[util] Add helper for 2D and 3D morton codes

src/util/util_bit.h

@@ -633,6 +633,54 @@ namespace dxvk::bit {
   }
 
 
+  /**
+   * \brief Inserts one null bit after each bit
+   */
+  inline uint32_t split2(uint32_t c) {
+    c = (c ^ (c << 8u)) & 0x00ff00ffu;
+    c = (c ^ (c << 4u)) & 0x0f0f0f0fu;
+    c = (c ^ (c << 2u)) & 0x33333333u;
+    c = (c ^ (c << 1u)) & 0x55555555u;
+    return c;
+  }
+
+
+  /**
+   * \brief Inserts two null bits after each bit
+   */
+  inline uint64_t split3(uint64_t c) {
+    c = (c | c << 32u) & 0x001f00000000ffffull;
+    c = (c | c << 16u) & 0x001f0000ff0000ffull;
+    c = (c | c <<  8u) & 0x100f00f00f00f00full;
+    c = (c | c <<  4u) & 0x10c30c30c30c30c3ull;
+    c = (c | c <<  2u) & 0x1249249249249249ull;
+    return c;
+  }
+
+
+  /**
+   * \brief Interleaves bits from two integers
+   *
+   * Both numbers must fit into 16 bits.
+   * \param [in] x X coordinate
+   * \param [in] y Y coordinate
+   * \returns Morton code of x and y
+   */
+  inline uint32_t interleave(uint16_t x, uint16_t y) {
+    return split2(x) | (split2(y) << 1u);
+  }
+
+
+  /**
+   * \brief Interleaves bits from three integers
+   *
+   * All three numbers must fit into 16 bits.
+   */
+  inline uint64_t interleave(uint16_t x, uint16_t y, uint16_t z) {
+    return split3(x) | (split3(y) << 1u) | (split3(z) << 2u);
+  }
+
+
   /**
    * \brief 48-bit integer storage type
    */