fix interp on ooks rope (#553)

include/d/actor/d_a_e_mb.h

@@ -44,6 +44,12 @@ public:
     /* 0x88C */ u8 field_0x88C[0x8C8 - 0x88C];
     /* 0x8C8 */ s8 field_0x8c8;
     /* 0x8C9 */ u8 mInitHIO;
+#if TARGET_PC
+    cXyz mRopeInterpPrev[16];
+    cXyz mRopeInterpCurr[16];
+    bool mRopeInterpPrevValid;
+    bool mRopeInterpCurrValid;
+#endif
 };
 
 STATIC_ASSERT(sizeof(e_mb_class) == 0x8cc);

src/d/actor/d_a_e_mb.cpp

@@ -12,6 +12,8 @@
 #include "d/d_bomb.h"
 #include "c/c_damagereaction.h"
 #include "Z2AudioLib/Z2Instances.h"
+#include "dusk/frame_interpolation.h"
+#include "dusk/settings.h"
 
 #define ACTION_STANDBY    0
 #define ACTION_WALK1      1
@@ -63,6 +65,22 @@ static void anm_init(e_mb_class* i_this, int i_anmID, f32 i_morf, u8 i_attr, f32
     i_this->mAnm = i_anmID;
 }
 
+#if TARGET_PC
+static void e_mb_rope_interp_callback(bool isSimFrame, void* pUserWork) {
+    e_mb_class* i_this = (e_mb_class*)pUserWork;
+    if (!i_this->mRopeInterpPrevValid || !i_this->mRopeInterpCurrValid) {
+        return;
+    }
+    const f32 alpha = dusk::frame_interp::get_interpolation_step();
+    cXyz* dst = i_this->mRopeMat.getPos(0);
+    for (int i = 0; i < 16; i++) {
+        const cXyz& p0 = i_this->mRopeInterpPrev[i];
+        const cXyz& p1 = i_this->mRopeInterpCurr[i];
+        dst[i] = p0 + (p1 - p0) * alpha;
+    }
+}
+#endif
+
 static int daE_MB_Draw(e_mb_class* i_this) {
     fopAc_ac_c* a_this = (fopAc_ac_c*)i_this;
 
@@ -86,6 +104,17 @@ static int daE_MB_Draw(e_mb_class* i_this) {
     static GXColor l_color = {0x14, 0x0F, 0x00, 0xFF};
     i_this->mRopeMat.update(16, l_color, &a_this->tevStr);
     dComIfGd_set3DlineMat(&i_this->mRopeMat);
+#if TARGET_PC
+    if (dusk::getSettings().game.enableFrameInterpolation) {
+        if (i_this->mRopeInterpCurrValid) {
+            memcpy(i_this->mRopeInterpPrev, i_this->mRopeInterpCurr, sizeof(i_this->mRopeInterpCurr));
+            i_this->mRopeInterpPrevValid = true;
+        }
+        memcpy(i_this->mRopeInterpCurr, i_this->mRopeMat.getPos(0), 16 * sizeof(cXyz));
+        i_this->mRopeInterpCurrValid = true;
+        dusk::frame_interp::add_interpolation_callback(&e_mb_rope_interp_callback, i_this);
+    }
+#endif
     return 1;
 }