audio - iOS. OpenGL. Several views simultaneously -

a couple of days before asked filling space between 2 curve lines gradient. since i've changed lots of in code - i'm using shaders. result need. but! again have problem using several opengl views simultaneously in 1 controller must absolutely independent between each other. so, unbelievable tutorial raywenderlich.com , code example bradley have next situation:

• two custom objects of class soundwaveview.swift (improved openglview.swift bradley);
• vertex/fragment shaders openglview object;
• controller create , add 2 soundwaveview objects (with same context!!!!!):

c

override func viewdidload() {     super.viewdidload()       let context = eaglcontext(api: eaglrenderingapi.opengles2)      let viewpos1: cgrect = cgrectmake(0, 150, uiscreen.mainscreen().bounds.size.width, 150);     let view1 = soundwaveview(frame: viewpos1, filename: "personal jesus", fileextention: "mp3", c: context)     view1.backgroundcolor = uicolor.graycolor()     self.view.addsubview(view1)       let viewpos2: cgrect = cgrectmake(0, 350, uiscreen.mainscreen().bounds.size.width, 150);     let view2 = soundwaveview(frame: viewpos2, filename: "imagine", fileextention: "mp3", c: context)     view2.backgroundcolor = uicolor.blackcolor()     self.view.addsubview(view2) } 

every soundwaveview-object compiles shaders in tutorials above:

    func compileshaders() {      let vertexshader = compileshader("simplevertex", shadertype: glenum(gl_vertex_shader))     let fragmentshader = compileshader("simplefragment", shadertype: glenum(gl_fragment_shader))      let programhandle: gluint = glcreateprogram()     glattachshader(programhandle, vertexshader)     glattachshader(programhandle, fragmentshader)     gllinkprogram(programhandle)      var linksuccess: glint = glint()     glgetprogramiv(programhandle, glenum(gl_link_status), &linksuccess)     if (linksuccess == gl_false) {         var message = [cchar](count: 256, repeatedvalue: cchar(0))         var length = glsizei(0)         glgetprograminfolog(programhandle, 256, &length, &message)         print("failed create shader program! : \( string(utf8string: message) ) ")         exit(1);     }      gluseprogram(programhandle)      .  .  .  .  .     shaderpeakid = glgetuniformlocation(programhandle, "peakid")      shaderwaveamp = glgetuniformlocation(programhandle, "waveamp");      glenablevertexattribarray(positionslot)     glenablevertexattribarray(colorslot)      gluniform1f(shaderscenewidth!,  float(self.frame.size.width));     gluniform1f(shadersceneheight!, float(self.frame.size.height));     gluniform1i(shaderpeakstotal!,  glint(total));     gluniform1i(shaderpeakid!,      glint(position));  } 

for rendering audio waves need pass shader values a) amplitude (i them avaudioplayer - work perfect , 2 objects create in controller have different amplitudes 2 different tracks) , b) wave number (aka peakid/position).

so first created object(grey) there position equal 1 , wave must red , placed in left part of screen. second object (black) position 3, wave blue , placed in right part. /position 2 center @ screen, not use now/

every audio update causes update opengl:

var waveamp :float = 0  .    .    .    .    .   func updatemeters(){      player!.updatemeters()     var normalizedvalue = normalizedpowerlevelfromdecibels(player!.averagepowerforchannel(0))      waveamp = normalizedvalue! }  func render(displaylink: cadisplaylink?) {          glblendfunc(glenum(gl_one), glenum(gl_one_minus_src_alpha))         glenable(glenum(gl_blend))          //            glclearcolor(0, 104.0/255.0, 55.0/255.0, 1.0)         glclearcolor(0, 0, 0, 0)         glclear(glenum(gl_color_buffer_bit) | glenum(gl_depth_buffer_bit))         glenable(glenum(gl_depth_test))          glviewport(0, 0, glsizei(self.frame.size.width), glsizei(self.frame.size.height))          glbindbuffer(glenum(gl_array_buffer), vertexbuffer)         glbindbuffer(glenum(gl_element_array_buffer), indexbuffer)          glvertexattribpointer(positionslot, 3, glenum(gl_float), glboolean(uint8(gl_false)), glsizei(sizeof(vertex)), nil)         glvertexattribpointer(colorslot, 4, glenum(gl_float), glboolean(uint8(gl_false)), glsizei(sizeof(vertex)), unsafepointer<void>(bitpattern: (sizeof(float) * 3)))          gldrawelements(glenum(gl_triangle_fan), glsizei(indices.size()), glenum(gl_unsigned_byte), nil)          glvertexattribpointer(positionslot, 3, glenum(gl_float), glboolean(uint8(gl_false)), glsizei(sizeof(vertex)), nil);         glvertexattribpointer(colorslot, 4, glenum(gl_float), glboolean(uint8(gl_false)), glsizei(sizeof(vertex)), unsafepointer<void>(bitpattern: (sizeof(float) * 3)));          context.presentrenderbuffer(int(gl_renderbuffer))       print("position=\(position)  waveamp=\(waveamp)")     gluniform1i(shaderpeakid!,  glint(position));     gluniform1f(shaderwaveamp!, waveamp); } 

log print()-function:

position=1  waveamp=0.209313 position=3  waveamp=0.47332 position=1  waveamp=0.207556 position=3  waveamp=0.446235 position=1  waveamp=0.20769 position=3  waveamp=0.446235 position=1  waveamp=0.246206 position=3  waveamp=0.430118 

i expect have 2 rectangles - 1 grey red wave on left , 1 black blue line on right. have next trouble! rendering take place in 1 (last) view , changes sequentially:

please anyone! how use 2 glviews simultaneously? or maybe need use 2 shaders in 1 view?

i want finish audio wave task , share them everyone. still don't understand problem

looking in code soundwaveview class posted, looks view handles initializing context, framebuffer context, , more you. since send same eaglcontext both views, means same context being initialized, re-initialized second view. doesn't seem right me. might work fine if make separate context other view, , gpu context-switch when rendering between these 2 views, , treat them if separate apps.

but that's not how application simple should designed. if want 2 objects drawn on screen @ same time, doesn't mean need 2 separate views. have build system handles taking information each waveform , converting appropriate draw calls automatically. act mini draw engine application. approach, write further support cooler techniques , drawings... maybe more waveforms, different textures/colors each of them, cool effects, etc.