Started work on putting fog in its own shader

core/src/main/resources/shaders/fog/fog.frag

@@ -0,0 +1,55 @@
+#version 150 core
+
+
+in vec4 vertexColor;
+in vec3 vertexWorldPos;
+in float vertexYPos;
+in vec4 vPos;
+
+out vec4 fragColor;
+
+
+uniform float fogScale;
+uniform float fogVerticalScale;
+uniform float nearFogStart;
+uniform float nearFogLength;
+uniform int fullFogMode;
+
+uniform vec4 fogColor;
+
+
+
+// method definitions
+// ==== The below 5 methods will be run-time generated. ====
+float getNearFogThickness(float dist);
+float getFarFogThickness(float dist);
+float getHeightFogThickness(float dist);
+float calculateFarFogDepth(float horizontal, float dist, float nearFogStart);
+float calculateHeightFogDepth(float vertical, float realY);
+float mixFogThickness(float near, float far, float height);
+// =========================================================
+
+
+
+
+/**
+ * Fragment shader for fog.
+ * This should be passed last so it applies above other affects like AO
+ *
+ * version: 7-2-2023
+ */
+void main() {
+    float horizontalDist = length(vertexWorldPos.xz) * fogScale;
+    float heightDist = calculateHeightFogDepth(
+        vertexWorldPos.y, vertexYPos) * fogVerticalScale;
+    float farDist = calculateFarFogDepth(horizontalDist,
+        length(vertexWorldPos.xyz) * fogScale, nearFogStart);
+
+    float nearFogThickness = getNearFogThickness(horizontalDist);
+    float farFogThickness = getFarFogThickness(farDist);
+    float heightFogThickness = getHeightFogThickness(heightDist);
+    float mixedFogThickness = clamp(mixFogThickness(
+        nearFogThickness, farFogThickness, heightFogThickness), 0.0, 1.0);
+
+    fragColor = mix(vertexColor, vec4(fogColor.rgb, 1.0), mixedFogThickness);
+}