try adding two math constants E and PI for FixedPoint

SFTtech · Dec 1, 2023 · 0a6c454 · 0a6c454
1 parent 2391847
commit 0a6c454
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Showing 2 changed files with 30 additions and 4 deletions.
diff --git a/libopenage/util/fixed_point.h b/libopenage/util/fixed_point.h
@@ -53,8 +53,8 @@ constexpr static
 
 
 /**
- * Helper function that performs either a safe shift-right (amount > 0),
- * or a safe shift-left (amount < 0).
+ * Helper function that performs either a safe shift-right (amount < 0),
+ * or a safe shift-left (amount >= 0).
  */
 template <int amount, typename T>
 constexpr static
@@ -169,6 +169,17 @@ class FixedPoint {
 		return FixedPoint::from_int(0);
 	}
 
+	/**
+	 * Constants
+	 */
+	static constexpr FixedPoint e() {
+		return from_fixedpoint(FixedPoint<int64_t, 61>::from_raw_value(6267931151224907085ll));
+	}
+
+	static constexpr FixedPoint pi() {
+		return from_fixedpoint(FixedPoint<int64_t, 61>::from_raw_value(7244019458077122842ll));
+	}
+
 	/**
 	 * Factory function to get a fixed-point number from an integer.
 	 */
@@ -193,10 +204,16 @@ class FixedPoint {
 	/**
 	 * Factory function to get a fixed-point number from a fixed-point number of different type.
 	 */
-	template <typename other_int_type, unsigned int other_fractional_bits>
+	template <typename other_int_type, unsigned int other_fractional_bits, typename std::enable_if<(fractional_bits > other_fractional_bits)>::type* = nullptr>
+	static constexpr FixedPoint from_fixedpoint(const FixedPoint<other_int_type, other_fractional_bits> &other) {
+		return FixedPoint::from_raw_value(
+			safe_shift<fractional_bits - other_fractional_bits, int_type>(static_cast<int_type>(other.get_raw_value())));
+	}
+
+	template <typename other_int_type, unsigned int other_fractional_bits, typename std::enable_if<(fractional_bits <= other_fractional_bits)>::type* = nullptr>
 	static constexpr FixedPoint from_fixedpoint(const FixedPoint<other_int_type, other_fractional_bits> &other) {
 		return FixedPoint::from_raw_value(
-			safe_shift<fractional_bits - other_fractional_bits, int_type>(other.get_raw_value()));
+			static_cast<int_type>(other.get_raw_value() / safe_shiftleft<other_fractional_bits - fractional_bits, other_int_type>(1)));
 	}
 
 	/**

diff --git a/libopenage/util/fixed_point_test.cpp b/libopenage/util/fixed_point_test.cpp
@@ -6,6 +6,7 @@
 
 #include "../testing/testing.h"
 #include "stringformatter.h"
+#include "math_constants.h"
 
 namespace openage {
 namespace util {
@@ -98,6 +99,14 @@ void fixed_point() {
 	std::stringstream sstr("1234.5678");
 	sstr >> e;
 	TESTEQUALS_FLOAT(e.to_double(), 1234.5678, 1e-7);
+
+	TESTEQUALS_FLOAT(TestType::e().to_double(), math::E, 1e-7);
+	TESTEQUALS_FLOAT(TestType::pi().to_double(), math::PI, 1e-7);
+
+	using TestTypeShort = FixedPoint<int32_t, 16>;
+	TESTEQUALS_FLOAT(TestTypeShort::e().to_double(), math::E, 1e-3);
+	TESTEQUALS_FLOAT(TestTypeShort::pi().to_double(), math::PI, 1e-3);
+
 }
 
 }}} // openage::util::tests