Fix some issues with Uint32 representation

This increases the maximum size of vertex and index buffers
to 4 billion elements, since the Uint32 types stored in memory are
now safely represented with Int64.

For vertex buffers, this increases their maximum size to 80 GiB,
and index buffers have a maximum size of 16 GiB, whereas both
were limited to 2 GiB prior.

common/src/main/java/net/caffeinemc/mods/sodium/client/gl/arena/GlBufferArena.java

@@ -26,8 +26,8 @@ public class GlBufferArena {
 
     private GlBufferSegment head;
 
-    private int capacity;
-    private int used;
+    private long capacity;
+    private long used;
 
     private final int stride;
 
@@ -46,14 +46,14 @@ public GlBufferArena(CommandList commands, int initialCapacity, int stride, Stag
         this.stagingBuffer = stagingBuffer;
     }
 
-    private void resize(CommandList commandList, int newCapacity) {
+    private void resize(CommandList commandList, long newCapacity) {
         if (this.used > newCapacity) {
             throw new UnsupportedOperationException("New capacity must be larger than used size");
         }
 
         this.checkAssertions();
 
-        int tail = newCapacity - this.used;
+        long tail = newCapacity - this.used;
 
         List<GlBufferSegment> usedSegments = this.getUsedSegments();
         List<PendingBufferCopyCommand> pendingCopies = this.buildTransferList(usedSegments, tail);
@@ -66,31 +66,31 @@ private void resize(CommandList commandList, int newCapacity) {
         if (usedSegments.isEmpty()) {
             this.head.setNext(null);
         } else {
-            this.head.setNext(usedSegments.get(0));
+            this.head.setNext(usedSegments.getFirst());
             this.head.getNext()
                     .setPrev(this.head);
         }
 
         this.checkAssertions();
     }
 
-    private List<PendingBufferCopyCommand> buildTransferList(List<GlBufferSegment> usedSegments, int base) {
+    private List<PendingBufferCopyCommand> buildTransferList(List<GlBufferSegment> usedSegments, long base) {
         List<PendingBufferCopyCommand> pendingCopies = new ArrayList<>();
         PendingBufferCopyCommand currentCopyCommand = null;
 
-        int writeOffset = base;
+        long writeOffset = base;
 
         for (int i = 0; i < usedSegments.size(); i++) {
             GlBufferSegment s = usedSegments.get(i);
 
-            if (currentCopyCommand == null || currentCopyCommand.readOffset + currentCopyCommand.length != s.getOffset()) {
+            if (currentCopyCommand == null || currentCopyCommand.getReadOffset() + currentCopyCommand.getLength() != s.getOffset()) {
                 if (currentCopyCommand != null) {
                     pendingCopies.add(currentCopyCommand);
                 }
 
                 currentCopyCommand = new PendingBufferCopyCommand(s.getOffset(), writeOffset, s.getLength());
             } else {
-                currentCopyCommand.length += s.getLength();
+                currentCopyCommand.setLength(currentCopyCommand.getLength() + s.getLength());
             }
 
             s.setOffset(writeOffset);
@@ -117,17 +117,21 @@ private List<PendingBufferCopyCommand> buildTransferList(List<GlBufferSegment> u
         return pendingCopies;
     }
 
-    private void transferSegments(CommandList commandList, Collection<PendingBufferCopyCommand> list, int capacity) {
+    private void transferSegments(CommandList commandList, Collection<PendingBufferCopyCommand> list, long capacity) {
+        if (capacity >= (1L << 32)) {
+            throw new IllegalArgumentException("Maximum arena buffer size is 4 GiB");
+        }
+
         GlMutableBuffer srcBufferObj = this.arenaBuffer;
         GlMutableBuffer dstBufferObj = commandList.createMutableBuffer();
 
         commandList.allocateStorage(dstBufferObj, capacity * this.stride, BUFFER_USAGE);
 
         for (PendingBufferCopyCommand cmd : list) {
             commandList.copyBufferSubData(srcBufferObj, dstBufferObj,
-                    cmd.readOffset * this.stride,
-                    cmd.writeOffset * this.stride,
-                    cmd.length * this.stride);
+                    cmd.getReadOffset() * this.stride,
+                    cmd.getWriteOffset() * this.stride,
+                    cmd.getLength() * this.stride);
         }
 
         commandList.deleteBuffer(srcBufferObj);
@@ -153,11 +157,11 @@ private ArrayList<GlBufferSegment> getUsedSegments() {
         return used;
     }
 
