probably fix the NPEs

start work on adaptive backend
extra sanity stuff for the render manager
massive speedup when rendering a lot of tile entities

src/main/java/com/simibubi/create/content/contraptions/base/KineticTileEntity.java

@@ -247,7 +247,7 @@ public abstract class KineticTileEntity extends SmartTileEntity
 			effects.triggerOverStressedEffect();
 
 		if (clientPacket)
-			CreateClient.kineticRenderer.update(this);
+			FastRenderDispatcher.enqueueUpdate(this);
 	}
 
 	public float getGeneratedSpeed() {

src/main/java/com/simibubi/create/content/contraptions/base/KineticTileInstance.java

@@ -27,8 +27,8 @@ public abstract class KineticTileInstance<T extends KineticTileEntity> extends T
 
     protected final Consumer<RotatingData> setupFunc(float speed, Direction.Axis axis) {
         return data -> {
-            data.setBlockLight(tile.getWorld().getLightLevel(LightType.BLOCK, pos))
+            data.setBlockLight(world.getLightLevel(LightType.BLOCK, pos))
-                .setSkyLight(tile.getWorld().getLightLevel(LightType.SKY, pos))
+                .setSkyLight(world.getLightLevel(LightType.SKY, pos))
                 .setTileEntity(tile)
                 .setRotationalSpeed(speed)
                 .setRotationOffset(getRotationOffset(axis))

src/main/java/com/simibubi/create/content/contraptions/base/SingleRotatingInstance.java

@@ -45,7 +45,6 @@ public class SingleRotatingInstance extends KineticTileInstance<KineticTileEntit
     @Override
     public void remove() {
         rotatingModelKey.delete();
-        rotatingModelKey = null;
     }
 
     protected BlockState getRenderedBlockState() {

src/main/java/com/simibubi/create/content/contraptions/components/fan/FanInstance.java

@@ -112,6 +112,5 @@ public class FanInstance extends KineticTileInstance<EncasedFanTileEntity> {
     public void remove() {
         shaft.delete();
         fan.delete();
-        shaft = fan = null;
     }
 }

src/main/java/com/simibubi/create/content/contraptions/relays/belt/BeltInstance.java

@@ -44,14 +44,13 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
 
     @Override
     protected void init() {
-        BlockState blockState = tile.getBlockState();
+        if (!AllBlocks.BELT.has(lastState))
-        if (!AllBlocks.BELT.has(blockState))
             return;
 
         keys = new ArrayList<>(2);
 
-        beltSlope = blockState.get(BeltBlock.SLOPE);
+        beltSlope = lastState.get(BeltBlock.SLOPE);
-        facing = blockState.get(BeltBlock.HORIZONTAL_FACING);
+        facing = lastState.get(BeltBlock.HORIZONTAL_FACING);
         upward = beltSlope == BeltSlope.UPWARD;
         diagonal = beltSlope.isDiagonal();
         sideways = beltSlope == BeltSlope.SIDEWAYS;
@@ -59,7 +58,7 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
         alongX = facing.getAxis() == Direction.Axis.X;
         alongZ = facing.getAxis() == Direction.Axis.Z;
 
-        BeltPart part = blockState.get(BeltBlock.PART);
+        BeltPart part = lastState.get(BeltBlock.PART);
         boolean start = part == BeltPart.START;
         boolean end = part == BeltPart.END;
 
@@ -67,7 +66,7 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
             AllBlockPartials beltPartial = BeltRenderer.getBeltPartial(diagonal, start, end, bottom);
             SpriteShiftEntry spriteShift = BeltRenderer.getSpriteShiftEntry(diagonal, bottom);
 
