glm/glm/core/func_packing.inl

///////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
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/// furnished to do so, subject to the following conditions:
/// 
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/// all copies or substantial portions of the Software.
/// 
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/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.
///
/// @ref core
/// @file glm/core/func_packing.inl
/// @date 2010-03-17 / 2011-06-15
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////

namespace glm
{
	GLM_FUNC_QUALIFIER uint32 packUnorm2x16(vec2 const & v)
	{
		uint16 A(uint16(round(clamp(v.x, 0.0f, 1.0f) * 65535.0f)));
		uint16 B(uint16(round(clamp(v.y, 0.0f, 1.0f) * 65535.0f)));
		return uint32((B << 16) | A);
	}

	GLM_FUNC_QUALIFIER vec2 unpackUnorm2x16(uint32 const & p)
	{
		uint32 Mask16((1 << 16) - 1);
		uint32 A((p >>  0) & Mask16);
		uint32 B((p >> 16) & Mask16);
		return vec2(A, B) * float(1.5259021896696421759365224689097e-5); // 1.0 / 65535.0
	}
	
	GLM_FUNC_QUALIFIER uint32 packSnorm2x16(vec2 const & v)
	{
		union iu
		{
			int16 i;
			uint16 u;
		} A, B;
		
		vec2 Unpack = round(clamp(v ,-1.0f, 1.0f) * 32767.0f);
		A.i = detail::int16(Unpack.x);
		B.i = detail::int16(Unpack.y);
		uint32 Pack = (uint32(B.u) << 16) | (uint32(A.u) << 0);
		return Pack;
	}

	GLM_FUNC_QUALIFIER vec2 unpackSnorm2x16(uint32 const & p)
	{
		union iu
		{
			int16 i;
			uint16 u;
		} A, B;
		
		uint32 Mask16((1 << 16) - 1);
		A.u = uint16((p >>  0) & Mask16);
		B.u = uint16((p >> 16) & Mask16);
		glm::vec2 Pack(A.i, B.i);
		
		return clamp(Pack * 1.0f / 32767.0f, -1.0f, 1.0f);
	}

	GLM_FUNC_QUALIFIER uint32 packUnorm4x8(vec4 const & v)
	{
		uint8 A((uint8)round(clamp(v.x, 0.0f, 1.0f) * 255.0f));
		uint8 B((uint8)round(clamp(v.y, 0.0f, 1.0f) * 255.0f));
		uint8 C((uint8)round(clamp(v.z, 0.0f, 1.0f) * 255.0f));
		uint8 D((uint8)round(clamp(v.w, 0.0f, 1.0f) * 255.0f));
		return uint32((D << 24) | (C << 16) | (B << 8) | A);
	}

	GLM_FUNC_QUALIFIER vec4 unpackUnorm4x8(uint32 const & p)
	{	
		uint32 Mask8((1 << 8) - 1);
		uint32 A((p >>  0) & Mask8);
		uint32 B((p >>  8) & Mask8);
		uint32 C((p >> 16) & Mask8);
		uint32 D((p >> 24) & Mask8);
		return glm::vec4(
			A * 1.0f / 255.0f, 
			B * 1.0f / 255.0f, 
			C * 1.0f / 255.0f, 
			D * 1.0f / 255.0f);
	}
	
	GLM_FUNC_QUALIFIER uint32 packSnorm4x8(vec4 const & v)
	{
		union iu
		{
			int8 i;
			uint8 u;
		} A, B, C, D;
	
		glm::vec4 Unpack = clamp(v ,-1.0f, 1.0f) * 127.0f;
		A.i = int8(round(Unpack.x));
		B.i = int8(round(Unpack.y));
		C.i = int8(round(Unpack.z));
		D.i = int8(round(Unpack.w));
		uint32 Pack = (uint32(D.u) << 24) | (uint32(C.u) << 16) | (uint32(B.u) << 8) | (uint32(A.u) << 0);
		return Pack;
	}
	
	GLM_FUNC_QUALIFIER glm::vec4 unpackSnorm4x8(uint32 const & p)
	{	
		union iu
		{
			int8 i;
			uint8 u;
		} A, B, C, D;
	
		uint32 Mask8((1 << 8) - 1);
		A.u = uint8((p >>  0) & Mask8);
		B.u = uint8((p >>  8) & Mask8);
		C.u = uint8((p >> 16) & Mask8);
		D.u = uint8((p >> 24) & Mask8);
		glm::vec4 Pack(A.i, B.i, C.i, D.i);
	
		return clamp(Pack * 1.0f / 127.0f, -1.0f, 1.0f);
	}

	GLM_FUNC_QUALIFIER double packDouble2x32(uvec2 const & v)
	{
		struct uint32_pair
		{
			uint32 x;
			uint32 y;
		};

		union helper
		{
			uint32_pair input;
			double output;
		} Helper;

		Helper.input.x = v.x;
		Helper.input.y = v.y;

		return Helper.output;
		//return *(double*)&v;
	}

	GLM_FUNC_QUALIFIER uvec2 unpackDouble2x32(double const & v)
	{
		struct uint32_pair
		{
			uint32 x;
			uint32 y;
		};

		union helper
		{
			double input;
			uint32_pair output;
		} Helper;

		Helper.input = v;

		return uvec2(Helper.output.x, Helper.output.y);
	}

	GLM_FUNC_QUALIFIER uint packHalf2x16(vec2 const & v)
	{
		union helper
		{
			uint other;
			struct
			{
				detail::hdata a, b;
			} orig;
		} Pack;

		Pack.orig.a = detail::toFloat16(v.x);
		Pack.orig.b = detail::toFloat16(v.y);
		return Pack.other;
	}

	GLM_FUNC_QUALIFIER vec2 unpackHalf2x16(uint const & v)
	{
		union helper
		{
			uint other;
			struct
			{
				detail::hdata a, b;
			} orig;
		} Unpack;
		Unpack.other = v;

		return vec2(detail::toFloat32(Unpack.orig.a), detail::toFloat32(Unpack.orig.b));
	}
}//namespace glm