Realign all nametags towards the camera when rendering 360° frames

src/main/java/eu/crushedpixel/replaymod/coremod/LoadingPlugin.java

@@ -12,6 +12,7 @@ public class LoadingPlugin implements IFMLLoadingPlugin {
                 CameraRollCT.class.getName(),
                 ForceChunkLoadingCT.class.getName(),
                 EntityRendererCT.class.getName(),
+                RenderManagerCT.class.getName(),
                 SoundManagerCT.class.getName(),
                 EnchantmentTimerCT.class.getName()
         };

src/main/java/eu/crushedpixel/replaymod/coremod/RenderManagerCT.java

@@ -0,0 +1,81 @@
+package eu.crushedpixel.replaymod.coremod;
+
+import net.minecraft.launchwrapper.IClassTransformer;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.tree.*;
+
+import java.util.ListIterator;
+
+import static org.objectweb.asm.Opcodes.*;
+
+/**
+ * Transforms the RenderManager class:
+ * - Adds a new field 'CubicEntityRenderer hook'
+ * - Injects CubicEntityRenderer.beforeEntityRender(dx, dy, dz) call at beginning of 'doRenderEntity'
+ */
+public class RenderManagerCT implements IClassTransformer {
+
+    private static final String HOOK = "eu.crushedpixel.replaymod.video.entity.CubicEntityRenderer";
+    private static final String HOOK_JVM = HOOK.replace('.', '/');
+    private static final String HOOK_TYPE = "L" + HOOK_JVM + ";";
+    private static final String RENDER_MANAGER = "net.minecraft.client.renderer.entity.RenderManager";
+
+    @Override
+    public byte[] transform(String name, String transformedName, byte[] bytes) {
+        if (RENDER_MANAGER.equals(transformedName)) {
+            if (name.equals(transformedName)) {
+                return transformRenderManager(bytes, "doRenderEntity", "(Lnet/minecraft/entity/Entity;DDDFFZ)Z");
+            } else {
+                return transformRenderManager(bytes, "a", "(Lwv;DDDFFZ)Z");
+            }
+        }
+        return bytes;
+    }
+
+    private byte[] transformRenderManager(byte[] bytes, String name_doRenderEntity, String desc_doRenderEntity) {
+        ClassReader classReader = new ClassReader(bytes);
+        ClassNode classNode = new ClassNode();
+        classReader.accept(classNode, 0);
+
+        // Add field
+        classNode.visitField(ACC_PUBLIC, "hook", HOOK_TYPE, null, null);
+
+        // Find method
+        MethodNode doRenderEntity = null;
+        for (MethodNode m : classNode.methods) {
+            if (name_doRenderEntity.equals(m.name) && desc_doRenderEntity.equals(m.desc)) {
+                doRenderEntity = m;
+            }
+        }
+        if (doRenderEntity == null) {
+            throw new NoSuchMethodError("doRenderEntity");
+        }
+
+        injectDoRenderEntity(classNode, doRenderEntity);
+
+        ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS);
+        classNode.accept(classWriter);
+        return classWriter.toByteArray();
+    }
+
+    private MethodNode injectDoRenderEntity(ClassNode classNode, MethodNode method) {
+        ListIterator<AbstractInsnNode> list = method.instructions.iterator();
+        list.add(new VarInsnNode(ALOAD, 0));
+        list.add(new FieldInsnNode(GETFIELD, classNode.name, "hook", HOOK_TYPE));
+        LabelNode labelNull = new LabelNode();
+        list.add(new JumpInsnNode(IFNULL, labelNull));
+
+        list.add(new VarInsnNode(ALOAD, 0)); // this
+        list.add(new FieldInsnNode(GETFIELD, classNode.name, "hook", HOOK_TYPE));
+        list.add(new VarInsnNode(DLOAD, 2)); // x
+        list.add(new VarInsnNode(DLOAD, 4)); // y
+        list.add(new VarInsnNode(DLOAD, 6)); // z
+        list.add(new MethodInsnNode(INVOKEVIRTUAL, HOOK_JVM, "beforeEntityRender", "(DDD)V", false));
+
+        list.add(labelNull);
+        list.add(new FrameNode(F_SAME, 0, null, 0, null));
+
+        return method;
+    }
+}

src/main/java/eu/crushedpixel/replaymod/video/entity/CubicEntityRenderer.java

@@ -5,9 +5,12 @@ import eu.crushedpixel.replaymod.settings.RenderOptions;
 import net.minecraft.client.particle.EntityFX;
 import net.minecraft.client.renderer.GlStateManager;
 import net.minecraft.client.renderer.WorldRenderer;
+import net.minecraft.client.renderer.entity.RenderManager;
 import net.minecraft.entity.Entity;
 import net.minecraft.util.ResourceLocation;
 
+import java.lang.reflect.Field;
+
 public class CubicEntityRenderer extends CustomEntityRenderer {
 
     public enum Direction {
@@ -39,6 +42,28 @@ public class CubicEntityRenderer extends CustomEntityRenderer {
     public CubicEntityRenderer(RenderOptions options, int frameSize, boolean stable) {
         super(options, frameSize, frameSize);
         this.stable = stable;
+
+        try {
+            Field hookField = RenderManager.class.getField("hook");
+            hookField.set(mc.getRenderManager(), this);
+        } catch (NoSuchFieldException e) {
+            throw new Error(e);
+        } catch (IllegalAccessException e) {
+            throw new Error(e);
+        }
+    }
+
+    @Override
+    public void cleanup() {
+        super.cleanup();
+        try {
+            Field hookField = RenderManager.class.getField("hook");
+            hookField.set(mc.getRenderManager(), null);
+        } catch (NoSuchFieldException e) {
+            throw new Error(e);
+        } catch (IllegalAccessException e) {
+            throw new Error(e);
+        }
     }
 
     public void setFrame(int id) {
@@ -144,4 +169,12 @@ public class CubicEntityRenderer extends CustomEntityRenderer {
 
         super.renderParticle(fx, worldRenderer, view, partialTicks, rotX, rotXZ, rotZ, rotYZ, rotXY);
     }
+
+    @SuppressWarnings("unused") // Called by ASM
+    public void beforeEntityRender(double dx, double dy, double dz) {
+        double pitch = -Math.atan2(dy, Math.sqrt(dx * dx + dz * dz));
+        double yaw = -Math.atan2(dx, dz);
+        mc.getRenderManager().playerViewX = (float) Math.toDegrees(pitch);
+        mc.getRenderManager().playerViewY = (float) Math.toDegrees(yaw);
+    }
 }