Floor Scrolling Interpolation (#176)

* Floor Scrolling Interpolation

* Scrolling Improvements

* Fix scroll stutter

* bump LUS & Torch

* missing prototype

---------

Co-authored-by: Sonic Dreamcaster <alejandro.asenjo88@gmail.com>

9 files changed, 170 insertions, 21 deletions

diff --git a/include/gfx.h b/include/gfx.h
index 3e22a976..99eb5252 100644
--- a/include/gfx.h
+++ b/include/gfx.h
@@ -26,6 +26,14 @@
                        ((height)-1) << G_TEXTURE_IMAGE_FRAC);                                                          \
     } while (0)
 
+#define gDPSetupTile2(pkt, fmt, siz, width, height, dw, dh,           \
+                     cms, cmt, masks, maskt, shifts, shiftt)         \
+{                                                                    \
+    gDPTileSync(pkt);                                                \
+    gDPSetTile(pkt, fmt, siz, (((width) * siz##_LINE_BYTES)+7)>>3, 0,\
+        G_TX_RENDERTILE, 0, cmt, maskt, shiftt, cms, masks, shifts); \
+}
+
 #define gDPSetupTile(pkt, fmt, siz, width, height, dw, dh,           \
                      cms, cmt, masks, maskt, shifts, shiftt)         \
 {                                                                    \
diff --git a/include/sf64context.h b/include/sf64context.h
index 90eb3079..e4bfaf61 100644
--- a/include/sf64context.h
+++ b/include/sf64context.h
@@ -65,6 +65,7 @@ extern f32 gSavedPathProgress;
 extern UNK_TYPE F_80177CB8;
 extern f32 gWaterLevel;
 extern f32 gPathGroundScroll;
+extern f32 gLastPathTexScroll;
 extern f32 gPathTexScroll;
 extern f32 gPathVelZ;
 extern f32 gPathProgress;
diff --git a/src/engine/fox_bg.c b/src/engine/fox_bg.c
index ac9683d6..31c6c59f 100644
--- a/src/engine/fox_bg.c
+++ b/src/engine/fox_bg.c
@@ -27,6 +27,8 @@
 
 #include "water_effect.inc"
 
+#include <libultra/gbi.h>
+
 f32 gWarpZoneBgAlpha;
 u8 D_bg_8015F964;  // related to water surfaces
 f32 D_bg_8015F968; // heat shimmer effect for SO and TI?
@@ -1386,10 +1388,32 @@ void Background_DrawGround(void) {
 
             if (gLevelMode == LEVELMODE_ON_RAILS) {
                 gDPSetTextureImage(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 1, SEGMENTED_TO_VIRTUAL(D_CO_601B6C0));
-                temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f)); // 0.64f / 3.0f
-                temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
-                gDPSetupTile(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
-                             G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+                
+				int interpolatedFrames = GameEngine_GetInterpolationFrameCount();
+
+				temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f)); // 0.64f / 3.0f
+				temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
+
+				float xScroll = temp_fv0;
+				float yScroll = temp_s0;
+
+				float inc = (2.0f * (gPathTexScroll - gLastPathTexScroll) * 0.2133333f) / (float)interpolatedFrames;
+
+				for (int i = 0; i < interpolatedFrames; i++)
+				{
+					gDPSetInterpolation(gMasterDisp++, i);
+
+					gDPSetupTile2(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
+						G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+					gDPSetTileSizeInterp(gMasterDisp, G_TX_RENDERTILE, xScroll, yScroll, 32 << 2, 32 << 2);
+
+					gMasterDisp += 3;
+
+					yScroll += inc >= 0 ? inc : -inc;
+					yScroll = fabs(Math_ModF(yScroll, 128.0f));
+				}
+
                 switch (gGroundSurface) {
                     case SURFACE_GRASS:
                         gDPLoadTileTexture(gMasterDisp++, D_CO_601B6C0, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32);
@@ -1482,10 +1506,34 @@ void Background_DrawGround(void) {
                     break;
             }
             gDPSetTextureImage(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 1, sp1C4);
-            temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f));
-            temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
-            gDPSetupTile(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
-                         G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+            
+            //gDPSetupTile(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
+                         //G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+			int interpolatedFrames = GameEngine_GetInterpolationFrameCount();
+
+			temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f));
+			temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
+
+			float xScroll = temp_fv0;
+			float yScroll = temp_s0;
+
+			float inc = (2.0f * (gPathTexScroll - gLastPathTexScroll) * 0.2133333f) / (float)interpolatedFrames;
+
+			for (int i = 0; i < interpolatedFrames; i++)
+			{
+				gDPSetInterpolation(gMasterDisp++, i);
+
+				gDPSetupTile2(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
+					G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+				gDPSetTileSizeInterp(gMasterDisp, G_TX_RENDERTILE, xScroll, yScroll, 32 << 2, 32 << 2);
+
+				gMasterDisp += 3;
+
+				yScroll += inc >= 0 ? inc : -inc;
+				yScroll = fabs(Math_ModF(yScroll, 128.0f));
+			}
 