-            InstancedModel<BeltData> beltModel = beltPartial.renderOnBelt(modelManager, blockState);
+            InstancedModel<BeltData> beltModel = beltPartial.renderOnBelt(modelManager, lastState);
             Consumer<BeltData> setupFunc = setupFunc(spriteShift);
 
             keys.add(beltModel.setupInstance(setupFunc));
@@ -76,7 +75,7 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
         }
 
         if (tile.hasPulley()) {
-            InstancedModel<RotatingData> pulleyModel = getPulleyModel(blockState);
+            InstancedModel<RotatingData> pulleyModel = getPulleyModel();
 
             pulleyKey = pulleyModel.setupInstance(setupFunc(tile.getSpeed(), getRotationAxis()));
         }
@@ -107,7 +106,6 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
         keys.forEach(InstanceKey::delete);
         keys.clear();
         if (pulleyKey != null) pulleyKey.delete();
-        pulleyKey = null;
     }
 
     private float getScrollSpeed() {
@@ -122,8 +120,8 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
         return speed;
     }
 
-    private InstancedModel<RotatingData> getPulleyModel(BlockState blockState) {
+    private InstancedModel<RotatingData> getPulleyModel() {
-        Direction dir = getOrientation(blockState);
+        Direction dir = getOrientation();
 
         Direction.Axis axis = dir.getAxis();
 
@@ -141,11 +139,11 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
             return modelTransform;
         };
 
-        return rotatingMaterial().getModel(AllBlockPartials.BELT_PULLEY, blockState, dir, ms);
+        return rotatingMaterial().getModel(AllBlockPartials.BELT_PULLEY, lastState, dir, ms);
     }
 
-    private Direction getOrientation(BlockState blockState) {
+    private Direction getOrientation() {
-        Direction dir = blockState.get(BeltBlock.HORIZONTAL_FACING)
+        Direction dir = lastState.get(BeltBlock.HORIZONTAL_FACING)
                                   .rotateY();
         if (beltSlope == BeltSlope.SIDEWAYS)
             dir = Direction.UP;
@@ -161,8 +159,8 @@ public class BeltInstance extends KineticTileInstance<BeltTileEntity> {
 
             BlockPos pos = tile.getPos();
             data.setTileEntity(tile)
-                .setBlockLight(tile.getWorld().getLightLevel(LightType.BLOCK, pos))
+                .setBlockLight(world.getLightLevel(LightType.BLOCK, pos))
-                .setSkyLight(tile.getWorld().getLightLevel(LightType.SKY, pos))
+                .setSkyLight(world.getLightLevel(LightType.SKY, pos))
                 .setRotation(rotX, rotY, rotZ)
                 .setRotationalSpeed(getScrollSpeed())
                 .setRotationOffset(0)

src/main/java/com/simibubi/create/content/contraptions/relays/encased/SplitShaftInstance.java

@@ -35,15 +35,14 @@ public class SplitShaftInstance extends KineticTileInstance<SplitShaftTileEntity
     protected void init() {
         keys = new ArrayList<>(2);
 
-        BlockState state = tile.getBlockState();
+        Block block = lastState.getBlock();
-        Block block = state.getBlock();
+        final Direction.Axis boxAxis = ((IRotate) block).getRotationAxis(lastState);
-        final Direction.Axis boxAxis = ((IRotate) block).getRotationAxis(state);
 
         float speed = tile.getSpeed();
 
         for (Direction dir : Iterate.directionsInAxis(boxAxis)) {
 
-            InstancedModel<RotatingData> half = AllBlockPartials.SHAFT_HALF.renderOnDirectionalSouthRotating(modelManager, state, dir);
+            InstancedModel<RotatingData> half = AllBlockPartials.SHAFT_HALF.renderOnDirectionalSouthRotating(modelManager, lastState, dir);
 
             float splitSpeed = speed * tile.getRotationSpeedModifier(dir);
 
@@ -53,9 +52,8 @@ public class SplitShaftInstance extends KineticTileInstance<SplitShaftTileEntity
 
     @Override
     public void onUpdate() {
-        BlockState state = tile.getBlockState();
+        Block block = lastState.getBlock();
-        Block block = state.getBlock();
+        final Direction.Axis boxAxis = ((IRotate) block).getRotationAxis(lastState);
-        final Direction.Axis boxAxis = ((IRotate) block).getRotationAxis(state);
 
         Direction[] directions = Iterate.directionsInAxis(boxAxis);
 
