Brush Pattern Textures

Palette swatches gain a new property: Pattern.

Patterns are grayscale textures that the swatch color will sample
against when drawing pixels to the level, by taking the world coordinate
modulo a value inside the texture.

A few algorithms were tried (Screen, Overlay), this branch lands on one
that tries to cast the color from grayscale which comes out rather dark;
to get a patterned color to look black while still seeing the pattern,
the color needs to be as bright as #777 to get the effect.

pkg/branding/branding.go

@@ -4,7 +4,7 @@ package branding
 const (
 	AppName   = "Sketchy Maze"
 	Summary   = "A drawing-based maze game"
-	Version   = "0.6.0-alpha"
+	Version   = "0.6.1-alpha"
 	Website   = "https://www.sketchymaze.com"
 	Copyright = "2021 Noah Petherbridge"
 

pkg/doodle.go

@@ -13,6 +13,7 @@ import (
 	"git.kirsle.net/apps/doodle/pkg/log"
 	"git.kirsle.net/apps/doodle/pkg/modal"
 	"git.kirsle.net/apps/doodle/pkg/native"
+	"git.kirsle.net/apps/doodle/pkg/pattern"
 	"git.kirsle.net/apps/doodle/pkg/shmem"
 	golog "git.kirsle.net/go/log"
 	"git.kirsle.net/go/render"
@@ -95,6 +96,9 @@ func (d *Doodle) SetupEngine() error {
 	// Initialize the UI modal manager.
 	modal.Initialize(d.Engine)
 
+	// Preload the builtin brush patterns.
+	pattern.LoadBuiltins(d.Engine)
+
 	return nil
 }
 

pkg/drawtool/stroke.go

@@ -18,6 +18,7 @@ type Stroke struct {
 	ID        int // Unique ID per each stroke
 	Shape     Shape
 	Color     render.Color
+	Pattern   string
 	Thickness int         // 0 = 1px; thickness creates a box N pixels away from each point
 	ExtraData interface{} // arbitrary storage for extra data to attach
 

pkg/level/chunk.go

@@ -8,6 +8,7 @@ import (
 
 	"git.kirsle.net/apps/doodle/pkg/balance"
 	"git.kirsle.net/apps/doodle/pkg/log"
+	"git.kirsle.net/apps/doodle/pkg/pattern"
 	"git.kirsle.net/apps/doodle/pkg/shmem"
 	"git.kirsle.net/go/render"
 	"github.com/google/uuid"
@@ -150,6 +151,7 @@ func (c *Chunk) ToBitmap(filename string, mask render.Color) (render.Texturer, e
 	img := image.NewRGBA(imgSize)
 
 	// Blank out the pixels.
+	// TODO PERF: may be slow?
 	for x := 0; x < img.Bounds().Max.X; x++ {
 		for y := 0; y < img.Bounds().Max.Y; y++ {
 			img.Set(x, y, balance.DebugChunkBitmapBackground.ToColor())
@@ -166,6 +168,12 @@ func (c *Chunk) ToBitmap(filename string, mask render.Color) (render.Texturer, e
 	// Blot all the pixels onto it.
 	for px := range c.Iter() {
 		var color = px.Swatch.Color
+
+		// If the swatch has a pattern, mesh it in.
+		if px.Swatch.Pattern != "" {
+			color = pattern.SampleColor(px.Swatch.Pattern, color, px.Point())
+		}
+
 		if mask != render.Invisible {
 			// A semi-transparent mask will overlay on top of the actual color.
 			if mask.Alpha < 255 {

pkg/level/palette.go

@@ -34,6 +34,7 @@ func DefaultPalette() *Palette {
 }
 
 // NewBlueprintPalette returns the blueprint theme's color palette.
+// DEPRECATED in favor of DefaultPalettes.
 func NewBlueprintPalette() *Palette {
 	return &Palette{
 		Swatches: []*Swatch{

pkg/level/swatch.go

@@ -9,8 +9,9 @@ import (
 
 // Swatch holds details about a single value in the palette.
 type Swatch struct {
-	Name  string       `json:"name"`
-	Color render.Color `json:"color"`
+	Name    string       `json:"name"`
+	Color   render.Color `json:"color"`
+	Pattern string       `json:"pattern"` // like "noise.png"
 
