# DX11 different colors when using XMVECTOR or XMFLOATs

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savail    333

So I'm following a tutorial http://www.rastertek.com/dx11tut04.html and managed to convert it from D3DX10math.h to DirectXMath.h but I can't get the same color values when using XMVECTOR or XMFLOATs for my vertices. I want to draw a green triangle and this is how I set positions and colors for vertices using XMVECTOR:

//vertices::position and vertices::color are XMVECTORs alligned to 16 bytes

vertices[0].position = DirectX::XMVectorSet(-1.0f, -1.0f, 0.0f, 0.0f);  // Bottom left.
vertices[0].color = DirectX::XMVectorSet(0.0f, 1.0f, 0.0f, 1.0f);

vertices[1].position = DirectX::XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f);  // Top middle.
vertices[1].color = DirectX::XMVectorSet(0.0f, 1.0f, 0.0f, 1.0f);

vertices[2].position = DirectX::XMVectorSet(1.0f, -1.0f, 0.0f, 0.0f);  // Bottom right.
vertices[2].color = DirectX::XMVectorSet(0.0f, 1.0f, 0.0f, 1.0f);

This gives me totally blue triangle, whereas such solution:

//vertices::position is XMFLOAT3 and vertices::color is XMFLOAT4

vertices[0].position = XMFLOAT3(-1.0f, -1.0f, 0.0f);  // Bottom left.
vertices[0].color = XMFLOAT4(0.0f, 1.0f, 0.0f, 1.0f);

vertices[1].position = XMFLOAT3(0.0f, 1.0f, 0.0f);  // Top middle.
vertices[1].color = XMFLOAT4(0.0f, 1.0f, 0.0f, 1.0f);

vertices[2].position = XMFLOAT3(1.0f, -1.0f, 0.0f);  // Bottom right.
vertices[2].color = XMFLOAT4(0.0f, 1.0f, 0.0f, 1.0f);

with types changed to XMFLOAT3 for position and XMFLOAT4 for color gives me correct green triangle.

I've played a bit with these coordinates and tried to make a green triangle using XMVECTORs but it doesn't seem to have any sense. The XMVECTOR solution returns wrong colors all the time whatever I set the coordinates to...

I know that it might be hard to guess what's the problem without some details but maybe somebody has an idea of what might be wrong?

PS: When I change the last parameter in XMVECTOR solution for vertices::position to 1.0f it changes the color near that vertex to pink, which is completely wierd for me as position shouldn't have impact on color?

Edited by savail

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savail    333

Thank you very much! Indeed, I had to change the format for my position in the layout from DXGI_FORMAT_R32G32B32_FLOAT to DXGI_FORMAT_R32G32B32A32_FLOAT and now everything works correctly! Thanks a lot again... there is so much to learn in DX 11 that one can easily get confused :(.

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