Initialized fine now

gldemo.rb

Dir.glob('*.jar').each {|jar| require jar }

java_import 'com.jogamp.opengl.GLCapabilities',
            'com.jogamp.opengl.GLDrawableFactory',
            'com.jogamp.opengl.GLProfile',
            'com.jogamp.opengl.GL4',
            'com.jogamp.nativewindow.util.Rectangle',
            'com.jogamp.newt.opengl.GLWindow',
            'com.jogamp.opengl.util.FPSAnimator',
            'com.jogamp.opengl.GLEventListener',
            'java.awt.GraphicsEnvironment',
            'java.nio.FloatBuffer'

# Vertex data
VERTS = [
    0.0,  0.5,  0.0,
    0.5, -0.5,  0.0,
   -0.5, -0.5,  0.0
]

# vertex shader
VERTEX_SHADER = "
    #version 400
    in vec3 vertex;
    void main(){
        gl_Position = vec4( vertex, 1.0 );
    }
"

# fragment shader
FRAGMENT_SHADER = "
    #version 400
    out vec4 color;
    void main(){
        color = vec4( 0.5, 0.0, 0.5, 1.0 );
    }
"

# Renderer
class Renderer
    include GL4, GLEventListener

    # Called when the renderer's GL state is initialized.
    def init( surface )
        gl = surface.gl
        puts "Initializing with: #{gl}"

        # Setup default states
        gl.gl_enable( GL_DEPTH_TEST )
        gl.gl_depth_func( GL_LESS )
        gl.gl_clear_color( 0.0, 0.0, 0.0, 1.0 )

        print "Creating VBO ... "
        b = [0].to_java( :int )
        gl.gl_gen_buffers( 1, b, 0 )
        @vbo = b[0]
        gl.gl_bind_buffer( GL_ARRAY_BUFFER, @vbo )
        v = FloatBuffer.wrap( VERTS.to_java( :float ) )
        gl.gl_buffer_data( GL_ARRAY_BUFFER, v.capacity, v, GL_STATIC_DRAW )
        puts "done."

        print "Creating Vertex Shader ... "
        vsh = gl.gl_create_shader( GL_VERTEX_SHADER )
        vss = VERTEX_SHADER.each_line.to_a
        gl.gl_shader_source( vsh, vss.length, vss.to_java( :string ), vss.map {|l| l.length }.to_java( :int ), 0 )
        gl.gl_compile_shader( vsh )
        puts "done."

        print "Creating Fragment Shader ... "
        fsh = gl.gl_create_shader( GL_FRAGMENT_SHADER )
        fss = FRAGMENT_SHADER.each_line.to_a
        gl.gl_shader_source( fsh, fss.length, fss.to_java( :string ), fss.map {|l| l.length }.to_java( :int ), 0 )
        gl.gl_compile_shader( fsh )
        puts "done."

        print "Creating Program ... "
        @prgm = gl.gl_create_program()
        gl.gl_attach_shader( @prgm, vsh )
        gl.gl_attach_shader( @prgm, fsh )
        gl.gl_link_program( @prgm )
        puts "done."

        print "Fetching VAO position from linked program... "
        @attribPosition = gl.glGetAttribLocation(@prgm, "vertex")

        print "Creating VAO ... "
        a = [0].to_java( :int )
        gl.gl_gen_vertex_arrays( 1, a, 0 )
        @vao = a[0]
        gl.gl_bind_vertex_array( @vao )
        gl.gl_bind_buffer( GL_ARRAY_BUFFER, @vbo )

        # fixme buffer data here

        gl.gl_vertex_attrib_pointer( @attribPosition , 3, GL_FLOAT, false, 0, 0 )
 
        gl.gl_enable_vertex_attrib_array( 0 )
        puts "done."


        puts "VBO: #{@vbo}", "VAO: #{@vao}", "VERTEX SHADER: #{vsh}", "FRAGMENT SHADER: #{fsh}", "PROGRAM: #{@prgm}"
    end

    # Called when the viewport is reshaped.
    def reshape( surface, x, y, w, h )
        surface.gl.gl_viewport( 0, 0, w.to_i, w.to_i )
    end

    # Called when the renderer and its underlying surface are being disposed of.
    def dispose( surface )
        # TODO
    end

    # Called for each frame to be rendered.
    def display( surface )
        gl = surface.gl
        gl.gl_clear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )

        # RENDERING CODE GOES HERE
        gl.gl_use_program( @prgm )
        gl.gl_bind_vertex_array( @vao )
        gl.gl_draw_arrays( GL_TRIANGLES, 0, 3 )
    end
end

# Get references
@gl_profile = GLProfile.get( GLProfile::GL4 )
@gl_capabilities = GLCapabilities.new( @gl_profile )

# Setup window
@window = GLWindow.create( @gl_capabilities )
@window.add_gl_event_listener( Renderer.new() )
@window.set_size( 500, 500 )

# Get animator
@animator = FPSAnimator.new( 
    @window,
    GraphicsEnvironment.local_graphics_environment.default_screen_device.display_mode.refresh_rate
)

# Go!
@window.set_visible( true )
@animator.start