you run opengl functions in form_run but opengl context has not yet available at that point. try put them inside the initialize callback. see the shader.ijs demo.
you can query the version of shader langauge in the initialize callback and determine whether you need the #version header. On Jun 27, 2015 8:28 AM, "Raul Miller" <[email protected]> wrote: > I am trying to implement a minimal example of using a shader within J. > > This means: no vertex shader. I just want to paint the screen a solid > color. > > This means: no #version header (which I believe is equivalent to #version > 110). > > Unfortunately, while this should work in principle, a number of > variations on the implementation have not worked for me. > > I can show that opengl is working, using the glClear mechanism, but > while that accomplishes the "set the screen to a single color" > subtask, it does not get me my minimal shader which was the point of > the exercise. > > Here's an example: > > load 'pacman' > 'install' jpkg 'graphics/gl2 api/gles' > require 'graphics/gl2 api/gles' > coinsert 'jgl2 jgles' > > FORM=: 0 : 0 > pc form closeok; > minwh 320 240; cc gl opengl flush; > ) > fshader=: 0 :0 > void main(void) { > gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); > } > ) > form_run=: 3 : 0 > wd FORM > 'err program'=: gl_makeprogram '';fshader > if.#err do. smoutput err return. end. > wd 'pshow' > gl_paint '' > ) > form_gl_paint=: 3 : 0 > smoutput 'painting' > glClearColor 0 0 1 1 > glClear GL_COLOR_BUFFER_BIT + GL_DEPTH_BUFFER_BIT > glUseProgram program > ) > form_run'' > > Now... > > Part of the problem is that I do not know what is happening in libjqt, > and those entry points are not documented. But I do not necessarily > need that, I hope, not right now anyways. > > Anyways, if I eliminate the glClearColor and glClear statements, the > image is black. But if the shader were to be used, the image would be > red. > > How do I make this work? > > Thanks, > > -- > Raul > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
