Finally safe vertex formats

- true to false for Pepper
 - IBufferedModel -> BufferedModel
 - VertexFormat -> BufferLayout
 - Use ImmutableList in BufferLayout
 - LayoutItem naming consistency
 - Try to reduce usage of raw BufferLayouts
 - Move vertex interfaces to api package
 - #createWriter and #createReader in VertexType
 - Some documentation

src/main/java/com/jozufozu/flywheel/api/struct/StructType.java

@@ -1,6 +1,6 @@
 package com.jozufozu.flywheel.api.struct;
 
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
 
 /**
  * A StructType contains metadata for a specific instance struct that Flywheel can interface with.
@@ -9,13 +9,13 @@ import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
 public interface StructType<S> {
 
 	/**
-	 * @return A new, zeroed instance of the struct.
+	 * @return A new, zeroed instance of S.
 	 */
 	S create();
 
 	/**
-	 * @return The format descriptor of the struct type.
+	 * @return The layout of S when buffered.
 	 */
-	VertexFormat format();
+	BufferLayout getLayout();
 
 }

src/main/java/com/jozufozu/flywheel/api/vertex/VertexList.java

@@ -1,5 +1,14 @@
-package com.jozufozu.flywheel.core.vertex;
+package com.jozufozu.flywheel.api.vertex;
 
+/**
+ * A read only view of a vertex buffer.
+ *
+ * <p>
+ *     VertexList assumes nothing about the layout of the vertices. Implementations should feel free to return constants
+ *     for values that are unused in their layout.
+ * </p>
+ * TODO: more flexible elements?
+ */
 public interface VertexList {
 	float getX(int index);
 

src/main/java/com/jozufozu/flywheel/api/vertex/VertexType.java

@@ -0,0 +1,42 @@
+package com.jozufozu.flywheel.api.vertex;
+
+import java.nio.ByteBuffer;
+
+import com.jozufozu.flywheel.core.layout.BufferLayout;
+
+/**
+ * A vertex type containing metadata about a specific vertex layout.
+ */
+public interface VertexType {
+
+	/**
+	 * The layout of this type of vertex when buffered.
+	 */
+	BufferLayout getLayout();
+
+	/**
+	 * Create a writer backed by the given ByteBuffer.
+	 *
+	 * <p>
+	 *     Implementors are encouraged to override the return type for ergonomics.
+	 * </p>
+	 */
+	VertexWriter createWriter(ByteBuffer buffer);
+
+	/**
+	 * Create a view of the given ByteBuffer as if it were already filled with vertices.
+	 *
+	 * <p>
+	 *     Implementors are encouraged to override the return type for ergonomics.
+	 * </p>
+	 */
+	VertexList createReader(ByteBuffer buffer, int vertexCount);
+
+	default int getStride() {
+		return getLayout().getStride();
+	}
+
+	default int byteOffset(int vertexIndex) {
+		return getStride() * vertexIndex;
+	}
+}

src/main/java/com/jozufozu/flywheel/api/vertex/VertexWriter.java

@@ -0,0 +1,15 @@
+package com.jozufozu.flywheel.api.vertex;
+
+public interface VertexWriter {
+	void writeVertex(VertexList list, int index);
+
+	void seekToVertex(int vertex);
+
+	VertexList intoReader();
+
+	default void writeVertexList(VertexList list) {
+		for (int i = 0; i < list.getVertexCount(); i++) {
+			this.writeVertex(list, i);
+		}
+	}
+}

src/main/java/com/jozufozu/flywheel/api/vertex/package-info.java

@@ -1,5 +1,5 @@
 @ParametersAreNonnullByDefault @MethodsReturnNonnullByDefault
-package com.jozufozu.flywheel.backend.gl.attrib;
+package com.jozufozu.flywheel.api.vertex;
 
 import javax.annotation.ParametersAreNonnullByDefault;
 

src/main/java/com/jozufozu/flywheel/backend/Backend.java

@@ -102,7 +102,7 @@ public class Backend {
 		}
 		materialRegistry.put(name, spec);
 
-		log.debug("registered material '" + name + "' with instance size " + spec.format().getStride());
+		log.debug("registered material '" + name + "' with instance size " + spec.getLayout().getStride());
 
 		return spec;
 	}

src/main/java/com/jozufozu/flywheel/backend/gl/attrib/CommonAttributes.java

@@ -1,21 +0,0 @@
-package com.jozufozu.flywheel.backend.gl.attrib;
-
-import com.jozufozu.flywheel.backend.gl.GlNumericType;
-
-public class CommonAttributes {
-
-	public static final VertexAttribSpec VEC4 = new VertexAttribSpec(GlNumericType.FLOAT, 4);
-	public static final VertexAttribSpec VEC3 = new VertexAttribSpec(GlNumericType.FLOAT, 3);
-	public static final VertexAttribSpec VEC2 = new VertexAttribSpec(GlNumericType.FLOAT, 2);
-	public static final VertexAttribSpec FLOAT = new VertexAttribSpec(GlNumericType.FLOAT, 1);
-
-	public static final VertexAttribSpec QUATERNION = new VertexAttribSpec(GlNumericType.FLOAT, 4);
-	public static final VertexAttribSpec NORMAL = new VertexAttribSpec(GlNumericType.BYTE, 3, true);
-	public static final VertexAttribSpec UV = new VertexAttribSpec(GlNumericType.FLOAT, 2);
-
-	public static final VertexAttribSpec RGBA = new VertexAttribSpec(GlNumericType.UBYTE, 4, true);
-	public static final VertexAttribSpec RGB = new VertexAttribSpec(GlNumericType.UBYTE, 3, true);
-	public static final VertexAttribSpec LIGHT = new VertexAttribSpec(GlNumericType.UBYTE, 2, true);
-
-	public static final VertexAttribSpec NORMALIZED_BYTE = new VertexAttribSpec(GlNumericType.BYTE, 1, true);
-}

src/main/java/com/jozufozu/flywheel/backend/gl/attrib/VertexFormat.java

@@ -1,61 +0,0 @@
-package com.jozufozu.flywheel.backend.gl.attrib;
-
-import java.util.ArrayList;
-import java.util.Collections;
-
-public class VertexFormat {
-
-	private final ArrayList<IAttribSpec> allAttributes;
-
-	private final int numAttributes;
-	private final int stride;
-
-	public VertexFormat(ArrayList<IAttribSpec> allAttributes) {
-		this.allAttributes = allAttributes;
-
-		int numAttributes = 0, stride = 0;
-		for (IAttribSpec spec : allAttributes) {
-			numAttributes += spec.getAttributeCount();
-			stride += spec.getSize();
-		}
-		this.numAttributes = numAttributes;
-		this.stride = stride;
-	}
-
-	public int getAttributeCount() {
-		return numAttributes;
-	}
-
-	public int getStride() {
-		return stride;
-	}
-
-	public void vertexAttribPointers(int index) {
-		int offset = 0;
-		for (IAttribSpec spec : this.allAttributes) {
-			spec.vertexAttribPointer(stride, index, offset);
-			index += spec.getAttributeCount();
-			offset += spec.getSize();
-		}
-	}
-
-	public static Builder builder() {
-		return new Builder();
-	}
-
-	public static class Builder {
-		private final ArrayList<IAttribSpec> allAttributes = new ArrayList<>();
-
-		public Builder() {
-		}
-
-		public Builder addAttributes(IAttribSpec... attributes) {
-			Collections.addAll(allAttributes, attributes);
-			return this;
-		}
-
-		public VertexFormat build() {
-			return new VertexFormat(allAttributes);
-		}
-	}
-}

src/main/java/com/jozufozu/flywheel/backend/instancing/AbstractInstancer.java

@@ -11,14 +11,14 @@ import com.jozufozu.flywheel.core.model.Model;
 
 public abstract class AbstractInstancer<D extends InstanceData> implements Instancer<D> {
 
-	protected final Supplier<D> type;
+	protected final Supplier<D> factory;
 	protected final Model modelData;
 	protected final ArrayList<D> data = new ArrayList<>();
 
 	protected boolean anyToRemove;
 
