OpenGL Instancing

Shows OpenGL instanced rendering. This instanced example drawing tutorial renders the same cube geometry using two different uniform matrix shader arguments.

[ryklin]

Valuable lesson... Need to go recode with this in mind. Still, it does seem that you're trading speed for memory because you're adding all these matrix multiplications to the paintgl() when you could be passing them as uniforms and letting the shader multiply them.

[peki_ooooooo]

Wow, this is the essence of instantiation.

[ORagnar]

I thought instancing meant one draw for everything.

[LesterShipMirOleg]

Really cool! Better than learning from books.

[JasonEwton]

Not sure if my hardware is the cause or if glm just has updated since this video (probably the later), but I had to use glm::radians(degrees) for both fovy parameter in glm::perspective and for the angle in glm::rotate to get the same results. I imagine these parameters in 2013 were using degrees but they now use radians.

[gnagtats]

Hey Jamie, strangley enough i have both cubes spawning and such but when i have the second cube on a rotation of 126* one of the cube's faces seem to disappear, i replaced the angle with 26* and now it works fine? haha

[mindstreamx]

hmm odd why is my left cube getting chopped off. I am using same transformations as the video. seems like its too close to the camera even though same perspective projection is being used.

[bgzdevtips]

So does the computer multiply 'projectionMatrix * translationMatrix * rotationMatrix' from right to left? Because if you did the math from left to right then that would mean you take the projection matrix first and multiply it by translation matrix and then finally multiply that output by rotation matrix which, since the rotation matrix is being multiplied last, would give you undesirable results.

[DariuszMakowski]

This appear to not be working in 2018, all I get is black window :- (

[dariusduesentrieb]

1:47:
if the GL-wall is open then its useless.