Make explicit the implicit

- Add @apiNotes explaining that flywheel/ is prepended to each shader
  ResourceLocation's path
- Document all InstanceType fields

common/src/api/java/dev/engine_room/flywheel/api/instance/InstanceType.java

@@ -15,11 +15,48 @@ public interface InstanceType<I extends Instance> {
 	 */
 	I create(InstanceHandle handle);
 
+	/**
+	 * The native memory layout of this instance type.
+	 *
+	 * <p>This layout determines what fields are made available to the instance type's shaders
+	 * as well as determining how the fields are arranged in memory.
+	 *
+	 * @return The layout of this instance type.
+	 */
 	Layout layout();
 
+	/**
+	 * The writer of this instance type.
+	 *
+	 * <p>The writer of an InstanceType is responsible for translating java instance objects
+	 * into contiguous native memory. The instance writer must write to the given pointer
+	 * according to the layout of this instance type.
+	 *
+	 * <p>It is undefined behavior to write outside the half closed range
+	 * {@code [ptr, ptr + layout().byteSize())}.
+	 *
+	 * @return The writer for this instance type.
+	 */
 	InstanceWriter<I> writer();
 
+	/**
+	 * <p>The vertex shader of an InstanceType is responsible for transforming vertices from mesh
+	 * space to world space in whatever way the instance type requires.
+	 *
+	 * @return The vertex shader for this instance type.
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation vertexShader();
 
+	/**
+	 * The cull shader of this instance type.
+	 *
+	 * <p>The cull shader of an InstanceType is responsible for transforming bounding spheres from mesh
+	 * space to world space, such that a mesh contained by the input bounding sphere and transformed
+	 * by the vertex shader would be contained by the output bounding sphere.
+	 *
+	 * @return The cull shader for this instance type.
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation cullShader();
 }

common/src/api/java/dev/engine_room/flywheel/api/material/CutoutShader.java

@@ -2,6 +2,12 @@
 
 import net.minecraft.resources.ResourceLocation;
 
+/**
+ * A shader that decides what colors should be discarded in the fragment shader.
+ */
 public interface CutoutShader {
+	/**
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation source();
 }

common/src/api/java/dev/engine_room/flywheel/api/material/FogShader.java

@@ -2,6 +2,12 @@
 
 import net.minecraft.resources.ResourceLocation;
 
+/**
+ * A shader that controls the fog effect on a material.
+ */
 public interface FogShader {
+	/**
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation source();
 }

common/src/api/java/dev/engine_room/flywheel/api/material/LightShader.java

@@ -2,6 +2,12 @@
 
 import net.minecraft.resources.ResourceLocation;
 
+/**
+ * A shader that controls the GPU-based light on a material.
+ */
 public interface LightShader {
+	/**
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation source();
 }

common/src/api/java/dev/engine_room/flywheel/api/material/MaterialShaders.java

@@ -2,8 +2,17 @@
 
 import net.minecraft.resources.ResourceLocation;
 
+/**
+ * A vertex and fragment shader pair that can be attached to a material.
+ */
 public interface MaterialShaders {
+	/**
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation vertexSource();
 
+	/**
+	 * @apiNote {@code flywheel/} is implicitly prepended to the {@link ResourceLocation}'s path.
+	 */
 	ResourceLocation fragmentSource();
 }