-	protected AbstractInstancer(Supplier<D> type, Model modelData) {
+	protected AbstractInstancer(Supplier<D> factory, Model modelData) {
-		this.type = type;
+		this.factory = factory;
 		this.modelData = modelData;
 	}
 
@@ -27,7 +27,7 @@ public abstract class AbstractInstancer<D extends InstanceData> implements Insta
 	 */
 	@Override
 	public D createInstance() {
-		return _add(type.get());
+		return _add(factory.get());
 	}
 
 	/**

src/main/java/com/jozufozu/flywheel/backend/instancing/instancing/GPUInstancer.java

@@ -1,21 +1,18 @@
 package com.jozufozu.flywheel.backend.instancing.instancing;
 
-import java.util.BitSet;
-
 import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.api.InstanceData;
 import com.jozufozu.flywheel.api.struct.Instanced;
-import com.jozufozu.flywheel.api.struct.StructType;
 import com.jozufozu.flywheel.api.struct.StructWriter;
 import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.backend.gl.GlVertexArray;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBuffer;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.backend.gl.buffer.MappedBuffer;
 import com.jozufozu.flywheel.backend.gl.error.GlError;
 import com.jozufozu.flywheel.backend.instancing.AbstractInstancer;
-import com.jozufozu.flywheel.backend.model.IBufferedModel;
+import com.jozufozu.flywheel.backend.model.BufferedModel;
 import com.jozufozu.flywheel.backend.model.ModelAllocator;
 import com.jozufozu.flywheel.core.model.Model;
 import com.jozufozu.flywheel.util.AttribUtil;
@@ -23,10 +20,10 @@ import com.jozufozu.flywheel.util.AttribUtil;
 public class GPUInstancer<D extends InstanceData> extends AbstractInstancer<D> {
 
 	private final ModelAllocator modelAllocator;
-	private final VertexFormat instanceFormat;
+	private final BufferLayout instanceFormat;
 	private final Instanced<D> instancedType;
 
-	private IBufferedModel model;
+	private BufferedModel model;
 	private GlVertexArray vao;
 	private GlBuffer instanceVBO;
 	private int glBufferSize = -1;
@@ -39,7 +36,7 @@ public class GPUInstancer<D extends InstanceData> extends AbstractInstancer<D> {
 	public GPUInstancer(Instanced<D> type, Model model, ModelAllocator modelAllocator) {
 		super(type::create, model);
 		this.modelAllocator = modelAllocator;
-		this.instanceFormat = type.format();
+		this.instanceFormat = type.getLayout();
 		instancedType = type;
 	}
 

src/main/java/com/jozufozu/flywheel/backend/model/BufferedModel.java

@@ -1,90 +1,41 @@
 package com.jozufozu.flywheel.backend.model;
 
-import static org.lwjgl.opengl.GL11.glDrawArrays;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
+import com.jozufozu.flywheel.api.vertex.VertexType;
 
-import org.lwjgl.opengl.GL31;
+public interface BufferedModel {
 
-import com.jozufozu.flywheel.Flywheel;
+	VertexType getType();
-import com.jozufozu.flywheel.backend.gl.GlPrimitive;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
-import com.jozufozu.flywheel.backend.gl.buffer.GlBuffer;
-import com.jozufozu.flywheel.backend.gl.buffer.GlBufferType;
-import com.jozufozu.flywheel.backend.gl.buffer.MappedBuffer;
-import com.jozufozu.flywheel.backend.gl.buffer.MappedGlBuffer;
-import com.jozufozu.flywheel.core.model.Model;
-import com.jozufozu.flywheel.util.AttribUtil;
 
-public class BufferedModel implements IBufferedModel {
+	int getVertexCount();
-
-	protected final Model model;
-	protected final GlPrimitive primitiveMode;
-	protected GlBuffer vbo;
-	protected boolean deleted;
-
-	public BufferedModel(GlPrimitive primitiveMode, Model model) {
-		this.model = model;
-		this.primitiveMode = primitiveMode;
-
-		vbo = new MappedGlBuffer(GlBufferType.ARRAY_BUFFER);
-
-		vbo.bind();
-		// allocate the buffer on the gpu
-		vbo.alloc(model.size());
-
-		// mirror it in system memory so we can write to it, and upload our model.
-		try (MappedBuffer buffer = vbo.getBuffer(0, model.size())) {
-			model.getType().copyInto(buffer.unwrap(), model.getReader());
-		} catch (Exception e) {
-			Flywheel.log.error(String.format("Error uploading model '%s':", model.name()), e);
-		}
-
-		vbo.unbind();
-	}
-
-	public boolean isDeleted() {
-		return deleted;
-	}
-
-	public VertexFormat getFormat() {
-		return model.format();
-	}
-
-	public int getVertexCount() {
-		return model.vertexCount();
-	}
 
 	/**
 	 * The VBO/VAO should be bound externally.
 	 */
-	public void setupState() {
+	void setupState();
-		vbo.bind();
-		AttribUtil.enableArrays(getAttributeCount());
-		getFormat().vertexAttribPointers(0);
-	}
 
-	public void clearState() {
+	void clearState();
-		AttribUtil.disableArrays(getAttributeCount());
-		vbo.unbind();
-	}
 
-	public void drawCall() {
+	void drawCall();
-		glDrawArrays(primitiveMode.glEnum, 0, getVertexCount());
-	}
 
 	/**
 	 * Draws many instances of this model, assuming the appropriate state is already bound.
 	 */
-	public void drawInstances(int instanceCount) {
+	void drawInstances(int instanceCount);
-		if (!valid()) return;
 
-		GL31.glDrawArraysInstanced(primitiveMode.glEnum, 0, getVertexCount(), instanceCount);
+	boolean isDeleted();
+
+	void delete();
+
+	default BufferLayout getFormat() {
+		return getType().getLayout();
 	}
 
-	public void delete() {
+	default boolean valid() {
-		if (deleted) return;
+		return getVertexCount() > 0 && !isDeleted();
+	}
 
-		deleted = true;
+	default int getAttributeCount() {
-		vbo.delete();
+		return getFormat().getAttributeCount();
 	}
 }
-

src/main/java/com/jozufozu/flywheel/backend/model/IBufferedModel.java

@@ -1,36 +0,0 @@
-package com.jozufozu.flywheel.backend.model;
-
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
-
-public interface IBufferedModel {
-
-	VertexFormat getFormat();
-
-	int getVertexCount();
-
-	/**
-	 * The VBO/VAO should be bound externally.
-	 */
-	void setupState();
-
-	void clearState();
-
-	void drawCall();
-
-	/**
-	 * Draws many instances of this model, assuming the appropriate state is already bound.
-	 */
-	void drawInstances(int instanceCount);
-
-	boolean isDeleted();
-
-	void delete();
-
-	default boolean valid() {
-		return getVertexCount() > 0 && !isDeleted();
-	}
-
-	default int getAttributeCount() {
-		return getFormat().getAttributeCount();
-	}
-}

src/main/java/com/jozufozu/flywheel/backend/model/ImmediateAllocator.java

@@ -7,7 +7,7 @@ public class ImmediateAllocator implements ModelAllocator {
 	public static final ImmediateAllocator INSTANCE = new ImmediateAllocator();
 
 	@Override
-	public IBufferedModel alloc(Model model, Callback allocationCallback) {
+	public BufferedModel alloc(Model model, Callback allocationCallback) {
 		IndexedModel out = new IndexedModel(model);
 		allocationCallback.onAlloc(out);
 		return out;

src/main/java/com/jozufozu/flywheel/backend/model/IndexedModel.java

@@ -11,7 +11,7 @@ import com.jozufozu.flywheel.core.model.Model;
  *
  * <br><em>This should be favored over a normal BufferedModel.</em>
  */
-public class IndexedModel extends BufferedModel {
+public class IndexedModel extends VBOModel {
 
 	protected ElementBuffer ebo;
 

src/main/java/com/jozufozu/flywheel/backend/model/ModelAllocator.java

@@ -9,10 +9,10 @@ public interface ModelAllocator {
 	 * @param model The model to allocate.
 	 * @return A handle to the allocated model.
 	 */
-	IBufferedModel alloc(Model model, Callback allocationCallback);
+	BufferedModel alloc(Model model, Callback allocationCallback);
 
