Noah Petherbridge
3c185528f9
Starts the implementation of the chunk-based pixel storage system for
levels and drawings.
Previously the levels had a Pixels structure which was just an array of
X,Y and palette index triplets. The new chunk system divides the map up
into square chunks, and lets each chunk manage its own memory layout.
The "MapAccessor" layout is implemented first which is a map of X,Y
coordinates to their Swatches (pointer to an index of the palette). When
serialized the MapAccessor maps the "X,Y": "index" similarly to the old
Pixels array.
The object hierarchy for the chunk system is like:
* Chunker: the manager of the chunks who keeps track of the ChunkSize
and a map of "chunk coordinates" to the chunk in charge of it.
* Chunk: a part of the drawing ChunkSize length square. A chunk has a
Type (of how it stores its data, 0 being a map[Point]Swatch and 1
being a [][]Swatch 2D array), and the chunk has an Accessor which
implements the underlying type.
* Accessor: an interface for a Chunk to provide access to its
pixels.
* MapAccessor: a "sparse map" of coordinates to their Swatches.
* GridAccessor: TBD, will be a "dense" 2D grid of Swatches.
The JSON files are loaded in two passes:
1. The chunks only load their swatch indexes from disk.
2. With the palette also loaded, the chunks are "inflated" and linked
to their swatch pointers.
Misc changes:
* The `level.Canvas` UI widget switches from the old Grid data type to
being able to directly use a `level.Chunker`
* The Chunker is a shared data type between the on-disk level format and
the actual renderer (level.Canvas), so saving the level is easy
because you can just pull the Chunker out from the canvas.
* ChunkSize is stored inside the level file and the default value is at
balance/numbers.go: 1000
90 lines
2.1 KiB
Go
90 lines
2.1 KiB
Go
package level
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
|
|
"git.kirsle.net/apps/doodle/render"
|
|
)
|
|
|
|
// Types of chunks.
|
|
const (
|
|
MapType int = iota
|
|
GridType
|
|
)
|
|
|
|
// Chunk holds a single portion of the pixel canvas.
|
|
type Chunk struct {
|
|
Type int // map vs. 2D array.
|
|
Accessor
|
|
}
|
|
|
|
// JSONChunk holds a lightweight (interface-free) copy of the Chunk for
|
|
// unmarshalling JSON files from disk.
|
|
type JSONChunk struct {
|
|
Type int `json:"type"`
|
|
Data json.RawMessage `json:"data"`
|
|
}
|
|
|
|
// Accessor provides a high-level API to interact with absolute pixel coordinates
|
|
// while abstracting away the details of how they're stored.
|
|
type Accessor interface {
|
|
Inflate(*Palette) error
|
|
Iter() <-chan Pixel
|
|
IterViewport(viewport render.Rect) <-chan Pixel
|
|
Get(render.Point) (*Swatch, error)
|
|
Set(render.Point, *Swatch) error
|
|
Delete(render.Point) error
|
|
Len() int
|
|
MarshalJSON() ([]byte, error)
|
|
UnmarshalJSON([]byte) error
|
|
}
|
|
|
|
// NewChunk creates a new chunk.
|
|
func NewChunk() *Chunk {
|
|
return &Chunk{
|
|
Type: MapType,
|
|
Accessor: NewMapAccessor(),
|
|
}
|
|
}
|
|
|
|
// Usage returns the percent of free space vs. allocated pixels in the chunk.
|
|
func (c *Chunk) Usage(size int) float64 {
|
|
return float64(c.Len()) / float64(size)
|
|
}
|
|
|
|
// MarshalJSON writes the chunk to JSON.
|
|
func (c *Chunk) MarshalJSON() ([]byte, error) {
|
|
data, err := c.Accessor.MarshalJSON()
|
|
if err != nil {
|
|
return []byte{}, err
|
|
}
|
|
|
|
generic := &JSONChunk{
|
|
Type: c.Type,
|
|
Data: data,
|
|
}
|
|
b, err := json.Marshal(generic)
|
|
return b, err
|
|
}
|
|
|
|
// UnmarshalJSON loads the chunk from JSON and uses the correct accessor to
|
|
// parse the inner details.
|
|
func (c *Chunk) UnmarshalJSON(b []byte) error {
|
|
// Parse it generically so we can hand off the inner "data" object to the
|
|
// right accessor for unmarshalling.
|
|
generic := &JSONChunk{}
|
|
err := json.Unmarshal(b, generic)
|
|
if err != nil {
|
|
return fmt.Errorf("Chunk.UnmarshalJSON: failed to unmarshal into generic JSONChunk type: %s", err)
|
|
}
|
|
|
|
switch c.Type {
|
|
case MapType:
|
|
c.Accessor = NewMapAccessor()
|
|
return c.Accessor.UnmarshalJSON(generic.Data)
|
|
default:
|
|
return fmt.Errorf("Chunk.UnmarshalJSON: unsupported chunk type '%d'", c.Type)
|
|
}
|
|
}
|