 	// Optional attributes.
 	Solid bool `json:"solid,omitempty"`

pkg/pattern/pattern.go

@@ -0,0 +1,230 @@
+// Package pattern applies a kind of brush texture to a palette swatch.
+package pattern
+
+import (
+	"errors"
+	"fmt"
+
+	"git.kirsle.net/apps/doodle/pkg/log"
+	"git.kirsle.net/apps/doodle/pkg/sprites"
+	"git.kirsle.net/go/render"
+	"git.kirsle.net/go/ui"
+)
+
+// Pattern applies a texture to a color in level drawings.
+type Pattern struct {
+	Name     string
+	Filename string
+	Hidden   bool // boolProp showHiddenDoodads true
+}
+
+// Builtins are the list of the game's built-in patterns.
+var Builtins = []Pattern{
+	{
+		Name:     "No pattern",
+		Filename: "",
+	},
+	{
+		Name:     "Noise",
+		Filename: "noise.png",
+	},
+	{
+		Name:     "Marker",
+		Filename: "marker.png",
+	},
+	{
+		Name:     "Ink",
+		Filename: "ink.png",
+	},
+	{
+		Name:     "Dashed Lines",
+		Filename: "circles.png",
+	},
+	{
+		Name:     "Grid",
+		Filename: "grid.png",
+	},
+	{
+		Name:     "Bars (debug)",
+		Filename: "bars.png",
+		Hidden:   true,
+	},
+}
+
+// Images is a map of file names to ui.Image widgets,
+// after LoadBuiltins had been called.
+var images map[string]*ui.Image
+
+// LoadBuiltins loads all of the PNG textures of built-in patterns
+// into ui.Image widgets.
+func LoadBuiltins(e render.Engine) {
+	images = map[string]*ui.Image{}
+
+	for _, pat := range Builtins {
+		if pat.Filename == "" {
+			continue
+		}
+
+		img, err := sprites.LoadImage(e, "assets/pattern/"+pat.Filename)
+		if err != nil {
+			log.Error("Load pattern %s: %s", pat.Filename, err)
+		}
+		images[pat.Filename] = img
+	}
+}
+
+// GetImage returns the ui.Image for a builtin pattern.
+func GetImage(filename string) (*ui.Image, error) {
+	if images == nil {
+		return nil, errors.New("pattern.GetImage: LoadBuiltins() was not called")
+	}
+
+	if im, ok := images[filename]; ok {
+		return im, nil
+	}
+	return nil, fmt.Errorf("pattern.GetImage: filename %s not found", filename)
+}
+
+// SampleColor samples a color with the pattern for a given coordinate in infinite space.
+func SampleColor(filename string, color render.Color, point render.Point) render.Color {
+	if filename == "" {
+		return color
+	}
+
+	// Not loaded in memory?
+	if _, ok := images[filename]; !ok {
+		return color
+	}
+
+	// Translate the world coord (point) into the bounds of the texture image.
+	var (
+		image  = images[filename].Image // the Go image.Image
+		bounds = image.Bounds()
+		coord  = render.Point{
+			// The world coordinate bounded to the pattern image size.
+			X: render.AbsInt(point.X % bounds.Max.X),
+			Y: render.AbsInt(point.Y % bounds.Max.Y),
+		}
+
+		// Sample the color from the pattern texture.
+		colorAt = render.FromColor(image.At(coord.X, coord.Y))
+
+		// Average the RGBA color out to a grayscale brightness.
+		// sourceAvgGray  = (int(color.Red) + int(color.Blue) + int(color.Green)/3) % 255
+		// patternAvgGray = (int(colorAt.Red) + int(colorAt.Blue) + int(colorAt.Green)/3) % 255