-    public int getDeviceUsedMemory() {
+    public long getDeviceUsedMemory() {
         return this.used * this.stride;
     }
 
-    public int getDeviceAllocatedMemory() {
+    public long getDeviceAllocatedMemory() {
         return this.capacity * this.stride;
     }
 
@@ -313,11 +317,11 @@ private boolean tryUpload(CommandList commandList, PendingUpload upload) {
         return true;
     }
 
-    public void ensureCapacity(CommandList commandList, int elementCount) {
+    public void ensureCapacity(CommandList commandList, long elementCount) {
         // Re-sizing the arena results in a compaction, so any free space in the arena will be
         // made into one contiguous segment, joined with the new segment of free space we're asking for
         // We calculate the number of free elements in our arena and then subtract that from the total requested
-        int elementsNeeded = elementCount - (this.capacity - this.used);
+        long elementsNeeded = elementCount - (this.capacity - this.used);
 
         // Try to allocate some extra buffer space unless this is an unusually large allocation
         this.resize(commandList, Math.max(this.capacity + this.resizeIncrement, this.capacity + elementsNeeded));
@@ -331,7 +335,7 @@ private void checkAssertions() {
 
     private void checkAssertions0() {
         GlBufferSegment seg = this.head;
-        int used = 0;
+        long used = 0;
 
         while (seg != null) {
             if (seg.getOffset() < 0) {

common/src/main/java/net/caffeinemc/mods/sodium/client/gl/arena/GlBufferSegment.java

@@ -1,52 +1,45 @@
 package net.caffeinemc.mods.sodium.client.gl.arena;
 
+import net.caffeinemc.mods.sodium.client.util.UInt32;
+
 public class GlBufferSegment {
     private final GlBufferArena arena;
 
     private boolean free = false;
 
-    private int offset;
-    private int length;
+    private int offset; /* Uint32 */
+    private int length; /* Uint32 */
 
     private GlBufferSegment next;
     private GlBufferSegment prev;
 
-    public GlBufferSegment(GlBufferArena arena, int offset, int length) {
+    public GlBufferSegment(GlBufferArena arena, long offset, long length) {
         this.arena = arena;
-        this.offset = offset;
-        this.length = length;
+        this.offset = UInt32.downcast(offset);
+        this.length = UInt32.downcast(length);
     }
 
-    public void delete() {
-        this.arena.free(this);
+    /* Uint32 */
+    protected long getEnd() {
+        return this.getOffset() + this.getLength();
     }
 
-    protected int getEnd() {
-        return this.offset + this.length;
+    /* Uint32 */
+    public long getOffset() {
+        return UInt32.upcast(this.offset);
     }
 
-    public int getLength() {
-        return this.length;
+    /* Uint32 */
+    public long getLength() {
+        return UInt32.upcast(this.length);
     }
 
-    protected void setLength(int len) {
-        if (len <= 0) {
-            throw new IllegalArgumentException("len <= 0");
-        }
-
-        this.length = len;
+    protected void setOffset(long offset /* Uint32 */) {
+        this.offset = UInt32.downcast(offset);
     }
 
-    public int getOffset() {
-        return this.offset;
-    }
-
-    protected void setOffset(int offset) {
-        if (offset < 0) {
-            throw new IllegalArgumentException("start < 0");
-        }
-
-        this.offset = offset;
+    protected void setLength(long length /* Uint32 */) {
+        this.length = UInt32.downcast(length);
     }
 
     protected void setFree(boolean free) {
@@ -73,6 +66,10 @@ protected void setPrev(GlBufferSegment prev) {
         this.prev = prev;
     }
 
+    public void delete() {
+        this.arena.free(this);
+    }
+
     protected void mergeInto(GlBufferSegment entry) {
         this.setLength(this.getLength() + entry.getLength());
         this.setNext(entry.getNext());

common/src/main/java/net/caffeinemc/mods/sodium/client/gl/arena/PendingBufferCopyCommand.java

@@ -1,14 +1,35 @@
 package net.caffeinemc.mods.sodium.client.gl.arena;
 
+import net.caffeinemc.mods.sodium.client.util.UInt32;
+
 class PendingBufferCopyCommand {
-    public final int readOffset;
-    public final int writeOffset;
+    private final int readOffset; /* Uint32 */
+    private final int writeOffset; /* Uint32 */
+
+    private int length;
 
