Buffing the old works

- GlBuffer no longer has an explicit bind method or binding target
- Use READ/WRITE BUFFER for all data operations
- Make MappedBuffer simpler and more RAII
- Remove dead methods from GlBuffer
- Don't actually need to clear the tail of GPUInstancers on shrink
- Implement actual capability check for indirect
  (I think I check all the extensions)

src/main/java/com/jozufozu/flywheel/backend/engine/UniformBuffer.java

@@ -9,7 +9,6 @@ import com.google.common.collect.ImmutableList;
 import com.jozufozu.flywheel.api.event.ReloadRenderersEvent;
 import com.jozufozu.flywheel.api.uniform.ShaderUniforms;
 import com.jozufozu.flywheel.gl.buffer.GlBuffer;
-import com.jozufozu.flywheel.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.gl.shader.GlProgram;
 import com.jozufozu.flywheel.lib.math.MoreMath;
 import com.jozufozu.flywheel.lib.math.RenderMath;
@@ -35,7 +34,7 @@ public class UniformBuffer {
 	private final GlBuffer buffer;
 
 	private UniformBuffer() {
-		buffer = new GlBuffer(GlBufferType.UNIFORM_BUFFER);
+		buffer = new GlBuffer();
 		providerSet = new ProviderSet(ShaderUniforms.REGISTRY.getAll());
 	}
 

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

@@ -11,7 +11,6 @@ import com.jozufozu.flywheel.api.layout.BufferLayout;
 import com.jozufozu.flywheel.backend.engine.AbstractInstancer;
 import com.jozufozu.flywheel.gl.array.GlVertexArray;
 import com.jozufozu.flywheel.gl.buffer.GlBuffer;
-import com.jozufozu.flywheel.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.gl.buffer.GlBufferUsage;
 import com.jozufozu.flywheel.gl.buffer.MappedBuffer;
 
@@ -41,7 +40,7 @@ public class GPUInstancer<I extends Instance> extends AbstractInstancer<I> {
 			return;
 		}
 
-		vbo = new GlBuffer(GlBufferType.ARRAY_BUFFER, GlBufferUsage.DYNAMIC_DRAW);
+		vbo = new GlBuffer(GlBufferUsage.DYNAMIC_DRAW);
 		vbo.setGrowthMargin(instanceStride * 16);
 	}
 
@@ -65,16 +64,11 @@ public class GPUInstancer<I extends Instance> extends AbstractInstancer<I> {
 			return;
 		}
 
-		int count = instances.size();
-		long clearStart = instanceStride * (long) count;
-		long clearLength = vbo.getSize() - clearStart;
-
 		try (MappedBuffer buf = vbo.map()) {
-			buf.clear(clearStart, clearLength);
-
-			long ptr = buf.getPtr();
+			long ptr = buf.ptr();
 			InstanceWriter<I> writer = type.getWriter();
 
+			int count = instances.size();
 			for (int i = changed.nextSetBit(0); i >= 0 && i < count; i = changed.nextSetBit(i + 1)) {
 				writer.write(ptr + instanceStride * i, instances.get(i));
 			}

src/main/java/com/jozufozu/flywheel/backend/engine/instancing/InstancedMeshPool.java

@@ -17,7 +17,6 @@ import com.jozufozu.flywheel.gl.GlPrimitive;
 import com.jozufozu.flywheel.gl.array.GlVertexArray;
 import com.jozufozu.flywheel.gl.buffer.ElementBuffer;
 import com.jozufozu.flywheel.gl.buffer.GlBuffer;
-import com.jozufozu.flywheel.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.gl.buffer.MappedBuffer;
 
 public class InstancedMeshPool {
@@ -39,7 +38,7 @@ public class InstancedMeshPool {
 	public InstancedMeshPool(VertexType vertexType) {
 		this.vertexType = vertexType;
 		int stride = vertexType.getLayout().getStride();
-		vbo = new GlBuffer(GlBufferType.ARRAY_BUFFER);
+		vbo = new GlBuffer();
 		vbo.setGrowthMargin(stride * 32);
 	}
 
@@ -75,20 +74,20 @@ public class InstancedMeshPool {
 	}
 
 	public void flush() {
-		if (dirty) {
-			if (anyToRemove) {
-				processDeletions();
-			}
-
-			if (realloc()) {
-				uploadAll();
-			} else {
-				uploadPending();
-			}
-
-			dirty = false;
-			pendingUpload.clear();
+		if (!dirty) {
+			return;
 		}
+
+		if (anyToRemove) {
+			processDeletions();
+		}
+
+		vbo.ensureCapacity(byteSize);
+
+		uploadPending();
+
+		dirty = false;
+		pendingUpload.clear();
 	}
 
 	private void processDeletions() {
@@ -117,35 +116,9 @@ public class InstancedMeshPool {
 		this.anyToRemove = false;
 	}
 
