Document render/update objects (#565)

* Document objects related code.
  * Including render/update objects code
* Various renamings

src/actors/boat.inc.c

@@ -1,3 +0,0 @@
-void update_actor_paddle_wheel(struct PaddleWheelBoat *boat) {
-    boat->wheelRot += 0x38E;
-}

src/actors/paddle_boat/render.inc.c

@@ -0,0 +1,45 @@
+#include <ultra64.h>
+#include <macros.h>
+#include <actor_types.h>
+#include "camera.h"
+#include "main.h"
+#include "actors.h"
+#include "courses/all_course_data.h"
+#include <PR/gbi.h>
+
+// This likely attaches the paddle wheel to the boat
+void render_actor_paddle_boat(Camera *arg0, struct PaddleWheelBoat *boat, UNUSED Mat4 arg2, u16 pathCounter) {
+    UNUSED s32 pad[3];
+    Vec3f sp120;
+    Mat4 spE0;
+    Mat4 spA0;
+    Mat4 sp60;
+    f32 temp;
+
+    if ((pathCounter > 20) && (pathCounter < 25)) { return; }
+    
+    temp = is_within_render_distance(arg0->pos, boat->pos, arg0->rot[1], 90000.0f, gCameraZoom[arg0 - camera1], 9000000.0f);
+
+    if (temp < 0.0f) { return; }
+
+        gSPSetLights1(gDisplayListHead++, D_800DC610[1]);
+        gSPSetGeometryMode(gDisplayListHead++, G_SHADE | G_LIGHTING | G_SHADING_SMOOTH);
+
+        mtxf_pos_rotation_xyz(spE0, boat->pos, boat->boatRot);
+        if (render_set_position(spE0, 1) != 0) {
+
+            gSPDisplayList(gDisplayListHead++, &d_course_dks_jungle_parkway_dl_E730);
+            gSPDisplayList(gDisplayListHead++, &d_course_dks_jungle_parkway_dl_E058);
+
+            mtxf_rotate_x(spE0, boat->wheelRot);
+            vec3f_set(sp120, 0, 16.0f, -255.0f);
+            mtxf_translate(spA0, sp120);
+            mtxf_multiplication(sp60, spE0, spA0);
+            if (render_set_position(sp60, 3) != 0) {
+                gSPClearGeometryMode(gDisplayListHead++, G_CULL_BACK);
+                gSPDisplayList(gDisplayListHead++, &d_course_dks_jungle_parkway_dl_FC28);
+                gSPPopMatrix(gDisplayListHead++, G_MTX_MODELVIEW);
+                gSPSetGeometryMode(gDisplayListHead++, G_CULL_BACK);
+            }
+        }
+}

src/actors/paddle_boat/update.inc.c

@@ -0,0 +1,11 @@
+#include <ultra64.h>
+#include <actor_types.h>
+
+/**
+ * @brief Rotates paddle boat's wheel.
+ * 
+ * @param boat 
+ */
+void update_actor_paddle_boat(struct PaddleWheelBoat *boat) {
+    boat->wheelRot += 0x38E;
+}