visuals

core.mod/src/WGDefault.cc

@@ -30,28 +30,14 @@ void WGDefault::drawBackground(const Swan::Context &ctx, Swan::Win &win, Swan::V
 
 SDL_Color WGDefault::backgroundColor(Swan::Vec2 pos) {
 	float y = pos.y;
-	float cave_start = 20;
-	float cave_end = cave_start + 100;
-	float deep_start = cave_end + 200;
-	float deep_end = deep_start + 300;
-	if (y < cave_start) {
-		return Swan::Draw::linearColor(
-			{ 128, 220, 250, 255 },
-			{ 107, 87, 5, 255 },
-			y / cave_start);
-	} else if (y < deep_start) {
-		return Swan::Draw::linearColor(
-			{ 107, 87, 5, 255 },
-			{ 15, 7, 7, 255 },
-			(y - cave_start) / (cave_end - cave_start));
-	} else if (y < deep_end) {
-		return Swan::Draw::linearColor(
-			{ 15, 7, 7, 255 },
-			{ 35, 0, 0, 255 },
-			(y - deep_start) / (deep_end - deep_start));
-	} else {
-		return { 35, 0, 0, 255 };
-	}
+	return Swan::Draw::linearGradient(y, {
+		{    0, { 128, 220, 250, 255 } },
+		{   70, { 107,  87,   5, 255 } },
+		{  100, { 107,  87,   5, 255 } },
+		{  200, {  20,  20,  23, 255 } },
+		{  300, {  20,  20,  23, 255 } },
+		{  500, {  25,  10,  10, 255 } },
+		{ 1000, {  65,  10,  10, 255 } } });
 }
 
 Swan::Tile::ID WGDefault::genTile(Swan::TilePos pos) {

libswan/include/swan/WorldGen.h

@@ -15,6 +15,13 @@ class World;
 class WorldPlane;
 class ImageResource;
 
+class WorldGenStructure {
+public:
+	virtual ~WorldGenStructure() = 0;
+
+	virtual bool isBase(TilePos pos);
+};
+
 class WorldGen {
 public:
 	class Factory {
@@ -33,11 +40,4 @@ public:
 	virtual BodyTrait::HasBody *spawnPlayer(WorldPlane &plane) = 0;
 };
 
-class WorldGenStructure {
-public:
-	virtual ~WorldGenStructure() = 0;
-
-	virtual bool isBase(TilePos pos);
-};
-
 }

libswan/include/swan/drawutil.h

@@ -2,13 +2,16 @@
 
 #include <SDL.h>
 #include <optional>
+#include <initializer_list>
+#include <utility>
 
 #include "Win.h"
 
 namespace Swan {
 namespace Draw {
 
-SDL_Color linearColor(SDL_Color from, SDL_Color to, float frac);
+SDL_Color linearGradient(
+		float val, std::initializer_list<std::pair<float, SDL_Color>> colors);
 
 void parallaxBackground(
 		Win &win, SDL_Texture *tex,

libswan/src/drawutil.cc

@@ -12,7 +12,7 @@ static Uint8 linearLine(float from, float to, float frac) {
 	return (Uint8)std::clamp(to * frac + from * (1 - frac), 0.0f, 255.0f);
 }
 
-SDL_Color linearColor(SDL_Color from, SDL_Color to, float frac) {
+static SDL_Color linearColor(SDL_Color from, SDL_Color to, float frac) {
 	return {
 		.r = linearLine(from.r, to.r, frac),
 		.g = linearLine(from.g, to.g, frac),
@@ -21,6 +21,29 @@ SDL_Color linearColor(SDL_Color from, SDL_Color to, float frac) {
 	};
 }
 
+SDL_Color linearGradient(
+		float val,
+		std::initializer_list<std::pair<float, SDL_Color>> colors) {
+
+	const std::pair<float, SDL_Color> *arr = colors.begin();
+	size_t size = colors.size();
+
+	if (val < arr[0].first)
+		return arr[0].second;
+
+	for (size_t i = 1; i < size; ++i) {
+		if (arr[i].first < val)
+			continue;
+
+		auto [fromv, fromc] = arr[i - 1];
+		auto [tov, toc] = arr[i];
+		float frac = (val - fromv) / (tov - fromv);
+		return linearColor(fromc, toc, frac);
+	}
+
+	return arr[size - 1].second;
+}
+
 void parallaxBackground(
 		Win &win, SDL_Texture *tex,
 		std::optional<SDL_Rect> srcrect, std::optional<SDL_Rect> destrect,