// XXX FIXME Hardcoded '4' in many places, here and in library_SDL, for RGBA

var LibraryGL = {
  $GL: {
    textures: {},
    textureCounter: 0,
  },

  glGetString: function(name_) {
    switch(name_) {
      case Module.ctxGL.VENDOR:
      case Module.ctxGL.RENDERER:
      case Module.ctxGL.VERSION:
        return allocate(intArrayFromString(Module.ctxGL.getParameter(name_)), 'i8', ALLOC_NORMAL);
      case 0x1F03: // Extensions
        return allocate(intArrayFromString(Module.ctxGL.getSupportedExtensions().join(' ')), 'i8', ALLOC_NORMAL);
      default:
        throw 'Failure: Invalid glGetString value: ' + name_;
    }
  },

  glGetIntegerv: function(name_, p) {
    switch(name_) {
      case Module.ctxGL.MAX_TEXTURE_SIZE:
        IHEAP[p] = Module.ctxGL.getParameter(name_);
        break;
      default:
        throw 'Failure: Invalid glGetIntegerv value: ' + name_;
    }
  },

  glGenTextures__deps: ['$GL'],
  glGenTextures: function(n, textures) {
    for (var i = 0; i < n; i++) {
      var id = GL.textureCounter++;
      GL.textures[id] = Module.ctxGL.createTexture();
      IHEAP[textures+QUANTUM_SIZE*i] = id;
    }
  },

  glDeleteTextures: function(n, textures) {
    for (var i = 0; i < n; i++) {
      var id = IHEAP[textures+QUANTUM_SIZE*i];
      Module.ctxGL.deleteTexture(GL.textures[id]);
      delete GL.textures[id];
    }
  },

  glTexImage2D: function(target, level, internalformat, width, height, border, format, type, pixels) {
    if (pixels) {
      pixels = new Uint8Array(IHEAP.slice(pixels, pixels + width*height*4)); // TODO: optimize
    }
    Module.ctxGL.texImage2D(target, level, internalformat, width, height, border, format, type, pixels);
  },

  glTexSubImage2D: function(target, level, xoffset, yoffset, width, height, format, type, pixels) {
    if (pixels) {
      pixels = new Uint8Array(IHEAP.slice(pixels, pixels + width*height*4)); // TODO: optimize
    }
    Module.ctxGL.texSubImage2D(target, level, xoffset, yoffset, width, height, format, type, pixels);
  },

  glBindTexture: function(target, texture) {
    Module.ctxGL.bindTexture(target, GL.textures[texture]);
  },

};

// Ignored stubs for fixed-function pipeline. We will need to emulate this
'begin end matrixMode loadIdentity ortho color3f texCoord2f vertex2f blendFunc pushMatrix popMatrix translatef scalef color4ub enableClientState disableClientState vertexPointer colorPointer normalPointer texCoordPointer drawArrays clientActiveTexture_'.split(' ').forEach(function(name_) {
  var cName = 'gl' + name_[0].toUpperCase() + name_.substr(1);
  LibraryGL[cName] = function(){};
});

// Simple pass-through functions
[[0, 'shadeModel fogi fogfv'],
 [1, 'clearDepth depthFunc enable disable frontFace cullFace'],
 [2, 'pixelStorei'],
 [3, 'texParameteri texParameterf'],
 [4, 'viewport clearColor']].forEach(function(data) {
  var num = data[0];
  var names = data[1];
  var args = range(num).map(function(i) { return 'x' + i }).join(', ');
  var stub = '(function(' + args + ') { ' + (num > 0 ? 'Module.ctxGL.NAME(' + args + ')' : '') + ' })';
  names.split(' ').forEach(function(name_) {
    var cName = 'gl' + name_[0].toUpperCase() + name_.substr(1);
    LibraryGL[cName] = eval(stub.replace('NAME', name_));
    //print(cName + ': ' + LibraryGL[cName]);
  });
});

mergeInto(LibraryManager.library, LibraryGL);