doodle/pkg/level/chunker.go

305 lines
7.5 KiB
Go

package level
import (
"encoding/json"
"fmt"
"math"
"git.kirsle.net/apps/doodle/pkg/log"
"git.kirsle.net/go/render"
"github.com/vmihailenco/msgpack"
)
// Chunker is the data structure that manages the chunks of a level, and
// provides the API to interact with the pixels using their absolute coordinates
// while abstracting away the underlying details.
type Chunker struct {
Size int `json:"size"`
Chunks ChunkMap `json:"chunks"`
}
// NewChunker creates a new chunk manager with a given chunk size.
func NewChunker(size int) *Chunker {
return &Chunker{
Size: size,
Chunks: ChunkMap{},
}
}
// Inflate iterates over the pixels in the (loaded) chunks and expands any
// Sparse Swatches (which have only their palette index, from the file format
// on disk) to connect references to the swatches in the palette.
func (c *Chunker) Inflate(pal *Palette) error {
for coord, chunk := range c.Chunks {
chunk.Point = coord
chunk.Size = c.Size
chunk.Inflate(pal)
}
return nil
}
// IterViewport returns a channel to iterate every point that exists within
// the viewport rect.
func (c *Chunker) IterViewport(viewport render.Rect) <-chan Pixel {
pipe := make(chan Pixel)
go func() {
// Get the chunk box coordinates.
var (
topLeft = c.ChunkCoordinate(render.NewPoint(viewport.X, viewport.Y))
bottomRight = c.ChunkCoordinate(render.Point{
X: viewport.X + viewport.W,
Y: viewport.Y + viewport.H,
})
)
for cx := topLeft.X; cx <= bottomRight.X; cx++ {
for cy := topLeft.Y; cy <= bottomRight.Y; cy++ {
if chunk, ok := c.GetChunk(render.NewPoint(cx, cy)); ok {
for px := range chunk.Iter() {
// Verify this pixel is also in range.
if px.Point().Inside(viewport) {
pipe <- px
}
}
}
}
}
close(pipe)
}()
return pipe
}
// IterViewportChunks returns a channel to iterate over the Chunk objects that
// appear within the viewport rect, instead of the pixels in each chunk.
func (c *Chunker) IterViewportChunks(viewport render.Rect) <-chan render.Point {
pipe := make(chan render.Point)
go func() {
sent := make(map[render.Point]interface{})
for x := viewport.X; x < viewport.W; x += (c.Size / 4) {
for y := viewport.Y; y < viewport.H; y += (c.Size / 4) {
// Constrain this chunksize step to a point within the bounds
// of the viewport. This can yield partial chunks on the edges
// of the viewport.
point := render.NewPoint(x, y)
if point.X < viewport.X {
point.X = viewport.X
} else if point.X > viewport.X+viewport.W {
point.X = viewport.X + viewport.W
}
if point.Y < viewport.Y {
point.Y = viewport.Y
} else if point.Y > viewport.Y+viewport.H {
point.Y = viewport.Y + viewport.H
}
// Translate to a chunk coordinate, dedupe and send it.
coord := c.ChunkCoordinate(render.NewPoint(x, y))
if _, ok := sent[coord]; ok {
continue
}
sent[coord] = nil
if _, ok := c.GetChunk(coord); ok {
pipe <- coord
}
}
}
close(pipe)
}()
return pipe
}
// IterPixels returns a channel to iterate over every pixel in the entire
// chunker.
func (c *Chunker) IterPixels() <-chan Pixel {
pipe := make(chan Pixel)
go func() {
for _, chunk := range c.Chunks {
for px := range chunk.Iter() {
pipe <- px
}
}
close(pipe)
}()
return pipe
}
// WorldSize returns the bounding coordinates that the Chunker has chunks to
// manage: the lowest pixels from the lowest chunks to the highest pixels of
// the highest chunks.
func (c *Chunker) WorldSize() render.Rect {
// Lowest and highest chunks.
var (
chunkLowest render.Point
chunkHighest render.Point
size = c.Size
)
for coord := range c.Chunks {
if coord.X < chunkLowest.X {
chunkLowest.X = coord.X
}
if coord.Y < chunkLowest.Y {
chunkLowest.Y = coord.Y
}
if coord.X > chunkHighest.X {
chunkHighest.X = coord.X
}
if coord.Y > chunkHighest.Y {
chunkHighest.Y = coord.Y
}
}
return render.Rect{
X: chunkLowest.X * size,
Y: chunkLowest.Y * size,
W: (chunkHighest.X * size) + (size - 1),
H: (chunkHighest.Y * size) + (size - 1),
}
}
// WorldSizePositive returns the WorldSize anchored to 0,0 with only positive
// coordinates.
