1. Home
  2. GameWorks OpenGL Graphics Samples
  3. Compute Basic GLSL Sample

Compute Basic GLSL Sample

Category:  Compute 
Min PC GPU: GeForce Fermi-class
Min Tegra Device: Tegra K1
@ GitHub: Compute Basic GLSL Sample Source Code

Description

This basic sample demonstrates how to interoperate between OpenGL [ES] and a simple OpenGL Compute Shader-based compute kernel.

Screenshot

APIs Used

  • GL_ARB_compute_shader
  • GL_COMPUTE_SHADER

Shared User Interface

The Graphics samples all share a common app framework and certain user interface elements, centered around the "Tweakbar" panel on the left side of the screen which lets you interactively control certain variables in each sample.

To show and hide the Tweakbar, simply click or touch the triangular button positioned in the top-left of the view.

Other controls are listed below.

Device Input Result
touch 1-Finger Drag Orbit-rotate the camera
2-Finger Drag Move up/down/left/right
2-Finger Pinch Scale the view
mouse Left-Button Drag Orbit-rotate the camera
Right-Button Drag Move up/down/left/right
Middle-Click Drag Scale the view (up:out, down:in)
keyboard Escape Quit the application
Tab Toggle TweakBar visibility
gamepad Start Toggle TweakBar visibility
Right ThumbStick Orbit-rotate the camera
Left ThumbStick Move forward/backward, Slide left/right
Left/Right Triggers Move up/down
A Show TweakBar, Toggle Focused Item
B Close Focused UI, Hide TweakBar
DPAD Up/Down Move Focus to Prev/Next Item
DPAD Left/Right Decrease/Increase Focused Item

Technical Details

This sample shows how to access GL textures efficiently from a compute shader, for both reading and writing.

It loads a source texture from a dds file, creates an output texture of equal size, then performs the following every frame:

  1. Bind both input and output textures to image units for compute use.

  2. Execute the compute kernel, which performs a simple color invert.

  3. Draw output texture to screen.

The Compute filter pass can be toggled from the UI.