OpenGL_Compute_Shaders_with_SSBO_in_Odin

The dream of having something resembling CUDA Computing on the GPU in simple OpenGL on open source drivers.

To perform general computing tasks, of the type of CUDA on the GPU using Compute Shaders and SSBO - Shader Storage Buffer Objects.

The following code has a bug and in my open source Linux drivers on a Integrated AMD GPU inside my CPU AMD Ryzen 4700 G, it crashes the computer. Not fun at all. But because there is so little information on the internet about how to use the Compute shaders and SSBO - Shader Storage Buffer Objects, I am posting this code anyway.

I implemented this code in Odin after doing a lot of research on the internet.
I post here the code and the references that I used to implement it.

There is also a other program inside the directory "opengl_simple_program_working", that works, I made it from following the learning OpenGL tutorial from the site: https://learnopengl.com and from one example of Odin of the GLFW library. That program doesn't use Compute Shaders and SSBO - Shader Storage Buffer Objects, but it works and it is a good starting point to learn how to use OpenGL in Odin.

• Medium Article on Compute Shaders with texture buffers, no SSBO.
  https://medium.com/@daniel.coady/compute-shaders-in-opengl-4-3-d1c741998c03

• GitHub of the previous article
  https://github.com/pondodev/opengl_compute/tree/29802608ead55c92184fadfac63042382d5592c3

• What is the difference between OpenCL and OpenGL's compute shader?
  https://stackoverflow.com/questions/15868498/what-is-the-difference-between-opencl-and-opengls-compute-shader/15874988

• StackOverFlow response - To resolve the fact than OpenGL calculation can be less accurate then IEEE float 32
  Those interested in OpenGL arithmetic precision guarantees should regard the ARB_shader_precision extension, introduced in OpenGL 4.1.a
  See: https://registry.khronos.org/OpenGL/extensions/ARB/ARB_shader_precision.txt
  Droid Coder
  Aug 11, 2019 at 11:22
  

• OpenGL (4.3) compute shader example
  http://wili.cc/blog/opengl-cs.html

• Compute Shader - Official documentation
  https://www.khronos.org/opengl/wiki/Compute_Shader

• It's More Fun to Compute
  An Introduction to Compute Shaders
  https://antongerdelan.net/opengl/compute.html

• Mike Bailey
  OpenGL Compute Shaders
  https://web.engr.oregonstate.edu/~mjb/cs557/Handouts/compute.shader.1pp.pdf

• In Python - Compute Shader Tutorial
  https://api.arcade.academy/en/latest/tutorials/compute_shader/index.html

• ktyldev - oglc -- Cat flynn
  https://github.com/ktyldev/oglc

• Textures
  https://learnopengl.com/Getting-started/Textures

• glCreateShader — Creates a shader object
  https://registry.khronos.org/OpenGL-Refpages/gl4/html/glCreateShader.xhtml

• Shader Storage Buffer Object
  https://www.khronos.org/opengl/wiki/Shader_Storage_Buffer_Object

• GPU Buffers: Introduction to OpenGL 4.3 Shader Storage Buffers Objects
  https://www.geeks3d.com/20140704/tutorial-introduction-to-opengl-4-3-shader-storage-buffers-objects-ssbo-demo/

• Buffer Object
  https://www.khronos.org/opengl/wiki/Buffer_Object

• glTexImage2D — specify a two-dimensional texture image
  https://registry.khronos.org/OpenGL-Refpages/gl4/html/glTexImage2D.xhtml

• glBindImageTexture — bind a level of a texture to an image unit
  https://registry.khronos.org/OpenGL-Refpages/gl4/html/glBindImageTexture.xhtml

• Shaders
  https://learnopengl.com/Getting-started/Shaders

• Compute Shaders - Inputs
  https://www.khronos.org/opengl/wiki/Compute_Shader#Inputs

• Compute Shaders - local_size
  https://www.khronos.org/opengl/wiki/Compute_Shader#Local_size

• glGetTexImage — return a texture image
  https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGetTexImage.xhtml

MIT Open Source License

Best regards,
João Nuno Carvalho