 	@FunctionalInterface
 	interface Callback {
-		void onAlloc(IBufferedModel arenaModel);
+		void onAlloc(BufferedModel arenaModel);
 	}
 }

src/main/java/com/jozufozu/flywheel/backend/model/ModelPool.java

@@ -1,6 +1,5 @@
 package com.jozufozu.flywheel.backend.model;
 
-import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -8,13 +7,13 @@ import org.lwjgl.opengl.GL32;
 
 import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.backend.gl.GlPrimitive;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBuffer;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.backend.gl.buffer.MappedBuffer;
 import com.jozufozu.flywheel.backend.gl.buffer.MappedGlBuffer;
 import com.jozufozu.flywheel.core.model.Model;
-import com.jozufozu.flywheel.core.vertex.VertexType;
+import com.jozufozu.flywheel.api.vertex.VertexType;
+import com.jozufozu.flywheel.api.vertex.VertexWriter;
 import com.jozufozu.flywheel.util.AttribUtil;
 
 public class ModelPool implements ModelAllocator {
@@ -118,13 +117,13 @@ public class ModelPool implements ModelAllocator {
 
 	private void uploadAll() {
 		try (MappedBuffer buffer = vbo.getBuffer(0, bufferSize)) {
-			ByteBuffer buf = buffer.unwrap();
+			VertexWriter writer = vertexType.createWriter(buffer.unwrap());
 
 			int vertices = 0;
 			for (PooledModel model : models) {
 				model.first = vertices;
 
-				buffer(buf, model);
+				buffer(writer, model);
 
 				vertices += model.getVertexCount();
 			}
@@ -136,9 +135,9 @@ public class ModelPool implements ModelAllocator {
 
 	private void uploadPending() {
 		try (MappedBuffer buffer = vbo.getBuffer(0, bufferSize)) {
-			ByteBuffer buf = buffer.unwrap();
+			VertexWriter writer = vertexType.createWriter(buffer.unwrap());
 			for (PooledModel model : pendingUpload) {
-				buffer(buf, model);
+				buffer(writer, model);
 			}
 			pendingUpload.clear();
 		} catch (Exception e) {
@@ -146,10 +145,9 @@ public class ModelPool implements ModelAllocator {
 		}
 	}
 
-	private void buffer(ByteBuffer buf, PooledModel model) {
+	private void buffer(VertexWriter writer, PooledModel model) {
-		int pos = model.first * vertexType.getStride();
+		writer.seekToVertex(model.first);
-		buf.position(pos);
+		writer.writeVertexList(model.model.getReader());
-		vertexType.copyInto(buf, model.model.getReader());
 		if (model.callback != null) model.callback.onAlloc(model);
 	}
 
@@ -161,7 +159,7 @@ public class ModelPool implements ModelAllocator {
 		vbo.delete();
 	}
 
-	public class PooledModel implements IBufferedModel {
+	public class PooledModel implements BufferedModel {
 
 		private final ElementBuffer ebo;
 		private Callback callback;
@@ -178,8 +176,8 @@ public class ModelPool implements ModelAllocator {
 		}
 
 		@Override
-		public VertexFormat getFormat() {
+		public VertexType getType() {
-			return model.format();
+			return ModelPool.this.vertexType;
 		}
 
 		@Override
@@ -192,7 +190,7 @@ public class ModelPool implements ModelAllocator {
 			vbo.bind();
 			ebo.bind();
 			AttribUtil.enableArrays(getAttributeCount());
-			getFormat().vertexAttribPointers(0);
+			ModelPool.this.vertexType.getLayout().vertexAttribPointers(0);
 		}
 
 		@Override

src/main/java/com/jozufozu/flywheel/backend/model/ModelRenderer.java

@@ -7,7 +7,7 @@ import com.jozufozu.flywheel.core.model.Model;
 public class ModelRenderer {
 
 	protected Supplier<Model> modelSupplier;
-	protected IBufferedModel model;
+	protected BufferedModel model;
 
 	protected boolean initialized;
 

src/main/java/com/jozufozu/flywheel/backend/model/VBOModel.java

@@ -0,0 +1,91 @@
+package com.jozufozu.flywheel.backend.model;
+
+import static org.lwjgl.opengl.GL11.glDrawArrays;
+
+import org.lwjgl.opengl.GL31;
+
+import com.jozufozu.flywheel.Flywheel;
+import com.jozufozu.flywheel.backend.gl.GlPrimitive;
+import com.jozufozu.flywheel.backend.gl.buffer.GlBuffer;
+import com.jozufozu.flywheel.backend.gl.buffer.GlBufferType;
+import com.jozufozu.flywheel.backend.gl.buffer.MappedBuffer;
+import com.jozufozu.flywheel.backend.gl.buffer.MappedGlBuffer;
+import com.jozufozu.flywheel.core.model.Model;
+import com.jozufozu.flywheel.api.vertex.VertexType;
+import com.jozufozu.flywheel.util.AttribUtil;
+
+public class VBOModel implements BufferedModel {
+
+	protected final Model model;
+	protected final GlPrimitive primitiveMode;
+	protected GlBuffer vbo;
+	protected boolean deleted;
+
+	public VBOModel(GlPrimitive primitiveMode, Model model) {
+		this.model = model;
+		this.primitiveMode = primitiveMode;
+
+		vbo = new MappedGlBuffer(GlBufferType.ARRAY_BUFFER);
+
+		vbo.bind();
+		// allocate the buffer on the gpu
+		vbo.alloc(model.size());
+
+		// mirror it in system memory so we can write to it, and upload our model.
+		try (MappedBuffer buffer = vbo.getBuffer(0, model.size())) {
+			model.writeInto(buffer.unwrap());
+		} catch (Exception e) {
+			Flywheel.log.error(String.format("Error uploading model '%s':", model.name()), e);
+		}
+
+		vbo.unbind();
+	}
+
+	public boolean isDeleted() {
+		return deleted;
+	}
+
+	@Override
+	public VertexType getType() {
+		return model.getType();
+	}
+
+	public int getVertexCount() {
+		return model.vertexCount();
+	}
+
+	/**
+	 * The VBO/VAO should be bound externally.
+	 */
+	public void setupState() {
+		vbo.bind();
+		AttribUtil.enableArrays(getAttributeCount());
+		getFormat().vertexAttribPointers(0);
+	}
+
+	public void clearState() {
+		AttribUtil.disableArrays(getAttributeCount());
+		vbo.unbind();
+	}
+
+	public void drawCall() {
+		glDrawArrays(primitiveMode.glEnum, 0, getVertexCount());
+	}
+
+	/**
+	 * Draws many instances of this model, assuming the appropriate state is already bound.
+	 */
+	public void drawInstances(int instanceCount) {
+		if (!valid()) return;
+
+		GL31.glDrawArraysInstanced(primitiveMode.glEnum, 0, getVertexCount(), instanceCount);
+	}
+
+	public void delete() {
+		if (deleted) return;
+
+		deleted = true;
+		vbo.delete();
+	}
+}
+

src/main/java/com/jozufozu/flywheel/backend/struct/BufferWriter.java

@@ -2,20 +2,17 @@ package com.jozufozu.flywheel.backend.struct;
 
 import com.jozufozu.flywheel.api.struct.StructType;
 import com.jozufozu.flywheel.api.struct.StructWriter;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
 import com.jozufozu.flywheel.backend.gl.buffer.VecBuffer;
 
 public abstract class BufferWriter<S> implements StructWriter<S> {
 	protected final VecBuffer backingBuffer;
 
-	protected final VertexFormat format;
 	protected final int stride;
 
 	protected BufferWriter(VecBuffer backingBuffer, StructType<S> vertexType) {
 		this.backingBuffer = backingBuffer;
 