             // CENTER FAR
             Matrix_Push(&gGfxMatrix);
@@ -1569,10 +1617,31 @@ void Background_DrawGround(void) {
                 //     gPathTexScroll -= (32.0f * 36.7f) / 2.0f;
                 // }
                 gDPSetTextureImage(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 1, sp1C4);
-                temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f)); // 0.64f / 3.0f
-                temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
-                gDPSetupTile(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
-                             G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+                
+				int interpolatedFrames = GameEngine_GetInterpolationFrameCount();
+
+				temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f)); // 0.64f / 3.0f
+				temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
+
+				float xScroll = temp_fv0;
+				float yScroll = temp_s0;
+
+				float inc = (2.0f * (gPathTexScroll - gLastPathTexScroll) * 0.2133333f) / (float)interpolatedFrames;
+
+				for (int i = 0; i < interpolatedFrames; i++)
+				{
+					gDPSetInterpolation(gMasterDisp++, i);
+
+					gDPSetupTile2(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
+						G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+					gDPSetTileSizeInterp(gMasterDisp, G_TX_RENDERTILE, xScroll, yScroll, 32 << 2, 32 << 2);
+
+					gMasterDisp += 3;
+
+					yScroll += inc >= 0 ? inc : -inc;
+					yScroll = fabs(Math_ModF(yScroll, 128.0f));
+				}
 
                 // Original Display (Center)
                 Matrix_Push(&gGfxMatrix);
@@ -1641,11 +1710,32 @@ void Background_DrawGround(void) {
                 gDPLoadTileTexture(gMasterDisp++, SEGMENTED_TO_VIRTUAL(D_AQ_600AB68), G_IM_FMT_RGBA, G_IM_SIZ_16b, 32,
                                    32);
                 gDPSetTextureImage(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 1, SEGMENTED_TO_VIRTUAL(D_AQ_600AB68));
-                temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f));
-                temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
-                gDPSetupTile(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
-                             G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
 
