Creating a projection matrix

[Sublixt]

I'm trying to create a projection matrix to use in my shaders. I've tried to use the algorithm from here(http://openglbook.com/the-book/chapter-4-entering-the-third-dimension/) to create the matrix, but when I multiply it with the model and view matrices that I've created nothing displays on the screen.
This is my translation of the C code.
Sorry if there are syntax errors. I wrote this in Scala and translated it to Java.

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public static Matrix4f projection(fov: Float, aspectRatio: Float, near: Float, far: Float) { Matrix4f out = new Matrix4f(); float yScale = 1.0f / scala.math.tan((fov / 2.0f).toRadians).toFloat; float xScale = yScale / aspectRatio; float frustumLength = far - near;           float[] tempArray = new float[16]; tempArray[0] = xScale; tempArray[5] = yScale; tempArray[10] = -((far + near) / frustumLength); tempArray[11] = -1; tempArray[14] = -((2 * near * far) / frustumLength);           FloatBuffer buf = BufferUtils.createFloatBuffer(16); buf.put(tempArray); buf.flip(); out.load(buf); return out; } //This is the method call Matrix.projection(60.0f, 800.0f / 600.0f, 1.0f, 100.0f); //and when I print the matrix that is returned I get this 1.2990382 0.0 0.0 0.0 0.0 1.7320509 0.0 0.0 0.0 0.0 -1.020202 -2.020202 0.0 0.0 -1.0 0.0

[ra4king]

That xScale doesn't look right. The article says f/aspect....you've interpreted 'f' to be the yScale, but how do you know?

[Sublixt]

I got yScale for f from the code sample at the top.

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Matrix CreateProjectionMatrix(    float fovy,    float aspect_ratio,    float near_plane,    float far_plane ) {    Matrix out = { { 0 } };    const float       y_scale = Cotangent(DegreesToRadians(fovy / 2)),       x_scale = y_scale / aspect_ratio,       frustum_length = far_plane - near_plane;    out.m[0] = x_scale;    out.m[5] = y_scale;    out.m[10] = -((far_plane + near_plane) / frustum_length);    out.m[11] = -1;    out.m[14] = -((2 * near_plane * far_plane) / frustum_length);        return out; }

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[Sublixt]

I found the problem. I multiplied the matrices in the wrong order.
I used

1	gl_Position = model * view * perspective * in_Position

when its should be

1	gl_Position = perspective * model * view * in_Position