-		this.format = vertexType.format();
+		this.stride = vertexType.getLayout().getStride();
-		this.stride = this.format.getStride();
 	}
 
 	@Override

src/main/java/com/jozufozu/flywheel/core/hardcoded/ModelPart.java

@@ -2,17 +2,17 @@ package com.jozufozu.flywheel.core.hardcoded;
 
 import java.util.List;
 
+import com.jozufozu.flywheel.core.Formats;
 import com.jozufozu.flywheel.core.model.Model;
-import com.jozufozu.flywheel.core.vertex.VertexList;
+import com.jozufozu.flywheel.api.vertex.VertexList;
-import com.jozufozu.flywheel.core.vertex.PosTexNormalVertexListUnsafe;
+import com.jozufozu.flywheel.core.vertex.PosTexNormalWriterUnsafe;
-import com.jozufozu.flywheel.core.vertex.PosTexNormalWriter;
 import com.mojang.blaze3d.platform.MemoryTracker;
 
 public class ModelPart implements Model {
 
 	private final int vertices;
 	private final String name;
-	private final PosTexNormalVertexListUnsafe reader;
+	private final VertexList reader;
 
 	public ModelPart(List<PartBuilder.CuboidBuilder> cuboids, String name) {
 		this.name = name;
@@ -25,7 +25,7 @@ public class ModelPart implements Model {
 			this.vertices = vertices;
 		}
 
-		PosTexNormalWriter writer = new PosTexNormalWriter(MemoryTracker.create(size()));
+		PosTexNormalWriterUnsafe writer = Formats.POS_TEX_NORMAL.createWriter(MemoryTracker.create(size()));
 		for (PartBuilder.CuboidBuilder cuboid : cuboids) {
 			cuboid.buffer(writer);
 		}

src/main/java/com/jozufozu/flywheel/core/hardcoded/PartBuilder.java

@@ -5,7 +5,7 @@ import java.util.EnumSet;
 import java.util.List;
 import java.util.Set;
 
-import com.jozufozu.flywheel.core.vertex.PosTexNormalWriter;
+import com.jozufozu.flywheel.core.vertex.PosTexNormalWriterUnsafe;
 import com.mojang.math.Matrix3f;
 import com.mojang.math.Quaternion;
 import com.mojang.math.Vector3f;
@@ -160,7 +160,7 @@ public class PartBuilder {
 			return visibleFaces.size() * 4;
 		}
 
-		public void buffer(PosTexNormalWriter buffer) {
+		public void buffer(PosTexNormalWriterUnsafe buffer) {
 
 			float sizeX = posX2 - posX1;
 			float sizeY = posY2 - posY1;
@@ -235,7 +235,7 @@ public class PartBuilder {
 			}
 		}
 
-		public void quad(PosTexNormalWriter buffer, Vector3f[] vertices, float minU, float minV, float maxU, float maxV, Vector3f normal) {
+		public void quad(PosTexNormalWriterUnsafe buffer, Vector3f[] vertices, float minU, float minV, float maxU, float maxV, Vector3f normal) {
 			buffer.putVertex(vertices[0].x(), vertices[0].y(), vertices[0].z(), normal.x(), normal.y(), normal.z(), maxU, minV);
 			buffer.putVertex(vertices[1].x(), vertices[1].y(), vertices[1].z(), normal.x(), normal.y(), normal.z(), minU, minV);
 			buffer.putVertex(vertices[2].x(), vertices[2].y(), vertices[2].z(), normal.x(), normal.y(), normal.z(), minU, maxV);

src/main/java/com/jozufozu/flywheel/core/hardcoded/package-info.java

@@ -0,0 +1,6 @@
+@ParametersAreNonnullByDefault @MethodsReturnNonnullByDefault
+package com.jozufozu.flywheel.core.hardcoded;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+
+import net.minecraft.MethodsReturnNonnullByDefault;

src/main/java/com/jozufozu/flywheel/core/layout/BufferLayout.java

@@ -0,0 +1,74 @@
+package com.jozufozu.flywheel.core.layout;
+
+import java.util.List;
+
+import com.google.common.collect.ImmutableList;
+import com.jozufozu.flywheel.api.vertex.VertexType;
+
+/**
+ * Classic Vertex Format struct with a clever name.
+ *
+ * <p>
+ *     Used for vertices and instance. Describes the layout of a datatype in a buffer object.
+ * </p>
+ *
+ * @see com.jozufozu.flywheel.api.struct.StructType
+ * @see VertexType
+ */
+public class BufferLayout {
+
+	private final List<LayoutItem> allAttributes;
+
+	private final int numAttributes;
+	private final int stride;
+
+	public BufferLayout(List<LayoutItem> allAttributes) {
+		this.allAttributes = allAttributes;
+
+		int numAttributes = 0, stride = 0;
+		for (LayoutItem spec : allAttributes) {
+			numAttributes += spec.getAttributeCount();
+			stride += spec.getSize();
+		}
+		this.numAttributes = numAttributes;
+		this.stride = stride;
+	}
+
+	public int getAttributeCount() {
+		return numAttributes;
+	}
+
+	public int getStride() {
+		return stride;
+	}
+
+	public void vertexAttribPointers(int index) {
+		int offset = 0;
+		for (LayoutItem spec : this.allAttributes) {
+			spec.vertexAttribPointer(stride, index, offset);
+			index += spec.getAttributeCount();
+			offset += spec.getSize();
+		}
+	}
+
+	public static Builder builder() {
+		return new Builder();
+	}
+
+	public static class Builder {
+		private final ImmutableList.Builder<LayoutItem> allItems;
+
+		public Builder() {
+			allItems = ImmutableList.builder();
+		}
+
+		public Builder addItems(LayoutItem... attributes) {
+			allItems.add(attributes);
+			return this;
+		}
+
+		public BufferLayout build() {
+			return new BufferLayout(allItems.build());
+		}
+	}
+}

src/main/java/com/jozufozu/flywheel/core/layout/CommonItems.java

@@ -0,0 +1,24 @@
+package com.jozufozu.flywheel.core.layout;
+
+import com.jozufozu.flywheel.backend.gl.GlNumericType;
+
+public class CommonItems {
+
+	public static final PrimitiveItem VEC4 = new PrimitiveItem(GlNumericType.FLOAT, 4);
+	public static final PrimitiveItem VEC3 = new PrimitiveItem(GlNumericType.FLOAT, 3);
+	public static final PrimitiveItem VEC2 = new PrimitiveItem(GlNumericType.FLOAT, 2);
+	public static final PrimitiveItem FLOAT = new PrimitiveItem(GlNumericType.FLOAT, 1);
+
+	public static final PrimitiveItem QUATERNION = new PrimitiveItem(GlNumericType.FLOAT, 4);
+	public static final PrimitiveItem NORMAL = new PrimitiveItem(GlNumericType.BYTE, 3, true);
+	public static final PrimitiveItem UV = new PrimitiveItem(GlNumericType.FLOAT, 2);
+
+	public static final PrimitiveItem RGBA = new PrimitiveItem(GlNumericType.UBYTE, 4, true);
+	public static final PrimitiveItem RGB = new PrimitiveItem(GlNumericType.UBYTE, 3, true);
+	public static final PrimitiveItem LIGHT = new PrimitiveItem(GlNumericType.UBYTE, 2, true);
+	public static final PrimitiveItem LIGHT_SHORT = new PrimitiveItem(GlNumericType.USHORT, 2, true);
+
+	public static final PrimitiveItem NORMALIZED_BYTE = new PrimitiveItem(GlNumericType.BYTE, 1, true);
+	public static final LayoutItem PADDING_BYTE = new PaddingItem(1);
+
+}

src/main/java/com/jozufozu/flywheel/core/layout/LayoutItem.java

@@ -1,6 +1,6 @@
-package com.jozufozu.flywheel.backend.gl.attrib;
+package com.jozufozu.flywheel.core.layout;
 
