Add image, Support writing PPM P3 image, Additional checks

.gitignore

@@ -1 +1,2 @@
-/humanshader
+/humanshader
+*.ppm

README.md

@@ -1,3 +1,5 @@
 # Human Shader Validator
 
-Validator for [Human Shader](https://humanshader.com/)
+Validator for [Human Shader](https://humanshader.com/)
+
+![Final image of Human Shader](humanshader.png)

hsv.go

@@ -10,24 +10,68 @@ import (
 
 func main() {
 	args := os.Args[1:]
-	var pxX int
-	var pxY int
-	if len(args) == 2 {
-		pxX, _ = strconv.Atoi(args[0])
-		pxY, _ = strconv.Atoi(args[1])
-	} else {
-		fmt.Print("Pixel x coordinate: ")
-		input := bufio.NewScanner(os.Stdin)
-		input.Scan()
-		pxX, _ = strconv.Atoi(input.Text())
-		fmt.Print("Pixel y coordinate: ")
-		input = bufio.NewScanner(os.Stdin)
-		input.Scan()
-		pxY, _ = strconv.Atoi(input.Text())
-	}
 
-	val := hsv.NewValidator(true)
-	val.Calculate(pxX, pxY)
-	r, g, b := val.GetColor()
-	fmt.Printf("R: %d\nG: %d\nB: %d\nHEX: #%02X%02X%02X\n", r, g, b, r, g, b)
+	// TODO: Better argument parsing
+	if len(args) == 1 || len(args) == 3 || len(args) == 5 {
+		fmt.Printf("Writing PPM image to %s.\n", args[0])
+		if len(args) == 3 || len(args) == 5 {
+			width, _ := strconv.Atoi(args[1])
+			height, _ := strconv.Atoi(args[2])
+			if len(args) == 5 {
+				startx, _ := strconv.Atoi(args[3])
+				starty, _ := strconv.Atoi(args[4])
+				writePPM(args[0], width, height, startx, starty)
+			} else {
+				writePPM(args[0], width, height, 0, 0)
+			}
+		} else {
+			writePPM(args[0], 71, 40, 0, 0)
+		}
+		fmt.Println("Done")
+	} else if len(args) == 2 {
+		pxX, _ := strconv.Atoi(args[0])
+		pxY, _ := strconv.Atoi(args[1])
+		fmt.Println()
+		printPixel(pxX, pxY)
+	} else {
+		input := bufio.NewScanner(os.Stdin)
+		fmt.Print("Pixel x coordinate: ")
+		input.Scan()
+		pxX, _ := strconv.Atoi(input.Text())
+		fmt.Print("Pixel y coordinate: ")
+		input.Scan()
+		pxY, _ := strconv.Atoi(input.Text())
+		fmt.Println()
+		printPixel(pxX, pxY)
+	}
+}
+
+func printPixel(x int, y int) {
+	val := hsv.NewValidator(true)
+	val.Calculate(x, y)
+	r, g, b := val.GetColor()
+	fmt.Printf("\nR: %d\nG: %d\nB: %d\nHEX: #%02X%02X%02X\n", r, g, b, r, g, b)
+}
+
+func writePPM(path string, width int, height int, startx int, starty int) {
+	f, err := os.Create(path)
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	bw := bufio.NewWriter(f)
+	bw.WriteString("P3\n")
+	bw.WriteString(fmt.Sprintf("%d %d\n", width, height))
+	bw.WriteString("255\n")
+	for y := startx; y < startx+height; y++ {
+		for x := starty; x < starty+width; x++ {
+			v := hsv.NewValidator(false)
+			v.Calculate(x, y)
+			r, g, b := v.GetColor()
+			bw.WriteString(fmt.Sprintf("%d %d %d ", r, g, b))
+		}
+		bw.WriteString("\n")
+	}
+	bw.Flush()
 }

validator/validator.go

@@ -26,22 +26,20 @@ func (val *Validator) Calculate(x int, y int) {
 	val.print("h = %d² + %d² = %d + %d = %d", u, v, u*u, v*v, h)
 	if h < 200 {
 		val.print("⇒ h < 200 → %d < 200", h)
-		val.print("=> Continuing to section B")
 		val.sectionB(u, v, h)
 	} else if v < 0 {
 		val.print("⇒ h < 200 → %d ≮ 200", h)
 		val.print("⇒ v < 0 → %d < 0", v)
-		val.print("=> Continuing to section C")
 		val.sectionC(u, v, h)
 	} else {
 		val.print("⇒ h < 200 → %d ≮ 200", h)
 		val.print("⇒ v < 0 → %d ≮ 0", v)
-		val.print("=> Continuing to section D")
 		val.sectionD(x, y)
 	}
 }
 
 func (val *Validator) sectionB(u int, v int, h int) {
+	val.print("=> Continuing to section B")
 	val.r = 420
 	val.print("R = %d", val.r)
 	val.b = 520
@@ -77,11 +75,11 @@ func (val *Validator) sectionB(u int, v int, h int) {
 		val.b = val.b + w
 		val.print("  B → B + %d ⇒ B = %d", w, val.b)
 	}
-	val.print("=> Continuing to section E")
 	val.sectionE()
 }
 
 func (val *Validator) sectionC(u int, v int, h int) {
+	val.print("=> Continuing to section C")
 	val.r = 150 + 2*v
 	val.print("R = 150 + 2 ⋅ %d = 150 + %d = %d", v, 2*v, val.r)
 	val.b = 50
@@ -112,30 +110,38 @@ func (val *Validator) sectionC(u int, v int, h int) {
 		val.r = val.r + d
 		val.print("  R → R + %d ⇒ R = %d", d, val.r)
 	}
-	val.print("=> Continuing to section E")
 	val.sectionE()
 }
 
 func (val *Validator) sectionD(x int, y int) {
+	val.print("=> Continuing to section D")
 	var c int = x + 4*y
 	val.print("c = %d + 4 ⋅ %d", x, y)
 	val.r = 132 + c
 	val.print("R = 132 + %d = %d", c, val.r)
 	val.b = 192 + c
 	val.print("R = 192 + %d = %d", c, val.b)
-	val.print("=> Continuing to section E")
 	val.sectionE()
 }
 
 func (val *Validator) sectionE() {
+	val.print("=> Continuing to section E")
 	if val.r > 255 {
 		val.r = 255
 		val.print("⇒ R > 255 → R = %d", val.r)
 	}
+	if val.r < 0 {
+		val.r = 0
+		val.print("⇒ R < 0 → R = %d", val.r)
+	}
 	if val.b > 255 {
 		val.b = 255
 		val.print("⇒ B > 255 → B = %d", val.b)
 	}
+	if val.b < 0 {
+		val.b = 0
+		val.print("⇒ B < 0 → B = %d", val.b)
+	}
 	val.g = val.mod(7*val.r+3*val.b, 1)
 	val.print("G = (7 + %d + 3 ⋅ %d) | 1 = (%d + %d) | 1 = %d | 1 = %d", val.r, val.b, 7+val.r, 3*val.b, 7*val.r+3*val.b, val.g)
 }