From 41ef7c88af0b393695ec63d0409cbadc469babc9 Mon Sep 17 00:00:00 2001
From: Rubidium <rubidium@openttd.org>
Date: Sat, 25 Feb 2023 23:58:46 +0100
Subject: [PATCH] Codechange: make a numer of Slope related functions constexpr

---
 src/core/bitmath_func.hpp |  2 +-
 src/slope_func.h          | 16 ++++++++--------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/core/bitmath_func.hpp b/src/core/bitmath_func.hpp
index 745a32afc4..b2d21dacbf 100644
--- a/src/core/bitmath_func.hpp
+++ b/src/core/bitmath_func.hpp
@@ -29,7 +29,7 @@
  * @return The selected bits, aligned to a LSB.
  */
 template <typename T>
-debug_inline static uint GB(const T x, const uint8 s, const uint8 n)
+debug_inline constexpr static uint GB(const T x, const uint8 s, const uint8 n)
 {
 	return (x >> s) & (((T)1U << n) - 1);
 }
diff --git a/src/slope_func.h b/src/slope_func.h
index 47a89bfcf9..afc49eeafa 100644
--- a/src/slope_func.h
+++ b/src/slope_func.h
@@ -21,7 +21,7 @@
  * @param corner A #Corner.
  * @return true iff corner is in a valid range.
  */
-static inline bool IsValidCorner(Corner corner)
+static constexpr inline bool IsValidCorner(Corner corner)
 {
 	return IsInsideMM(corner, 0, CORNER_END);
 }
@@ -33,7 +33,7 @@ static inline bool IsValidCorner(Corner corner)
  * @param s The given #Slope.
  * @return True if the slope is steep, else false.
  */
-static inline bool IsSteepSlope(Slope s)
+static constexpr inline bool IsSteepSlope(Slope s)
 {
 	return (s & SLOPE_STEEP) != 0;
 }
@@ -44,7 +44,7 @@ static inline bool IsSteepSlope(Slope s)
  * @param s The given #Slope.
  * @return True if the slope is non-continuous, else false.
  */
-static inline bool IsHalftileSlope(Slope s)
+static constexpr inline bool IsHalftileSlope(Slope s)
 {
 	return (s & SLOPE_HALFTILE) != 0;
 }
@@ -57,7 +57,7 @@ static inline bool IsHalftileSlope(Slope s)
  * @param s A #Slope.
  * @return The slope s without its halftile slope.
  */
-static inline Slope RemoveHalftileSlope(Slope s)
+static constexpr inline Slope RemoveHalftileSlope(Slope s)
 {
 	return s & ~SLOPE_HALFTILE_MASK;
 }
@@ -145,7 +145,7 @@ static inline Corner GetHighestSlopeCorner(Slope s)
  * @param s The #Slope.
  * @return  The corner of the leveled halftile.
  */
-static inline Corner GetHalftileSlopeCorner(Slope s)
+static constexpr inline Corner GetHalftileSlopeCorner(Slope s)
 {
 	assert(IsHalftileSlope(s));
 	return (Corner)((s >> 6) & 3);
@@ -157,7 +157,7 @@ static inline Corner GetHalftileSlopeCorner(Slope s)
  * @param s The #Slope.
  * @return Relative height of highest corner.
  */
-static inline int GetSlopeMaxZ(Slope s)
+static constexpr inline int GetSlopeMaxZ(Slope s)
 {
 	if (s == SLOPE_FLAT) return 0;
 	if (IsSteepSlope(s)) return 2;
@@ -170,7 +170,7 @@ static inline int GetSlopeMaxZ(Slope s)
  * @param s The #Slope.
  * @return Relative height of highest corner.
  */
-static inline int GetSlopeMaxPixelZ(Slope s)
+static constexpr inline int GetSlopeMaxPixelZ(Slope s)
 {
 	return GetSlopeMaxZ(s) * TILE_HEIGHT;
 }
@@ -271,7 +271,7 @@ static inline Slope InclinedSlope(DiagDirection dir)
  * @param corner The #Corner of the halftile.
  * @return The #Slope s with the halftile slope added.
  */
-static inline Slope HalftileSlope(Slope s, Corner corner)
+static constexpr inline Slope HalftileSlope(Slope s, Corner corner)
 {
 	assert(IsValidCorner(corner));
 	return (Slope)(s | SLOPE_HALFTILE | (corner << 6));