-public interface IAttribSpec {
+public interface LayoutItem {
 
 	void vertexAttribPointer(int stride, int index, int offset);
 

src/main/java/com/jozufozu/flywheel/core/layout/MatrixItems.java

@@ -1,10 +1,10 @@
-package com.jozufozu.flywheel.backend.gl.attrib;
+package com.jozufozu.flywheel.core.layout;
 
 import org.lwjgl.opengl.GL20;
 
 import com.jozufozu.flywheel.backend.gl.GlNumericType;
 
-public enum MatrixAttributes implements IAttribSpec {
+public enum MatrixItems implements LayoutItem {
 	MAT3(3, 3),
 	MAT4(4, 4),
 	;
@@ -12,7 +12,7 @@ public enum MatrixAttributes implements IAttribSpec {
 	private final int rows;
 	private final int cols;
 
-	MatrixAttributes(int rows, int cols) {
+	MatrixItems(int rows, int cols) {
 		this.rows = rows;
 		this.cols = cols;
 	}

src/main/java/com/jozufozu/flywheel/core/layout/PaddingItem.java

@@ -0,0 +1,19 @@
+package com.jozufozu.flywheel.core.layout;
+
+record PaddingItem(int bytes) implements LayoutItem {
+
+	@Override
+	public void vertexAttribPointer(int stride, int index, int offset) {
+
+	}
+
+	@Override
+	public int getSize() {
+		return bytes;
+	}
+
+	@Override
+	public int getAttributeCount() {
+		return 0;
+	}
+}

src/main/java/com/jozufozu/flywheel/core/layout/PrimitiveItem.java

@@ -1,10 +1,10 @@
-package com.jozufozu.flywheel.backend.gl.attrib;
+package com.jozufozu.flywheel.core.layout;
 
 import org.lwjgl.opengl.GL20;
 
 import com.jozufozu.flywheel.backend.gl.GlNumericType;
 
-public class VertexAttribSpec implements IAttribSpec {
+public class PrimitiveItem implements LayoutItem {
 
 	private final GlNumericType type;
 	private final int count;
@@ -12,11 +12,11 @@ public class VertexAttribSpec implements IAttribSpec {
 	private final int attributeCount;
 	private final boolean normalized;
 
-	public VertexAttribSpec(GlNumericType type, int count) {
+	public PrimitiveItem(GlNumericType type, int count) {
 		this(type, count, false);
 	}
 
-	public VertexAttribSpec(GlNumericType type, int count, boolean normalized) {
+	public PrimitiveItem(GlNumericType type, int count, boolean normalized) {
 		this.type = type;
 		this.count = count;
 		this.size = type.getByteWidth() * count;

src/main/java/com/jozufozu/flywheel/core/layout/package-info.java

@@ -0,0 +1,6 @@
+@ParametersAreNonnullByDefault @MethodsReturnNonnullByDefault
+package com.jozufozu.flywheel.core.layout;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+
+import net.minecraft.MethodsReturnNonnullByDefault;

src/main/java/com/jozufozu/flywheel/core/materials/BasicWriterUnsafe.java

@@ -6,9 +6,9 @@ import com.jozufozu.flywheel.api.struct.StructType;
 import com.jozufozu.flywheel.backend.gl.buffer.VecBuffer;
 import com.jozufozu.flywheel.backend.struct.UnsafeBufferWriter;
 
-public abstract class UnsafeBasicWriter<D extends BasicData> extends UnsafeBufferWriter<D> {
+public abstract class BasicWriterUnsafe<D extends BasicData> extends UnsafeBufferWriter<D> {
 
-	public UnsafeBasicWriter(VecBuffer backingBuffer, StructType<D> vertexType) {
+	public BasicWriterUnsafe(VecBuffer backingBuffer, StructType<D> vertexType) {
 		super(backingBuffer, vertexType);
 	}
 

src/main/java/com/jozufozu/flywheel/core/materials/model/ModelType.java

@@ -3,9 +3,9 @@ package com.jozufozu.flywheel.core.materials.model;
 import com.jozufozu.flywheel.api.struct.Batched;
 import com.jozufozu.flywheel.api.struct.Instanced;
 import com.jozufozu.flywheel.api.struct.StructWriter;
-import com.jozufozu.flywheel.backend.gl.attrib.CommonAttributes;
+import com.jozufozu.flywheel.core.layout.CommonItems;
-import com.jozufozu.flywheel.backend.gl.attrib.MatrixAttributes;
+import com.jozufozu.flywheel.core.layout.MatrixItems;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
 import com.jozufozu.flywheel.backend.gl.buffer.VecBuffer;
 import com.jozufozu.flywheel.core.Programs;
 import com.jozufozu.flywheel.core.model.ModelTransformer;
@@ -14,9 +14,9 @@ import net.minecraft.resources.ResourceLocation;
 
 public class ModelType implements Instanced<ModelData>, Batched<ModelData> {
 
-	public static final VertexFormat FORMAT = VertexFormat.builder()
+	public static final BufferLayout FORMAT = BufferLayout.builder()
-			.addAttributes(CommonAttributes.LIGHT, CommonAttributes.RGBA)
+			.addItems(CommonItems.LIGHT, CommonItems.RGBA)
-			.addAttributes(MatrixAttributes.MAT4, MatrixAttributes.MAT3)
+			.addItems(MatrixItems.MAT4, MatrixItems.MAT3)
 			.build();
 
 	@Override
@@ -25,13 +25,13 @@ public class ModelType implements Instanced<ModelData>, Batched<ModelData> {
 	}
 
 	@Override
-	public VertexFormat format() {
+	public BufferLayout getLayout() {
 		return FORMAT;
 	}
 
 	@Override
 	public StructWriter<ModelData> getWriter(VecBuffer backing) {
-		return new UnsafeModelWriter(backing, this);
+		return new ModelWriterUnsafe(backing, this);
 	}
 
 	@Override

src/main/java/com/jozufozu/flywheel/core/materials/model/ModelWriterUnsafe.java

@@ -2,12 +2,12 @@ package com.jozufozu.flywheel.core.materials.model;
 
 import com.jozufozu.flywheel.backend.gl.buffer.VecBuffer;
 import com.jozufozu.flywheel.api.struct.StructType;
-import com.jozufozu.flywheel.core.materials.UnsafeBasicWriter;
+import com.jozufozu.flywheel.core.materials.BasicWriterUnsafe;
 import com.jozufozu.flywheel.util.WriteUnsafe;
 
-public class UnsafeModelWriter extends UnsafeBasicWriter<ModelData> {
+public class ModelWriterUnsafe extends BasicWriterUnsafe<ModelData> {
 
-	public UnsafeModelWriter(VecBuffer backingBuffer, StructType<ModelData> vertexType) {
+	public ModelWriterUnsafe(VecBuffer backingBuffer, StructType<ModelData> vertexType) {
 		super(backingBuffer, vertexType);
 	}
 

src/main/java/com/jozufozu/flywheel/core/materials/oriented/OrientedType.java

@@ -3,8 +3,8 @@ package com.jozufozu.flywheel.core.materials.oriented;
 import com.jozufozu.flywheel.api.struct.Batched;
 import com.jozufozu.flywheel.api.struct.Instanced;
 import com.jozufozu.flywheel.api.struct.StructWriter;
-import com.jozufozu.flywheel.backend.gl.attrib.CommonAttributes;
+import com.jozufozu.flywheel.core.layout.CommonItems;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
 import com.jozufozu.flywheel.backend.gl.buffer.VecBuffer;
 import com.jozufozu.flywheel.core.Programs;
 import com.jozufozu.flywheel.core.model.ModelTransformer;
@@ -14,9 +14,9 @@ import net.minecraft.resources.ResourceLocation;
 
 public class OrientedType implements Instanced<OrientedData>, Batched<OrientedData> {
 
-	public static final VertexFormat FORMAT = VertexFormat.builder()
+	public static final BufferLayout FORMAT = BufferLayout.builder()
-			.addAttributes(CommonAttributes.LIGHT, CommonAttributes.RGBA)
+			.addItems(CommonItems.LIGHT, CommonItems.RGBA)
-			.addAttributes(CommonAttributes.VEC3, CommonAttributes.VEC3, CommonAttributes.QUATERNION)
+			.addItems(CommonItems.VEC3, CommonItems.VEC3, CommonItems.QUATERNION)
 			.build();
 