@@ -80,7 +78,6 @@ public class SplitShaftInstance extends KineticTileInstance<SplitShaftTileEntity
     protected void updateRotation(InstanceKey<RotatingData> key, Direction dir) {
         key.modifyInstance(data -> {
             Direction.Axis axis = dir.getAxis();
-            final BlockPos pos = tile.getPos();
 
             data.setRotationalSpeed(tile.getSpeed() * tile.getRotationSpeedModifier(dir))
                 .setRotationOffset(getRotationOffset(axis))

src/main/java/com/simibubi/create/content/contraptions/relays/gearbox/GearboxInstance.java

@@ -37,13 +37,10 @@ public class GearboxInstance extends KineticTileInstance<GearboxTileEntity> {
     protected void init() {
         keys = new EnumMap<>(Direction.class);
 
-        BlockState state = tile.getBlockState();
+        final Direction.Axis boxAxis = lastState.get(BlockStateProperties.AXIS);
 
-        final Direction.Axis boxAxis = state.get(BlockStateProperties.AXIS);
+        int blockLight = world.getLightLevel(LightType.BLOCK, pos);
-
+        int skyLight = world.getLightLevel(LightType.SKY, pos);
-        BlockPos pos = tile.getPos();
-        int blockLight = tile.getWorld().getLightLevel(LightType.BLOCK, pos);
-        int skyLight = tile.getWorld().getLightLevel(LightType.SKY, pos);
         updateSourceFacing();
 
         for (Direction direction : Iterate.directions) {
@@ -51,7 +48,7 @@ public class GearboxInstance extends KineticTileInstance<GearboxTileEntity> {
             if (boxAxis == axis)
                 continue;
 
-            InstancedModel<RotatingData> shaft = AllBlockPartials.SHAFT_HALF.renderOnDirectionalSouthRotating(modelManager, state, direction);
+            InstancedModel<RotatingData> shaft = AllBlockPartials.SHAFT_HALF.renderOnDirectionalSouthRotating(modelManager, lastState, direction);
 
             InstanceKey<RotatingData> key = shaft.setupInstance(data -> {
                 data.setBlockLight(blockLight)
@@ -79,7 +76,7 @@ public class GearboxInstance extends KineticTileInstance<GearboxTileEntity> {
 
     protected void updateSourceFacing() {
         if (tile.hasSource()) {
-            BlockPos source = tile.source.subtract(tile.getPos());
+            BlockPos source = tile.source.subtract(pos);
             sourceFacing = Direction.getFacingFromVector(source.getX(), source.getY(), source.getZ());
         } else {
             sourceFacing = null;
@@ -89,7 +86,6 @@ public class GearboxInstance extends KineticTileInstance<GearboxTileEntity> {
     @Override
     public void onUpdate() {
         updateSourceFacing();
-        BlockPos pos = tile.getPos();
         for (Map.Entry<Direction, InstanceKey<RotatingData>> key : keys.entrySet()) {
             key.getValue().modifyInstance(data -> {
                 Direction direction = key.getKey();
@@ -104,7 +100,6 @@ public class GearboxInstance extends KineticTileInstance<GearboxTileEntity> {
 
     @Override
     public void updateLight() {
-        BlockPos pos = tile.getPos();
         int blockLight = tile.getWorld().getLightLevel(LightType.BLOCK, pos);
         int skyLight = tile.getWorld().getLightLevel(LightType.SKY, pos);
 
@@ -115,10 +110,7 @@ public class GearboxInstance extends KineticTileInstance<GearboxTileEntity> {
 
     @Override
     public void remove() {
-        for (InstanceKey<RotatingData> key : keys.values()) {
+        keys.values().forEach(InstanceKey::delete);
-            key.delete();
-        }
-
         keys.clear();
     }
 }

src/main/java/com/simibubi/create/foundation/mixin/CancelTileEntityRenderMixin.java

@@ -27,18 +27,6 @@ public class CancelTileEntityRenderMixin {
     private void noRenderInstancedTiles(CallbackInfoReturnable<List<TileEntity>> cir) {
         List<TileEntity> tiles = cir.getReturnValue();
 
