Hello everyone,

I already asked this question in another forum but didn't get any answers so far. Hopefully you are able to help me regarding a question about camera rotation. Following multiple tutorials (LWJGL-Wiki MVP:

http://www.lwjgl.org/wiki/index.php?title=The_Quad_with_Projection,_View_and_Model_matrices & OpenGL-Tutorial.org:

http://www.opengl-tutorial.org/beginners-tutorials/tutorial-6-keyboard-and-mouse/) I was able to create some cubes that are rendered with the use of model-, view- and projectionmatrices in Java 7 using LWJGL. Since yesterday morning I am trying to implement camera movement and rotation. Everything seems to work fine, but with a closer look the camera (respectively the world) seems to translate when rotating.

Is that behavior normal or is something seriously wrong?

The following video shows what I am trying to describe:

http://www.youtube.com/watch?v=no4iTw4WPMw Here is the code, that creates the matrices, Projection (with 45f, 1280f / 720f, 0.1f, 100f):

`[code]public static Matrix4f projectionMatrix(float fov, float aspect, float near, float far) {`

float frustum = far - near;

float scaleY = (float)(1f / Math.tan(Math.toRadians(fov / 2f)));

float scaleX = scaleY / aspect;

Matrix4f result = new Matrix4f();

result.m00 = scaleX;

result.m11 = scaleY;

result.m22 = -((far + near) / frustum);

result.m23 = -1;

result.m32 = -((2 * near * far) / frustum);

return result;

}

View (eye is the cameras position, up is (0f, 1f, 0f):

`public static Matrix4f lookAtMatrix(Vector3f eye, Vector3f target, Vector3f up) {`

Vector3f zaxis = new Vector3f(

target.x - eye.x,

target.y - eye.y,

target.z - eye.z

);

zaxis.normalise();

Vector3f xaxis = new Vector3f();

Vector3f.cross(up, zaxis, xaxis);

xaxis.normalise();

Vector3f yaxis = new Vector3f();

Vector3f.cross(zaxis, xaxis, yaxis);

Matrix4f rotation = new Matrix4f();

rotation.m00 = xaxis.x;

rotation.m01 = yaxis.x;

rotation.m02 = zaxis.x;

rotation.m10 = xaxis.y;

rotation.m11 = yaxis.y;

rotation.m12 = zaxis.y;

rotation.m20 = xaxis.z;

rotation.m21 = yaxis.z;

rotation.m22 = zaxis.z;

rotation.m33 = 1;

Matrix4f translation = new Matrix4f();

translation.m00 = 1;

translation.m11 = 1;

translation.m22 = 1;

translation.m30 = -eye.x;

translation.m31 = -eye.y;

translation.m32 = -eye.z;

translation.m33 = 1;

Matrix4f result = new Matrix4f();

Matrix4f.mul(rotation, translation, result);

return result;

}

I calculate the target with the following code (position, yaw and pitch are attributes of the camera):

`Vector3f target = new Vector3f(`

position.x - (float) (Math.cos(Math.toRadians(pitch)) * Math.sin(Math.toRadians(yaw))),

position.y + (float) (Math.sin(Math.toRadians(pitch))),

position.z + (float) (Math.cos(Math.toRadians(pitch)) * Math.cos(Math.toRadians(yaw)))

);

The model matrices shouldn't be the problem.

The vertex shader calculates the MVP (but also shouldn't be the problem):

`#version 330 core`

uniform mat4 projectionMatrix;

uniform mat4 viewMatrix;

uniform mat4 modelMatrix;

in vec4 in_Position;

in vec4 in_Color;

out vec4 pass_Color;

void main(void) {

gl_Position = projectionMatrix * viewMatrix * modelMatrix * in_Position;

pass_Color = in_Color;

}

Hope, someone is able to help me.

Thanks, rejooh.[/code]