 	@Override
@@ -25,13 +25,13 @@ public class OrientedType implements Instanced<OrientedData>, Batched<OrientedDa
 	}
 
 	@Override
-	public VertexFormat format() {
+	public BufferLayout getLayout() {
 		return FORMAT;
 	}
 
 	@Override
 	public StructWriter<OrientedData> getWriter(VecBuffer backing) {
-		return new UnsafeOrientedWriter(backing, this);
+		return new OrientedWriterUnsafe(backing, this);
 	}
 
 	@Override

src/main/java/com/jozufozu/flywheel/core/materials/oriented/OrientedWriterUnsafe.java

@@ -4,10 +4,10 @@ import org.lwjgl.system.MemoryUtil;
 
 import com.jozufozu.flywheel.backend.gl.buffer.VecBuffer;
 import com.jozufozu.flywheel.api.struct.StructType;
-import com.jozufozu.flywheel.core.materials.UnsafeBasicWriter;
+import com.jozufozu.flywheel.core.materials.BasicWriterUnsafe;
 
-public class UnsafeOrientedWriter extends UnsafeBasicWriter<OrientedData> {
+public class OrientedWriterUnsafe extends BasicWriterUnsafe<OrientedData> {
-	public UnsafeOrientedWriter(VecBuffer backingBuffer, StructType<OrientedData> vertexType) {
+	public OrientedWriterUnsafe(VecBuffer backingBuffer, StructType<OrientedData> vertexType) {
 		super(backingBuffer, vertexType);
 	}
 

src/main/java/com/jozufozu/flywheel/core/model/BlockModel.java

@@ -1,7 +1,7 @@
 package com.jozufozu.flywheel.core.model;
 
-import com.jozufozu.flywheel.core.vertex.VertexList;
+import com.jozufozu.flywheel.core.Formats;
-import com.jozufozu.flywheel.core.vertex.BlockVertexListUnsafe;
+import com.jozufozu.flywheel.api.vertex.VertexList;
 import com.mojang.blaze3d.vertex.PoseStack;
 
 import net.minecraft.client.Minecraft;
@@ -29,7 +29,7 @@ public class BlockModel implements Model {
 	}
 
 	public BlockModel(BakedModel model, BlockState referenceState, PoseStack ms) {
-		reader = new BlockVertexListUnsafe(ModelUtil.getBufferBuilder(model, referenceState, ms));
+		reader = Formats.BLOCK.createReader(ModelUtil.getBufferBuilder(model, referenceState, ms));
 		name = referenceState.toString();
 	}
 

src/main/java/com/jozufozu/flywheel/core/model/Model.java

@@ -1,11 +1,12 @@
 package com.jozufozu.flywheel.core.model;
 
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import java.nio.ByteBuffer;
+
 import com.jozufozu.flywheel.backend.model.ElementBuffer;
 import com.jozufozu.flywheel.core.Formats;
 import com.jozufozu.flywheel.core.QuadConverter;
-import com.jozufozu.flywheel.core.vertex.VertexList;
+import com.jozufozu.flywheel.api.vertex.VertexList;
-import com.jozufozu.flywheel.core.vertex.VertexType;
+import com.jozufozu.flywheel.api.vertex.VertexType;
 
 /**
  * A model that can be rendered by flywheel.
@@ -49,13 +50,6 @@ public interface Model {
 		return Formats.POS_TEX_NORMAL;
 	}
 
-	/**
-	 * @return The format of this model's vertices
-	 */
-	default VertexFormat format() {
-		return getType().getFormat();
-	}
-
 	/**
 	 * Create an element buffer object that indexes the vertices of this model.
 	 *
@@ -75,7 +69,7 @@ public interface Model {
 	 * The size in bytes that this model's data takes up.
 	 */
 	default int size() {
-		return vertexCount() * format().getStride();
+		return getType().byteOffset(vertexCount());
 	}
 
 	/**
@@ -85,4 +79,8 @@ public interface Model {
 	default boolean empty() {
 		return vertexCount() == 0;
 	}
+
+	default void writeInto(ByteBuffer buffer) {
+		getType().createWriter(buffer).writeVertexList(getReader());
+	}
 }

src/main/java/com/jozufozu/flywheel/core/model/ModelTransformer.java

@@ -1,6 +1,6 @@
 package com.jozufozu.flywheel.core.model;
 
-import com.jozufozu.flywheel.core.vertex.VertexList;
+import com.jozufozu.flywheel.api.vertex.VertexList;
 import com.jozufozu.flywheel.util.RenderMath;
 import com.jozufozu.flywheel.util.transform.Transform;
 import com.mojang.blaze3d.vertex.PoseStack;

src/main/java/com/jozufozu/flywheel/core/model/ModelUtil.java

@@ -55,7 +55,7 @@ public class ModelUtil {
 
 		builder.begin(VertexFormat.Mode.QUADS, DefaultVertexFormat.BLOCK);
 		blockRenderer.tesselateBlock(VirtualEmptyBlockGetter.INSTANCE, model, referenceState, BlockPos.ZERO, ms, builder,
-				true, new Random(), 42, OverlayTexture.NO_OVERLAY, VirtualEmptyModelData.INSTANCE);
+				false, new Random(), 42, OverlayTexture.NO_OVERLAY, VirtualEmptyModelData.INSTANCE);
 		builder.end();
 		return builder;
 	}

src/main/java/com/jozufozu/flywheel/core/model/WorldModel.java

@@ -3,9 +3,8 @@ package com.jozufozu.flywheel.core.model;
 import java.util.Collection;
 
 import com.jozufozu.flywheel.core.Formats;
-import com.jozufozu.flywheel.core.vertex.VertexList;
+import com.jozufozu.flywheel.api.vertex.VertexList;
-import com.jozufozu.flywheel.core.vertex.VertexType;
+import com.jozufozu.flywheel.api.vertex.VertexType;
-import com.jozufozu.flywheel.core.vertex.BlockVertexListUnsafe;
 
 import net.minecraft.client.renderer.RenderType;
 import net.minecraft.world.level.BlockAndTintGetter;
@@ -17,7 +16,7 @@ public class WorldModel implements Model {
 	private final String name;
 
 	public WorldModel(BlockAndTintGetter renderWorld, RenderType layer, Collection<StructureTemplate.StructureBlockInfo> blocks, String name) {
-		reader = new BlockVertexListUnsafe(ModelUtil.getBufferBuilderFromTemplate(renderWorld, layer, blocks));
+		reader = Formats.BLOCK.createReader(ModelUtil.getBufferBuilderFromTemplate(renderWorld, layer, blocks));
 		this.name = name;
 	}
 

src/main/java/com/jozufozu/flywheel/core/vertex/BlockVertex.java

@@ -2,70 +2,49 @@ package com.jozufozu.flywheel.core.vertex;
 
 import java.nio.ByteBuffer;
 
-import org.lwjgl.system.MemoryUtil;
+import com.jozufozu.flywheel.api.vertex.VertexList;
-
+import com.jozufozu.flywheel.api.vertex.VertexType;
-import com.jozufozu.flywheel.backend.gl.attrib.CommonAttributes;
+import com.jozufozu.flywheel.core.layout.CommonItems;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
-import com.jozufozu.flywheel.util.RenderMath;
+import com.mojang.blaze3d.vertex.BufferBuilder;
-
+import com.mojang.blaze3d.vertex.DefaultVertexFormat;
-import net.minecraft.client.renderer.LightTexture;
+import com.mojang.datafixers.util.Pair;
 
 public class BlockVertex implements VertexType {
 
-	public static final VertexFormat FORMAT = VertexFormat.builder()
+	public static final BufferLayout FORMAT = BufferLayout.builder()
-			.addAttributes(CommonAttributes.VEC3,
+			.addItems(CommonItems.VEC3,
-					CommonAttributes.UV,
+					CommonItems.RGBA,
-					CommonAttributes.RGBA,
+					CommonItems.UV,
-					CommonAttributes.LIGHT,
+					CommonItems.LIGHT_SHORT,
-					CommonAttributes.NORMAL)
+					CommonItems.NORMAL,
+					CommonItems.PADDING_BYTE)
 			.build();
 
