Added packF3x9_E1x5 and unpackF3x9_E1x5 to GTC_packing for RGB9E5 #416

glm/gtc/packing.hpp

@@ -472,6 +472,28 @@ namespace glm
 	/// @see uint32 packF2x11_1x10(vec3 const & v)
 	GLM_FUNC_DECL vec3 unpackF2x11_1x10(uint32 p);
 
+
+	/// First, converts the first two components of the normalized floating-point value v into 11-bit signless floating-point values.
+	/// Then, converts the third component of the normalized floating-point value v into a 10-bit signless floating-point value.
+	/// Then, the results are packed into the returned 32-bit unsigned integer.
+	///
+	/// The first vector component specifies the 11 least-significant bits of the result; 
+	/// the last component specifies the 10 most-significant bits.
+	///
+	/// @see gtc_packing
+	/// @see vec3 unpackF3x9_E1x5(uint32 const & p)
+	GLM_FUNC_DECL uint32 packF3x9_E1x5(vec3 const & v);
+
+	/// First, unpacks a single 32-bit unsigned integer p into two 11-bit signless floating-point values and one 10-bit signless floating-point value . 
+	/// Then, each component is converted to a normalized floating-point value to generate the returned three-component vector.
+	/// 
+	/// The first component of the returned vector will be extracted from the least significant bits of the input; 
+	/// the last component will be extracted from the most significant bits.
+	/// 
+	/// @see gtc_packing
+	/// @see uint32 packF3x9_E1x5(vec3 const & v)
+	GLM_FUNC_DECL vec3 unpackF3x9_E1x5(uint32 p);
+
 	/// @}
 }// namespace glm
 

glm/gtc/packing.inl

@@ -248,6 +248,18 @@ namespace detail
 		uint32 pack;
 	};
 
+	union u9u9u9e5
+	{
+		struct
+		{
+			uint x : 9;
+			uint y : 9;
+			uint z : 9;
+			uint w : 5;
+		} data;
+		uint32 pack;
+	};
+
 }//namespace detail
 
 	GLM_FUNC_QUALIFIER uint8 packUnorm1x8(float v)
@@ -486,4 +498,31 @@ namespace detail
 			detail::packed10bitToFloat(v >> 22));
 	}
 
+	GLM_FUNC_QUALIFIER uint32 packF3x9_E1x5(vec3 const & v)
+	{
+		float const SharedExpMax = (pow(2.0f, 9.0f - 1.0f) / pow(2.0f, 9.0f)) * pow(2.0f, 31.f - 15.f);
+		vec3 const Color = clamp(v, 0.0f, SharedExpMax);
+		float const MaxColor = max(Color.x, max(Color.y, Color.z));
+
+		float const ExpSharedP = max(-15.f - 1.f, floor(log2(MaxColor))) + 1.0f + 15.f;
+		float const MaxShared = floor(MaxColor / pow(2.0f, (ExpSharedP - 16.f - 9.f)) + 0.5f);
+		float const ExpShared = MaxShared == pow(2.0f, 9.0f) ? ExpSharedP + 1.0f : ExpSharedP;
+
+		uvec3 const ColorComp(floor(Color / pow(2.f, (ExpShared - 15.f - 9.f)) + 0.5f));
+
+		detail::u9u9u9e5 Unpack;
+		Unpack.data.x = ColorComp.x;
+		Unpack.data.y = ColorComp.y;
+		Unpack.data.z = ColorComp.z;
+		Unpack.data.w = uint(ExpShared);
+		return Unpack.pack;
+	}
+
+	GLM_FUNC_QUALIFIER vec3 unpackF3x9_E1x5(uint32 v)
+	{
+		detail::u9u9u9e5 Unpack;
+		Unpack.pack = v;
+
+		return vec3(Unpack.data.x, Unpack.data.y, Unpack.data.z) * pow(2.0f, Unpack.data.w - 15.f - 9.f);
+	}
 }//namespace glm

readme.md

@@ -54,6 +54,7 @@ glm::mat4 camera(float Translate, glm::vec2 const & Rotate)
 #### [GLM 0.9.7.2](https://github.com/g-truc/glm/releases/latest) - 2015-XX-XX
 ##### Improvements:
 - Added compNormalize and compScale functions to GTX_component_wise
+- Added packF3x9_E1x5 and unpackF3x9_E1x5 to GTC_packing for RGB9E5 #416
 
 ##### Fixes:
 - Fixed GTC_round floorMultiple/ceilMultiple #412

test/gtc/gtc_packing.cpp

@@ -254,6 +254,30 @@ int test_F2x11_1x10()
 	return Error;
 }
 
+int test_F3x9_E1x5()
+{
+	int Error = 0;
+
+	std::vector<glm::vec3> Tests;
+	Tests.push_back(glm::vec3(1.0f));
+	Tests.push_back(glm::vec3(0.0f));
+	Tests.push_back(glm::vec3(2.0f));
+	Tests.push_back(glm::vec3(0.1f));
+	Tests.push_back(glm::vec3(0.5f));
+	Tests.push_back(glm::vec3(0.9f));
+
+	for (std::size_t i = 0; i < Tests.size(); ++i)
+	{
+		glm::uint32 p0 = glm::packF3x9_E1x5(Tests[i]);
+		glm::vec3 v0 = glm::unpackF3x9_E1x5(p0);
+		glm::uint32 p1 = glm::packF3x9_E1x5(v0);
+		glm::vec3 v1 = glm::unpackF3x9_E1x5(p1);
+		Error += glm::all(glm::epsilonEqual(v0, v1, 0.01f)) ? 0 : 1;
+	}
+
+	return Error;
+}
+
 int test_packUnorm1x16()
 {
 	int Error = 0;
@@ -522,6 +546,7 @@ int main()
 	Error += test_packUnorm4x8();
 
 	Error += test_F2x11_1x10();
+	Error += test_F3x9_E1x5();
 	Error += test_Snorm3x10_1x2();
 	Error += test_Unorm3x10_1x2();
 	Error += test_I3x10_1x2();