Implemented skybox interpolation

include/PR/gu.h

@@ -13,6 +13,8 @@ void guPerspective(Mtx *m, u16 *perspNorm, float fovy, float aspect, float near,
                    float far, float scale);
 void guOrtho(Mtx *m, float left, float right, float bottom, float top,
              float near, float far, float scale);
+void guOrthoInterp(Mtx *m, float left, float right, float bottom, float top,
+             float near, float far, float scale);
 void guTranslate(Mtx *m, float x, float y, float z);
 void guRotate(Mtx *m, float a, float x, float y, float z);
 void guScale(Mtx *m, float x, float y, float z);

lib/src/guOrthoF.c

@@ -26,3 +26,13 @@ void guOrtho(Mtx *m, float left, float right, float bottom, float top, float nea
     guOrthoF(sp28, left, right, bottom, top, near, far, scale);
     guMtxF2L(sp28, m);
 }
+
+
+void guOrthoInterp(Mtx *m, float left, float right, float bottom, float top, float near, float far,
+             float scale) {
+    FrameInterpolation_RecordOrtho(m, left, right, bottom, top, near, far, scale);
+
+    float sp28[4][4];
+    guOrthoF(sp28, left, right, bottom, top, near, far, scale);
+    guMtxF2L(sp28, m);
+}

src/game/rendering_graph_node.c

@@ -232,7 +232,7 @@ static void geo_process_ortho_projection(struct GraphNodeOrthoProjection *node)
         f32 bottom = (gCurGraphNodeRoot->y + gCurGraphNodeRoot->height) / 2.0f * node->scale;
 
         FrameInterpolation_RecordOpenChild("geo_process_ortho_projection", (uintptr_t)node);
-        guOrtho(mtx, left, right, bottom, top, -2.0f, 2.0f, 1.0f);
+        guOrthoInterp(mtx, left, right, bottom, top, -2.0f, 2.0f, 1.0f);
         gSPPerspNormalize(gDisplayListHead++, 0xFFFF);
         gSPMatrix(gDisplayListHead++, VIRTUAL_TO_PHYSICAL(mtx), G_MTX_PROJECTION | G_MTX_LOAD | G_MTX_NOPUSH);
 

src/game/skybox.c

@@ -11,6 +11,7 @@
 #include "segment2.h"
 #include "sm64.h"
 #include "skybox_table.h"
+#include "port/interpolation/FrameInterpolation.h"
 
 /**
  * @file skybox.c
@@ -291,7 +292,7 @@ void *create_skybox_ortho_matrix(s8 player) {
     }
 
     if (mtx != NULL) {
-        guOrtho(mtx, left, right, bottom, top, 0.0f, 3.0f, 1.0f);
+        guOrthoInterp(mtx, left, right, bottom, top, 0.0f, 3.0f, 1.0f);
     } else {
     }
 

src/port/interpolation/FrameInterpolation.cpp

@@ -12,6 +12,7 @@
 
 extern "C" {
 extern Mat4* gInterpolationMatrix;
+void guOrtho(Mtx* dest, float left, float right, float bottom, float top, float near, float far, float scale);
 }
 /*
 Frame interpolation.
@@ -61,6 +62,7 @@ enum class Op {
     MatrixPut,
     MatrixMult,
     MatrixTranslate,
+    Ortho,
     MatrixScale,
     MatrixRotate1Coord,
     MatrixRotateXYCoords,
@@ -114,6 +116,17 @@ union Data {
         Vec3fInterp b;
     } matrix_translate;
 
+    struct {
+        Mtx* m;
+        float left;
+        float right;
+        float bottom;
+        float top;
+        float near;
+        float far;
+        float scale;
+    } ortho;
+
     struct {
         Mat4* matrix;
         f32 scale;
@@ -444,6 +457,28 @@ struct InterpolateCtx {
 
                             translate_mtxf(*gInterpolationMatrix, temp);
                             break;
+                        case Op::Ortho: {
+                            // Only interpolate if the difference is significant to avoid jitter
+                            constexpr float THRESHOLD = 2.0f;
+                            if (fabsf(old_op.ortho.left - new_op.ortho.left) < THRESHOLD &&
+                                fabsf(old_op.ortho.right - new_op.ortho.right) < THRESHOLD &&
+                                fabsf(old_op.ortho.bottom - new_op.ortho.bottom) < THRESHOLD &&
+                                fabsf(old_op.ortho.top - new_op.ortho.top) < THRESHOLD &&
+                                fabsf(old_op.ortho.near - new_op.ortho.near) < THRESHOLD &&
+                                fabsf(old_op.ortho.far - new_op.ortho.far) < THRESHOLD &&
+                                fabsf(old_op.ortho.scale - new_op.ortho.scale) < THRESHOLD) {
+                                break;
+                            }
+                            float left = lerp(old_op.ortho.left, new_op.ortho.left);
+                            float right = lerp(old_op.ortho.right, new_op.ortho.right);
+                            float bottom = lerp(old_op.ortho.bottom, new_op.ortho.bottom);
+                            float top = lerp(old_op.ortho.top, new_op.ortho.top);
+                            float near = lerp(old_op.ortho.near, new_op.ortho.near);
+                            float far = lerp(old_op.ortho.far, new_op.ortho.far);
+                            float scale = lerp(old_op.ortho.scale, new_op.ortho.scale);
+                            guOrtho(new_replacement(new_op.ortho.m), left, right, bottom, top, near, far, scale);
+                            break;
+                        }
                         case Op::MatrixPosRotXYZ: {
                             Vec3f tempF;
                             Vec3s tempS;
@@ -758,6 +793,14 @@ void FrameInterpolation_RecordMatrixTranslate(Mat4* matrix, Vec3f b) {
     append(Op::MatrixTranslate).matrix_translate = { matrix, *((Vec3fInterp*)b) };
 }
 
+void FrameInterpolation_RecordOrtho(Mtx* m, f32 left, f32 right, f32 bottom, f32 top, f32 near, f32 far,
+                                    f32 scale) {
+    if (!check_if_recording()) {
+        return;
+    }
+    append(Op::Ortho).ortho = { m, left, right, bottom, top, near, far, scale };
+}
+
 void FrameInterpolation_RecordMatrixScale(Mat4* matrix, f32 scale) {
     if (!check_if_recording()) {
         return;

src/port/interpolation/FrameInterpolation.h

@@ -88,6 +88,8 @@ void FrameInterpolation_RecordCalculateOrientationMatrix(Mat3*, f32, f32, f32, s
 
 void FrameInterpolation_RecordTranslateRotate(Mat4* dest, Vec3f pos, Vec3s rotation);
 
+void FrameInterpolation_RecordOrtho(Mtx* m, f32 left, f32 right, f32 bottom, f32 top, f32 near, f32 far, f32 scale);
+
 //void FrameInterpolation_func_80062B18(f32* arg0, f32* arg1, f32* arg2, arg3, arg4, arg5, arg6, arg7);
 
 #ifdef __cplusplus