How to generate GLSL code for image blur?
In addition, the GLSL code can be generated by running the sample, selecting the required kernel width and clicking on the “Gaussian Blur” interface button repeatedly a few times. So, we’ve got a good Gaussian blur implementation – but our “getting-hit” in-game effect requires a large blur kernel and our target hardware is a high res mobile device.
Which is the best GPU for image blur?
– Give an example of the techniques that runs on Windows Desktop OpenGL and Android OpenGL ES 3.0 and 3.1, including compute shader use on OpenGL ES 3.1. …but I realised that it might take more than one blog post (and a lot more work) to properly explore the topic, so below is the first installment.
How long does compute shader take in OpenGL?
I expected the compute shader to be similarly fast, but processing a 512×512 image this way takes half a second! I made sure that there is no initial slowdown in case the driver defers some operations by running the compute operation 20 times, but this results in a 20 second wall-clock time wait.
When does blur need to happen in real time?
So far we have ignored actual hardware implementation, but when we apply this algorithm to a real world scenario, the Gaussian blur filter pass needs to happen in real time, often on images with 1280×720 or more pixels.
Are there any drawbacks to using a blur buffer?
Blurring using intermediate lower resolution buffer at approx. 1/6 of the computation cost The main drawback is that with a small amount of blur (small blur kernels), the “blockiness” pattern from down-sampling to lower resolution and back becomes obvious, so this can be problematic if an effect needs to fade in/out, especially with moving images.
How does blur effect work on a GPU?
Well, it turns out it is fairly common to sacrifice some quality and, since blurring is a low-pass filter (preserves low frequency signals while attenuating high frequency ones), down-scale to a smaller resolution buffer, for example to ½ by ½, perform the blur effect and then up-scale back to the original frame buffer.