-    public int length;
+    PendingBufferCopyCommand(long readOffset, long writeOffset, long length) {
+        this.readOffset = UInt32.downcast(readOffset);
+        this.writeOffset = UInt32.downcast(writeOffset);
+        this.length = UInt32.downcast(length);
+    }
+
+    /* Uint32 */
+    public long getReadOffset() {
+        return UInt32.upcast(this.readOffset);
+    }
+
+    /* Uint32 */
+    public long getWriteOffset() {
+        return UInt32.upcast(this.writeOffset);
+    }
+
+    /* Uint32 */
+    public long getLength() {
+        return UInt32.upcast(this.length);
+    }
 
-    PendingBufferCopyCommand(int readOffset, int writeOffset, int length) {
-        this.readOffset = readOffset;
-        this.writeOffset = writeOffset;
-        this.length = length;
+    public void setLength(long length /* Uint32 */) {
+        this.length = UInt32.downcast(length);
     }
 }

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/DefaultChunkRenderer.java

@@ -23,6 +23,7 @@
 import net.caffeinemc.mods.sodium.client.render.chunk.vertex.format.ChunkVertexType;
 import net.caffeinemc.mods.sodium.client.render.viewport.CameraTransform;
 import net.caffeinemc.mods.sodium.client.util.BitwiseMath;
+import net.caffeinemc.mods.sodium.client.util.UInt32;
 import org.lwjgl.system.MemoryUtil;
 
 import java.util.Iterator;
@@ -148,26 +149,11 @@ private static void fillCommandBuffer(MultiDrawBatch batch,
                 continue;
             }
 
-            addDrawCommands(batch, pMeshData, slices);
-        }
-    }
-
-    /**
-     * Add the draw command into the multi draw batch of the current region for one
-     * section. The section's mesh data is given as a pointer into the render data
-     * storage's allocated memory. It goes through each direction and writes the
-     * offsets and lengths of the already uploaded vertex and index data. The multi
-     * draw batch provides pointers to arrays where each of the section's data is
-     * stored. The batch's size counts how many commands it contains.
-     */
-    private static void addDrawCommands(MultiDrawBatch batch, long pMeshData, int mask) {
-        int elementOffset = SectionRenderDataUnsafe.getBaseElement(pMeshData);
-
-        // If high bit is set, the indices should be sourced from the arena's index buffer
-        if ((elementOffset & SectionRenderDataUnsafe.BASE_ELEMENT_MSB) != 0) {
-            addIndexedDrawCommands(batch, pMeshData, mask);
-        } else {
-            addNonIndexedDrawCommands(batch, pMeshData, mask);
+            if (pass.isTranslucent()) {
+                addIndexedDrawCommands(batch, pMeshData, slices);
+            } else {
+                addNonIndexedDrawCommands(batch, pMeshData, slices);
+            }
         }
     }
 
@@ -183,8 +169,9 @@ private static void addNonIndexedDrawCommands(MultiDrawBatch batch, long pMeshDa
         int size = batch.size;
 
         for (int facing = 0; facing < ModelQuadFacing.COUNT; facing++) {
-            MemoryUtil.memPutInt(pBaseVertex + (size << 2), SectionRenderDataUnsafe.getVertexOffset(pMeshData, facing));
-            MemoryUtil.memPutInt(pElementCount + (size << 2), SectionRenderDataUnsafe.getElementCount(pMeshData, facing));
+            // Uint32 -> Int32 cast is always safe and should be optimized away
+            MemoryUtil.memPutInt(pBaseVertex + (size << 2), (int) SectionRenderDataUnsafe.getVertexOffset(pMeshData, facing));
+            MemoryUtil.memPutInt(pElementCount + (size << 2), (int) SectionRenderDataUnsafe.getElementCount(pMeshData, facing));
             MemoryUtil.memPutAddress(pElementPointer + (size << 3), 0 /* using a shared index buffer */);
 
             size += (mask >> facing) & 1;
@@ -205,16 +192,17 @@ private static void addIndexedDrawCommands(MultiDrawBatch batch, long pMeshData,
 
         int size = batch.size;
 