+	)
+
+	// See if the gray average is brighter or lower than the color.
+	// if sourceAvgGray < patternAvgGray {
+	// 	delta := patternAvgGray - sourceAvgGray
+	// 	color = color.Lighten(delta)
+	// } else if sourceAvgGray > patternAvgGray {
+	// 	color = color.Darken(sourceAvgGray - patternAvgGray)
+	// }
+
+	// return OverlayFilter(color, colorAt)
+	// return ScreenFilter(color, colorAt)
+	return GrayToColor(color, colorAt)
+
+	// log.Info("color: %s at point: %s image point: %s", color, point, coord)
+
+	// return color
+}
+
+// GrayToColor samples a colorful swatch with the grayscale pattern img.
+func GrayToColor(color, grayscale render.Color) render.Color {
+	// The grayscale image ranges from 0 to 255.
+	// The color might be #FF0000 (red)
+	// 127 in grayscale should be FF0000 (perfectly red)
+	// 0 (black) in grayscale should be black in output
+	// 255 (white) in grayscale should be white in output
+	var (
+		AR = float64(color.Red)
+		AG = float64(color.Green)
+		AB = float64(color.Blue)
+		BR = float64(grayscale.Red)
+		BG = float64(grayscale.Green)
+		BB = float64(grayscale.Blue)
+	)
+
+	// If the pattern has a fully transparent pixel here, return transparent.
+	if grayscale.Alpha == 0 {
+		return render.RGBA(1, 0, 0, 1)
+	}
+
+	convert := func(cc, gs float64) uint8 {
+		var delta float64
+		if gs < 127 {
+			// return uint8(cc + cc/gs)
+			delta = cc * (gs / 255)
+		} else {
+			delta = cc * (gs / 255)
+		}
+		return uint8(delta)
+	}
+
+	return render.RGBA(
+		convert(AR, BR),
+		convert(AG, BG),
+		convert(AB, BB),
+		255,
+	)
+}
+
+// ScreenFilter applies a "screen" blend mode between the two colors (a > b).
+func ScreenFilter(a, b render.Color) render.Color {
+	// The algorithm we're going for is:
+	// 1 - (1 - a) * (1 - b)
+	var (
+		AR = a.Red
+		AG = a.Green
+		AB = a.Blue
+		BR = b.Red
+		BG = b.Green
+		BB = b.Blue
+
+		deltaR = 255 - (255-AR)*(255-BR)
+		deltaG = 255 - (255-AG)*(255-BG)
+		deltaB = 255 - (255-AB)*(255-BB)
+	)
+
+	// If the pattern has a fully transparent pixel here, return transparent.
+	// if b.Alpha == 0 {
+	// 	return render.RGBA(1, 0, 0, 1)
+	// }
+
+	return render.RGBA(deltaR, deltaG, deltaB, a.Alpha)
+}
+
+// OverlayFilter applies an "overlay" blend mode between the two colors.
+func OverlayFilter(a, b render.Color) render.Color {
+	// The algorithm we're going for is:
+	// If a < 0.5: 2ab
+	//  Otherwise: 1 - 2(1 - a)(1 - b)
+	munch := func(a, b uint8) uint8 {
+		if a < 127 {
+			return 2 * a * b
+		}
+		return 255 - (2 * (255 - a) * (255 - b))
+	}
+
+	// If the pattern has a fully transparent pixel here, return transparent.
+	if b.Alpha == 0 {
+		return render.RGBA(1, 0, 0, 0)
+	}
+
+	var (
+		AR = a.Red
+		AG = a.Green
+		AB = a.Blue
+		BR = b.Red
+		BG = b.Green
+		BB = b.Blue
+
+		deltaR = munch(AR, BR)
+		deltaG = munch(AG, BG)
+		deltaB = munch(AB, BB)
+	)
+
+	return render.RGBA(deltaR, deltaG, deltaB, a.Alpha)
+}

