When using OpenGL the easiest way would be a textured Quad. Set texture wrap mode to GL_REPEAT, then you can rotate each wheel simply by setting texture coordinates. It's possible SDL is also able to do this, I'm not familiar with SDL.



I don't see how a cone would help here. However, you could use a textured cylinder. When rendering in 3D this would cause some nice perspective effects: The slot-wheel would really look like a wheel. Also there would be no need to change the texture coords, you could simply rotate the wheel using glRotate.

Ok for Quad, but then i would be limited to 4 sides / different symbols?

but I would like to try with Opengl since i would also need to add motion blur effect for better look.

i dont understand how many symbols i could max "glue" to cylinder,

how big cylinder i would need to make?

and i would need to make 5 cylinders so i could roll each cylinder independantly?

No. Using the Quad you can display a small window of your symbol texture. This has the size of one single symbol and scrolls over the texture. The number of symbols is only limited by the texture size.
This is basically the same as when drawing an image using SDL. The only difference is that in the OpenGL case the trick is done by graphics hardware, while SDL does use the CPU. However, performance is not a problem here since you only need a few wheels.


Just render each wheel multiply times with slightly different positions in rotation direction. All rendered images are combined together with additive blending, which does result in some kind of average image.



In a simple case factor is just "1 / image count". However, I recommend to use a Gauss function for factor, because it does not produce artifacts. For details on Gauss functions take a look on this shader article:
http://wiki.delphigl.com/index.php/shad ... schreibung
Don't bother what a "shader" is, just take a look on the image and formula.


Just wrap the texture around the cylinder. Just imagine a real cylinder: You can wrap a piece of paper of length 2*PI*radius around it. The number of symbols is again only limited by the texture size. However, if the texture gets larger, the display size of each symbol will be smaller, since you will have to scale the texture to 2*PI*radius height.


As big as a real cylinder would be. If you need 10 symbols, each symbol would get 360/10 = 36 degree on the wheel. So you need to scale the wheel so that a 36 degree window does match your favored size.


No, you could use the same cylinder rendered multiple times with different symbol textures and positions.

Have a look at the pictures in "Tutorial_Matrix2". That may help.

As Far as I remember, the cylinder is oriented along the Z-axis.
So you have to add an additional rotation, to see the correct side of the cylinder.

No. Using the Quad you can display a small window of your symbol texture. This has the size of one single symbol and scrolls over the texture. The number of symbols is only limited by the texture size.
This is basically the same as when drawing an image using SDL. The only difference is that in the OpenGL case the trick is done by graphics hardware, while SDL does use the CPU. However, performance is not a problem here since you only need a few wheels.


Just render each wheel multiply times with slightly different positions in rotation direction. All rendered images are combined together with additive blending, which does result in some kind of average image.



In a simple case factor is just "1 / image count". However, I recommend to use a Gauss function for factor, because it does not produce artifacts. For details on Gauss functions take a look on this shader article:
http://wiki.delphigl.com/index.php/shad ... schreibung
Don't bother what a "shader" is, just take a look on the image and formula.


Just wrap the texture around the cylinder. Just imagine a real cylinder: You can wrap a piece of paper of length 2*PI*radius around it. The number of symbols is again only limited by the texture size. However, if the texture gets larger, the display size of each symbol will be smaller, since you will have to scale the texture to 2*PI*radius height.


As big as a real cylinder would be. If you need 10 symbols, each symbol would get 360/10 = 36 degree on the wheel. So you need to scale the wheel so that a 36 degree window does match your favored size.


No, you could use the same cylinder rendered multiple times with different symbol textures and positions.

and how to apply each sprite(symbol) to one cylinder side? (byt coordinates or?)

and how to apply each sprite(symbol) to one cylinder side? (byt coordinates or?)

but you said that i can do it with just one cylinder?

You could either use 5 different textures and bind the correct texture each time when you draw the cylinder.

The other way would be using one single big texture and select the correct column using a texture matrix:
Let n be the number of columns and i the column you want do select starting with zero. Texture coordinates (s,t) run always from 0 to 1. To select a column you need to map t-coordinates i/n ... (i+1)/n to the full size 0 ... 1. This can be done using a Texture matrix. Each texture coordinate is multiplied by this matrix. The mapping you need to do is:

In OpenGL this does look like this:


It's possible that you have to swap glScale and glTranslate.