fix: hide ysm head in first person on 26.1 without breaking mod captures

src/main/java/dev/tr7zw/firstperson/FirstPersonModelCore.java

@@ -23,7 +23,16 @@
     @Deprecated
     public static boolean enabled = true;
     @Deprecated
     public static boolean isRenderingPlayer = false;
+    /**
+     * True while the render state of the camera entity is being extracted and
+     * the mod is active. Widens {@link #isRenderingPlayer()} for mods that build
+     * their render data at extraction time (e.g. YSM), without marking the
+     * extracted states themselves, so captures of other mods (RealCamera, GUIs)
+     * evaluate with the flag down and keep rendering the full model with its
+     * head.
+     */
+    public static boolean cameraEntityExtract = false;
     private CameraType lastCameraType = null;
     @Deprecated
     private int tickCounterWorkaround = 0;
@@ -96,6 +105,19 @@
         tickCounterWorkaround++;
     }
 
+    @Override
+    public boolean isRenderingPlayer() {
+        return super.isRenderingPlayer() || cameraEntityExtract;
+    }
+
+    /**
+     * The un-widened flag. Only true while FirstPerson itself extracts/renders
+     * the camera entity, not for third party extractions.
+     */
+    public boolean isRenderingPlayerRaw() {
+        return super.isRenderingPlayer();
+    }
+
     @Override
     public void setRenderingPlayer(boolean isRenderingPlayer) {
         super.setRenderingPlayer(isRenderingPlayer);

src/main/java/dev/tr7zw/firstperson/mixins/LivingEntityRendererMixin.java

@@ -181,8 +181,10 @@ public void renderPostAnim(LivingEntity livingEntity, float f, float g, PoseStac
     @Inject(method = "extractRenderState(Lnet/minecraft/world/entity/LivingEntity;Lnet/minecraft/client/renderer/entity/state/LivingEntityRenderState;F)V", at = @At("HEAD"))
     private void checkIfCameraEntity(LivingEntity livingEntity, LivingEntityRenderState livingEntityRenderState,
             float f, CallbackInfo ci) {
+        // Raw flag: only states extracted by FirstPerson itself are marked, so
+        // third party captures (RealCamera, GUIs) keep rendering the head.
         ((LivingEntityRenderStateAccess) livingEntityRenderState)
-                .setIsCameraEntity(FirstPersonModelCore.instance.isRenderingPlayer());
+                .setIsCameraEntity(FirstPersonModelCore.instance.isRenderingPlayerRaw());
     }
     //? }
 

src/main/java/dev/tr7zw/firstperson/mixins/PlayerMixin.java

@@ -19,7 +19,7 @@ public class PlayerMixin {
 
     @Inject(method = "getItemBySlot", at = @At("HEAD"), cancellable = true)
     public void getItemBySlot(EquipmentSlot slot, CallbackInfoReturnable<ItemStack> ci) {
-        if (FirstPersonModelCore.instance.isRenderingPlayer() && Minecraft.getInstance().isSameThread()
+        if (FirstPersonModelCore.instance.isRenderingPlayerRaw() && Minecraft.getInstance().isSameThread()
                 && (Object) this instanceof Player player) {
             if (slot == EquipmentSlot.HEAD) {
                 ci.setReturnValue(ItemStack.EMPTY);

src/main/java/dev/tr7zw/firstperson/mixins/RenderDispatcherMixin.java

@@ -2,12 +2,16 @@
 
 import com.mojang.blaze3d.vertex.*;
 import dev.tr7zw.firstperson.*;
+import dev.tr7zw.firstperson.access.*;
 import lombok.*;
 import net.minecraft.client.*;
 import net.minecraft.client.renderer.*;
 import net.minecraft.client.renderer.entity.*;
 //? if >= 1.21.2
 import net.minecraft.client.renderer.entity.state.*;
+//? if >= 26.1 {
+import net.minecraft.client.renderer.state.level.*;
+//? }
 import net.minecraft.world.level.*;
 import org.spongepowered.asm.mixin.*;
 import org.spongepowered.asm.mixin.injection.*;
@@ -33,8 +37,60 @@
 
     private static Minecraft fpmMcInstance = Minecraft.getInstance();
 
