A few tweaks

mapgen/map_generator.cpp

@@ -45,6 +45,27 @@ static double curve(double x) {
 	return 3.0 * pow(x, 2.0) - 2.0 * pow(x, 3.0);
 }
 
+//fix the overflow
+static double curl(double x) {
+	if (x > 1.0) {
+		return -curl(x-1) +1;
+	}
+	if (x < 0.0) {
+		return curl(-x);
+	}
+	return x;
+}
+
+static double cut(double x) {
+	if (x > 1.0) {
+		return 1.0;
+	}
+	if (x < 0.0) {
+		return 0.0;
+	}
+	return x;
+}
+
 //-------------------------
 //Public methods
 //-------------------------
@@ -85,10 +106,15 @@ double MapGenerator::ScaledNoise(double x, double y, double width, double height
 	return curve((b - a) / height);
 }
 
-double MapGenerator::ScaleOctave(double x, double y, double width, double height, double octave) {
+double MapGenerator::ScaledOctave(double x, double y, double width, double height, double octave) {
 	double ret = 0;
 	if (octave > 1) {
-		ret += ScaleOctave(x, y, width/2, height/2, octave-1);
+		ret += ScaledOctave(x, y, width/2, height/2, octave-1);
 	}
 	return ret / octave + ScaledNoise(x, y, width, height);
 }
+
+double MapGenerator::GetPixel(double x, double y, double width, double height, double octave) {
+	//use this as a decorator function
+	return curl(ScaledOctave(x, y, width, height, octave));
+}

mapgen/map_generator.hpp

@@ -34,7 +34,8 @@ public:
 	Vector2 RawNoise(Vector2 const&);
 	double Influence(Vector2 const& gridPoint, Vector2 const& queryPoint, double width, double height);
 	double ScaledNoise(double x, double y, double width, double height);
-	double ScaleOctave(double x, double y, double width, double height, double octave);
+	double ScaledOctave(double x, double y, double width, double height, double octave);
+	double GetPixel(double x, double y, double width, double height, double octave);
 
 private:
 	SimpleRNG rng;

src/shell_scene.cpp

@@ -54,6 +54,31 @@ int convertToColour(SDL_PixelFormat* format, double x) {
 	return SDL_MapRGB(format, 255*x, 255*x, 255*x);
 }
 
+int convertToTerrain(SDL_PixelFormat* format, double x) {
+	//water
+	if (x < 0.4) {
+		return SDL_MapRGB(format, 0, 0, 255);
+	}
+	//sand
+	if (x < 0.5) {
+		return SDL_MapRGB(format, 255, 255, 0);
+	}
+	//grass
+	if (x < 0.6) {
+		return SDL_MapRGB(format, 0, 255, 0);
+	}
+	//forest
+	if (x < 0.8) {
+		return SDL_MapRGB(format, 0, 128, 0);
+	}
+	//snow
+	if (x < 0.8) {
+		return SDL_MapRGB(format, 255, 255, 255);
+	}
+	//dark snow
+	return SDL_MapRGB(format, 128, 128, 128);
+}
+
 ShellScene::ShellScene() {
 	//test the generator
 	int width = 256;
@@ -66,7 +91,7 @@ ShellScene::ShellScene() {
 	std::cout << "Beggining generation" << std::endl;
 	for (int i = 0; i < image.GetSurface()->w; i++) {
 		for (int j = 0; j < image.GetSurface()->h; j++) {
-			value = generator.ScaleOctave(i, j, width, height, 8);
+			value = generator.GetPixel(i, j, width, height, 8);
 			colour = convertToColour(image.GetSurface()->format, value);
 			setPixel(image.GetSurface(), i, j, colour);
 		}