How do you calculate perspective division in OpenGL?
How do you calculate perspective division in OpenGL?
OpenGL requires that the visible coordinates fall between the range -1.0 and 1.0 as the final vertex shader output, thus once the coordinates are in clip space, perspective division is applied to the clip space coordinates: o u t = (x / w y / w z / w)
Where is the camera located in OpenGL?
As far as OpenGL is concerned, there is no camera. More specifically, the camera is always located at the eye space coordinate (0.0, 0.0, 0.0).
What is the difference between clip space coordinates and view space coordinates?
If the coordinate system of the view space is a Right-handed system, where the X-axis points to the right and the Y-axis points up, then the Z-axis points out of the view (Note in a right hand system the Z-Axis is the cross product of the X-Axis and the Y-Axis). Clip space coordinates are Homogeneous coordinates.
How to transform vertex coordinates from view to clip-space?
To transform vertex coordinates from view to clip-space we define a so called projection matrix that specifies a range of coordinates e.g. -1000 and 1000 in each dimension. The projection matrix then transforms coordinates within this specified range to normalized device coordinates (-1.0, 1.0).
How do I rotate a quaternion in GLSL?
Convert your quaternion to a rotation matrix, and use it in the Model Matrix. Your vertices will be rotated as usual, with the MVP matrix. In some cases, you might actually want to use quaternions in GLSL, for instance if you do skeletal animation on the GPU.
What are the matrices in openopengl?
OpenGL has two matrices related to the display of geometry, the ModelView and the Projection. Both are applied to coordinates before the data becomes visible on the screen. First the ModelView matrix is applied, transforming the data from model space into view space.
Why is my triangle not showing up in my OpenGL drawing?
You are drawing the triangle in a left handed, or clockwise method, whereas the default for OpenGL is a right handed, or counterclockwise coordinate system. This means that, if you are culling backfaces (which you are probably not, but will likely move onto as you get more advanced), you would not see the triangle as expected.
