require 'ruboto'

java_import "android.opengl.GLSurfaceView"

java_import "javax.microedition.khronos.egl.EGL10"
java_import "javax.microedition.khronos.egl.EGLConfig"
java_import "javax.microedition.khronos.opengles.GL10"

java_import "java.nio.ByteBuffer"
java_import "java.nio.ByteOrder"
java_import "java.nio.IntBuffer"

ruboto_import "org.ruboto.irb.RubotoGLSurfaceViewRenderer"

$activity.start_ruboto_activity "$glsurface" do
  setTitle "GLSurfaceView"

  setup_content do
    @surface_view = GLSurfaceView.new(self)
    @surface_view.setRenderer(@renderer)
    @surface_view
  end

  handle_resume do
    @surface_view.onResume
  end

  handle_pause do
    @surface_view.onPause
  end

  @renderer = RubotoGLSurfaceViewRenderer.new
  @translucent_background = false
  @cube = Cube.new
  @angle = 0.0

  @renderer.handle_draw_frame do |gl|
    gl.glClear(GL10::GL_COLOR_BUFFER_BIT | GL10::GL_DEPTH_BUFFER_BIT)

    gl.glMatrixMode(GL10::GL_MODELVIEW)
    gl.glLoadIdentity
    gl.glTranslatef(0, 0, -3.0)
    gl.glRotatef(@angle,       0, 1, 0)
    gl.glRotatef(@angle*0.25,  1, 0, 0)

    gl.glEnableClientState(GL10::GL_VERTEX_ARRAY)
    gl.glEnableClientState(GL10::GL_COLOR_ARRAY)

    @cube.draw(gl)

    gl.glRotatef(@angle*2.0, 0, 1, 1)
    gl.glTranslatef(0.5, 0.5, 0.5)

    @cube.draw(gl)

    @angle += 1.2
  end

  @renderer.handle_surface_changed do |gl, width, height|
    gl.glViewport(0, 0, width, height)
    ratio = width.to_f / height.to_f
    gl.glMatrixMode(GL10::GL_PROJECTION)
    gl.glLoadIdentity
    gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10)
  end

  @renderer.handle_surface_created do |gl, config|
    gl.glDisable(GL10::GL_DITHER)

    gl.glHint(GL10::GL_PERSPECTIVE_CORRECTION_HINT, GL10::GL_FASTEST)

    if (@translucent_background)
      gl.glClearColor(0,0,0,0)
    else
      gl.glClearColor(1,1,1,1)
    end
    gl.glEnable(GL10::GL_CULL_FACE)
    gl.glShadeModel(GL10::GL_SMOOTH)
    gl.glEnable(GL10::GL_DEPTH_TEST)
  end
end

class Cube
  def initialize
    one = 0x10000
    vertices = [
      -one, -one, -one,
       one, -one, -one,
       one,  one, -one,
      -one,  one, -one,
      -one, -one,  one,
       one, -one,  one,
       one,  one,  one,
      -one,  one,  one,
    ]

    colors = [
        0,    0,    0,  one,
      one,    0,    0,  one,
      one,  one,    0,  one,
        0,  one,    0,  one,
        0,    0,  one,  one,
      one,    0,  one,  one,
      one,  one,  one,  one,
        0,  one,  one,  one,
     ]

    indices = [
      0, 4, 5,    0, 5, 1,
      1, 5, 6,    1, 6, 2,
      2, 6, 7,    2, 7, 3,
      3, 7, 4,    3, 4, 0,
      4, 7, 6,    4, 6, 5,
      3, 0, 1,    3, 1, 2
    ]

    vbb = ByteBuffer.allocateDirect(vertices.length*4)
    vbb.order(ByteOrder.nativeOrder)
    @vertex_buffer = vbb.asIntBuffer
    @vertex_buffer.put(vertices.to_java(:int))
    @vertex_buffer.position(0)

    cbb = ByteBuffer.allocateDirect(colors.length*4)
    cbb.order(ByteOrder.nativeOrder)
    @color_buffer = cbb.asIntBuffer
    @color_buffer.put(colors.to_java(:int))
    @color_buffer.position(0)

    @index_buffer = ByteBuffer.allocateDirect(indices.length)
    @index_buffer.put(indices.to_java(:byte))
    @index_buffer.position(0)
  end

  def draw(gl)
    gl.glFrontFace(GL10::GL_CW)
    gl.glVertexPointer(3, GL10::GL_FIXED, 0, @vertex_buffer)
    gl.glColorPointer(4, GL10::GL_FIXED, 0, @color_buffer)
    gl.glDrawElements(GL10::GL_TRIANGLES, 36, GL10::GL_UNSIGNED_BYTE, @index_buffer)
  end
end