+				int interpolatedFrames = GameEngine_GetInterpolationFrameCount();
+
+				temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f));
+				temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
+
+				float xScroll = temp_fv0;
+				float yScroll = temp_s0;
+
+				float inc = (2.0f * (gPathTexScroll - gLastPathTexScroll) * 0.2133333f) / (float)interpolatedFrames;
+
+				for (int i = 0; i < interpolatedFrames; i++)
+				{
+					gDPSetInterpolation(gMasterDisp++, i);
+
+					gDPSetupTile2(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
+						G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+					gDPSetTileSizeInterp(gMasterDisp, G_TX_RENDERTILE, xScroll, yScroll, 32 << 2, 32 << 2);
+
+					gMasterDisp += 3;
+
+					yScroll += inc >= 0 ? inc : -inc;
+					yScroll = fabs(Math_ModF(yScroll, 128.0f));
+				}
+			
                 // CENTER FAR
                 Matrix_Push(&gGfxMatrix);
                 Matrix_Translate(gGfxMatrix, 0.0f, 0.0f, -3000.0f, MTXF_APPLY);
@@ -1695,10 +1785,32 @@ void Background_DrawGround(void) {
                 gDPLoadTileTexture(gMasterDisp++, SEGMENTED_TO_VIRTUAL(D_AQ_602ACC0), G_IM_FMT_RGBA, G_IM_SIZ_16b, 32,
                                    32);
                 gDPSetTextureImage(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 1, SEGMENTED_TO_VIRTUAL(D_AQ_602ACC0));
-                temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f));
-                temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
-                gDPSetupTile(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
-                             G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+				int interpolatedFrames = GameEngine_GetInterpolationFrameCount();
+
+				temp_s0 = fabsf(Math_ModF(2.0f * (gPathTexScroll * 0.2133333f), 128.0f));
+				temp_fv0 = Math_ModF((10000.0f - gPlayer[gPlayerNum].xPath) * 0.32f, 128.0f);
+
+				float xScroll = temp_fv0;
+				float yScroll = temp_s0;
+
+				float inc = (2.0f * (gPathTexScroll - gLastPathTexScroll) * 0.2133333f) / (float)interpolatedFrames;
+
+				for (int i = 0; i < interpolatedFrames; i++)
+				{
+					gDPSetInterpolation(gMasterDisp++, i);
+
+					gDPSetupTile2(gMasterDisp++, G_IM_FMT_RGBA, G_IM_SIZ_16b, 32, 32, temp_fv0, temp_s0,
+						G_TX_NOMIRROR | G_TX_WRAP, G_TX_NOMIRROR | G_TX_WRAP, 5, 5, G_TX_NOLOD, G_TX_NOLOD);
+
+					gDPSetTileSizeInterp(gMasterDisp, G_TX_RENDERTILE, xScroll, yScroll, 32 << 2, 32 << 2);
+
+					gMasterDisp += 3;
+
+					yScroll += inc >= 0 ? inc : -inc;
+					yScroll = fabs(Math_ModF(yScroll, 128.0f));
+				}
+
                 if (gAqDrawMode != 0) {
                     RCP_SetupDL(&gMasterDisp, SETUPDL_47);
                 } else {
diff --git a/src/engine/fox_context.c b/src/engine/fox_context.c
index b5fa2454..25b1ec72 100644
--- a/src/engine/fox_context.c
+++ b/src/engine/fox_context.c
@@ -77,6 +77,7 @@ f32 gSavedPathProgress;
 UNK_TYPE F_80177CB8;
 f32 gWaterLevel;
 f32 gPathGroundScroll;
+f32 gLastPathTexScroll;
 f32 gPathTexScroll;
 f32 gPathVelZ;
 f32 gPathProgress;
diff --git a/src/engine/fox_game.c b/src/engine/fox_game.c
index 25c2e770..a0266dc6 100644
--- a/src/engine/fox_game.c
+++ b/src/engine/fox_game.c
@@ -612,6 +612,8 @@ void Game_Update(void) {
 
         // @port: @event: Call GamePostUpdateEvent
         CALL_EVENT(GamePostUpdateEvent);
+
+		gLastPathTexScroll = gPathTexScroll;
     }
 }
 
diff --git a/src/engine/fox_hud.c b/src/engine/fox_hud.c
index 377a5ae4..2b30ab7b 100644
--- a/src/engine/fox_hud.c
+++ b/src/engine/fox_hud.c
@@ -6260,6 +6260,7 @@ void Venom1_LevelStart2(Player* player) {
 
         player->pos.x += player->vel.x;
         player->pos.y += player->vel.y;
+		gLastPathTexScroll = gPathTexScroll;
         gPathTexScroll += player->vel.z;
 
         player->bankAngle = player->rot.z + player->zRotBank + player->zRotBarrelRoll;
diff --git a/src/port/Engine.cpp b/src/port/Engine.cpp
index 4da6fd77..e0307752 100644
--- a/src/port/Engine.cpp
+++ b/src/port/Engine.cpp
@@ -452,8 +452,11 @@ void GameEngine::RunCommands(Gfx* Commands, const std::vector<std::unordered_map
     // Process window events for resize, mouse, keyboard events
     wnd->HandleEvents();
 
