What would you need their API for? It is only needed to create a Shadertoy
web player that could be integrated directly in your app similar to an ordinary web-browser control.
In fact, you don't need that. The pixel (a.k.a. fragment) shaders for specific user entries are available on the Shadertoy entry's respective page. Though they are designed for WebGL and customized a little further specifically for the Shadertoy API engine, they are still legible enough to be reversed to plain GLSL usable in OpenGL, and consequently, in ObjReader.
Note that Shadertoy doesn't accept models as vertex shader input. All entries share a common vertex shader that would only draw the shader output quad from VRAM to the on-screen OpenGL (actually, WebGL) viewport. It is equivalent to our common screen quad vertex shader as used now in drawing the post-processed FBO frames. All simulated 3D shapes and entities you're seeing in the Shadertoy player are being drawn exclusively in
the entry's fragment shader(s) as seen on the entry page by means of ray-marching technique.
You can modify Shadertoy fragment shader code and recompile it to see the effect of your mods directly in the entry's shader code editor. Those shaders that use only one yellow tab in the code editor ("Image") are suitable for use in ObjReader in 99.5% cases with only minimal fixes to comply with OpenGL, rather than WebGL, syntax and uniform naming convention. More than one tab in the code editor means the shader is multipass and requires several FBOs to be ping-ponged in VRAM before actual on-screen output. Those aren't yet implemented in OR and, after all, such multipass raymarching shaders are wa-a-a-ay too heavy on GPU to be used for low-priority purposes such as animated wallpapers.
My friend, it is much much easier and faster for me to just implement Shadertoy code based animated backgrounds in OR myself than guide you through the GLSL language in which I am still pretty much a newbie.
But you can provide a great service to OR by surfing through Snadertoy's entire shader base to select those shaders that look promising from the artistic perspective as OR's animated wallpapers.
(be prepared for frequent freezes of your browser as WebGL windows are still very difficult for it to render!) I can then supply you with a simple FBSL demo proggy for each of them where you will have a standalone fragment shader code file to fiddle with its parameters right on your desktop.
See the fragment shader in
AG.fs. See simple FBSL BASIC code (without includes) in
GLSL_AcidGalaxies.fbs to run a Shadertoy example in a user program. Press Alt+Enter to toggle the full screen mode, Esc to quit.