-        List<TileEntity> out = new ArrayList<>(tiles.size());
+        tiles.removeIf(tile -> tile instanceof IInstanceRendered && !((IInstanceRendered) tile).shouldRenderAsTE());
-
-        for (TileEntity tile : tiles) {
-            if (tile instanceof IInstanceRendered) {
-                IInstanceRendered instanceRendered = (IInstanceRendered) tile;
-
-                if (!instanceRendered.shouldRenderAsTE()) continue;
-            }
-
-            out.add(tile);
-        }
-
-        cir.setReturnValue(out);
     }
 }

src/main/java/com/simibubi/create/foundation/render/BufferedModel.java

@@ -1,11 +1,12 @@
 package com.simibubi.create.foundation.render;
 
+import com.simibubi.create.foundation.render.gl.Backend;
 import com.simibubi.create.foundation.render.gl.GlBuffer;
 import com.simibubi.create.foundation.render.gl.GlVertexArray;
 import com.simibubi.create.foundation.render.instancing.VertexFormat;
 import net.minecraft.client.renderer.BufferBuilder;
 import org.lwjgl.opengl.GL15;
-import org.lwjgl.opengl.GL40;
+import org.lwjgl.opengl.GL20;
 
 import java.nio.ByteBuffer;
 
@@ -35,7 +36,7 @@ public abstract class BufferedModel extends TemplateBuffer {
 
         int numAttributes = getTotalShaderAttributeCount();
         for (int i = 0; i <= numAttributes; i++) {
-            GL40.glEnableVertexAttribArray(i);
+            GL20.glEnableVertexAttribArray(i);
         }
 
         invariantVBO.bind(GL15.GL_ARRAY_BUFFER);
@@ -44,13 +45,11 @@ public abstract class BufferedModel extends TemplateBuffer {
         GL15.glBufferData(GL15.GL_ARRAY_BUFFER, invariantSize, GL15.GL_STATIC_DRAW);
 
         // mirror it in system memory so we can write to it
-        ByteBuffer constant = GL15.glMapBuffer(GL15.GL_ARRAY_BUFFER, GL15.GL_WRITE_ONLY);
+        Backend.MAP_BUFFER.mapBuffer(GL15.GL_ARRAY_BUFFER, invariantSize, buffer -> {
-
             for (int i = 0; i < vertexCount; i++) {
-            copyVertex(constant, i);
+                copyVertex(buffer, i);
             }
-        constant.rewind();
+        });
-        GL15.glUnmapBuffer(GL15.GL_ARRAY_BUFFER);
 
         getModelFormat().informAttributes(0);
 

src/main/java/com/simibubi/create/foundation/render/FastRenderDispatcher.java

@@ -27,16 +27,16 @@ import net.minecraft.world.chunk.Chunk;
 import org.lwjgl.opengl.GL11;
 
 import javax.annotation.Nullable;
+import java.util.ArrayList;
 import java.util.Map;
-import java.util.Queue;
+import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.function.Consumer;
 
 public class FastRenderDispatcher {
 
-    public static WorldAttached<ConcurrentLinkedQueue<TileEntity>> queuedUpdates = new WorldAttached<>(ConcurrentLinkedQueue::new);
+    public static WorldAttached<ConcurrentHashMap.KeySetView<TileEntity, Boolean>> queuedUpdates = new WorldAttached<>(ConcurrentHashMap::newKeySet);
-    public static WorldAttached<ConcurrentLinkedQueue<TileEntity>> queuedRemovals = new WorldAttached<>(ConcurrentLinkedQueue::new);
+    public static WorldAttached<ConcurrentHashMap.KeySetView<TileEntity, Boolean>> queuedRemovals = new WorldAttached<>(ConcurrentHashMap::newKeySet);
-    public static WorldAttached<ConcurrentLinkedQueue<TileEntityInstance<?>>> addedLastTick = new WorldAttached<>(ConcurrentLinkedQueue::new);
+    public static WorldAttached<ConcurrentHashMap.KeySetView<TileEntityInstance<?>, Boolean>> addedLastTick = new WorldAttached<>(ConcurrentHashMap::newKeySet);
 
     private static Matrix4f projectionMatrixThisFrame = null;
 
