C++ (Cpp) LLVector4a::div Examples

Example #1

// Shrink the model to fit
// on a 1x1x1 cube centered at the origin.
// The positions and extents
// multiplied by  mNormalizedScale
// and offset by mNormalizedTranslation
// to be the "original" extents and position.
// Also, the positions will fit
// within the unit cube.
void LLModel::normalizeVolumeFaces()
{

	// ensure we don't have too many faces
	if (mVolumeFaces.size() > LL_SCULPT_MESH_MAX_FACES)
		mVolumeFaces.resize(LL_SCULPT_MESH_MAX_FACES);
	
	if (!mVolumeFaces.empty())
	{
		LLVector4a min, max;
		
		// For all of the volume faces
		// in the model, loop over
		// them and see what the extents
		// of the volume along each axis.
		min = mVolumeFaces[0].mExtents[0];
		max = mVolumeFaces[0].mExtents[1];

		for (U32 i = 1; i < mVolumeFaces.size(); ++i)
		{
			LLVolumeFace& face = mVolumeFaces[i];

			update_min_max(min, max, face.mExtents[0]);
			update_min_max(min, max, face.mExtents[1]);

			if (face.mTexCoords)
			{
				LLVector2& min_tc = face.mTexCoordExtents[0];
				LLVector2& max_tc = face.mTexCoordExtents[1];

				min_tc = face.mTexCoords[0];
				max_tc = face.mTexCoords[0];

				for (U32 j = 1; j < (U32)face.mNumVertices; ++j)
				{
					update_min_max(min_tc, max_tc, face.mTexCoords[j]);
				}
			}
			else
			{
				face.mTexCoordExtents[0].set(0,0);
				face.mTexCoordExtents[1].set(1,1);
			}
		}

		// Now that we have the extents of the model
		// we can compute the offset needed to center
		// the model at the origin.

		// Compute center of the model
		// and make it negative to get translation
		// needed to center at origin.
		LLVector4a trans;
		trans.setAdd(min, max);
		trans.mul(-0.5f);

		// Compute the total size along all
		// axes of the model.
		LLVector4a size;
		size.setSub(max, min);

		// Prevent division by zero.
		F32 x = size[0];
		F32 y = size[1];
		F32 z = size[2];
		F32 w = size[3];
		if (fabs(x)<F_APPROXIMATELY_ZERO)
		{
			x = 1.0;
		}
		if (fabs(y)<F_APPROXIMATELY_ZERO)
		{
			y = 1.0;
		}
		if (fabs(z)<F_APPROXIMATELY_ZERO)
		{
			z = 1.0;
		}
		size.set(x,y,z,w);

		// Compute scale as reciprocal of size
		LLVector4a scale;
		scale.splat(1.f);
		scale.div(size);

		LLVector4a inv_scale(1.f);
		inv_scale.div(scale);

		for (U32 i = 0; i < mVolumeFaces.size(); ++i)
		{
			LLVolumeFace& face = mVolumeFaces[i];

			// We shrink the extents so
			// that they fall within
			// the unit cube.
			face.mExtents[0].add(trans);
			face.mExtents[0].mul(scale);

			face.mExtents[1].add(trans);
			face.mExtents[1].mul(scale);

			// For all the positions, we scale
			// the positions to fit within the unit cube.
			LLVector4a* pos = (LLVector4a*) face.mPositions;
			LLVector4a* norm = (LLVector4a*) face.mNormals;

			for (U32 j = 0; j < (U32)face.mNumVertices; ++j)
			{
			 	pos[j].add(trans);
				pos[j].mul(scale);
				if (norm && !norm[j].equals3(LLVector4a::getZero()))
				{
					norm[j].mul(inv_scale);
					norm[j].normalize3();
				}
			}
		}

		// mNormalizedScale is the scale at which
		// we would need to multiply the model
		// by to get the original size of the
		// model instead of the normalized size.
		LLVector4a normalized_scale;
		normalized_scale.splat(1.f);
		normalized_scale.div(scale);
		mNormalizedScale.set(normalized_scale.getF32ptr());
		mNormalizedTranslation.set(trans.getF32ptr());
		mNormalizedTranslation *= -1.f; 
	}
}