# Tag Info

Accepted

### What is the correct order of transformations scale, rotate and translate and why?

Usually you scale first, then rotate and finally translate. The reason is because usually you want the scaling to happen along the axis of the object and rotation about the center of the object. In ...
• 3,666
Accepted

• 156
Accepted

### Why do I need to inverse the orientation matrix of a camera to be able to translate it in the direction it is facing?

People always forget that there is no "camera" in OpenGL. In order to simulate a camera you have to move the whole world inversely. So if you want ur camera looking 30 degrees downward, you move the ...
• 2,478
Accepted

### Zoom in orthographic vs perspective projection

Perspective projection changes the size of an object as it's distance changes, while orthographic projection does not. That is part of the definition of those projection types. To simplify things a ...
• 7,801

• 341

### Image rotation using FFT

Yes, it is possible. Remember that a shift in space is equivalent to a linear-phase multiplication in frequency. A rotation can be accomplished by a shearing operation in one direction followed by a ...

### Transforming fragment-to-camera to tangent space for parallax occlusion mapping

Without looking at the code, from the look of the pictures, my intuition would be that somewhere the code is using the inverse of the matrix it should. Looking at the code seems to confirm so, but ...
• 4,420

### Screenspace Normals - Creation, Normal Maps, and Unpacking

How are screenspace normals created, and is this step before or after using normal maps or bump maps? They are created after using normal maps. In deferred rendering, you write to the various buffers ...
• 1,353

### What's a parent vector space or coordinate system?

You have to step outside the world of mathematics for a while and look at what we are trying to achieve. Mathematics in its purest form only tells us what kinds of properties certain constructs have, ...
• 8,447
Accepted

### Calculate a rotation around an arbitrary axis

Take a point $P$ and it's rotated point $P'$. Find the plan that runs through the middle between them $C = \frac{P+P'}{2}$ and is perpendicular to the line connecting them. Do this for all 3 of them ...
• 5,970
Accepted

### Supporting multiple camera types in a deferred renderer without specializing the shaders or in the shaders

Projective transformations (represented by 4×4 projection matrices) are invertible. You can go from NDC coordinates back to view space using the inverse of the projection matrix, in the same way that ...
• 25.1k
Accepted

### Curve rotation in GLSL fragment shader

You are doing completely different things in Matlab than in your Fragment Shaders. In Matlab you are generating bunch of points that can be drawn anywhere on the screen and then you are transforming ...
• 56
Accepted

### Need help with change of basis (world to camera frame)

Since the transformation that is asked for includes a translation (the camera is located at a position other than the origin), you will indeed have to use homogeneous coordinates to describe this ...