-	/**
-	 * Assumes vbo is bound.
-	 *
-	 * @return true if the buffer was reallocated
-	 */
-	private boolean realloc() {
-		return vbo.ensureCapacity(byteSize);
-	}
-
-	private void uploadAll() {
-		try (MappedBuffer mapped = vbo.map()) {
-			long ptr = mapped.getPtr();
-
-			int byteIndex = 0;
-			for (BufferedMesh mesh : allBuffered) {
-				mesh.byteIndex = byteIndex;
-
-				mesh.buffer(ptr);
-
-				byteIndex += mesh.size();
-			}
-		} catch (Exception e) {
-			Flywheel.LOGGER.error("Error uploading pooled meshes:", e);
-		}
-	}
-
 	private void uploadPending() {
 		try (MappedBuffer mapped = vbo.map()) {
-			long ptr = mapped.getPtr();
+			long ptr = mapped.ptr();
 
 			for (BufferedMesh mesh : pendingUpload) {
 				mesh.buffer(ptr);

src/main/java/com/jozufozu/flywheel/gl/buffer/GlBuffer.java

@@ -4,21 +4,13 @@ import static org.lwjgl.opengl.GL15.glBufferData;
 import static org.lwjgl.opengl.GL15.glDeleteBuffers;
 import static org.lwjgl.opengl.GL15.glGenBuffers;
 import static org.lwjgl.opengl.GL15.nglBufferData;
-import static org.lwjgl.opengl.GL30.GL_MAP_WRITE_BIT;
-import static org.lwjgl.opengl.GL30.nglMapBufferRange;
 import static org.lwjgl.opengl.GL31.glCopyBufferSubData;
 
-import org.lwjgl.system.MemoryUtil;
-
 import com.jozufozu.flywheel.gl.GlObject;
-import com.jozufozu.flywheel.gl.error.GlError;
-import com.jozufozu.flywheel.gl.error.GlException;
 import com.jozufozu.flywheel.lib.memory.FlwMemoryTracker;
 import com.jozufozu.flywheel.lib.memory.MemoryBlock;
 
 public class GlBuffer extends GlObject {
-
-	public final GlBufferType type;
 	protected final GlBufferUsage usage;
 	/**
 	 * The size (in bytes) of the buffer on the GPU.
@@ -29,16 +21,18 @@ public class GlBuffer extends GlObject {
 	 */
 	protected int growthMargin;
 
-	public GlBuffer(GlBufferType type) {
-		this(type, GlBufferUsage.STATIC_DRAW);
+	public GlBuffer() {
+		this(GlBufferUsage.STATIC_DRAW);
 	}
 
-	public GlBuffer(GlBufferType type, GlBufferUsage usage) {
+	public GlBuffer(GlBufferUsage usage) {
 		setHandle(glGenBuffers());
-		this.type = type;
 		this.usage = usage;
 	}
 
+	/**
+	 * @return true if the buffer was recreated.
+	 */
 	public boolean ensureCapacity(long size) {
 		if (size < 0) {
 			throw new IllegalArgumentException("Size " + size + " < 0");
@@ -50,8 +44,8 @@ public class GlBuffer extends GlObject {
 
 		if (this.size == 0) {
 			this.size = size;
-			bind();
-			glBufferData(type.glEnum, size, usage.glEnum);
+			GlBufferType.COPY_WRITE_BUFFER.bind(handle());
+			glBufferData(GlBufferType.COPY_WRITE_BUFFER.glEnum, size, usage.glEnum);
 			FlwMemoryTracker._allocGPUMemory(size);
 
 			return true;
@@ -76,36 +70,25 @@ public class GlBuffer extends GlObject {
 		var newHandle = glGenBuffers();
 
 		GlBufferType.COPY_READ_BUFFER.bind(oldHandle);
-		type.bind(newHandle);
+		GlBufferType.COPY_WRITE_BUFFER.bind(newHandle);
 
