change: tweak nebulas to be more detailed, higher res, more performant

src/main/java/codes/ztereohype/nicerskies/sky/nebula/NebulaSkyboxPainter.java

@@ -22,7 +22,7 @@ public class NebulaSkyboxPainter extends SkyboxPainter {
     }
 
     @Override
-    int getColour(float x, float y, float z) {
+    int getTexelColour(float x, float y, float z) {
         // Get projection
         float[] projCoords = this.projectOnSphere(x, y, z);
         x = projCoords[0];
@@ -38,10 +38,7 @@ public class NebulaSkyboxPainter extends SkyboxPainter {
         // Value of noise at coord, 0..1
         double noiseValue = Mth.clamp(noise.getValue(x * scalingFactor, y * scalingFactor, z * scalingFactor) + 0.5, 0, 1);
 
-        // Value to be subtracted from noise at coord, 0..1
+        // Get the derivatives of the first (largest) octave of noise to shift the colour around with.
-        double subtractionValue = Mth.clamp(noise.getOctaveNoise(1)
-                                                 .noise(x * scalingFactor, y * scalingFactor, z * scalingFactor) + 0.5, 0D, 1D);
-
         double[] ds = new double[3];
         noise.getOctaveNoise(0).noiseWithDerivative(x * scalingFactor, y * scalingFactor, z * scalingFactor, ds);
 
@@ -58,15 +55,17 @@ public class NebulaSkyboxPainter extends SkyboxPainter {
             nebulaFactor = 0;
         }
 
+        // Get the colour of the nebula and the amount of background colour to show at the current factor.
         int[] nebula = nebulaGradient.getAt(nebulaFactor);
         double bgFactor = Mth.clamp(Math.log10(-nebulaFactor + 1) + 1, 0, 1);
 
-        // todo: try and reduce brownish colours by reducing the green channel smoothly [failed attempt]
+        // Merge everything:
-
+        // colour = nebulaFactor * [colour of nebula in that pixel] - [noise derivative in that pixel] * nebulaFactor + background colour * bgFactor
-        int r = Mth.clamp((int) ((nebulaFactor * nebula[0]) + baseR * bgFactor) - (int) (ds[0] * nebulaFactor * 128), 0, 255);
+        int r = Mth.clamp((int) (nebulaFactor * nebula[0] - ds[0] * nebulaFactor * 128 + baseR * bgFactor), 0, 255);
-        int g = Mth.clamp((int) ((nebulaFactor * nebula[1]) + baseG * bgFactor) - (int) (ds[1] * nebulaFactor * 64 * subtractionValue), 0, 255);
+        int g = Mth.clamp((int) (nebulaFactor * nebula[1] - ds[1] * nebulaFactor * 64  + baseG * bgFactor), 0, 255);
-        int b = Mth.clamp((int) ((nebulaFactor * nebula[2]) + baseB * bgFactor) - (int) (ds[2] * nebulaFactor * 128), 0, 255);
+        int b = Mth.clamp((int) (nebulaFactor * nebula[2] - ds[2] * nebulaFactor * 128 + baseB * bgFactor), 0, 255);
 
+        // Get the alpha depending on the background factor
         int alpha = Mth.clamp((int) ((1 - bgFactor) * 255), 50, 255);
 
         return FastColor.ARGB32.color(alpha, b, g, r);

src/main/java/codes/ztereohype/nicerskies/sky/nebula/Skybox.java

@@ -3,7 +3,12 @@ package codes.ztereohype.nicerskies.sky.nebula;
 import codes.ztereohype.nicerskies.NicerSkies;
 import com.mojang.blaze3d.platform.NativeImage;
 import com.mojang.blaze3d.systems.RenderSystem;
-import com.mojang.blaze3d.vertex.*;
+import com.mojang.blaze3d.vertex.BufferBuilder;
+import com.mojang.blaze3d.vertex.DefaultVertexFormat;
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.Tesselator;
+import com.mojang.blaze3d.vertex.VertexBuffer;
+import com.mojang.blaze3d.vertex.VertexFormat;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 import net.minecraft.client.Minecraft;
@@ -21,7 +26,7 @@ import java.util.function.BiFunction;
 
 
 public class Skybox {
-    public static final int RESOLUTION = 512;
+    public static final int RESOLUTION = 768;
 
     private final DynamicTexture skyTexture = new DynamicTexture(RESOLUTION * 4, RESOLUTION * 4, false);
 
@@ -79,7 +84,7 @@ public class Skybox {
                     float y = location.getYFunc().apply(texX, texY);
                     float z = location.getZFunc().apply(texX, texY);
 
-                    skyNativeTex.setPixelRGBA(location.getXLocation(texX), location.getYLocation(texY), painter.getColour(x, y, z));
+                    skyNativeTex.setPixelRGBA(location.getXLocation(texX), location.getYLocation(texY), painter.getTexelColour(x, y, z));
                 }
             }
 
@@ -94,7 +99,7 @@ public class Skybox {
             NEG_ONE((texX, texY) -> -1F);
 
             @Getter
-            private BiFunction<Integer, Integer, Float> map;
+            private final BiFunction<Integer, Integer, Float> map;
         }
 
         @AllArgsConstructor

src/main/java/codes/ztereohype/nicerskies/sky/nebula/SkyboxPainter.java

@@ -10,7 +10,7 @@ public abstract class SkyboxPainter {
         this.noise = noise;
     }
 
-    abstract int getColour(float x, float y, float z);
+    abstract int getTexelColour(float x, float y, float z);
 
     public float[] projectOnSphere(float x, float y, float z) {
         float invDistance = Mth.fastInvSqrt(x * x + y * y + z * z);