pkg/uix/canvas_editable.go

@@ -146,6 +146,7 @@ func (w *Canvas) loopEditable(ev *event.State) error {
 			// Initialize a new Stroke for this atomic drawing operation?
 			if w.currentStroke == nil {
 				w.currentStroke = drawtool.NewStroke(drawtool.Freehand, w.Palette.ActiveSwatch.Color)
+				w.currentStroke.Pattern = w.Palette.ActiveSwatch.Pattern
 				w.currentStroke.Thickness = w.BrushSize
 				w.currentStroke.ExtraData = w.Palette.ActiveSwatch
 				w.AddStroke(w.currentStroke)
@@ -198,6 +199,7 @@ func (w *Canvas) loopEditable(ev *event.State) error {
 			// Initialize a new Stroke for this atomic drawing operation?
 			if w.currentStroke == nil {
 				w.currentStroke = drawtool.NewStroke(drawtool.Line, w.Palette.ActiveSwatch.Color)
+				w.currentStroke.Pattern = w.Palette.ActiveSwatch.Pattern
 				w.currentStroke.Thickness = w.BrushSize
 				w.currentStroke.ExtraData = w.Palette.ActiveSwatch
 				w.currentStroke.PointA = render.NewPoint(cursor.X, cursor.Y)
@@ -219,6 +221,7 @@ func (w *Canvas) loopEditable(ev *event.State) error {
 			// Initialize a new Stroke for this atomic drawing operation?
 			if w.currentStroke == nil {
 				w.currentStroke = drawtool.NewStroke(drawtool.Rectangle, w.Palette.ActiveSwatch.Color)
+				w.currentStroke.Pattern = w.Palette.ActiveSwatch.Pattern
 				w.currentStroke.Thickness = w.BrushSize
 				w.currentStroke.ExtraData = w.Palette.ActiveSwatch
 				w.currentStroke.PointA = render.NewPoint(cursor.X, cursor.Y)
@@ -237,6 +240,7 @@ func (w *Canvas) loopEditable(ev *event.State) error {
 		if ev.Button1 {
 			if w.currentStroke == nil {
 				w.currentStroke = drawtool.NewStroke(drawtool.Ellipse, w.Palette.ActiveSwatch.Color)
+				w.currentStroke.Pattern = w.Palette.ActiveSwatch.Pattern
 				w.currentStroke.Thickness = w.BrushSize
 				w.currentStroke.ExtraData = w.Palette.ActiveSwatch
 				w.currentStroke.PointA = render.NewPoint(cursor.X, cursor.Y)

pkg/uix/canvas_strokes.go

@@ -5,6 +5,7 @@ import (
 	"git.kirsle.net/apps/doodle/pkg/drawtool"
 	"git.kirsle.net/apps/doodle/pkg/level"
 	"git.kirsle.net/apps/doodle/pkg/log"
+	"git.kirsle.net/apps/doodle/pkg/pattern"
 	"git.kirsle.net/apps/doodle/pkg/shmem"
 	"git.kirsle.net/go/render"
 	"git.kirsle.net/go/ui"
@@ -237,6 +238,12 @@ func (w *Canvas) DrawStrokes(e render.Engine, strokes []*drawtool.Stroke) {
 					continue
 				}
 
+				// Does the swatch have a pattern to sample?
+				color := stroke.Color
+				if stroke.Pattern != "" {
+					color = pattern.SampleColor(stroke.Pattern, color, rect.Point())
+				}
+
 				// Destination rectangle to draw to screen, taking into account
 				// the position of the Canvas itself.
 				dest := render.Rect{
@@ -264,7 +271,7 @@ func (w *Canvas) DrawStrokes(e render.Engine, strokes []*drawtool.Stroke) {
 				if balance.DebugCanvasStrokeColor != render.Invisible {
 					e.DrawBox(balance.DebugCanvasStrokeColor, dest)
 				} else {
-					e.DrawBox(stroke.Color, dest)
+					e.DrawBox(color, dest)
 				}
 			}
 		} else {
@@ -273,6 +280,12 @@ func (w *Canvas) DrawStrokes(e render.Engine, strokes []*drawtool.Stroke) {
 					continue
 				}
 
+				// Does the swatch have a pattern to sample?
+				color := stroke.Color
+				if stroke.Pattern != "" {
+					color = pattern.SampleColor(stroke.Pattern, color, point)
+				}
+
 				dest := render.Point{
 					X: P.X + w.Scroll.X + w.BoxThickness(1) + point.X,
 					Y: P.Y + w.Scroll.Y + w.BoxThickness(1) + point.Y,
@@ -281,7 +294,7 @@ func (w *Canvas) DrawStrokes(e render.Engine, strokes []*drawtool.Stroke) {
 				if balance.DebugCanvasStrokeColor != render.Invisible {
 					e.DrawPoint(balance.DebugCanvasStrokeColor, dest)
 				} else {
-					e.DrawPoint(stroke.Color, dest)
+					e.DrawPoint(color, dest)
 				}
 			}
 		}

pkg/windows/palette_editor.go

@@ -7,6 +7,7 @@ import (
 	"git.kirsle.net/apps/doodle/pkg/balance"
 	"git.kirsle.net/apps/doodle/pkg/level"
 	"git.kirsle.net/apps/doodle/pkg/log"
+	"git.kirsle.net/apps/doodle/pkg/pattern"
 	"git.kirsle.net/apps/doodle/pkg/shmem"
 	"git.kirsle.net/go/render"
 	"git.kirsle.net/go/ui"
@@ -44,8 +45,9 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 		height = (buttonSize * balance.DoodadDropperRows) + 64 // account for button borders :(
 
