Patch sharing: Point clouds with antialiasing, motion blur and DoF processed by geometry shader

Hi guys,

I'd like to share with you a patch I'm currently working on. It consists of a particle rendering system with some of the eye candy we know and love (antialiasing, motion blur and depth of field) created by a geometry shader.

The particle system is divided in two parts:
- a point "displacer" done with jit.gl.tf
- a particle rendering shader

The first part is quite simple and random; it just provides some moving points for the sake of example.

The key part is the rendering shader. Around each point is constructed a set of vertices in a circular path. In the geometry shader the radius of each circle and the color of each vertex is defined independently.

The depth of field is created by enlarging the radius of the circles according to the distance from the camera (z depth) and a focus distance, and by reducing the transparency of the circles far from the focus distance. This gives the illusion of "out of focus" objects.

The motion blur effect is achieved by elongating the geometry against the direction of motion. This is done by retrieving the position of the particles at the previous frame from [jit.gl.tf] and varying what is considered the center to construct the circle around according to the angle formed by the center and the vertices at the circle border. The color of the elongated part is then faded in order to make it appear more like a trail than a solid object.

The antialiasing is achieved by giving a transparent color to the vertices at the border of the circle and by deciding (in the fragment shader) at witch distance from the center to start fading the color.
An issue if found is that I should have worked in another space, because enlarging the window causes the geometry to deform.
What i'd like to introduce is curved motion blur trails done by keeping in a buffer the velocity of the particles at the previous frame and generating more vetices in the geometry shader following the curve the particle "might have done".

I'd also like to extend the same principle to lines.

I'd love if you could contribute to this or spread some suggestions.

Here it is the patch and the shaders:

Ciao!