how to make skills and their animations in opengl ? are skills 3d model or 2d?

Question

1)slash effect 2)area skills like dota2 crystal maiden ulti and first skill 3)over an enemy skills example dota2 crystal maiden second skill

how they make in opengl

i know opengl billboards way and texture atlas i can make basic flame effect with using these 2 way together. But how they make others ? area skills are 3d model animation ? then its texture is changing every frame? over an enemy skills can 3d model i think? how they make skills transparent ? with glblend ? what is best way to make them sorry for bad english i searched but i couldn't find any suggestion help please im using c++,sdl,opengl

Answer 1

First of all, you seem very confused.

You want to create an visual effect whenever the player attacks another player. These are called Particle Systems. Here is a simple definition of a texture atlas and billboarding:

Texture Atlas

A texture atlas looks something like this:

all it does is storing a bunch of textures in one single image, so that we can specify some coordinates(relative to this texture atlas) and get a specific texture.

Billboards

Billboarding let's you rotate something(a quad in this case) towards the camera, so that the object is always facing you.

Making these effects:

To make these effects, we need to use particle systems and animated quads(simple textured quads with an animation). Here is an example seen in the video:

Basically, you need a textured quad, that gets spawned onto the terrain (looks like it's projected onto the terrain, but this is the easiest way i can think of), once that is done, you need to spawn some particle systems(the fire) relative to the position of the quad.

For the other particle systems like this one:

all you need to do is get a position on the terrain, and spawn the 3D models on top of that position.