Add the view-map command and some exploration of results

.gitignore

@@ -1,3 +1,4 @@
 /investigation
 /loader
 /orig
+/view-map

Makefile

@@ -3,3 +3,5 @@ srcfiles = $(shell find . -iname *.go)
 loader: $(srcfiles)
 	go build -o loader ur.gs/chaos-gate/cmd/load
 
+view-map: $(srcfiles)
+	go build -o view-map ur.gs/chaos-gate/cmd/view-map

cmd/view-map/main.go

@@ -0,0 +1,208 @@
+package main
+
+import (
+	"flag"
+	"log"
+	"math"
+	"os"
+	"time"
+
+	"github.com/faiface/pixel"
+	"github.com/faiface/pixel/imdraw"
+	"github.com/faiface/pixel/pixelgl"
+	"golang.org/x/image/colornames"
+
+	"ur.gs/chaos-gate/internal/maps"
+)
+
+var (
+	gamePath = flag.String("game-path", "./orig", "Path to a WH40K: Chaos Gate installation")
+	mapFile  = flag.String("map", "", "Prefix path to a .map file, e.g. ./orig/Maps/Chapter01.MAP")
+	txtFile  = flag.String("txt", "", "Prefix path to a .txt file, e.g. ./orig/Maps/Chapter01.txt")
+
+	winX = flag.Int("win-x", 1280, "width of the view-map window")
+	winY = flag.Int("win-y", 1024, "height of the view-map window")
+)
+
+func main() {
+	flag.Parse()
+
+	if *gamePath == "" || *mapFile == "" || *txtFile == "" {
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	gameMap, err := maps.LoadGameMapByFiles(*mapFile, *txtFile)
+	if err != nil {
+		log.Fatalf("Couldn't load map file: %v", err)
+	}
+
+	// The main thread now belongs to pixelgl
+	pixelgl.Run(func() { run(gameMap) })
+}
+
+type runState struct {
+	redraw     bool
+	started    time.Time
+	autoUpdate bool
+	gameMap    *maps.GameMap
+
+	zoom float64
+
+	zIdx    int
+	cellIdx int
+}
+
+func run(gameMap *maps.GameMap) {
+	cfg := pixelgl.WindowConfig{
+		Title:  "View Map " + *mapFile,
+		Bounds: pixel.R(0, 0, float64(*winX), float64(*winY)),
+		VSync:  true,
+	}
+
+	win, err := pixelgl.NewWindow(cfg)
+	if err != nil {
+		log.Fatal("Couldn't create window: %v", err)
+	}
+
+	state := &runState{
+		redraw:     true,
+		started:    time.Now(),
+		autoUpdate: true,
+		gameMap:    gameMap,
+		zoom:       1.0,
+	}
+
+	for !win.Closed() {
+		if state.redraw {
+			log.Printf("z=%d cellIdx=%d", state.zIdx, state.cellIdx)
+			presentFull(win, state)
+		}
+
+		state = runStep(win, state)
+
+		win.Update()
+	}
+}
+
+// TODO: cut this down to showing just the viewport?
+// The naive approach using gameMap.Width() / Height() cuts half the map off :/
+func presentFull(win *pixelgl.Window, state *runState) {
+	gameMap := state.gameMap
+	center := win.Bounds().Center()
+	sz := win.Bounds().Size()
+	imd := imdraw.New(nil)
+
+	// Rotate everything 45' anticlockwise to get an isometric view with the
+	// lowest coordinates at the (now) top corner
+	imd.SetMatrix(pixel.IM.Rotated(center, -math.Pi/4))
+
+	xPerCell := sz.X / float64(maps.MaxWidth)
+	yPerCell := sz.Y / float64(maps.MaxLength)
+