 	@Override
-	public VertexFormat getFormat() {
+	public BufferLayout getLayout() {
 		return FORMAT;
 	}
 
 	@Override
-	public void copyInto(ByteBuffer buffer, VertexList reader) {
+	public BlockWriterUnsafe createWriter(ByteBuffer buffer) {
-		int stride = getStride();
+		return new BlockWriterUnsafe(this, buffer);
-		long addr = MemoryUtil.memAddress(buffer);
-
-		int vertexCount = reader.getVertexCount();
-		for (int i = 0; i < vertexCount; i++) {
-			float x = reader.getX(i);
-			float y = reader.getY(i);
-			float z = reader.getZ(i);
-
-			float xN = reader.getNX(i);
-			float yN = reader.getNY(i);
-			float zN = reader.getNZ(i);
-
-			float u = reader.getU(i);
-			float v = reader.getV(i);
-
-			byte r = reader.getR(i);
-			byte g = reader.getG(i);
-			byte b = reader.getB(i);
-			byte a = reader.getA(i);
-
-			int light = reader.getLight(i);
-
-			MemoryUtil.memPutFloat(addr, x);
-			MemoryUtil.memPutFloat(addr + 4, y);
-			MemoryUtil.memPutFloat(addr + 8, z);
-			MemoryUtil.memPutFloat(addr + 12, u);
-			MemoryUtil.memPutFloat(addr + 16, v);
-			MemoryUtil.memPutByte(addr + 20, r);
-			MemoryUtil.memPutByte(addr + 21, g);
-			MemoryUtil.memPutByte(addr + 22, b);
-			MemoryUtil.memPutByte(addr + 23, a);
-			MemoryUtil.memPutByte(addr + 24, (byte) (LightTexture.block(light) << 4));
-			MemoryUtil.memPutByte(addr + 25, (byte) (LightTexture.sky(light) << 4));
-			MemoryUtil.memPutByte(addr + 26, RenderMath.nb(xN));
-			MemoryUtil.memPutByte(addr + 27, RenderMath.nb(yN));
-			MemoryUtil.memPutByte(addr + 28, RenderMath.nb(zN));
-
-			addr += stride;
 	}
+
+	@Override
+	public BlockVertexListUnsafe createReader(ByteBuffer buffer, int vertexCount) {
+		return new BlockVertexListUnsafe(buffer, vertexCount);
+	}
+
+	public VertexList createReader(BufferBuilder bufferBuilder) {
+		// TODO: try to avoid virtual model rendering
+		Pair<BufferBuilder.DrawState, ByteBuffer> pair = bufferBuilder.popNextBuffer();
+		BufferBuilder.DrawState drawState = pair.getFirst();
+
+		if (drawState.format() != DefaultVertexFormat.BLOCK) {
+			throw new RuntimeException("Cannot use BufferBuilder with " + drawState.format());
+		}
+
+		return new BlockVertexListUnsafe(pair.getSecond(), drawState.vertexCount());
 	}
 }

src/main/java/com/jozufozu/flywheel/core/vertex/BlockVertexList.java

@@ -2,6 +2,7 @@ package com.jozufozu.flywheel.core.vertex;
 
 import java.nio.ByteBuffer;
 
+import com.jozufozu.flywheel.api.vertex.VertexList;
 import com.jozufozu.flywheel.util.RenderMath;
 import com.mojang.blaze3d.vertex.BufferBuilder;
 import com.mojang.datafixers.util.Pair;

src/main/java/com/jozufozu/flywheel/core/vertex/BlockVertexListUnsafe.java

@@ -4,27 +4,23 @@ import java.nio.ByteBuffer;
 
 import org.lwjgl.system.MemoryUtil;
 
+import com.jozufozu.flywheel.api.vertex.VertexList;
 import com.jozufozu.flywheel.util.RenderMath;
-import com.mojang.blaze3d.vertex.BufferBuilder;
-import com.mojang.blaze3d.vertex.VertexFormat;
-import com.mojang.datafixers.util.Pair;
 
 public class BlockVertexListUnsafe implements VertexList {
 
+	private final ByteBuffer buffer;
 	private final int vertexCount;
-	private final int stride;
 	private final long base;
 
-	public BlockVertexListUnsafe(BufferBuilder builder) {
+	public BlockVertexListUnsafe(ByteBuffer buffer, int vertexCount) {
-		VertexFormat vertexFormat = builder.getVertexFormat();
+		this.buffer = buffer;
-		Pair<BufferBuilder.DrawState, ByteBuffer> data = builder.popNextBuffer();
+		this.base = MemoryUtil.memAddress(buffer);
-		this.base = MemoryUtil.memAddress(data.getSecond());
+		this.vertexCount = vertexCount;
-		this.vertexCount = data.getFirst().vertexCount();
-		this.stride = vertexFormat.getVertexSize();
 	}
 
 	private long ptr(long index) {
-		return base + index * stride;
+		return base + index * 32;
 	}
 
 	@Override

src/main/java/com/jozufozu/flywheel/core/vertex/BlockWriterUnsafe.java

@@ -0,0 +1,57 @@
+package com.jozufozu.flywheel.core.vertex;
+
+import java.nio.ByteBuffer;
+
+import org.lwjgl.system.MemoryUtil;
+
+import com.jozufozu.flywheel.api.vertex.VertexList;
+import com.jozufozu.flywheel.util.RenderMath;
+
+public class BlockWriterUnsafe extends VertexWriterUnsafe<BlockVertex> {
+
+	public BlockWriterUnsafe(BlockVertex type, ByteBuffer buffer) {
+		super(type, buffer);
+	}
+
+	@Override
+	public void writeVertex(VertexList list, int i) {
+		float x = list.getX(i);
+		float y = list.getY(i);
+		float z = list.getZ(i);
+
+		float xN = list.getNX(i);
+		float yN = list.getNY(i);
+		float zN = list.getNZ(i);
+
+		float u = list.getU(i);
+		float v = list.getV(i);
+
+		byte r = list.getR(i);
+		byte g = list.getG(i);
+		byte b = list.getB(i);
+		byte a = list.getA(i);
+
+		int light = list.getLight(i);
+
+		putVertex(x, y, z, u, v, r, g, b, a, light, xN, yN, zN);
+	}
+
+	public void putVertex(float x, float y, float z, float u, float v, byte r, byte g, byte b, byte a, int light, float nX, float nY, float nZ) {
+		MemoryUtil.memPutFloat(ptr, x);
+		MemoryUtil.memPutFloat(ptr + 4, y);
+		MemoryUtil.memPutFloat(ptr + 8, z);
+		MemoryUtil.memPutByte(ptr + 12, r);
+		MemoryUtil.memPutByte(ptr + 13, g);
+		MemoryUtil.memPutByte(ptr + 14, b);
+		MemoryUtil.memPutByte(ptr + 15, a);
+		MemoryUtil.memPutFloat(ptr + 16, u);
+		MemoryUtil.memPutFloat(ptr + 20, v);
+		MemoryUtil.memPutInt(ptr + 24, light);
+		MemoryUtil.memPutByte(ptr + 28, RenderMath.nb(nX));
+		MemoryUtil.memPutByte(ptr + 29, RenderMath.nb(nY));
+		MemoryUtil.memPutByte(ptr + 30, RenderMath.nb(nZ));
+
+		ptr += 32;
+		advance();
+	}
+}

src/main/java/com/jozufozu/flywheel/core/vertex/PosTexNormalVertex.java

@@ -2,38 +2,28 @@ package com.jozufozu.flywheel.core.vertex;
 
 import java.nio.ByteBuffer;
 
