Fix planar fog

Author: lowercasebtw

src/main/java/org/visuals/legacy/animatium/util/rendering/ImmediateRenderer.java

@@ -388,7 +388,7 @@ public DynamicTransforms withModelOffset(Vector3f vector3f) {
         }
 
         public Matrix4f getModelViewMatrix() {
-            return this.modelViewMatrix == null ? new Matrix4f(RenderSystem.getModelViewMatrixCopy()) : this.modelViewMatrix;
+            return this.modelViewMatrix == null ? new Matrix4f(RenderSystem.getModelViewStack()) : this.modelViewMatrix;
         }
 
         public Matrix4f getTextureMatrix() {

src/main/resources/animatium.accesswidener

@@ -7,8 +7,6 @@ accessible class com/mojang/blaze3d/pipeline/MainTarget$Dimension
 accessible class net/minecraft/client/renderer/CloudRenderer$RelativeCameraPos
 accessible class net/minecraft/client/gui/components/AbstractSelectionList$Entry
 
-accessible class com/mojang/blaze3d/opengl/GlDevice
-
 accessible method com/mojang/blaze3d/pipeline/MainTarget$Dimension listWithFallback (II)Ljava/util/List;
 accessible field net/minecraft/client/renderer/item/ItemStackRenderState displayContext Lnet/minecraft/world/item/ItemDisplayContext;
 accessible method net/minecraft/client/gui/components/debug/DebugScreenEntries register (Lnet/minecraft/resources/Identifier;Lnet/minecraft/client/gui/components/debug/DebugScreenEntry;)Lnet/minecraft/resources/Identifier;

src/main/resources/assets/animatium/shaders/core/legacy_sky.vsh

@@ -10,12 +10,14 @@ out float cylindricalVertexDistance;
 out float sphericalVertexDistance;
 
 void main() {
-    gl_Position = ProjMat * ModelViewMat * vec4(Position, 1.0);
+    vec4 eye = ModelViewMat * vec4(Position, 1.0);
 #ifdef PLANAR_FOG
-    cylindricalVertexDistance = gl_Position.z;
-    sphericalVertexDistance = gl_Position.z;
+    float dist = -eye.z;
+    cylindricalVertexDistance = dist;
+    sphericalVertexDistance = dist;
 #else
     cylindricalVertexDistance = fog_cylindrical_distance(Position);
     sphericalVertexDistance = fog_spherical_distance(Position);
 #endif
+    gl_Position = ProjMat * eye;
 }