Refactor: make yet more fcurve evaluation functions take const fcurves

This follows on after #121788.

Pull Request: https://projects.blender.org/blender/blender/pulls/121882

source/blender/animrig/ANIM_fcurve.hh

@@ -94,7 +94,7 @@ SingleKeyingResult insert_vert_fcurve(FCurve *fcu,
  * \param r_samples: Is expected to be an array large enough to hold `sample_count`.
  */
 void sample_fcurve_segment(
-    FCurve *fcu, float start_frame, float sample_rate, float *samples, int sample_count);
+    const FCurve *fcu, float start_frame, float sample_rate, float *samples, int sample_count);
 
 enum class BakeCurveRemove {
   NONE = 0,

source/blender/animrig/intern/fcurve.cc

@@ -288,7 +288,7 @@ void initialize_bezt(BezTriple *beztr,
  * that, since that's not how the "only insert needed" feature is supposed to
  * work.
  */
-static bool new_key_needed(FCurve &fcu, const float frame, const float value)
+static bool new_key_needed(const FCurve &fcu, const float frame, const float value)
 {
   if (fcu.totvert == 0) {
     return true;
@@ -376,7 +376,7 @@ SingleKeyingResult insert_vert_fcurve(FCurve *fcu,
   return SingleKeyingResult::SUCCESS;
 }
 
-void sample_fcurve_segment(FCurve *fcu,
+void sample_fcurve_segment(const FCurve *fcu,
                            const float start_frame,
                            const float sample_rate,
                            float *samples,

source/blender/blenkernel/BKE_fcurve.hh

@@ -599,7 +599,7 @@ void BKE_fcurve_correct_bezpart(const float v1[2], float v2[2], float v3[2], con
 
 /* evaluate fcurve */
 float evaluate_fcurve(const FCurve *fcu, float evaltime);
-float evaluate_fcurve_only_curve(FCurve *fcu, float evaltime);
+float evaluate_fcurve_only_curve(const FCurve *fcu, float evaltime);
 float evaluate_fcurve_driver(PathResolvedRNA *anim_rna,
                              FCurve *fcu,
                              ChannelDriver *driver_orig,

source/blender/blenkernel/intern/fcurve.cc

@@ -2449,7 +2449,7 @@ float evaluate_fcurve(const FCurve *fcu, float evaltime)
   return evaluate_fcurve_ex(fcu, evaltime, 0.0);
 }
 
-float evaluate_fcurve_only_curve(FCurve *fcu, float evaltime)
+float evaluate_fcurve_only_curve(const FCurve *fcu, float evaltime)
 {
   /* Can be used to evaluate the (key-framed) f-curve only.
    * Also works for driver-f-curves when the driver itself is not relevant.

source/blender/blenkernel/intern/tracking_solver.cc

@@ -71,7 +71,7 @@ static libmv_Tracks *libmv_tracks_new(MovieClip *clip, ListBase *tracksbase, int
 
   track = static_cast<MovieTrackingTrack *>(tracksbase->first);
   while (track) {
-    FCurve *weight_fcurve = id_data_find_fcurve(
+    const FCurve *weight_fcurve = id_data_find_fcurve(
         &clip->id, track, &RNA_MovieTrackingTrack, "weight", 0, nullptr);
 
     for (int a = 0; a < track->markersnr; a++) {

source/blender/blenkernel/intern/tracking_stabilize.cc

@@ -137,7 +137,7 @@ static FCurve *retrieve_track_weight_animation(MovieClip *clip, MovieTrackingTra
   return id_data_find_fcurve(&clip->id, track, &RNA_MovieTrackingTrack, "weight_stab", 0, nullptr);
 }
 
-static float fetch_from_fcurve(FCurve *animationCurve,
+static float fetch_from_fcurve(const FCurve *animationCurve,
                                int framenr,
                                StabContext *ctx,
                                float default_value)

source/blender/editors/animation/anim_draw.cc

@@ -332,7 +332,7 @@ short ANIM_get_normalization_flags(SpaceLink *space_link)
 }
 
 static void fcurve_scene_coord_range_get(Scene *scene,
-                                         FCurve *fcu,
+                                         const FCurve *fcu,
                                          float *r_min_coord,
                                          float *r_max_coord)
 {

source/blender/editors/armature/pose_slide.cc

@@ -331,7 +331,7 @@ static bool pose_frame_range_from_object_get(tPoseSlideOp *pso,
 /**
  * Helper for apply() - perform sliding for some value.
  */
-static void pose_slide_apply_val(tPoseSlideOp *pso, FCurve *fcu, Object *ob, float *val)
+static void pose_slide_apply_val(tPoseSlideOp *pso, const FCurve *fcu, Object *ob, float *val)
 {
   float prev_frame, next_frame;
   float prev_weight, next_weight;

source/blender/editors/space_graph/graph_select.cc

@@ -689,8 +689,11 @@ static short ok_bezier_always_ok(KeyframeEditData * /*ked*/, BezTriple * /*bezt*
 #define ABOVE 1
 #define INSIDE 0
 #define BELOW -1
-static int rectf_curve_zone_y(
-    FCurve *fcu, const rctf *rectf, const float offset, const float unit_scale, const float eval_x)
+static int rectf_curve_zone_y(const FCurve *fcu,
+                              const rctf *rectf,
+                              const float offset,
+                              const float unit_scale,
+                              const float eval_x)
 {
   const float fcurve_y = (evaluate_fcurve(fcu, eval_x) + offset) * unit_scale;
   return fcurve_y < rectf->ymin ? BELOW : fcurve_y <= rectf->ymax ? INSIDE : ABOVE;