Add ColorPacker

docs/methods.md

@@ -523,6 +523,13 @@ to encode the given set into a `PointerBuffer` that is allocated
 on the given `MemoryStack`. This is for instance useful for
 populating `ppEnabledLayerNames`.
 
+### Color packing
+The `ColorPacker` class provides a `rgb` and `argb` method that
+can be used to pack 8-bit red, green, blue, and alpha components
+into a (32-bit) `int`. It also provides methods to extract
+the red, green, blue, and alpha components from the `int`s that
+it has produced.
+
 ### pNext chains
 You can use `NextChain.findAddress(pNext, sType)` to find the
 memory address of the struct with the given `sType` in the

src/main/java/com/github/knokko/boiler/utilities/ColorPacker.java

@@ -0,0 +1,83 @@
+package com.github.knokko.boiler.utilities;
+
+/**
+ * Helper class to pack RGB(A) colors into a single <b>int</b>. This is similar to what <i>java.awt.Color</i> does,
+ * but the component order is different. The  advantage of this class over <i>java.awt.Color</i>,
+ * is that no objects need to be allocated, you don't need to ship <i>java.desktop</i>,
+ * and you don't risk triggering AWT on macOS, which could sabotage GLFW.
+ */
+public class ColorPacker {
+
+	/**
+	 * Packs red, green, blue, and alpha into an integer. The red component will be stored in the least-significant
+	 * 8 bits, the green component will be stored in the next 8 bits, etc...
+	 */
+	public static int rgba(byte red, byte green, byte blue, byte alpha) {
+		return unsigned(red) | (unsigned(green) << 8) | (unsigned(blue) << 16) | (unsigned(alpha) << 24);
+	}
+
+	/**
+	 * Packs red, green, blue, and alpha into an integer. The red component will be stored in the least-significant
+	 * 8 bits, the green component will be stored in the next 8 bits, etc...<br>
+	 *
+	 * You can give the parameters either in the range [-128, 127] or [0, 255].
+	 */
+	public static int rgba(int red, int green, int blue, int alpha) {
+		return rgba((byte) red, (byte) green, (byte) blue, (byte) alpha);
+	}
+
+	/**
+	 * Packs red, green, and blue into an integer. The red component will be stored in the least-significant
+	 * 8 bits, the green component will be stored in the next 8 bits, and the blue component will be stored next to
+	 * green. The 8 most-significant bits will be set to 1, making the stored color opaque.
+	 */
+	public static int rgb(byte red, byte green, byte blue) {
+		return rgba(red, green, blue, (byte) 255);
+	}
+
+	/**
+	 * Packs red, green, and blue into an integer. The red component will be stored in the least-significant
+	 * 8 bits, the green component will be stored in the next 8 bits, and the blue component will be stored next to
+	 * green. The 8 most-significant bits will be set to 1, making the stored color opaque.<br>
+	 *
+	 * You can give the parameters either in the range [-128, 127] or [0, 255].
+	 */
+	public static int rgb(int red, int green, int blue) {
+		return rgba(red, green, blue, 255);
+	}
+
+	/**
+	 * Extracts the red component from a rgba value generated by the <i>rgba</i> method
+	 */
+	public static byte red(int rgba) {
+		return (byte) rgba;
+	}
+
+	/**
+	 * Extracts the green component from a rgba value generated by the <i>rgba</i> method
+	 */
+	public static byte green(int rgba) {
+		return (byte) (rgba >> 8);
+	}
+
+	/**
+	 * Extracts the blue component from a rgba value generated by the <i>rgba</i> method
+	 */
+	public static byte blue(int rgba) {
+		return (byte) (rgba >> 16);
+	}
+
+	/**
+	 * Extracts the alpha component from a rgba value generated by the <i>rgba</i> method
+	 */
+	public static byte alpha(int rgba) {
+		return (byte) (rgba >> 24);
+	}
+
+	/**
+	 * Converts a <b>byte</b> (in the range [-128, 127]) to an <b>int</b> in the range [0, 255]
+	 */
+	public static int unsigned(byte value) {
+		return value & 0xFF;
+	}
+}

src/test/java/com/github/knokko/boiler/utilities/TestColorPacker.java

@@ -0,0 +1,54 @@
+package com.github.knokko.boiler.utilities;
+
+import org.junit.jupiter.api.Test;
+
+import static com.github.knokko.boiler.utilities.ColorPacker.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class TestColorPacker {
+
+	@Test
+	public void testSimplePackingRGBA() {
+		assertEquals(0, rgba(0, 0, 0, 0));
+		assertEquals(-1, rgba(255, 255, 255, 255));
+		assertEquals(-1, rgba(-1, -1, -1, -1));
+		assertEquals(-1, rgba((byte) 255, (byte) 255, (byte) 255, (byte) 255));
+		assertEquals(-1, rgba((byte) -1, (byte) -1, (byte) -1, (byte) -1));
+
+		int high = rgba((byte) 255, (byte) 254, (byte) 253, (byte) 252);
+		assertEquals(high, rgba(255, 254, 253, 252));
+		assertEquals(high, rgba(-1, -2, -3, -4));
+		assertEquals((byte) 255, red(high));
+		assertEquals((byte) 254, green(high));
+		assertEquals((byte) 253, blue(high));
+		assertEquals((byte) 252, alpha(high));
+		assertEquals(255, unsigned(red(high)));
+		assertEquals(254, unsigned(green(high)));
+		assertEquals(253, unsigned(blue(high)));
+		assertEquals(252, unsigned(alpha(high)));
+
+		int low = rgba((byte) 1, (byte) 2, (byte) 3, (byte) 4);
+		assertEquals(low, rgba(1, 2, 3, 4));
+		assertEquals(1, red(low));
+		assertEquals(2, green(low));
+		assertEquals(3, blue(low));
+		assertEquals(4, alpha(low));
+		assertEquals(1, unsigned(red(low)));
+		assertEquals(2, unsigned(green(low)));
+		assertEquals(3, unsigned(blue(low)));
+		assertEquals(4, unsigned(alpha(low)));
+	}
+
+	@Test
+	public void testSimplePackingRGB() {
+		assertEquals(rgba(0, 0, 0, 255), rgb(0, 0, 0));
+		assertEquals(rgba(0, 0, 0, 255), rgb((byte) 0, (byte) 0, (byte) 0));
+		assertEquals(-1, rgb(255, -1, 255));
+		assertEquals(-1, rgb((byte) -1, (byte) 255, (byte) -1));
+		assertEquals(rgba(250, 251, 252, 255), rgb(250, 251, 252));
+		assertEquals(rgba(250, 251, 252, 255), rgb((byte) 250, (byte) 251, (byte) 252));
+		assertEquals(rgba(250, 251, 252, 255), rgb(-6, -5, -4));
+		assertEquals(rgba(1, 2, 3, 255), rgb(1, 2, 3));
+		assertEquals(rgba(1, 2, 3, 255), rgb((byte) 1, (byte) 2, (byte) 3));
+	}
+}