+	for y := 0; y < maps.MaxLength; y++ {
+		for x := 0; x < maps.MaxWidth; x++ {
+			min := pixel.Vec{X: float64(x) * xPerCell, Y: float64(y) * yPerCell}
+			max := pixel.Vec{X: min.X + xPerCell, Y: min.Y + yPerCell}
+
+			cell := gameMap.Cells.At(int(x), int(y), int(state.zIdx))
+			// TODO: represent the state of the cell *sensibly*, using colour.
+			// Need to understand the contents better first, so for now optimize
+			// for exploration
+			//
+			// CellIndex=3 shows walls & elevation changes
+			imd.Color = makeColour(cell, state.cellIdx)
+			imd.Push(min, max)
+			imd.Rectangle(0.0)
+		}
+	}
+
+	cam := pixel.IM.Scaled(center, state.zoom)
+	win.SetMatrix(cam)
+	win.Clear(colornames.Black)
+	imd.Draw(win)
+}
+
+func makeColour(cell maps.Cell, colIdx int) pixel.RGBA {
+	return pixel.RGB(
+		float64(cell[colIdx]),
+		float64(cell[colIdx]),
+		float64(cell[colIdx]),
+	)
+}
+
+func runStep(win *pixelgl.Window, state *runState) *runState {
+	nextState := *state
+	nextState.redraw = false
+
+	// Enable / disable auto-update with the enter key
+	if win.JustPressed(pixelgl.KeyEnter) {
+		nextState.autoUpdate = !state.autoUpdate
+		log.Printf("autoUpdate=%v", nextState.autoUpdate)
+
+		if nextState.autoUpdate {
+			nextState.started = time.Now()
+		}
+	}
+
+	// Automatically cycle every second when auto-update is on
+	if nextState.autoUpdate && time.Now().Sub(nextState.started) > time.Second {
+		nextState.redraw = true
+		nextState.cellIdx = nextState.cellIdx + 1
+		if nextState.cellIdx >= maps.CellSize {
+			nextState.cellIdx = 0
+			nextState.zIdx = nextState.zIdx + 1
+		}
+
+		if nextState.zIdx >= maps.MaxHeight {
+			nextState.zIdx = 0
+		}
+
+		nextState.started = time.Now()
+	}
+
+	if win.JustPressed(pixelgl.KeyDown) {
+		if nextState.zIdx <= 0 {
+			log.Printf("z index is already at minimum")
+		} else {
+			nextState.redraw = true
+			nextState.zIdx = nextState.zIdx - 1
+		}
+	}
+
+	if win.JustPressed(pixelgl.KeyUp) {
+		if nextState.zIdx >= maps.MaxHeight-1 {
+			log.Printf("z index is already at maximum")
+		} else {
+			nextState.redraw = true
+			nextState.zIdx = nextState.zIdx + 1
+		}
+	}
+
+	if win.JustPressed(pixelgl.KeyLeft) {
+		if nextState.cellIdx <= 0 {
+			log.Printf("cell index is already at minimum")
+		} else {
+			nextState.redraw = true
+			nextState.cellIdx = nextState.cellIdx - 1
+		}
+	}
+
+	if win.JustPressed(pixelgl.KeyRight) {
+		if nextState.cellIdx >= maps.CellSize-1 {
+			log.Printf("cell index is already at maximum")
+		} else {
+			nextState.redraw = true
+			nextState.cellIdx = nextState.cellIdx + 1
+		}
+	}
+
+	// Zoom in and out with the mouse wheel
+	nextState.zoom *= math.Pow(1.2, win.MouseScroll().Y)
+	if nextState.zoom != state.zoom {
+		log.Printf("zoom=%.2f", nextState.zoom)
+		nextState.redraw = true
+	}
+
+	return &nextState
+}