-        int elementOffset = SectionRenderDataUnsafe.getBaseElement(pMeshData)
-                & ~SectionRenderDataUnsafe.BASE_ELEMENT_MSB;
+        long elementOffset = SectionRenderDataUnsafe.getBaseElement(pMeshData);
 
         for (int facing = 0; facing < ModelQuadFacing.COUNT; facing++) {
-            final var elementCount = SectionRenderDataUnsafe.getElementCount(pMeshData, facing);
+            final long vertexOffset = SectionRenderDataUnsafe.getVertexOffset(pMeshData, facing);
+            final long elementCount = SectionRenderDataUnsafe.getElementCount(pMeshData, facing);
 
-            MemoryUtil.memPutInt(pBaseVertex + (size << 2), SectionRenderDataUnsafe.getVertexOffset(pMeshData, facing));
-            MemoryUtil.memPutInt(pElementCount + (size << 2), elementCount);
+            // Uint32 -> Int32 cast is always safe and should be optimized away
+            MemoryUtil.memPutInt(pBaseVertex + (size << 2), UInt32.uncheckedDowncast(vertexOffset));
+            MemoryUtil.memPutInt(pElementCount + (size << 2), UInt32.uncheckedDowncast(elementCount));
 
-            // * 4 to convert to bytes (the buffer contains 32-bit integers)
+            // * 4 to convert to bytes (the index buffer contains integers)
             // the section render data storage for the indices stores the offset in indices (also called elements)
             MemoryUtil.memPutAddress(pElementPointer + (size << 3), elementOffset << 2);
 

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/data/SectionRenderDataStorage.java

@@ -3,6 +3,7 @@
 import net.caffeinemc.mods.sodium.client.gl.arena.GlBufferSegment;
 import net.caffeinemc.mods.sodium.client.model.quad.properties.ModelQuadFacing;
 import net.caffeinemc.mods.sodium.client.render.chunk.region.RenderRegion;
+import net.caffeinemc.mods.sodium.client.util.UInt32;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -58,13 +59,16 @@ public void setVertexData(int localSectionIndex,
         var pMeshData = this.getDataPointer(localSectionIndex);
 
         int sliceMask = 0;
-        int vertexOffset = allocation.getOffset();
+
+        long vertexOffset = allocation.getOffset();
 
         for (int facingIndex = 0; facingIndex < ModelQuadFacing.COUNT; facingIndex++) {
-            int vertexCount = vertexCounts[facingIndex];
+            long vertexCount = vertexCounts[facingIndex];
 
-            SectionRenderDataUnsafe.setVertexOffset(pMeshData, facingIndex, vertexOffset);
-            SectionRenderDataUnsafe.setElementCount(pMeshData, facingIndex, (vertexCount >> 2) * 6);
+            SectionRenderDataUnsafe.setVertexOffset(pMeshData, facingIndex,
+                    UInt32.downcast(vertexOffset));
+            SectionRenderDataUnsafe.setElementCount(pMeshData, facingIndex,
+                    UInt32.downcast((vertexCount >> 2) * 6));
 
             if (vertexCount > 0) {
                 sliceMask |= 1 << facingIndex;
@@ -91,8 +95,7 @@ public void setIndexData(int localSectionIndex, GlBufferSegment allocation) {
 
         var pMeshData = this.getDataPointer(localSectionIndex);
 
-        SectionRenderDataUnsafe.setBaseElement(pMeshData,
-                allocation.getOffset() | SectionRenderDataUnsafe.BASE_ELEMENT_MSB);
+        SectionRenderDataUnsafe.setBaseElement(pMeshData, allocation.getOffset());
     }
 
     public void removeData(int localSectionIndex) {
@@ -157,7 +160,7 @@ private void updateMeshes(int sectionIndex) {
             return;
         }
 
-        var offset = allocation.getOffset();
+        long offset = allocation.getOffset();
         var data = this.getDataPointer(sectionIndex);
 
         for (int facing = 0; facing < ModelQuadFacing.COUNT; facing++) {
@@ -177,8 +180,7 @@ public void onIndexBufferResized() {
             var allocation = this.elementAllocations[sectionIndex];
 
             if (allocation != null) {
-                SectionRenderDataUnsafe.setBaseElement(this.getDataPointer(sectionIndex),
-                        allocation.getOffset() | SectionRenderDataUnsafe.BASE_ELEMENT_MSB);
+                SectionRenderDataUnsafe.setBaseElement(this.getDataPointer(sectionIndex), allocation.getOffset());
             }
         }
     }