-import com.jozufozu.flywheel.backend.gl.attrib.CommonAttributes;
+import com.jozufozu.flywheel.api.vertex.VertexType;
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
+import com.jozufozu.flywheel.core.layout.CommonItems;
+import com.jozufozu.flywheel.core.layout.BufferLayout;
 
 public class PosTexNormalVertex implements VertexType {
 
-	public static final VertexFormat FORMAT = VertexFormat.builder()
+	public static final BufferLayout FORMAT = BufferLayout.builder()
-			.addAttributes(CommonAttributes.VEC3, CommonAttributes.UV, CommonAttributes.NORMAL)
+			.addItems(CommonItems.VEC3, CommonItems.UV, CommonItems.NORMAL)
 			.build();
 
 	@Override
-	public VertexFormat getFormat() {
+	public BufferLayout getLayout() {
 		return FORMAT;
 	}
 
 	@Override
-	public void copyInto(ByteBuffer buffer, VertexList reader) {
+	public PosTexNormalWriterUnsafe createWriter(ByteBuffer buffer) {
-		PosTexNormalWriter writer = new PosTexNormalWriter(buffer);
+		return new PosTexNormalWriterUnsafe(this, buffer);
-
-		int vertexCount = reader.getVertexCount();
-		for (int i = 0; i < vertexCount; i++) {
-			float x = reader.getX(i);
-			float y = reader.getY(i);
-			float z = reader.getZ(i);
-
-			float u = reader.getU(i);
-			float v = reader.getV(i);
-
-			float xN = reader.getNX(i);
-			float yN = reader.getNY(i);
-			float zN = reader.getNZ(i);
-
-			writer.putVertex(x, y, z, xN, yN, zN, u, v);
 	}
+
+	@Override
+	public PosTexNormalVertexListUnsafe createReader(ByteBuffer buffer, int vertexCount) {
+		return new PosTexNormalVertexListUnsafe(buffer, vertexCount);
 	}
 }

src/main/java/com/jozufozu/flywheel/core/vertex/PosTexNormalVertexListUnsafe.java

@@ -4,6 +4,7 @@ import java.nio.ByteBuffer;
 
 import org.lwjgl.system.MemoryUtil;
 
+import com.jozufozu.flywheel.api.vertex.VertexList;
 import com.jozufozu.flywheel.util.RenderMath;
 
 public class PosTexNormalVertexListUnsafe implements VertexList {

src/main/java/com/jozufozu/flywheel/core/vertex/PosTexNormalWriter.java

@@ -1,42 +0,0 @@
-package com.jozufozu.flywheel.core.vertex;
-
-import java.nio.ByteBuffer;
-
-import org.lwjgl.system.MemoryUtil;
-
-import com.jozufozu.flywheel.util.RenderMath;
-
-public class PosTexNormalWriter {
-
-	private final ByteBuffer buffer;
-	private long addr;
-
-	private int vertexCount;
-
-	public PosTexNormalWriter(ByteBuffer buffer) {
-		this.buffer = buffer;
-		addr = MemoryUtil.memAddress(buffer);
-	}
-
-	public void putVertex(float x, float y, float z, float nX, float nY, float nZ, float u, float v) {
-		MemoryUtil.memPutFloat(addr, x);
-		MemoryUtil.memPutFloat(addr + 4, y);
-		MemoryUtil.memPutFloat(addr + 8, z);
-		MemoryUtil.memPutFloat(addr + 12, u);
-		MemoryUtil.memPutFloat(addr + 16, v);
-		MemoryUtil.memPutByte(addr + 20, RenderMath.nb(nX));
-		MemoryUtil.memPutByte(addr + 21, RenderMath.nb(nY));
-		MemoryUtil.memPutByte(addr + 22, RenderMath.nb(nZ));
-
-		addr += 23;
-		vertexCount++;
-	}
-
-	public int getVertexCount() {
-		return vertexCount;
-	}
-
-	public PosTexNormalVertexListUnsafe intoReader() {
-		return new PosTexNormalVertexListUnsafe(buffer, vertexCount);
-	}
-}

src/main/java/com/jozufozu/flywheel/core/vertex/PosTexNormalWriterUnsafe.java

@@ -0,0 +1,45 @@
+package com.jozufozu.flywheel.core.vertex;
+
+import java.nio.ByteBuffer;
+
+import org.lwjgl.system.MemoryUtil;
+
+import com.jozufozu.flywheel.api.vertex.VertexList;
+import com.jozufozu.flywheel.util.RenderMath;
+
+public class PosTexNormalWriterUnsafe extends VertexWriterUnsafe<PosTexNormalVertex> {
+
+	public PosTexNormalWriterUnsafe(PosTexNormalVertex type, ByteBuffer buffer) {
+		super(type, buffer);
+	}
+
+	@Override
+	public void writeVertex(VertexList list, int i) {
+		float x = list.getX(i);
+		float y = list.getY(i);
+		float z = list.getZ(i);
+
+		float u = list.getU(i);
+		float v = list.getV(i);
+
+		float xN = list.getNX(i);
+		float yN = list.getNY(i);
+		float zN = list.getNZ(i);
+
+		putVertex(x, y, z, xN, yN, zN, u, v);
+	}
+
+	public void putVertex(float x, float y, float z, float nX, float nY, float nZ, float u, float v) {
+		MemoryUtil.memPutFloat(ptr, x);
+		MemoryUtil.memPutFloat(ptr + 4, y);
+		MemoryUtil.memPutFloat(ptr + 8, z);
+		MemoryUtil.memPutFloat(ptr + 12, u);
+		MemoryUtil.memPutFloat(ptr + 16, v);
+		MemoryUtil.memPutByte(ptr + 20, RenderMath.nb(nX));
+		MemoryUtil.memPutByte(ptr + 21, RenderMath.nb(nY));
+		MemoryUtil.memPutByte(ptr + 22, RenderMath.nb(nZ));
+
+		ptr += 23;
+		advance();
+	}
+}

src/main/java/com/jozufozu/flywheel/core/vertex/VertexType.java

@@ -1,16 +0,0 @@
-package com.jozufozu.flywheel.core.vertex;
-
-import java.nio.ByteBuffer;
-
-import com.jozufozu.flywheel.backend.gl.attrib.VertexFormat;
-
-public interface VertexType {
-
-	VertexFormat getFormat();
-
-    void copyInto(ByteBuffer buffer, VertexList reader);
-
-	default int getStride() {
-		return getFormat().getStride();
-	}
-}

src/main/java/com/jozufozu/flywheel/core/vertex/VertexWriterUnsafe.java

@@ -0,0 +1,41 @@
+package com.jozufozu.flywheel.core.vertex;
+
+import java.nio.ByteBuffer;
+
+import org.lwjgl.system.MemoryUtil;
+
+import com.jozufozu.flywheel.api.vertex.VertexList;
+import com.jozufozu.flywheel.api.vertex.VertexType;
+import com.jozufozu.flywheel.api.vertex.VertexWriter;
+
+public abstract class VertexWriterUnsafe<V extends VertexType> implements VertexWriter {
+
+	public final V type;
+	protected final ByteBuffer buffer;
+	private int totalVertices;
+	private int writeVertex;
+	protected long ptr;
+
+	protected VertexWriterUnsafe(V type, ByteBuffer buffer) {
+		this.type = type;
+		this.buffer = buffer;
+		this.ptr = MemoryUtil.memAddress(buffer);
+	}
+
+	protected void advance() {
+		writeVertex++;
+		if (writeVertex > totalVertices) totalVertices = writeVertex;
+	}
+
+	@Override
+	public void seekToVertex(int vertex) {
+		buffer.position(type.byteOffset(vertex));
+		writeVertex = vertex;
+		ptr = MemoryUtil.memAddress(buffer);
+	}
+
+	@Override
+	public VertexList intoReader() {
+		return type.createReader(buffer, totalVertices);
+	}
+}

src/main/java/com/jozufozu/flywheel/core/vertex/package-info.java

@@ -0,0 +1,6 @@
+@ParametersAreNonnullByDefault @MethodsReturnNonnullByDefault
+package com.jozufozu.flywheel.core.vertex;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+
+import net.minecraft.MethodsReturnNonnullByDefault;