+	gInterpolationIndex = 0;
+
     for (const auto& m : mtx_replacements) {
         wnd->DrawAndRunGraphicsCommands(Commands, m);
+		gInterpolationIndex++;
     }
 
     bool curAltAssets = CVarGetInteger("gEnhancements.Mods.AlternateAssets", 0);
@@ -538,6 +541,15 @@ uint32_t GameEngine::GetInterpolationFPS() {
                               CVarGetInteger("gInterpolationFPS", 60));
 }
 
+uint32_t GameEngine::GetInterpolationFrameCount()
+{
+	return ceil((float)GetInterpolationFPS() / 30.0f);
+}
+
+extern "C" uint32_t GameEngine_GetInterpolationFrameCount() {
+	return GameEngine::GetInterpolationFrameCount();
+}
+
 void GameEngine::ShowMessage(const char* title, const char* message, SDL_MessageBoxFlags type) {
 #if defined(__SWITCH__)
     SPDLOG_ERROR(message);
diff --git a/src/port/Engine.h b/src/port/Engine.h
index 26f9109f..43dbf066 100644
--- a/src/port/Engine.h
+++ b/src/port/Engine.h
@@ -39,7 +39,8 @@ class GameEngine {
     static void AudioExit();
     static void RunCommands(Gfx* Commands, const std::vector<std::unordered_map<Mtx*, MtxF>>& mtx_replacements);
     static void Destroy();
-    static uint32_t GetInterpolationFPS();
+	static uint32_t GetInterpolationFPS();
+	static uint32_t GetInterpolationFrameCount();
     static void ProcessGfxCommands(Gfx* commands);
 
     static int ShowYesNoBox(const char* title, const char* box);
@@ -80,5 +81,7 @@ uint32_t OTRGetGameRenderWidth();
 uint32_t OTRGetGameRenderHeight();
 void* GameEngine_Malloc(size_t size);
 void GameEngine_GetTextureInfo(const char* path, int32_t* width, int32_t* height, float* scale, bool* custom);
+void gDPSetTileSizeInterp(Gfx* pkt, int t, float uls, float ult, float lrs, float lrt);
+uint32_t GameEngine_GetInterpolationFrameCount();
 #define memalloc(size) GameEngine_Malloc(size)
 #endif
\ No newline at end of file
diff --git a/src/port/GBIMiddleware.cpp b/src/port/GBIMiddleware.cpp
index 5e35e312..e0355a6d 100644
--- a/src/port/GBIMiddleware.cpp
+++ b/src/port/GBIMiddleware.cpp
@@ -20,6 +20,15 @@ extern "C" void gSPDisplayList(Gfx* pkt, Gfx* dl) {
     __gSPDisplayList(pkt, dl);
 }
 
+extern "C" void gDPSetTileSizeInterp(Gfx* pkt, int t, float uls, float ult, float lrs, float lrt) 
+{
+	__gDPSetTileSizeInterp(pkt++, t, 0, 0, 0, 0);
+	memcpy(&pkt[0].words.w0, &uls, sizeof(float));
+	memcpy(&pkt[0].words.w1, &ult, sizeof(float));
+	memcpy(&pkt[1].words.w0, &lrs, sizeof(float));
+	memcpy(&pkt[1].words.w1, &lrt, sizeof(float));
+}
+
 extern "C" void gSPVertex(Gfx* pkt, uintptr_t v, int n, int v0) {
 
     if (GameEngine_OTRSigCheck((char*)v) == 1) {