doc/formats/maps.md

@@ -293,6 +293,8 @@ Total number of possible coordinates is 100x130x7 = 91,000 = 1,456,000 bytes.
 Uncompressed file size is always 1,458,915 bytes, leaving 2,915 bytes over for
 header and any trailing data.
 
+How are the rows structured? `[z][y][x]`?
+
 Looking at the data around 0x163890, we see:
 
 ```
@@ -328,6 +330,67 @@ So this looks like a good working theory.
 Wherever they start, these rows must refer to the object sets somehow. We also
 need to work out how they're arranged.
 
+Disassembly of WH40K_TD.EXE suggests a file `Engine::CellInfo` at 0x4226F0. It
+dumps the following information:
+
+* Mission exit: true / false
+* Smoke: true / false
+* Sprite: true / false
+* Vehicle: true / false
+* Net start: true / false
+* Spell: true / false
+* Trigger: true / false
+* Breadcrumb: true / false
+* Door: true / false
+* Lock: true / false
+* Reactor: true / false
+* Objective: true / false
+* Canister number %d
+* Cell visible %d
+* Tile visible %d
+* N0 - N7: true / false (seems to be a bitfield)
+* Object 0 SURFACE: true / false
+* Object area %d
+* Curr sprite %d
+* Object 1 LEFT: true / false
+* Object area %d
+* Curr sprite %d
+* Object 2 RIGHT: true / false
+* Object area %d
+* Curr sprite %d
+* Object 3 CENTRE: true / false
+* Object area %d
+* Curr sprite %d
+
+Presumably at least some of these attributes come from the records identified
+above. Will need to experiment to establish correlations. Items of interest:
+
+* A cell can have 4 objects in it - a surface, a left, a right, and a centre.
+* Presumably a surface is what we show on the ground, and it will be set for
+  "ground level" data.
+
+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
+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.
+
+Here's a side-by-side comparison of Chapter3.MAP, investigating CellIndex=3 and
+Z index = 0
+
+![Map comparison](img/chapter_01_cell_index_3.png)
+
+Incrementing the Z index shows the building and terrain progressively changing
+as expected, so this is a good hint that the data is actually arranged in
+`[z][y][x][16]` blocks and that I either have the right offset, or I'm out by a
+well-aligned amount.
+
+Trying to constrict to the viewport currently cuts off much of this displayed
+map, suggesting that I've got something wrong in the calculation somewhere. Need
+to dig into that more.
+
 ## Trailer
 
 Assuming the theory above is correct, we have trailer data starting at

internal/maps/maps.go

@@ -5,6 +5,7 @@ import (
 	"compress/gzip"
 	"encoding/binary"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"log"
 	"os"
@@ -18,6 +19,17 @@ var (
 	notImplemented        = fmt.Errorf("Not implemented")
 )
 
+const (
+	MaxHeight = 7   // Z coordinate
+	MaxLength = 100 // Y coordinate
+	MaxWidth  = 130 // X coordinate
+
+	CellSize = 16 // seems to be
+
+	cellDataOffset = 0x100 // tentatively
+	cellDataSize   = MaxHeight * MaxLength * MaxWidth * CellSize
+)
+
 type Header struct {
 	IsCampaignMap uint32 // Tentatively: 0 = no, 1 = yes
 	MinWidth      uint32
@@ -31,7 +43,37 @@ type Header struct {
 	Magic         [8]byte // "\x08\x00WHMAP\x00"
 	Unknown5      uint32
 	Unknown6      uint32
-	SetName       [8]byte // Or is it a null-terminated string?
+	SetName       [8]byte // Links to a filename in `/Sets/*.set`
+	// Need to investigate the rest of the header too
+}
+
+func (h Header) Width() int {
+	return int(h.MaxWidth - h.MinWidth)
+}
+
+func (h Header) Length() int {
+	return int(h.MaxLength - h.MinLength)
+}
+
+func (h Header) Height() int {
+	return MaxHeight
+}
+
+type Cell []byte // FIXME: need to deconstruct this into the various fields
+
+// Cells is always a fixed size; use At to get a cell according to x,y,z
+type Cells []byte
+
+// FIXME: Ordering may be incorrect? I assume z,y,x for now...
+func (c Cells) At(x, y, z int) Cell {
+	start :=
+		(z * MaxLength * MaxWidth * CellSize) +
+			(y * MaxWidth * CellSize) +
+			(x * CellSize)
+
+	end := start + CellSize
+
+	return Cell(c[start:end:end])
 }
 
 func (h Header) Check() []error {
@@ -49,7 +91,7 @@ func (h Header) Check() []error {
 
 type GameMap struct {
 	Header
-
+	Cells
 	// TODO: parse this into sections
 	Text string
 }
@@ -57,8 +99,8 @@ type GameMap struct {
 // A game map contains a .txt and a .map. If they're in the same directory,
 // just pass the directory + basename to load both
 func LoadGameMap(prefix string) (*GameMap, error) {
-	for _, mapExt := range []string{".MAP", ".map"} {
 	for _, txtExt := range []string{".TXT", ".txt"} {
+		for _, mapExt := range []string{".MAP", ".map"} {
 			out, err := LoadGameMapByFiles(prefix+mapExt, prefix+txtExt)
 			if err != nil && !os.IsNotExist(err) {
 				return nil, err
@@ -146,5 +188,16 @@ func loadMapFile(filename string) (*GameMap, error) {
 		return nil, fmt.Errorf("Error parsing %s: %v", filename, err)
 	}
 
+	// no gzip.SeekReader, so discard unread header bytes for now
+	discardSize := int64(cellDataOffset - binary.Size(&out.Header))
+	if _, err := io.CopyN(ioutil.Discard, zr, discardSize); err != nil {
+		return nil, err
+	}
+
+	out.Cells = make(Cells, cellDataSize)
+	if err := binary.Read(zr, binary.LittleEndian, &out.Cells); err != nil {
+		return nil, fmt.Errorf("Error parsing %s: %v", filename, err)
+	}
+
 	return &out, nil
 }