Jump to content
  • Advertisement
Sign in to follow this  

Software Rasterizer

This topic is 1043 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello every one,
i'm having a bit of a trouble tracking a bug,
i'm getting weird edges at the end of a triangle only when using SSE, the output is just fine with scalars,
here is an image tothe problem,
and that's the code, it basically performs a point triangle intersection test based on fgiesen blog series

for (p.y = iMinY; p.y <= iMaxY; p.y += SEdge::s_iYStepSize, iIdx += iDepthBufferWidth)
			Simd::I32x4 i4w0 = i4W0Row;
			Simd::I32x4 i4w1 = i4W1Row;
			Simd::I32x4 i4w2 = i4W2Row;
			I32 iXIdx = iIdx;

			for (p.x = iMinX; p.x <= iMaxX; p.x += SEdge::s_iXStepSize,
				iXIdx += SEdge::s_iXStepSize,
				// one step to the right.
				i4w0 = Simd::AddPackedI32(i4w0, e12.i4StepX),
				i4w1 = Simd::AddPackedI32(i4w1, e20.i4StepX),
				i4w2 = Simd::AddPackedI32(i4w2, e01.i4StepX))
				const Simd::I32x4 i4Mask = _mm_cmplt_epi32(zero, Simd::OrPackedI32(i4w0, Simd::OrPackedI32(i4w1, i4w2)));
				if (_mm_test_all_zeros(i4Mask, i4Mask))

				Simd::F32x4 depth = z0;
				depth = Simd::AddPacked(depth, Simd::MulPacked(_mm_cvtepi32_ps(i4w1), z1));
				depth = Simd::AddPacked(depth, Simd::MulPacked(_mm_cvtepi32_ps(i4w2), z2));

				Simd::F32x4 prevDepth = _mm_load_ps(&pRenderTarget[iXIdx]);
				Simd::F32x4 depthMask = _mm_cmplt_ps(depth, prevDepth);
				Simd::I32x4 finalMask = _mm_and_si128(i4Mask, _mm_castps_si128(depthMask));
				depth = Simd::BlendPacked(prevDepth, depth, _mm_castsi128_ps(finalMask));

				Simd::StorePacked(&pRenderTarget[iXIdx], depth);

			i4W0Row = Simd::AddPackedI32(i4W0Row, e12.i4StepY);
			i4W1Row = Simd::AddPackedI32(i4W1Row, e20.i4StepY);
			i4W2Row = Simd::AddPackedI32(i4W2Row, e01.i4StepY);

Share this post

Link to post
Share on other sites

SIMD Swizzle ? xyzw <->wzyx ?

i don't think so, the store implicitly changes the order, and i'v tried it but it didn't work.



Actually that this solve those edges, but now introduces interiors


Edited by medigames

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!