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PODirect3D & iPhone Accelerometer Matrix
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693665
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CreationDate
2009-03-28T22:30:54.673
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2009-08-28T21:26:16.753
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84124
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I am using a WinSock connection to get the accelerometer info off and iPhone and into a Direct3D application. I have modified Apples GLGravity's sample code to get my helicopter moving in relation to gravity, however I need to "cap" the movement so the helicopter can't fly upside down! I have tried to limit the output of the accelerometer like so <pre><code>if (y < -0.38f) { y = -0.38f; } </code></pre> Except this doesn't seem to work!? The only thing I can think of is I need to modify the custom matrix, but I can't seem to get my head around what I need to be changing. The matrix is code is below. <pre><code> _x = acceleration.x; _y = acceleration.y; _z = acceleration.z; float length; D3DXMATRIX matrix, t; memset(matrix, '\0', sizeof(matrix)); D3DXMatrixIdentity(&matrix); // Make sure acceleration value is big enough. length = sqrtf(_x * _x + _y * _y + _z * _z); if (length >= 0.1f && kInFlight == TRUE) { // We have a acceleration value good enough to work with. matrix._44 = 1.0f; // // First matrix column is a gravity vector. matrix._11 = _x / length; matrix._12 = _y / length; matrix._13 = _z / length; // Second matrix is arbitrary vector in the plane perpendicular to the gravity vector {Gx, Gy, Gz}. // defined by the equation Gx * x + Gy * y + Gz * z = 0 in which we set x = 0 and y = 1. matrix._21 = 0.0f; matrix._22 = 1.0f; matrix._23 = -_y / _z; length = sqrtf(matrix._21 * matrix._21 + matrix._22 * matrix._22 + matrix._23 * matrix._23); matrix._21 /= length; matrix._22 /= length; matrix._23 /= length; // Set third matrix column as a cross product of the first two. matrix._31 = matrix._12 * matrix._23 - matrix._13 * matrix._22; matrix._32 = matrix._21 * matrix._13 - matrix._23 * matrix._11; matrix._33 = matrix._11 * matrix._22 - matrix._12 * matrix._21; } </code></pre> If anyone can help it would be much appreciated!
Tags
<c++><iphone><directx><direct3d><matrix>
Title
Direct3D & iPhone Accelerometer Matrix
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1. This table or related slice is empty.
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1. This table or related slice is empty.
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1. PTQuestion
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1. This table or related slice is empty.
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1. USuser84124
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1. PO
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 PTAnswer
2. PO
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1. VO
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 PODirect3D & iPhone Accelerometer Matrix
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