-    //? if >= 1.21.9 {
+    //? if >= 26.1 {
 
+    private boolean fpmSubmittingCameraEntity = false;
+
+    /**
+     * YSM (and potentially other mods) defer their animation evaluation to the
+     * submit of the render state and check {@link FirstPersonModelCore#isRenderingPlayer()}
+     * at that point to decide when to hide the head. Two windows keep the flag
+     * up for exactly those moments:
+     * - extraction of the camera entity: widens the flag (without marking the
+     *   states themselves, so third party captures stay unflagged) which makes
+     *   YSM attach its first person context and re-evaluate the head visibility
+     *   on every submit,
+     * - the submit of the state FPM extracted (marked via isCameraEntity): the
+     *   only evaluation that must see the flag up, hiding the head for the
+     *   actual frame render. Evaluations triggered by other mods (RealCamera,
+     *   GUIs) run with the flag down and keep the model headed.
+     */
+    @Inject(method = "extractEntity(Lnet/minecraft/world/entity/Entity;F)Lnet/minecraft/client/renderer/entity/state/EntityRenderState;",
+            at = @At("HEAD"), expect = 0, require = 0)
+    private void fpmExtractStart(Entity entity, float f, CallbackInfoReturnable<EntityRenderState> cir) {
+        Minecraft mc = Minecraft.getInstance();
+        if (entity == mc.getCameraEntity() && mc.options.getCameraType() == CameraType.FIRST_PERSON
+                && FirstPersonModelCore.instance.getLogicHandler().shouldApplyThirdPerson(false)) {
+            FirstPersonModelCore.cameraEntityExtract = true;
+        }
+    }
+
+    @Inject(method = "extractEntity(Lnet/minecraft/world/entity/Entity;F)Lnet/minecraft/client/renderer/entity/state/EntityRenderState;",
+            at = @At("TAIL"), expect = 0, require = 0)
+    private void fpmExtractEnd(Entity entity, float f, CallbackInfoReturnable<EntityRenderState> cir) {
+        FirstPersonModelCore.cameraEntityExtract = false;
+    }
+
+    @Inject(method = "submit(Lnet/minecraft/client/renderer/entity/state/EntityRenderState;Lnet/minecraft/client/renderer/state/level/CameraRenderState;DDDLcom/mojang/blaze3d/vertex/PoseStack;Lnet/minecraft/client/renderer/SubmitNodeCollector;)V",
+            at = @At("HEAD"), expect = 0, require = 0)
+    private void fpmSubmitStart(EntityRenderState renderState, CameraRenderState camera, double x, double y, double z,
+            PoseStack poseStack, SubmitNodeCollector submitNodeCollector, CallbackInfo ci) {
+        if (renderState instanceof LivingEntityRenderState livingState
+                && ((LivingEntityRenderStateAccess) (Object) livingState).isCameraEntity()) {
+            fpmSubmittingCameraEntity = true;
+            FirstPersonModelCore.instance.setRenderingPlayer(true);
+        }
+    }
+
+    @Inject(method = "submit(Lnet/minecraft/client/renderer/entity/state/EntityRenderState;Lnet/minecraft/client/renderer/state/level/CameraRenderState;DDDLcom/mojang/blaze3d/vertex/PoseStack;Lnet/minecraft/client/renderer/SubmitNodeCollector;)V",
+            at = @At("TAIL"), expect = 0, require = 0)
+    private void fpmSubmitEnd(EntityRenderState renderState, CameraRenderState camera, double x, double y, double z,
+            PoseStack poseStack, SubmitNodeCollector submitNodeCollector, CallbackInfo ci) {
+        if (fpmSubmittingCameraEntity) {
+            fpmSubmittingCameraEntity = false;
+            FirstPersonModelCore.instance.setRenderingPlayer(false);
+        }
+    }
     //? } else if >= 1.21.3 {
     /*