 		// Column sizes of the palette table.
-		col1 = 30  // ID no.
+		col1 = 15  // ID no.
 		col2 = 24  // Color
+		col5 = 24  // Texture
 		col3 = 130 // Name
 		col4 = 140 // Attributes
 		// col5 = 150 // Delete
@@ -80,6 +82,7 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 	}{
 		{"ID", col1},
 		{"Col", col2},
+		{"Tex", col5},
 		{"Name", col3},
 		{"Attributes", col4},
 		// {"Delete", col5},
@@ -125,6 +128,7 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 				row.Hide()
 			}
 
+			//////////////
 			// ID label.
 			idLabel := ui.NewLabel(ui.Label{
 				Text: idStr + ".",
@@ -135,6 +139,7 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 				Height: 24,
 			})
 
+			//////////////
 			// Name button (click to rename the swatch)
 			btnName := ui.NewButton("Name", ui.NewLabel(ui.Label{
 				TextVariable: &swatch.Name,
@@ -157,6 +162,7 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 			})
 			config.Supervisor.Add(btnName)
 
+			//////////////
 			// Color Choice button.
 			btnColor := ui.NewButton("Color", ui.NewFrame("Color Frame"))
 			btnColor.SetStyle(&style.Button{
@@ -209,6 +215,43 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 			})
 			config.Supervisor.Add(btnColor)
 
+			//////////////
+			// Texture (pattern) option.
+			selTexture := ui.NewSelectBox("Texture", ui.Label{
+				Font: balance.MenuFont,
+			})
+			selTexture.Configure(ui.Config{
+				Width:  col5,
+				Height: 24,
+			})
+
+			for _, t := range pattern.Builtins {
+				if t.Hidden && !balance.ShowHiddenDoodads {
+					continue
+				}
+
+				selTexture.AddItem(t.Name, t.Filename, func() {})
+			}
+			selTexture.SetValue(swatch.Pattern)
+			setImageOnSelect(selTexture, swatch.Pattern)
+
+			selTexture.Handle(ui.Change, func(ed ui.EventData) error {
+				if val, ok := selTexture.GetValue(); ok {
+					filename, _ := val.Value.(string)
+					setImageOnSelect(selTexture, filename)
+
+					swatch.Pattern = filename
+					if config.OnChange != nil {
+						config.OnChange()
+					}
+				}
+				return nil
+			})
+
+			selTexture.Supervise(config.Supervisor)
+			config.Supervisor.Add(selTexture)
+
+			//////////////
 			// Attribute flags.
 			attrFrame := ui.NewFrame("Attributes")
 			attrFrame.Configure(ui.Config{
@@ -254,6 +297,7 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 				}
 			}
 
+			//////////////
 			// Pack all the widgets.
 			row.Pack(idLabel, ui.Pack{
 				Side: ui.W,
@@ -263,6 +307,10 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 				Side: ui.W,
 				PadX: 2,
 			})
+			row.Pack(selTexture, ui.Pack{
+				Side: ui.W,
+				PadX: 2,
+			})
 			row.Pack(btnName, ui.Pack{
 				Side: ui.W,
 				PadX: 2,
@@ -377,3 +425,14 @@ func NewPaletteEditor(config PaletteEditor) *ui.Window {
 	window.Hide()
 	return window
 }
+
+// Helper function to get the Tex (pattern) select box to
+// show the image by its filename... for both onChange and
+// initial render needs.
+func setImageOnSelect(sel *ui.SelectBox, filename string) {
+	if image, err := pattern.GetImage(filename); err == nil {
+		sel.SetImage(image)
+	} else {
+		sel.SetImage(nil)
+	}
+}