opengl - Getting data back from compute shader -

i'm new opengl , found myself in situation need data compute shader miss critical knowledge can't work. came here, maybe can give me hints.

say have compute shader this:

#version 430 core struct rmtriangle {   vec4 probecenter;   vec4 triangles[3]; };  layout(std430, binding=9) buffer trianglebuffer {   rmtriangle triangles[]; }trbuffer;  //other uniforms, variables , stuff  void main() {   //here make computations , assign values   //trbuffer's triangles array } 

now use trbuffer's data in application. told make shader storage buffer did:

private int ssbo; gl.glgenbuffers(1, &ssbo); gl.glbindbuffer(gl_shader_storage_buffer, ssbo); //just allocate enough amount of memory gl.glbufferdata(gl_shader_storage_buffer, max_triangles * sizeof_triangle, null, gl_dynamic_read); 

then this:

int blockindex = gl.glgetprogramresourceindex(program,gl_shader_storage_block, name.getbytes(), 0); if (blockindex != gl_invalid_index) {     gl.glshaderstorageblockbinding(program, blockindex, index); } else {     system.err.println("warning: binding " + name + " not found"); } 

where name = "trianglebuffer" , index = 9

i know how access ssbo created in application. don't know how assign/transfer triangebuffer data ssbo.

add glbindbufferbase(gl_shader_storage_buffer, 9, ssbo);

also, when fetch data ssbos glmapbufferrange , memcpy stuff need.