@@ -56,18 +56,21 @@ public class FastRenderDispatcher {
         ClientWorld world = Minecraft.getInstance().world;
 
         runQueue(addedLastTick.get(world), TileEntityInstance::updateLight);
-        runQueue(queuedUpdates.get(world), CreateClient.kineticRenderer::update);
         runQueue(queuedRemovals.get(world), CreateClient.kineticRenderer::remove);
+        CreateClient.kineticRenderer.clean();
+
+        runQueue(queuedUpdates.get(world), CreateClient.kineticRenderer::update);
     }
 
-    private static <T> void runQueue(@Nullable Queue<T> q, Consumer<T> action) {
+    private static <T> void runQueue(@Nullable ConcurrentHashMap.KeySetView<T, Boolean> changed, Consumer<T> action) {
-        if (q == null) return;
+        if (changed == null) return;
 
-        while (!q.isEmpty()) {
+        // because of potential concurrency issues, we make a copy of what's in the set at the time we get here
-            T t = q.poll();
+        ArrayList<T> tiles = new ArrayList<>(changed);
 
-            action.accept(t);
+        tiles.forEach(action);
-        }
+
+        changed.removeAll(tiles);
     }
 
     public static void renderLayer(RenderType type, MatrixStack stack, double cameraX, double cameraY, double cameraZ) {

src/main/java/com/simibubi/create/foundation/render/InstancedTileRenderer.java

@@ -4,13 +4,16 @@ import com.simibubi.create.foundation.render.gl.shader.Shader;
 import com.simibubi.create.foundation.render.gl.shader.ShaderCallback;
 import com.simibubi.create.foundation.render.gl.shader.ShaderHelper;
 import com.simibubi.create.foundation.render.instancing.*;
+import com.simibubi.create.foundation.utility.AnimationTickHolder;
 import net.minecraft.client.renderer.Matrix4f;
 import net.minecraft.client.renderer.RenderType;
 import net.minecraft.tileentity.TileEntity;
 
 import javax.annotation.Nullable;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 public class InstancedTileRenderer {
     protected Map<TileEntity, TileEntityInstance<?>> renderers = new HashMap<>();
@@ -31,12 +34,17 @@ public class InstancedTileRenderer {
         return (RenderMaterial<M>) materials.get(materialType);
     }
 
+    @Nullable
+    public <T extends TileEntity> TileEntityInstance<? super T> getInstance(T tile) {
+        return getInstance(tile, true);
+    }
+
     @SuppressWarnings("unchecked")
     @Nullable
-    public <T extends TileEntity> TileEntityInstance<? super T> getRenderer(T tile) {
+    public <T extends TileEntity> TileEntityInstance<? super T> getInstance(T tile, boolean create) {
         if (renderers.containsKey(tile)) {
             return (TileEntityInstance<? super T>) renderers.get(tile);
-        } else {
+        } else if (create) {
             TileEntityInstance<? super T> renderer = InstancedTileRenderRegistry.instance.create(this, tile);
 
             if (renderer != null) {
@@ -45,38 +53,49 @@ public class InstancedTileRenderer {
             }
 
             return renderer;
+        } else {
+            return null;
         }
     }
 
     public <T extends TileEntity> void onLightUpdate(T tile) {
         if (tile instanceof IInstanceRendered) {
-            TileEntityInstance<? super T> renderer = getRenderer(tile);
+            TileEntityInstance<? super T> instance = getInstance(tile);
 
-            if (renderer != null)
+            if (instance != null)
-                renderer.updateLight();
+                instance.updateLight();
         }
     }
 
     public <T extends TileEntity> void update(T tile) {
         if (tile instanceof IInstanceRendered) {
-            TileEntityInstance<? super T> renderer = getRenderer(tile);
+            TileEntityInstance<? super T> instance = getInstance(tile);
 