func (c *Chunker) WorldSizePositive() render.Rect {
S := c.WorldSize()
return render.Rect{
X: 0,
Y: 0,
W: int(math.Abs(float64(S.X))) + S.W,
H: int(math.Abs(float64(S.Y))) + S.H,
}
}
// GetChunk gets a chunk at a certain position. Returns false if not found.
func (c *Chunker) GetChunk(p render.Point) (*Chunk, bool) {
chunk, ok := c.Chunks[p]
return chunk, ok
}
// Get a pixel at the given coordinate. Returns the Palette entry for that
// pixel or else returns an error if not found.
func (c *Chunker) Get(p render.Point) (*Swatch, error) {
// Compute the chunk coordinate.
coord := c.ChunkCoordinate(p)
if chunk, ok := c.Chunks[coord]; ok {
return chunk.Get(p)
}
return nil, fmt.Errorf("no chunk %s exists for point %s", coord, p)
}
// Set a pixel at the given coordinate.
func (c *Chunker) Set(p render.Point, sw *Swatch) error {
coord := c.ChunkCoordinate(p)
chunk, ok := c.Chunks[coord]
if !ok {
chunk = NewChunk()
c.Chunks[coord] = chunk
chunk.Point = coord
chunk.Size = c.Size
}
return chunk.Set(p, sw)
}
// SetRect sets a rectangle of pixels to a color all at once.
func (c *Chunker) SetRect(r render.Rect, sw *Swatch) error {
var (
xMin = r.X
yMin = r.Y
xMax = r.X + r.W
yMax = r.Y + r.H
)
for x := xMin; x < xMax; x++ {
for y := yMin; y < yMax; y++ {
c.Set(render.NewPoint(x, y), sw)
}
}
return nil
}
// Delete a pixel at the given coordinate.
func (c *Chunker) Delete(p render.Point) error {
coord := c.ChunkCoordinate(p)
defer c.pruneChunk(coord)
if chunk, ok := c.Chunks[coord]; ok {
return chunk.Delete(p)
}
return fmt.Errorf("no chunk %s exists for point %s", coord, p)
}
// DeleteRect deletes a rectangle of pixels between two points.
// The rect is a relative one with a width and height, and the X,Y values are
// an absolute world coordinate.
func (c *Chunker) DeleteRect(r render.Rect) error {
var (
xMin = r.X
yMin = r.Y
xMax = r.X + r.W
yMax = r.Y + r.H
)
for x := xMin; x < xMax; x++ {
for y := yMin; y < yMax; y++ {
c.Delete(render.NewPoint(x, y))
}
}
return nil
}
// pruneChunk will remove an empty chunk from the chunk map, called after
// delete operations.
func (c *Chunker) pruneChunk(coord render.Point) {
if chunk, ok := c.Chunks[coord]; ok {
if chunk.Len() == 0 {
log.Info("Chunker.pruneChunk: %s has become empty", coord)
delete(c.Chunks, coord)
}
}
}
// ChunkCoordinate computes a chunk coordinate from an absolute coordinate.
func (c *Chunker) ChunkCoordinate(abs render.Point) render.Point {
if c.Size == 0 {
return render.Point{}
}
size := float64(c.Size)
return render.NewPoint(
int(math.Floor(float64(abs.X)/size)),
int(math.Floor(float64(abs.Y)/size)),
)
}
// ChunkMap maps a chunk coordinate to its chunk data.
type ChunkMap map[render.Point]*Chunk
// MarshalJSON to convert the chunk map to JSON. This is needed for writing so
// the JSON encoder knows how to serializes a `map[Point]*Chunk` but the inverse
// is not necessary to implement.
func (c ChunkMap) MarshalJSON() ([]byte, error) {
dict := map[string]*Chunk{}
for point, chunk := range c {
dict[point.String()] = chunk
}
out, err := json.Marshal(dict)
return out, err
}
// MarshalMsgpack to convert the chunk map to binary.
func (c ChunkMap) MarshalMsgpack() ([]byte, error) {
dict := map[string]*Chunk{}
for point, chunk := range c {
dict[point.String()] = chunk
}
out, err := msgpack.Marshal(dict)
return out, err
}