import upstream maccel baseline

2026-03-24 12:10:31 +00:00
parent 6e948d7b39
commit 5f1254d11a
108 changed files with 18930 additions and 0 deletions
@@ -0,0 +1,64 @@
+#ifndef __ACCEL_SYNCHRONOUS_H_
+#define __ACCEL_SYNCHRONOUS_H_
+
+#include "../fixedptc.h"
+
+struct synchronous_curve_args {
+  fpt gamma;
+  fpt smooth;
+  fpt motivity;
+  fpt sync_speed;
+};
+
+/**
+ * Sensitivity Function for `Synchronous` Acceleration
+ */
+static inline fpt __synchronous_sens_fun(fpt input_speed,
+                                         struct synchronous_curve_args args) {
+  fpt log_motivity = fpt_ln(args.motivity);
+  fpt gamma_const = fpt_div(args.gamma, log_motivity);
+  fpt log_syncspeed = fpt_ln(args.sync_speed);
+  fpt syncspeed = args.sync_speed;
+  fpt sharpness = args.smooth == 0 ? fpt_rconst(16.0)
+                                   : fpt_div(fpt_rconst(0.5), args.smooth);
+  int use_linear_clamp = sharpness >= fpt_rconst(16.0);
+  fpt sharpness_recip = fpt_div(FIXEDPT_ONE, sharpness);
+  fpt minimum_sens = fpt_div(FIXEDPT_ONE, args.motivity);
+  fpt maximum_sens = args.motivity;
+
+  // if sharpness >= 16, use linear clamp for activation function.
+  // linear clamp means: fpt_clamp(input_speed, -1, 1).
+  if (use_linear_clamp) {
+    fpt log_space = fpt_mul(gamma_const, (fpt_ln(input_speed) - log_syncspeed));
+
+    if (log_space < -FIXEDPT_ONE) {
+      return minimum_sens;
+    }
+
+    if (log_space > FIXEDPT_ONE) {
+      return maximum_sens;
+    }
+
+    return fpt_exp(fpt_mul(log_space, log_motivity));
+  }
+
+  if (input_speed == syncspeed) {
+    return FIXEDPT_ONE;
+  }
+
+  fpt log_x = fpt_ln(input_speed);
+  fpt log_diff = log_x - log_syncspeed;
+
+  if (log_diff > 0) {
+    fpt log_space = fpt_mul(gamma_const, log_diff);
+    fpt exponent =
+        fpt_pow(fpt_tanh(fpt_pow(log_space, sharpness)), sharpness_recip);
+    return fpt_exp(fpt_mul(exponent, log_motivity));
+  } else {
+    fpt log_space = fpt_mul(-gamma_const, log_diff);
+    fpt exponent =
+        -fpt_pow(fpt_tanh(fpt_pow(log_space, sharpness)), sharpness_recip);
+    return fpt_exp(fpt_mul(exponent, log_motivity));
+  }
+}
+#endif