From f889fa0522553def726bc8258bb3b556a4f0bdb3 Mon Sep 17 00:00:00 2001
From: jaburns <j@jaburns.net>
Date: Sun, 18 Oct 2020 16:56:35 -0600
Subject: [PATCH] Add missing functions

---
 src/engine/math_util.c           | 34 ++++++++++++++++++++++++++++++++
 src/engine/math_util.h           |  6 ++++++
 src/game/platform_displacement.c |  2 ++
 3 files changed, 42 insertions(+)

diff --git a/src/engine/math_util.c b/src/engine/math_util.c
index 0ef1283..1f56801 100644
--- a/src/engine/math_util.c
+++ b/src/engine/math_util.c
@@ -2313,3 +2313,37 @@ s32 anim_spline_poll(Vec3f result) {
 
     return hasEnded;
 }
+
+
+
+// From object_helpers.c
+
+/**
+ * Multiply a vector by a matrix of the form
+ * | ? ? ? 0 |
+ * | ? ? ? 0 |
+ * | ? ? ? 0 |
+ * | 0 0 0 1 |
+ * i.e. a matrix representing a linear transformation over 3 space.
+ */
+void linear_mtxf_mul_vec3f(Mat4 m, Vec3f dst, Vec3f v) {
+    s32 i;
+    for (i = 0; i < 3; i++) {
+        dst[i] = m[0][i] * v[0] + m[1][i] * v[1] + m[2][i] * v[2];
+    }
+}
+
+/**
+ * Multiply a vector by the transpose of a matrix of the form
+ * | ? ? ? 0 |
+ * | ? ? ? 0 |
+ * | ? ? ? 0 |
+ * | 0 0 0 1 |
+ * i.e. a matrix representing a linear transformation over 3 space.
+ */
+void linear_mtxf_transpose_mul_vec3f(Mat4 m, Vec3f dst, Vec3f v) {
+    s32 i;
+    for (i = 0; i < 3; i++) {
+        dst[i] = m[i][0] * v[0] + m[i][1] * v[1] + m[i][2] * v[2];
+    }
+}
diff --git a/src/engine/math_util.h b/src/engine/math_util.h
index f65a8cb..5f089e5 100644
--- a/src/engine/math_util.h
+++ b/src/engine/math_util.h
@@ -73,4 +73,10 @@ void spline_get_weights(Vec4f result, f32 t, UNUSED s32 c);
 void anim_spline_init(Vec4s *keyFrames);
 s32 anim_spline_poll(Vec3f result);
 
+
+// From object_helpers.c
+void linear_mtxf_mul_vec3f(Mat4 m, Vec3f dst, Vec3f v);
+void linear_mtxf_transpose_mul_vec3f(Mat4 m, Vec3f dst, Vec3f v);
+
+
 #endif // MATH_UTIL_H
diff --git a/src/game/platform_displacement.c b/src/game/platform_displacement.c
index ff6adb5..c9b3f12 100644
--- a/src/game/platform_displacement.c
+++ b/src/game/platform_displacement.c
@@ -1,3 +1,5 @@
+#include <math.h>
+
 #include "../engine/math_util.h"
 #include "../engine/surface_collision.h"
 #include "level_update.h"