-            if (renderer != null)
+            if (instance != null)
-                renderer.update();
+                instance.update();
         }
     }
 
     public <T extends TileEntity> void remove(T tile) {
         if (tile instanceof IInstanceRendered) {
-            TileEntityInstance<? super T> renderer = getRenderer(tile);
+            TileEntityInstance<? super T> instance = getInstance(tile, false);
 
-            if (renderer != null) {
+            if (instance != null) {
-                renderer.remove();
+                instance.remove();
                 renderers.remove(tile);
             }
         }
     }
 
+    public void clean() {
+        // Clean up twice a second. This doesn't have to happen every tick,
+        // but this does need to be run to ensure we don't miss anything.
+        if (AnimationTickHolder.ticks % 10 == 0) {
+            List<TileEntity> removed = renderers.keySet().stream().filter(TileEntity::isRemoved).collect(Collectors.toList());
+            removed.forEach(renderers::remove);
+        }
+    }
+
     public void invalidate() {
         for (RenderMaterial<?> material : materials.values()) {
             material.delete();

src/main/java/com/simibubi/create/foundation/render/contraption/RenderedContraption.java

@@ -91,7 +91,7 @@ public class RenderedContraption {
         if (!tileEntities.isEmpty()) {
             for (TileEntity te : tileEntities) {
                 if (te instanceof IInstanceRendered) {
-                    kinetics.getRenderer(te); // this is enough to instantiate the model instance
+                    kinetics.getInstance(te); // this is enough to instantiate the model instance
                 }
             }
         }

src/main/java/com/simibubi/create/foundation/render/gl/Backend.java

@@ -0,0 +1,7 @@
+package com.simibubi.create.foundation.render.gl;
+
+import com.simibubi.create.foundation.render.gl.backend.MapBuffer;
+
+public class Backend {
+    public static final MapBuffer MAP_BUFFER = MapBuffer.GL30_RANGE;
+}

src/main/java/com/simibubi/create/foundation/render/gl/backend/MapBuffer.java

@@ -0,0 +1,58 @@
+package com.simibubi.create.foundation.render.gl.backend;
+
+import org.lwjgl.opengl.ARBMapBufferRange;
+import org.lwjgl.opengl.GL15;
+import org.lwjgl.opengl.GL30;
+
+import java.nio.ByteBuffer;
+import java.util.function.Consumer;
+
+public enum MapBuffer {
+
+    GL30_RANGE {
+        @Override
+        public void mapBuffer(int target, int offset, int length, Consumer<ByteBuffer> upload) {
+            ByteBuffer buffer = GL30.glMapBufferRange(target, offset, length, GL30.GL_MAP_WRITE_BIT | GL30.GL_MAP_INVALIDATE_RANGE_BIT);
+
+            upload.accept(buffer);
+            buffer.rewind();
+
+            GL30.glUnmapBuffer(target);
+        }
+    },
+    ARB_RANGE {
+        @Override
+        public void mapBuffer(int target, int offset, int length, Consumer<ByteBuffer> upload) {
+            ByteBuffer buffer = ARBMapBufferRange.glMapBufferRange(target, offset, length, GL30.GL_MAP_WRITE_BIT | GL30.GL_MAP_INVALIDATE_RANGE_BIT);
+
+            upload.accept(buffer);
+            buffer.rewind();
+
+            GL30.glUnmapBuffer(target);
+        }
+    },
+    GL15_MAP {
+        @Override
+        public void mapBuffer(int target, int offset, int length, Consumer<ByteBuffer> upload) {
+            ByteBuffer buffer = GL15.glMapBuffer(target, GL15.GL_WRITE_ONLY);
+
+            buffer.position(offset);
+            upload.accept(buffer);
+            buffer.rewind();
+            GL15.glUnmapBuffer(target);
+        }
+    },
+    UNSUPPORTED {
+        @Override
+        public void mapBuffer(int target, int offset, int length, Consumer<ByteBuffer> upload) {
+            throw new UnsupportedOperationException("glMapBuffer not supported");
+        }
+    };
+
+
+    public abstract void mapBuffer(int target, int offset, int length, Consumer<ByteBuffer> upload);
+
+    public final void mapBuffer(int target, int size, Consumer<ByteBuffer> upload) {
+        mapBuffer(target, 0, size, upload);
+    }
+}

src/main/java/com/simibubi/create/foundation/render/instancing/InstancedModel.java

