feat: additional --preview-interval values (#1915)

Co-authored-by: leejet <leejet714@gmail.com>
2026-09-29 01:18:05 -05:00 · 2026-08-30 21:47:11 +08:00
parent 134c8212de
commit d9b6e27e9f
4 changed files with 81 additions and 21 deletions
@@ -0,0 +1,45 @@
+#ifndef __SD_RUNTIME_PREVIEW_INTERVAL_H__
+#define __SD_RUNTIME_PREVIEW_INTERVAL_H__
+
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+
+namespace sd::preview {
+
+    constexpr std::uint64_t logical_sample_step(int step) {
+        return step < 0 ? static_cast<std::uint64_t>(-static_cast<std::int64_t>(step))
+                        : static_cast<std::uint64_t>(step);
+    }
+
+    constexpr bool sample_step_is_complete(int step,
+                                           std::size_t total_steps,
+                                           bool terminal_sigma_is_zero) {
+        return step > 0 ||
+               (terminal_sigma_is_zero &&
+                step < 0 &&
+                logical_sample_step(step) == static_cast<std::uint64_t>(total_steps));
+    }
+
+    constexpr bool should_preview_sample_step(int step,
+                                              std::size_t total_steps,
+                                              bool terminal_sigma_is_zero,
+                                              int interval,
+                                              bool preview_final_step) {
+        if (interval > 0) {
+            return step % interval == 0;
+        }
+        if (!sample_step_is_complete(step, total_steps, terminal_sigma_is_zero)) {
+            return false;
+        }
+
+        std::uint64_t logical_step = logical_sample_step(step);
+        if (interval < 0) {
+            std::uint64_t requested_step = static_cast<std::uint64_t>(-static_cast<std::int64_t>(interval));
+            return logical_step == requested_step;
+        }
+        return preview_final_step && logical_step == static_cast<std::uint64_t>(total_steps);
+    }
+}  // namespace sd::preview
+
+#endif  // __SD_RUNTIME_PREVIEW_INTERVAL_H__