This is a Mandelbrot shader, designed for the Raspberry Pi version of GLSL Hacker (though it will run on any GLSL Hacker version). Grab GLSL Hacker from: http://www.geeks3d.com/20131031/glsl-hacker-0-6-0-0-physx-3-mac-os-x-10-9-autdesk-fbx-raspberry-pi-programming

GLSLHacker_Mandelbrot.xml

<?xml version="1.0" encoding="ISO-8859-1" standalone="yes"?>

<glsl_hacker>
	
  <window name="win3d01" title="Mandelbrot Demo for PiCymru (OpenGL ES 2.0)" 
          width="1920" height="1080" 
          gl_version_major="2" gl_version_minor="2"
          build_opengl_extensions_list="0" />


<gpu_program name="gpu_program" >
	<raw_data_vs><![CDATA[	 
attribute vec4 gxl3d_Position;
//attribute vec4 gxl3d_TexCoord0;
invariant gl_Position;
uniform mat4 gxl3d_ModelViewProjectionMatrix;
//varying vec4 Vertex_UV;
void main()
{	
  //Vertex_UV = gxl3d_TexCoord0;
  //gl_Position = gxl3d_ModelViewProjectionMatrix * gxl3d_Position;		
  gl_Position = gxl3d_Position;
}
  ]]></raw_data_vs>
  
	<raw_data_ps><![CDATA[	 

	// This is the pixel shader.. the part that draws the mandelbrot - DC
	
	uniform vec3      iResolution;     // viewport resolution (in pixels)
	uniform float     iGlobalTime;     // shader playback time (in seconds)
	uniform vec4      iMouse;          // mouse pixel coords. xy: current (if MLB down), zw: click

	void main(void) {
	vec2 position = ( gl_FragCoord.xy / iResolution.x );
	float zoom = abs(sin(iGlobalTime / 1.5) * 13.0);

	float real = (position.x - 0.5) * zoom;
	float imaginary = (position.y - 0.3) * zoom;	
	float const_real = real;
	float const_imaginary = imaginary;

	float z2 = 0.0;

	int iter_count = 0;

	for(int iter = 0; (iter) < 25; ++iter)
	{
	   float temp_real = real;
	   
	   real = (temp_real * temp_real) - (imaginary * imaginary) + const_real;
	   imaginary = 2.0 * temp_real * imaginary + const_imaginary;
	   z2 = real * real + imaginary * imaginary;

	   iter_count = iter;

	   if (z2 > 4.0) 
		  break;
	}

	if (z2 < 4.0)
	   gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
	else	
	   gl_FragColor = vec4(mix(vec3(0.0, 0.0, 0.2), vec3(1.0, 1.0, 1.0), fract(float(iter_count)*0.02)), 1.0);
	}
  
  
  
  ]]></raw_data_ps>

</gpu_program>


  
  
	<script name="init_scene" run_mode="INIT" >
		<raw_data><![CDATA[	
    
winW, winH = gh_window.getsize()
   
--font_a = gh_utils.font_create("Tahoma", 14)


camera_ortho = gh_camera.create_ortho(-winW/2, winW/2, -winH/2, winH/2, 1.0, -1.0)
gh_camera.set_viewport(camera_ortho, 0, 0, winW, winH)
gh_camera.set_position(camera_ortho, 0, 0, 1)


gpu_prog_01 = gh_node.getid("gpu_program")

-- local abs_path=0
-- tex01 = gh_texture.create_from_file("data/233.jpg", 3, abs_path)

mesh_quad = gh_mesh.create_quad(winW, winH)
gh_object.use_opengl21(mesh_quad, 0) 

gh_renderer.set_vsync(1)
gh_renderer.set_scissor_state(0)

		]]></raw_data>
	</script> 
  
	<script name="update_scene" run_mode="FRAME" >
		<raw_data><![CDATA[	

elapsed_time = gh_utils.get_elapsed_time()

gh_renderer.set_depth_test_state(1)

gh_camera.bind(camera_ortho)

gh_renderer.clear_color_depth_buffers(0.2, 0.2, 0.2, 1.0, 1.0)

gh_gpu_program.bind(gpu_prog_01)
gh_gpu_program.uniform1f(gpu_prog_01, "iGlobalTime", elapsed_time)
gh_gpu_program.uniform3f(gpu_prog_01, "iResolution", winW, winH, 0)
-- mouse_x, mouse_y = gh_input.mouse_getpos() 
local mouse_x = winW/2
local mouse_y = winH/2
gh_gpu_program.uniform4f(gpu_prog_01, "iMouse", mouse_x, winH-mouse_y, 0, 0)
-- gh_gpu_program.uniform1i(gpu_prog_01, "iChannel0", 0);

-- gh_texture.bind(tex01, 0)
gh_object.render(mesh_quad)

--gh_utils.font_render(font_a, 10, 20, 0.2, 1.0, 0.0, 1.0, "GLSL Hacker demo - Shader Toy Demo (www.shadertoy.com)")

		]]></raw_data>
	</script> 
	

	<script name="resize_scene" run_mode="SIZE" >
		<raw_data><![CDATA[	

winW, winH = gh_window.getsize(0)

aspect = 1.333
if (winH > 0) then
  aspect = winW / winH
end  
gh_camera.update_ortho(camera_ortho, -winW/2, winW/2, -winH/2, winH/2, 1.0, -1.0)
gh_camera.set_viewport(camera_ortho, 0, 0, winW, winH)

--gh_utils.font_set_viewport_info(font_a, 0, 0, winW, winH)

gh_mesh.update_quad_size(mesh_quad, winW, winH)

		]]></raw_data>
	</script> 
  
  
</glsl_hacker>