	// ones \o/
-	orig := pixel.V(xPos, yPos)
-	iso := pixel.V(orig.X-orig.Y, (orig.X+orig.Y)/2.0)
+	iso := s.cellToPix(pixel.V(fX, fY))
 
 	for _, sprite := range sprites {
 		if sprite != nil {
@@ -208,6 +194,27 @@ func (s *state) renderCell(x, y, z int, pWin *pixelgl.Window) {
 	}
 }
 
+var (
+	cellWidth  = 64.0
+	cellHeight = 64.0
+)
+
+// Doesn't take the camera or Z level into account
+func (s *state) cellToPix(cell pixel.Vec) pixel.Vec {
+	return pixel.V(
+		(cell.X-cell.Y)*cellWidth,
+		(cell.X+cell.Y)*cellHeight/2.0,
+	)
+}
+
+// Doesn't take the camera or Z level into account
+func (s *state) pixToCell(pix pixel.Vec) pixel.Vec {
+	return pixel.V(
+		pix.Y/cellHeight+pix.X/(cellWidth*2.0),
+		pix.Y/cellHeight-pix.X/(cellWidth*2.0),
+	)
+}
+
 func (s *state) runStep(pWin *pixelgl.Window) *state {
 	newState := *s
 	newState.handleKeys(pWin)
@@ -216,6 +223,17 @@ func (s *state) runStep(pWin *pixelgl.Window) *state {
 }
 
 func (s *state) handleKeys(pWin *pixelgl.Window) {
+	// Do this first to avoid taking the below mutations into account
+	// FIXME: this suggests we should pass the next state into here and
+	// modify it instead
+	if pWin.JustPressed(pixelgl.MouseButton1) {
+		cell := s.pixToCell(s.cam.Unproject(pWin.MousePosition()))
+		if s.zIdx != 0 {
+			log.Printf("WARNING: z-index not yet taken into account")
+		}
+		log.Printf("X=%v Y=%v, zIdx=%v", cell.X, cell.Y, s.zIdx)
+	}
+
 	if pWin.Pressed(pixelgl.KeyLeft) {
 		s.camPos.X -= 64
 	}