@@ -1,11 +1,16 @@
 package com.simibubi.create.foundation.render.instancing;
 
 
+import com.google.common.collect.Range;
 import com.simibubi.create.foundation.render.BufferedModel;
 import com.simibubi.create.foundation.render.RenderMath;
+import com.simibubi.create.foundation.render.gl.Backend;
 import com.simibubi.create.foundation.render.gl.GlBuffer;
 import net.minecraft.client.renderer.BufferBuilder;
-import org.lwjgl.opengl.*;
+import org.lwjgl.opengl.GL11;
+import org.lwjgl.opengl.GL15;
+import org.lwjgl.opengl.GL31;
+import org.lwjgl.opengl.GL33;
 
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
@@ -23,6 +28,7 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
     protected final ArrayList<InstanceKey<D>> keys = new ArrayList<>();
     protected final ArrayList<D> data = new ArrayList<>();
     protected int minIndexChanged = -1;
+    protected int maxIndexChanged = -1;
 
     public InstancedModel(BufferBuilder buf) {
         super(buf);
@@ -67,10 +73,6 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
 
     }
 
-    public void markDirty() {
-        minIndexChanged = 0;
-    }
-
     protected void deleteInternal() {
         super.deleteInternal();
         instanceVBO.delete();
@@ -91,7 +93,8 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
             keys.get(i).index--;
         }
 
-        setMinIndexChanged(key.index);
+        markIndexChanged(index - 1);
+        maxIndexChanged = keys.size() - 1;
 
         key.invalidate();
     }
@@ -103,7 +106,7 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
 
         edit.accept(data);
 
-        setMinIndexChanged(key.index);
+        markIndexChanged(key.index);
     }
 
     public synchronized InstanceKey<D> setupInstance(Consumer<D> setup) {
@@ -114,16 +117,22 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
         data.add(instanceData);
         keys.add(key);
 
-        setMinIndexChanged(key.index);
+        markIndexChanged(key.index);
 
         return key;
     }
 
-    protected void setMinIndexChanged(int index) {
+    protected void markIndexChanged(int index) {
         if (minIndexChanged < 0) {
             minIndexChanged = index;
-        } else {
+        } else if (index < minIndexChanged) {
-            minIndexChanged = Math.min(minIndexChanged, index);
+            minIndexChanged = index;
+        }
+
+        if (maxIndexChanged < 0) {
+            maxIndexChanged = index;
+        } else if (index > maxIndexChanged) {
+            maxIndexChanged = index;
         }
     }
 
@@ -161,16 +170,17 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
             GL15.glBufferData(GL15.GL_ARRAY_BUFFER, instanceSize, GL15.GL_STATIC_DRAW);
             glBufferSize = instanceSize;
             minIndexChanged = 0;
+            maxIndexChanged = data.size() - 1;
         }
 
-        ByteBuffer buffer = GL15.glMapBuffer(GL15.GL_ARRAY_BUFFER, GL15.GL_WRITE_ONLY);
+        int offset = minIndexChanged * stride;
+        int length = (1 + maxIndexChanged - minIndexChanged) * stride;
 
-        buffer.position(stride * minIndexChanged);
+        Backend.MAP_BUFFER.mapBuffer(GL15.GL_ARRAY_BUFFER, offset, length, buffer -> {
-        for (int i = minIndexChanged; i < data.size(); i++) {
+            for (int i = minIndexChanged; i <= maxIndexChanged; i++) {
                 data.get(i).write(buffer);
             }
-        buffer.rewind();
+        });
-        GL15.glUnmapBuffer(GL15.GL_ARRAY_BUFFER);
 
         glInstanceCount = data.size();
 
@@ -184,5 +194,6 @@ public abstract class InstancedModel<D extends InstanceData> extends BufferedMod
         instanceVBO.unbind(GL15.GL_ARRAY_BUFFER);
 
         minIndexChanged = -1;
+        maxIndexChanged = -1;
     }
 }