Correctly render all four objects for every cell in a map

cmd/view-map/main.go

@@ -163,8 +163,10 @@ func (s *state) present(pWin *pixelgl.Window) {
 
 			cell := gameMap.Cells.At(x, y, z)
 
-			surfaceSprite, _ := s.env.getSprite(s.env.set.SurfacePalette, cell.Surface)
-			centerSprite, _ := s.env.getSprite(s.env.set.CenterPalette, cell.Center)
+			surfaceSprite, _ := s.env.getSprite(s.env.set.Palette, cell.Surface)
+			centerSprite, _ := s.env.getSprite(s.env.set.Palette, cell.Center)
+			leftSprite, _ := s.env.getSprite(s.env.set.Palette, cell.Left)
+			rightSprite, _ := s.env.getSprite(s.env.set.Palette, cell.Right)
 
 			fX := float64(x)
 			fY := float64(y)
@@ -185,6 +187,14 @@ func (s *state) present(pWin *pixelgl.Window) {
 			if centerSprite != nil {
 				centerSprite.Spr.Draw(pWin, pixel.IM.Moved(iso))
 			}
+
+			if leftSprite != nil {
+				leftSprite.Spr.Draw(pWin, pixel.IM.Moved(iso))
+			}
+
+			if rightSprite != nil {
+				rightSprite.Spr.Draw(pWin, pixel.IM.Moved(iso))
+			}
 		}
 	}
 }

doc/formats/maps.md

@@ -375,7 +375,7 @@ Press "U" to get to the screen!
 
 ![Debug screen](img/cell-information-debug.png)
 
-I've added a `view-map` command to explore the data graphically. Each of the 16
+I've added a `view-minimap` command to explore the data graphically. Each of the 16
 bytes in a cell row must have a function; comparing a known map to how it looks
 in WH40K_TD.exe can help me to unravel that function.
 
@@ -431,7 +431,20 @@ maps.Cell{
 
 So `CellIdx == 9` points to the center object's Area, looked up in the set file!
 
-![Pinning down cell index 9](img/chapter01_cell_index_9.png
+![Pinning down cell index 9](img/chapter01_cell_index_9.png)
+
+It seems the area numbers are absolute indexes into the set, rather than having
+a new set of indices for each type.
+
+With this information, we can render a given Z index for a map quite easily,
+using the new `view-map` binary. It draws the four objects for every cell, and
+gives results like this:
+
+![Rendering all map objects](img/chapter01-rendering-objects.png)
+
+Some colours are off, but I've verified that I'm using the correct palette, so
+this must be due to other things. Perhaps `Data/Cycle.cyc` is the culprit, or
+maybe I need to revisit .obj file parsing a few more times!
 
 ## Trailer