Add Chromium-only Blender WebEngine parity work

blender-5.2.0/source/blender/gpu/GPU_select.hh

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+/* SPDX-FileCopyrightText: 2014 Blender Authors
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup gpu
+ */
+
+#pragma once
+
+#include "BLI_span.hh"
+#include "BLI_sys_types.h"
+#include "BLI_vector.hh"
+
+namespace blender {
+
+struct rcti;
+
+/** Flags for mode of operation. */
+enum GPUSelectMode {
+  GPU_SELECT_INVALID = 0,
+  GPU_SELECT_ALL = 1,
+  /* gpu_select_query */
+  GPU_SELECT_NEAREST_FIRST_PASS = 2,
+  GPU_SELECT_NEAREST_SECOND_PASS = 3,
+  /* gpu_select_pick */
+  GPU_SELECT_PICK_ALL = 4,
+  GPU_SELECT_PICK_NEAREST = 5,
+};
+
+/**
+ * The result of calling #GPU_select_begin & #GPU_select_end.
+ */
+struct GPUSelectResult {
+  /** The selection identifier matching the value passed in by #GPU_select_load_id. */
+  unsigned int id;
+  /**
+   * The nearest depth.
+   * - Only supported by picking modes (#GPU_SELECT_PICK_ALL and #GPU_SELECT_PICK_NEAREST)
+   *   since occlusion quires don't provide a convenient way of accessing the depth-buffer.
+   * - OpenGL's `GL_SELECT` supported both near and far depths,
+   *   this has not been included as Blender doesn't need this however support could be added.
+   */
+  unsigned int depth;
+};
+
+using GPUSelectStorage = Vector<GPUSelectResult, 2500>;
+struct GPUSelectBuffer {
+  GPUSelectStorage storage;
+};
+
+/**
+ * Initialize and provide buffer for results.
+ */
+void GPU_select_begin(GPUSelectBuffer *buffer, const rcti *input, GPUSelectMode mode, int oldhits);
+/**
+ * Initialize and provide buffer for results.
+ * Uses the new Select-Next engine if enabled.
+ */
+void GPU_select_begin_next(
+    GPUSelectBuffer *buffer, const rcti *input, int radius, GPUSelectMode mode, int oldhits);
+/**
+ * Loads a new selection id and ends previous query, if any.
+ * In second pass of selection it also returns
+ * if id has been hit on the first pass already.
+ * Thus we can skip drawing un-hit objects.
+ *
+ * \warning We rely on the order of object rendering on passes to be the same for this to work.
+ */
+bool GPU_select_load_id(unsigned int id);
+void GPU_select_finalize();
+/**
+ * Cleanup and flush selection results to buffer.
+ * Return number of hits and hits in buffer.
+ * if \a dopass is true, we will do a second pass with occlusion queries to get the closest hit.
+ */
+unsigned int GPU_select_end();
+
+/* Cache selection region. */
+
+bool GPU_select_is_cached();
+void GPU_select_cache_begin();
+void GPU_select_cache_load_id();
+void GPU_select_cache_end();
+
+/* Utilities. */
+
+/**
+ * Helper function, nothing special but avoids doing inline since hits aren't sorted by depth
+ * and purpose of 4x buffer indices isn't so clear.
+ *
+ * Note that comparing depth as uint is fine.
+ */
+const GPUSelectResult *GPU_select_buffer_near(const Span<GPUSelectResult> hit_results);
+/**
+ * Compare result of `GPU_select`: #GPUSelectResult,
+ * Needed for stable sorting, so cycling through all items near the cursor behaves predictably.
+ */
+int gpu_select_buffer_depth_id_cmp(const void *sel_a_p, const void *sel_b_p);
+uint GPU_select_buffer_remove_by_id(MutableSpan<GPUSelectResult> hit_results, uint select_id);
+/**
+ * Part of the solution copied from `rect_subregion_stride_calc`.
+ */
+void GPU_select_buffer_stride_realign(const rcti *src, const rcti *dst, uint *r_buf);
+
+}  // namespace blender