-		glBufferData(type.glEnum, newSize, usage.glEnum);
-		glCopyBufferSubData(GlBufferType.COPY_READ_BUFFER.glEnum, type.glEnum, 0, 0, oldSize);
+		glBufferData(GlBufferType.COPY_WRITE_BUFFER.glEnum, newSize, usage.glEnum);
+		glCopyBufferSubData(GlBufferType.COPY_READ_BUFFER.glEnum, GlBufferType.COPY_WRITE_BUFFER.glEnum, 0, 0, oldSize);
 
 		glDeleteBuffers(oldHandle);
 		setHandle(newHandle);
 	}
 
 	public void upload(MemoryBlock directBuffer) {
-		bind();
 		FlwMemoryTracker._freeGPUMemory(size);
-		nglBufferData(type.glEnum, directBuffer.size(), directBuffer.ptr(), usage.glEnum);
+		GlBufferType.COPY_WRITE_BUFFER.bind(handle());
+		nglBufferData(GlBufferType.COPY_WRITE_BUFFER.glEnum, directBuffer.size(), directBuffer.ptr(), usage.glEnum);
 		this.size = directBuffer.size();
 		FlwMemoryTracker._allocGPUMemory(size);
 	}
 
 	public MappedBuffer map() {
-		bind();
-		long ptr = nglMapBufferRange(type.glEnum, 0, size, GL_MAP_WRITE_BIT);
-
-		if (ptr == MemoryUtil.NULL) {
-			throw new GlException(GlError.poll(), "Could not map buffer");
-		}
-
-		return new MappedBuffer(this, ptr, 0, size);
-	}
-
-	public boolean isPersistent() {
-		return false;
+		return new MappedBuffer(handle(), size);
 	}
 
 	public void setGrowthMargin(int growthMargin) {
@@ -116,18 +99,6 @@ public class GlBuffer extends GlObject {
 		return size;
 	}
 
-	public GlBufferType getType() {
-		return type;
-	}
-
-	public void bind() {
-		type.bind(handle());
-	}
-
-	public void unbind() {
-		type.unbind();
-	}
-
 	protected void deleteInternal(int handle) {
 		glDeleteBuffers(handle);
 		FlwMemoryTracker._freeGPUMemory(size);

src/main/java/com/jozufozu/flywheel/gl/buffer/MappedBuffer.java

@@ -1,59 +1,42 @@
 package com.jozufozu.flywheel.gl.buffer;
 
+import static org.lwjgl.opengl.GL30.GL_MAP_WRITE_BIT;
+import static org.lwjgl.opengl.GL30.nglMapBufferRange;
 import static org.lwjgl.system.MemoryUtil.NULL;
 
 import org.lwjgl.opengl.GL15;
 import org.lwjgl.system.MemoryUtil;
 
-public class MappedBuffer implements AutoCloseable {
+import com.jozufozu.flywheel.gl.error.GlError;
+import com.jozufozu.flywheel.gl.error.GlException;
 
-	private final long offset;
-	private final long length;
-	private final GlBuffer owner;
-	private final boolean persistent;
+public class MappedBuffer implements AutoCloseable {
+	private final int glBuffer;
 	private long ptr;
 
-	public MappedBuffer(GlBuffer owner, long ptr, long offset, long length) {
-		this.ptr = ptr;
-		this.owner = owner;
-		this.offset = offset;
-		this.length = length;
-		persistent = owner.isPersistent();
+	public MappedBuffer(int glBuffer, long size) {
+		this.glBuffer = glBuffer;
+
+		GlBufferType.COPY_READ_BUFFER.bind(glBuffer);
+		ptr = nglMapBufferRange(GlBufferType.COPY_READ_BUFFER.glEnum, 0, size, GL_MAP_WRITE_BIT);
+
+		if (ptr == MemoryUtil.NULL) {
+			throw new GlException(GlError.poll(), "Could not map buffer");
+		}
 	}
 
-	/**
-	 * Make the changes in client memory available to the GPU.
-	 */
-	public void flush() {
-		if (persistent) return;
-
-		if (ptr == NULL) return;
-
-		owner.bind();
-		GL15.glUnmapBuffer(owner.getType().glEnum);
-		ptr = NULL;
+	public long ptr() {
+		return ptr;
 	}
 
 	@Override
 	public void close() {
-		flush();
-	}
-
-	public long getPtr() {
-		return ptr;
-	}
-
-	public void clear(long clearStart, long clearLength) {
-		if (clearLength <= 0) {
+		if (ptr == NULL) {
 			return;
 		}
 
