From 567b368fa6ebcd75b7a347e171ccbcb8c6f894ff Mon Sep 17 00:00:00 2001
From: Wenzel Jakob <wenzel@cs.cornell.edu>
Date: Thu, 2 Jan 2014 01:31:41 +0100
Subject: [PATCH] rewired some functions in qmc.h for better convenience

---
 include/mitsuba/core/qmc.h | 67 +++++++++++++++++++++-----------------
 1 file changed, 38 insertions(+), 29 deletions(-)

diff --git a/include/mitsuba/core/qmc.h b/include/mitsuba/core/qmc.h
index 940667af..eb01f39b 100644
--- a/include/mitsuba/core/qmc.h
+++ b/include/mitsuba/core/qmc.h
@@ -155,11 +155,10 @@ inline uint64_t sampleTEA(uint32_t v0, uint32_t v1, int rounds = 4) {
 	return ((uint64_t) v1 << 32) + v0;
 }
 
-#if defined(DOUBLE_PRECISION)
 /**
  * \brief Generate fast and reasonably good pseudorandom numbers using the
  * Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham.
- * 
+ *
  * This function uses \ref sampleTEA to return single precision floating point
  * numbers on the interval <tt>[0, 1)</tt>
  *
@@ -173,7 +172,35 @@ inline uint64_t sampleTEA(uint32_t v0, uint32_t v1, int rounds = 4) {
  * \return
  *     A uniformly distributed floating point number on the interval <tt>[0, 1)</tt>
  */
-inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
+inline float sampleTEASingle(uint32_t v0, uint32_t v1, int rounds = 4) {
+	/* Trick from MTGP: generate an uniformly distributed
+	   single precision number in [1,2) and subtract 1. */
+	union {
+		uint32_t u;
+		float f;
+	} x;
+	x.u = ((sampleTEA(v0, v1, rounds) & 0xFFFFFFFF) >> 9) | 0x3f800000UL;
+	return x.f - 1.0f;
+}
+
+/**
+ * \brief Generate fast and reasonably good pseudorandom numbers using the
+ * Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham.
+ *
+ * This function uses \ref sampleTEA to return single precision floating point
+ * numbers on the interval <tt>[0, 1)</tt>
+ *
+ * \param v0
+ *     First input value to be encrypted (could be the sample index)
+ * \param v1
+ *     Second input value to be encrypted (e.g. the requested random number dimension)
+ * \param rounds
+ *     How many rounds should be executed? The default for random number
+ *     generation is 4.
+ * \return
+ *     A uniformly distributed floating point number on the interval <tt>[0, 1)</tt>
+ */
+inline double sampleTEADouble(uint32_t v0, uint32_t v1, int rounds = 4) {
 	/* Trick from MTGP: generate an uniformly distributed
 	   single precision number in [1,2) and subtract 1. */
 	union {
@@ -184,33 +211,15 @@ inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
 	return x.f - 1.0;
 }
 
-#else
-/**
- * \brief Generate fast and reasonably good pseudorandom numbers using the
- * Tiny Encryption Algorithm (TEA) by David Wheeler and Roger Needham.
- * 
- * This function uses \ref sampleTEA to return single precision floating point
- * numbers on the interval <tt>[0, 1)</tt>
- *
- * \param v0
- *     First input value to be encrypted (could be the sample index)
- * \param v1
- *     Second input value to be encrypted (e.g. the requested random number dimension)
- * \param rounds
- *     How many rounds should be executed? The default for random number
- *     generation is 4.
- * \return
- *     A uniformly distributed floating point number on the interval <tt>[0, 1)</tt>
- */
+#if defined(SINGLE_PRECISION)
+/// Alias to \ref sampleTEASingle or \ref sampleTEADouble based on compilation flags
 inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
-	/* Trick from MTGP: generate an uniformly distributed
-	   single precision number in [1,2) and subtract 1. */
-	union {
-		uint32_t u;
-		float f;
-	} x;
-	x.u = ((sampleTEA(v0, v1, rounds) & 0xFFFFFFFF) >> 9) | 0x3f800000UL;
-	return x.f - 1.0f;
+	return sampleTEASingle(v0, v1, rounds);
+}
+#else
+/// Alias to \ref sampleTEASingle or \ref sampleTEADouble based on compilation flags
+inline Float sampleTEAFloat(uint32_t v0, uint32_t v1, int rounds = 4) {
+	return sampleTEADouble(v0, v1, rounds);
 }
 #endif