#ifdef GL_ES
precision mediump int;
precision mediump float;
#endif

#define USE_OGRE_FROM_FUTURE
#include <OgreUnifiedShader.h>

SAMPLER2D(Input, 0);

OGRE_UNIFORMS(
uniform vec4 blurAmount;
)

MAIN_PARAMETERS
IN(vec2 oUv0, TEXCOORD0)
MAIN_DECLARATION
{
  int i;
  vec4 tmpOutColor;
  float diffuseGlowFactor;
  vec2 offsets[4];
  /*
  // hazy blur
  -1.8, -1.8,
  -1.8, 1.8,
  1.8, -1.8,
  1.8, 1.8
  */
  /*
  // less-hazy blur
  -1.0,  2.0,
  -1.0, -1.0,
  1.0, -1.0,
  1.0,  1.0
  */
  /*
    -0.326212, -0.405805,
    -0.840144, -0.073580,
    -0.695914,  0.457137,
    -0.203345,  0.620716
  */

  offsets[0] = vec2(-0.3,  0.4);
  offsets[1] = vec2(-0.3,  -0.4);
  offsets[2] = vec2(0.3,  -0.4);
  offsets[3] = vec2(0.3,  0.4);

  tmpOutColor = texture2D(Input, oUv0); // UV coords are in image space

  // calculate glow amount
  diffuseGlowFactor = 0.0113 * (2.0 - max(tmpOutColor.r, tmpOutColor.g));

  // basic blur filter
  for (i = 0; i < 4; i++)
  {
    tmpOutColor += texture2D(Input, oUv0 + vec2_splat(blurAmount.x * diffuseGlowFactor) * offsets[i]);
  }

  tmpOutColor *= vec4_splat(0.25);

  // TIPS (old-skool strikes again!)
  // Pay attention here! If you use the "out float4 outColor" directly
  // in your steps while creating the output color (like you remove
  // the "tmpOutColor" var and just use the "outColor" directly)
  // your pixel-color output IS CHANGING EACH TIME YOU DO AN ASSIGNMENT TOO!
  // A temporary variable, instead, acts like a per-pixel double buffer, and
  // best of all, lead to better performance.
  gl_FragColor = tmpOutColor;
}