-		if (clearStart < offset || clearStart + clearLength > offset + length) {
-			throw new IndexOutOfBoundsException("Clear range [" + clearStart + "," + (clearStart + clearLength) + "] is not mapped");
-		}
-
-		long addr = ptr + clearStart;
-
-		MemoryUtil.memSet(addr, 0, clearLength);
+		GlBufferType.COPY_READ_BUFFER.bind(glBuffer);
+		GL15.glUnmapBuffer(GlBufferType.COPY_READ_BUFFER.glEnum);
+		ptr = NULL;
 	}
 }

src/main/java/com/jozufozu/flywheel/gl/versioned/GlCompat.java

@@ -1,7 +1,7 @@
 package com.jozufozu.flywheel.gl.versioned;
 
 import java.nio.ByteBuffer;
-import java.util.Arrays;
+import java.util.Optional;
 
 import org.lwjgl.PointerBuffer;
 import org.lwjgl.opengl.GL;
@@ -18,17 +18,18 @@ import net.minecraft.Util;
  * system.
  */
 public class GlCompat {
+	private static final GLCapabilities caps;
 	public static final VertexArray vertexArray;
 	public static final BufferStorage bufferStorage;
 	public static final boolean amd;
 	public static final boolean supportsIndirect;
 
 	static {
-		GLCapabilities caps = GL.createCapabilities();
-		bufferStorage = getLatest(BufferStorage.class, caps);
-		vertexArray = getLatest(VertexArray.class, caps);
-		supportsIndirect = caps.OpenGL46;
-		amd = _isAmdWindows();
+		caps = GL.createCapabilities();
+		bufferStorage = getLatest(BufferStorage.class);
+		vertexArray = getLatest(VertexArray.class);
+		supportsIndirect = _decideIfWeSupportIndirect();
+		amd = _decideIfWeAreAMDWindows();
 	}
 
 	private GlCompat() {
@@ -46,29 +47,30 @@ public class GlCompat {
 		return supportsIndirect;
 	}
 
-	public static boolean bufferStorageSupported() {
-		return bufferStorage != BufferStorage.UNSUPPORTED;
+	private static boolean _decideIfWeSupportIndirect() {
+		return caps.OpenGL46 || (
+				caps.GL_ARB_compute_shader &&
+				caps.GL_ARB_shader_draw_parameters &&
+				caps.GL_ARB_base_instance &&
+				caps.GL_ARB_multi_draw_indirect &&
+				caps.GL_ARB_direct_state_access);
 	}
 
 	/**
 	 * Get the most compatible version of a specific OpenGL feature by iterating over enum constants in order.
 	 *
-	 * @param clazz The class of the versioning enum.
-	 * @param caps  The current system's supported features.
 	 * @param <V>   The type of the versioning enum.
+	 * @param clazz The class of the versioning enum.
 	 * @return The first defined enum variant to return true.
 	 */
-	private static <V extends Enum<V> & GlVersioned> V getLatest(Class<V> clazz, GLCapabilities caps) {
-		V[] constants = clazz.getEnumConstants();
-		V last = constants[constants.length - 1];
-		if (!last.supported(caps)) {
-			throw new IllegalStateException("");
+	private static <V extends Enum<V> & GlVersioned> V getLatest(Class<V> clazz) {
+		for (V it : clazz.getEnumConstants()) {
+			if (it.supported(GlCompat.caps)) {
+				return Optional.of(it)
+						.get();
+			}
 		}
-
-		return Arrays.stream(constants)
-				.filter(it -> it.supported(caps))
-				.findFirst()
-				.get();
+		throw new IllegalStateException("Invalid versioned enum, must provide at least one supported constant");
 	}
 
 	/**
@@ -92,7 +94,7 @@ public class GlCompat {
 		}
 	}
 
-	private static boolean _isAmdWindows() {
+	private static boolean _decideIfWeAreAMDWindows() {
 		if (Util.getPlatform() != Util.OS.WINDOWS) {
 			return false;
 		}

src/main/java/com/jozufozu/flywheel/lib/util/FullscreenQuad.java

@@ -10,7 +10,6 @@ import com.jozufozu.flywheel.api.layout.BufferLayout;
 import com.jozufozu.flywheel.gl.GlStateTracker;
 import com.jozufozu.flywheel.gl.array.GlVertexArray;
 import com.jozufozu.flywheel.gl.buffer.GlBuffer;
-import com.jozufozu.flywheel.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.gl.buffer.MappedBuffer;
 import com.jozufozu.flywheel.lib.layout.CommonItems;
 import com.jozufozu.flywheel.util.Lazy;
@@ -35,10 +34,10 @@ public class FullscreenQuad {
 
 	private FullscreenQuad() {
 		try (var restoreState = GlStateTracker.getRestoreState()) {
-			vbo = new GlBuffer(GlBufferType.ARRAY_BUFFER);
+			vbo = new GlBuffer();
 			vbo.ensureCapacity(bufferSize);
 			try (MappedBuffer buffer = vbo.map()) {
-				var ptr = buffer.getPtr();
+				var ptr = buffer.ptr();
 
 				for (var i = 0; i < vertices.length; i++) {
 					MemoryUtil.memPutFloat(ptr + i * Float.BYTES, vertices[i]);