cleaner implementation of tiling support in sd cpp

Author: Phylliida

rope.hpp

@@ -50,24 +50,36 @@ namespace Rope {
             omega[i] = 1.0 / std::pow(theta, scale[i]);
         }
 
-        int pos_size = pos.size();
-        std::vector<std::vector<float>> out(pos_size, std::vector<float>(half_dim));
-        for (int i = 0; i < pos_size; ++i) {
+        for (size_t i = 0; i < pos.size(); ++i) {
+            float position = pos[i];
             for (int j = 0; j < half_dim; ++j) {
-                out[i][j] = pos[i] * omega[j];
-            }
-        }
-
-        std::vector<std::vector<float>> result(pos_size, std::vector<float>(half_dim * 4));
-        for (int i = 0; i < pos_size; ++i) {
-            for (int j = 0; j < half_dim; ++j) {
-                result[i][4 * j]     = std::cos(out[i][j]);
-                result[i][4 * j + 1] = -std::sin(out[i][j]);
-                result[i][4 * j + 2] = std::sin(out[i][j]);
-                result[i][4 * j + 3] = std::cos(out[i][j]);
+                float omega_val       = omega[j];
+                float original_angle  = position * omega_val;
+                float angle           = original_angle;
+                if (sd_is_circular_padding_enabled()) {
+                    constexpr float TWO_PI = 6.28318530717958647692f;
+                    float wrap_f            = static_cast<float>(wrap);
+                    float cycles            = omega_val * wrap_f / TWO_PI;
+                    float rounded           = std::round(cycles);  // closest periodic harmonic
+                    float periodic_omega    = TWO_PI * rounded / wrap_f;
+                    float periodic_angle    = position * periodic_omega;
+                    float rel_pos           = std::fmod(position, wrap_f);
+                    if (rel_pos < 0.0f) {
+                        rel_pos += wrap_f;
+                    }
+                    float t       = wrap_f > 0.0f ? rel_pos / wrap_f : 0.0f;
+                    float window  = 0.5f - 0.5f * std::cos(TWO_PI * t);  // 0 at edges, 1 in the middle
+                    window        = std::clamp(window, 0.0f, 1.0f);
+                    angle         = periodic_angle + window * (original_angle - periodic_angle);
+                }
+                float sin_val = std::sin(angle);
+                float cos_val = std::cos(angle);
+                result[i][4 * j]     = cos_val;
+                result[i][4 * j + 1] = -sin_val;
+                result[i][4 * j + 2] = sin_val;
+                result[i][4 * j + 3] = cos_val;
             }
         }
-
         return result;
     }