Pitch becomes yaw as camera gets near object

Question

I have been having trouble with my camera, first encountering the roll tilt that is so many times asked... I fixed that issue by following the instructions at this link: Unwanted roll when rotating camera with pitch and yaw But now I find another issue, whenever I get close to my triangle, pitch becomes roll, and instead of moving up and down the triangle, the camera rotates around the plane of that triangle, see:

This is my code, I follow the same logic as the link above!

  float spitch = pitch * camera.sensitivity, syaw = yaw * camera.sensitivity;
  float npitch = Math_Quaternion_GetPitch(camera.rotation) + spitch;
  if(npitch > Math_Degrees_ToRadians(85) || npitch < Math_Degrees_ToRadians(-85)) return;
  Math_Quaternion yaw_quat;
  Math_Quaternion pitch_quat;
  Math_Vec3 up = {0, 1, 0};
  Math_Vec3 left = {1, 0, 0};
  Math_Quaternion_RotationAroundAxis(yaw_quat, up, syaw);
  Math_Quaternion_MultiplyVec3(left, camera.rotation, \* this is out! *\ left);
  Math_Quaternion_RotationAroundAxis(pitch_quat, left, spitch);
  Math_Quaternion_Multiply(pitch_quat, camera.rotation, camera.rotation);
  Math_Quaternion_Multiply(yaw_quat, camera.rotation, camera.rotation);
  Math_Quaternion_Normalize(camera.rotation);

Edit: Also, switching the quaternion multiplication order or just using a normal pitch yaw roll method fixes the problem, but then the roll problem comes back!

It's a bit tough to get a sense of the motion happening in the animation. Are you able to record one with a visible horizon/sky to use as a global up/down reference? — DMGregory, Mar 11 '18 at 21:12
I fixed it by omiting the multiplyVec3(left... line and just using left as (1, 0, 0); — Whiteclaws, Mar 11 '18 at 21:20

Whiteclaws · Accepted Answer · 2018-03-11T23:38:50.127

0

I fixed it by omiting the multiplyVec3(left... line and just using left as (1, 0, 0); Edit: I just clumsily moved the code, made a mistake and it solved the issue, but I believe I'm locking the rotation around the x and y axis hence left and up instead of rotating my object relative to the quaternion's own up and left vectors... I'm not sure why it fixes the problem but it does!

edited Mar 11 '18 at 23:38

answered Mar 11 '18 at 21:20

Whiteclaws

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This answer would be even better if it included some insight into why this fixes the issue, to help others who run into similar problems. – DMGregory Mar 11 '18 at 23:02

Pitch becomes yaw as camera gets near object

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