doodle/render/point.go

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Implement Chunk System for Pixel Data 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
2018-09-23 22:20:45 +00:00
package render
import (
"fmt"
"strconv"
"strings"
)
// Point holds an X,Y coordinate value.
type Point struct {
X int32
Y int32
}
// NewPoint makes a new Point at an X,Y coordinate.
func NewPoint(x, y int32) Point {
return Point{
X: x,
Y: y,
}
}
func (p Point) String() string {
return fmt.Sprintf("%d,%d", p.X, p.Y)
}
// ParsePoint to parse a point from its string representation.
func ParsePoint(v string) (Point, error) {
halves := strings.Split(v, ",")
if len(halves) != 2 {
return Point{}, fmt.Errorf("'%s': not a valid coordinate string", v)
}
x, errX := strconv.Atoi(halves[0])
y, errY := strconv.Atoi(halves[1])
if errX != nil || errY != nil {
return Point{}, fmt.Errorf("invalid coordinate string (X: %v; Y: %v)",
errX,
errY,
)
}
return Point{
X: int32(x),
Y: int32(y),
}, nil
}
// IsZero returns if the point is the zero value.
func (p Point) IsZero() bool {
return p.X == 0 && p.Y == 0
}
// Inside returns whether the Point falls inside the rect.
func (p Point) Inside(r Rect) bool {
var (
x1 = r.X
y1 = r.Y
x2 = r.X + r.W
y2 = r.Y + r.H
)
return p.X >= x1 && p.X <= x2 && p.Y >= y1 && p.Y <= y2
}
// Add (or subtract) the other point to your current point.
func (p *Point) Add(other Point) {
p.X += other.X
p.Y += other.Y
}
// MarshalText to convert the point into text so that a render.Point may be used
// as a map key and serialized to JSON.
func (p *Point) MarshalText() ([]byte, error) {
return []byte(fmt.Sprintf("%d,%d", p.X, p.Y)), nil
}
// UnmarshalText to restore it from text.
func (p *Point) UnmarshalText(b []byte) error {
halves := strings.Split(strings.Trim(string(b), `"`), ",")
if len(halves) != 2 {
return fmt.Errorf("'%s': not a valid coordinate string", b)
}
x, errX := strconv.Atoi(halves[0])
y, errY := strconv.Atoi(halves[1])
if errX != nil || errY != nil {
return fmt.Errorf("Point.UnmarshalJSON: Atoi errors (X=%s Y=%s)",
errX,
errY,
)
}
p.X = int32(x)
p.Y = int32(y)
return nil
}