noita-mapcap/bin/stitch/entities.go

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// Copyright (c) 2022 David Vogel
//
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT
package main
import (
"encoding/json"
"image"
"os"
"github.com/tdewolff/canvas"
"github.com/tdewolff/canvas/renderers/rasterizer"
)
type Entities []Entity
func LoadEntities(path string) (Entities, error) {
file, err := os.Open(path)
if err != nil {
return nil, err
}
var result Entities
jsonDec := json.NewDecoder(file)
if err := jsonDec.Decode(&result); err != nil {
return nil, err
}
return result, nil
}
// Draw implements the StitchedImageOverlay interface.
func (e Entities) Draw(destImage *image.RGBA) {
destRect := destImage.Bounds()
// Same as destImage, but top left is translated to (0, 0).
originImage := destImage.SubImage(destRect).(*image.RGBA)
originImage.Rect = originImage.Rect.Sub(destRect.Min)
c := canvas.New(float64(destRect.Dx()), float64(destRect.Dy()))
ctx := canvas.NewContext(c)
ctx.SetCoordSystem(canvas.CartesianIV)
ctx.SetCoordRect(canvas.Rect{X: -float64(destRect.Min.X), Y: -float64(destRect.Min.Y), W: float64(destRect.Dx()), H: float64(destRect.Dy())}, float64(destRect.Dx()), float64(destRect.Dy()))
// Set drawing style.
ctx.Style = playerPathDisplayStyle
for _, entity := range e {
// Check if entity origin is near or around the current image rectangle.
entityOrigin := image.Point{int(entity.Transform.X), int(entity.Transform.Y)}
if entityOrigin.In(destRect.Inset(-512)) {
entity.Draw(ctx)
}
}
// Theoretically we would need to linearize imgRGBA first, but DefaultColorSpace assumes that the color space is linear already.
r := rasterizer.FromImage(originImage, canvas.DPMM(1.0), canvas.DefaultColorSpace)
c.RenderTo(r)
r.Close() // This just transforms the image's luminance curve back from linear into non linear.
}