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Clean up rotation mess (and leave a comment about why it's wobbly)

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This commit is contained in:
Ben Visness
2018-06-30 20:00:47 +02:00
parent 33f24a8289
commit 449091185e
2 changed files with 9 additions and 65 deletions
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70
example/src/FollowCam.h
View File

@@ -29,73 +29,10 @@ public:
// LookAt thing, you can just always pass world up to it.
void Tick(float deltaSeconds) override {
// rotation = HMM_QuaternionFromAxisAngle(target->worldPosition() - worldPosition(), 0.0f);
// rotation = HMM_QuaternionFromAxisAngle(HMM_Vec3(0.0f, 1.0f, 0.0f), HMM_ToRadians(0.0f));
// rotation = HMM_Qu
hmm_vec3 fwd = (parentModelMatrix * HMM_Vec4(1.0f, 0.0f, 0.0f, 0.0f)).XYZ;
hmm_vec3 up = (parentModelMatrix * HMM_Vec4(0.0f, 1.0f, 0.0f, 0.0f)).XYZ;
hmm_vec3 to = target->worldPosition() - worldPosition();
float dot = HMM_DotVec3(fwd, HMM_NormalizeVec3(to));
if (HMM_ABS(dot - 1.0f) < 0.000001f) {
// do nothing to the rotation
} else if (HMM_ABS(dot + 1.0f) < 0.000001f) {
// rotate 180 I guess but for now do nothing
} else {
hmm_vec3 cross = HMM_Normalize(HMM_Cross(fwd, to));
rotation = HMM_QuaternionFromAxisAngle(
cross,
HMM_ACOSF(dot)
);
rotation *= HMM_QuaternionFromAxisAngle(
HMM_Vec3(1.0f, 0.0f, 0.0f),
-HMM_ACOSF(HMM_DotVec3(cross, up))
);
}
printf("Sort of working:\n");
printQuaternion(rotation);
printVec4(HMM_QuaternionToMat4(rotation) * HMM_Vec4(1.0f, 0.0f, 0.0f, 0.0f));
printMat4(HMM_QuaternionToMat4(rotation));
// return;
hmm_mat4 look = HMM_LookAt(HMM_Vec3(0.0f, 0.0f, 0.0f), HMM_Normalize(target->worldPosition() - worldPosition()), HMM_Vec3(0.0f, 1.0f, 0.0f));
rotation = HMM_Mat4ToQuaternion(look);
printf("New stuff:\n");
printQuaternion(rotation);
printVec4(HMM_QuaternionToMat4(rotation) * HMM_Vec4(1.0f, 0.0f, 0.0f, 0.0f));
printMat4(HMM_QuaternionToMat4(rotation));
// return;
rotation = HMM_QuaternionFromVectors(HMM_Vec3(0.001462f, -0.449079f, -0.893491f), HMM_Vec3(0.0f, 1.0f, 0.0f));
printf("Newer stuff:\n");
printQuaternion(rotation);
printVec4(HMM_QuaternionToMat4(rotation) * HMM_Vec4(1.0f, 0.0f, 0.0f, 0.0f));
printMat4(HMM_QuaternionToMat4(rotation));
// return;
printf("nighttime genius:\n");
hmm_vec3 right = HMM_Cross(to, up);
hmm_quaternion tiltUp = HMM_QuaternionFromAxisAngle(
right,
HMM_PI / 2 - HMM_ACosF(HMM_Dot(HMM_Normalize(to), HMM_Normalize(up)))
);
hmm_vec3 tiltedFwd = (HMM_QuaternionToMat4(tiltUp) * HMM_Vec4v(fwd, 0.0f)).XYZ;
hmm_quaternion pointAt = HMM_QuaternionFromAxisAngle(
HMM_Cross(right, to),
HMM_ACosF(HMM_Dot(HMM_Normalize(tiltedFwd), HMM_Normalize(to)))
);
rotation = tiltUp * pointAt;
printQuaternion(rotation);
printVec4(HMM_QuaternionToMat4(rotation) * HMM_Vec4(1.0f, 0.0f, 0.0f, 0.0f));
printMat4(HMM_QuaternionToMat4(rotation));
// dot products make this bad :(
// rotate around up vector first?
// just look, forget the up direction for a bit
hmm_quaternion justPointAt = HMM_QuaternionFromAxisAngle(
HMM_Cross(fwd, to),
HMM_ACosF(HMM_Dot(HMM_Normalize(fwd), HMM_Normalize(to)))
@@ -103,6 +40,13 @@ public:
hmm_vec3 newUp = (HMM_QuaternionToMat4(justPointAt) * HMM_Vec4v(up, 0.0f)).XYZ;
hmm_quaternion backUpright = HMM_QuaternionFromAxisAngle(
to,
// TODO: This angle is not quite right! After this corrective rotation,
// the new up vector will *not* necessarily align with world up! So this
// will overshoot a little bit.
//
// You should probably project the world up vector onto the plane of the
// to vector before you do the dot product. This is a good opportunity to
// add the vector projection stuff that we somehow have left out!
-HMM_ACosF(HMM_Dot(HMM_Normalize(newUp), HMM_Vec3(0.0f, 1.0f, 0.0f)))
);
rotation = backUpright * justPointAt;

4
example/src/main.cpp
View File

@@ -75,8 +75,8 @@ int main()
monkey.renderComponent = new MeshRenderComponent("MonkeySmooth.obj");
FollowCam cam = FollowCam(&monkey);
// cam.position = HMM_Vec3(-3.0f, -1.0f, 0.0f);
cam.position = HMM_Vec3(3.0f, 3.0f, 5.0f);
cam.position = HMM_Vec3(-3.0f, -1.0f, 0.0f);
// cam.position = HMM_Vec3(3.0f, 3.0f, 5.0f);
// cam.rotation = HMM_QuaternionFromAxisAngle(HMM_Vec3(0.0f, 1.0f, 0.0f), HMM_ToRadians(90.0f));
// Cube c = Cube();