From aabb3e82deed035f4cf4c2f2d88cff14aee175fe Mon Sep 17 00:00:00 2001
From: knokko <knokogator@hotmail.com>
Date: Fri, 25 Oct 2024 00:04:35 +0200
Subject: [PATCH] Add MappedVkbBufferRange

---
 docs/methods.md                               |  9 +++
 .../boiler/buffers/MappedVkbBuffer.java       | 17 ++++
 .../boiler/buffers/MappedVkbBufferRange.java  | 79 +++++++++++++++++++
 3 files changed, 105 insertions(+)
 create mode 100644 src/main/java/com/github/knokko/boiler/buffers/MappedVkbBufferRange.java

diff --git a/docs/methods.md b/docs/methods.md
index a48fdee..6d626ed 100644
--- a/docs/methods.md
+++ b/docs/methods.md
@@ -28,6 +28,15 @@ tuple `(buffer, byteOffset, byteSize)`. You can obtain an instance by
 calling the `range(...)` or `fullRange()` method of a `DeviceVkbBuffer` or
 a `MappedVkbBuffer`.
 
+### MappedVkbBufferRange
+The `MappedVkbBufferRange` represents a range of a `MappedVkbBuffer`,
+which is a tuple `(mappedBuffer, byteOffset, byteSize)`. You can obtain
+an instance by calling the `mappedRange(...)` or `mappedFullRange()`
+method of a `MappedVkbBuffer`. It provides `byteBuffer()`,
+`shortBuffer()`, etc... methods to create Java NIO buffers whose memory
+is backed by the buffer range. It also provides a `range(...)` method to
+create a corresponding `VkbBufferRange`.
+
 ### Encoding/decoding images
 You can use `boiler.buffers.encodeBufferedImageRGBA(...)` to encode/store a
 `BufferedImage` in a `MappedVkbBuffer` in RGBA8 format. You can use this to
diff --git a/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBuffer.java b/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBuffer.java
index de79e6f..f34d860 100644
--- a/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBuffer.java
+++ b/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBuffer.java
@@ -5,4 +5,21 @@
  * host-visible memory, and must be mapped at <i>hostAddress</i> during its lifetime.
  */
 public record MappedVkbBuffer(long vkBuffer, long vmaAllocation, long size, long hostAddress) implements VkbBuffer {
+
+	/**
+	 * @return a <i>MappedVkbBufferRange</i> that covers this whole buffer
+	 */
+	public MappedVkbBufferRange fullMappedRange() {
+		return new MappedVkbBufferRange(this, 0L, size);
+	}
+
+	/**
+	 * @param offset The offset, in bytes
+	 * @param rangeSize The size of the range, in bytes
+	 * @return a <i>MappedVkbBufferRange</i> that covers the bytes [offset, offset + rangeSize> from this buffer
+	 */
+	public MappedVkbBufferRange mappedRange(long offset, long rangeSize) {
+		if (offset + rangeSize > size) throw new IllegalArgumentException(offset + " + " + rangeSize + " > " + size);
+		return new MappedVkbBufferRange(this, offset, rangeSize);
+	}
 }
diff --git a/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBufferRange.java b/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBufferRange.java
new file mode 100644
index 0000000..6ea1d00
--- /dev/null
+++ b/src/main/java/com/github/knokko/boiler/buffers/MappedVkbBufferRange.java
@@ -0,0 +1,79 @@
+package com.github.knokko.boiler.buffers;
+
+import java.nio.*;
+
+import static org.lwjgl.system.MemoryUtil.*;
+
+/**
+ * Represents a range/section of a <i>MappedVkbBuffer</i>
+ * @param buffer The mapped buffer
+ * @param offset The offset into the mapped buffer, in bytes
+ * @param size The size of this range, in bytes
+ */
+public record MappedVkbBufferRange(MappedVkbBuffer buffer, long offset, long size) {
+
+	/**
+	 * @return The start host address of this buffer range
+	 */
+	public long hostAddress() {
+		return buffer.hostAddress() + offset;
+	}
+
+	/**
+	 * @return The size of this range <b>in bytes</b>, but represented as integer
+	 * @throws UnsupportedOperationException When the size is larger than <i>Integer.MAX_VALUE</i>
+	 */
+	public int intSize() {
+		if (size > Integer.MAX_VALUE) throw new UnsupportedOperationException("Size (" + size + ") is too large");
+		return (int) size;
+	}
+
+	/**
+	 * @return The corresponding <i>VkbBufferRange</i>
+	 */
+	public VkbBufferRange range() {
+		return new VkbBufferRange(buffer, offset, size);
+	}
+
+	/**
+	 * @return A direct byte buffer that starts at the start of this range, and has the same capacity
+	 */
+	public ByteBuffer byteBuffer() {
+		return memByteBuffer(hostAddress(), intSize());
+	}
+
+	/**
+	 * @return A direct short buffer that starts at the start of this range, with a capacity of <i>size / Short.BYTES</i>
+	 */
+	public ShortBuffer shortBuffer() {
+		return memShortBuffer(hostAddress(), intSize() / Short.BYTES);
+	}
+
+	/**
+	 * @return A direct int buffer that starts at the start of this range, with a capacity of <i>size / Int.BYTES</i>
+	 */
+	public IntBuffer intBuffer() {
+		return memIntBuffer(hostAddress(), intSize() / Integer.BYTES);
+	}
+
+	/**
+	 * @return A direct float buffer that starts at the start of this range, with a capacity of <i>size / Float.BYTES</i>
+	 */
+	public FloatBuffer floatBuffer() {
+		return memFloatBuffer(hostAddress(), intSize() / Float.BYTES);
+	}
+
+	/**
+	 * @return A direct long buffer that starts at the start of this range, with a capacity of <i>size / Long.BYTES</i>
+	 */
+	public LongBuffer longBuffer() {
+		return memLongBuffer(hostAddress(), intSize() / Long.BYTES);
+	}
+
+	/**
+	 * @return A direct double buffer that starts at the start of this range, with a capacity of <i>size / Double.BYTES</i>
+	 */
+	public DoubleBuffer doubleBuffer() {
+		return memDoubleBuffer(hostAddress(), intSize() / Double.BYTES);
+	}
+}