/* derived from https://github.com/libretro/common-shaders/blob/master/Motionblur/Motionblur-blue.cg
   to increase the effect, uncomment more PREVX lines in each color channel
*/

struct previous
{
   uniform sampler2D texture;
   float2 tex_coord;
};

struct input
{
	float2 video_size;
	float2 texture_size;
	float2 output_size;
	float frame_count;
	float frame_direction;
	float frame_rotation;
};

struct tex_coords
{
   float2 tex;
   float2 prev;
   float2 prev1;
   float2 prev2;
   float2 prev3;
   float2 prev4;
   float2 prev5;
   float2 prev6;
};

void main_vertex
(
   float4 position : POSITION,
   out float4 oPosition : POSITION,
   uniform float4x4 modelViewProj,
   float2 tex : TEXCOORD,

   previous PREV,
   previous PREV1,
   previous PREV2,
   previous PREV3,
   previous PREV4,
   previous PREV5,
   previous PREV6,
   out tex_coords coords
)
{
   oPosition = mul(modelViewProj, position);
   coords = tex_coords(tex, PREV.tex_coord,
      PREV1.tex_coord,
      PREV2.tex_coord,
      PREV3.tex_coord,
      PREV4.tex_coord,
      PREV5.tex_coord,
      PREV6.tex_coord);
}

float4 main_fragment (uniform sampler2D s0 : TEXUNIT0, uniform input IN, tex_coords coords,
      previous PREV,
      previous PREV1,
      previous PREV2,
      previous PREV3,
      previous PREV4,
      previous PREV5,
      previous PREV6
) : COLOR
{
   float red_result =
      tex2D(PREV.texture,  coords.prev).r +
      tex2D(PREV1.texture, coords.prev1).r /*+
      tex2D(PREV2.texture, coords.prev2).r +
      tex2D(PREV3.texture, coords.prev3).r +
      tex2D(PREV4.texture, coords.prev4).r +
      tex2D(PREV5.texture, coords.prev5).r +
      tex2D(PREV6.texture, coords.prev6).r*/;
      
   float green_result =
      tex2D(PREV.texture,  coords.prev).g +
      tex2D(PREV1.texture, coords.prev1).g /*+
      tex2D(PREV2.texture, coords.prev2).g +
      tex2D(PREV3.texture, coords.prev3).g +
      tex2D(PREV4.texture, coords.prev4).g +
      tex2D(PREV5.texture, coords.prev5).g +
      tex2D(PREV6.texture, coords.prev6).g*/;
      
   float blue_result =
      tex2D(PREV.texture,  coords.prev).b +
      tex2D(PREV1.texture, coords.prev1).b /*+
      tex2D(PREV2.texture, coords.prev2).b +
      tex2D(PREV3.texture, coords.prev3).b +
      tex2D(PREV4.texture, coords.prev4).b +
      tex2D(PREV5.texture, coords.prev5).b +
      tex2D(PREV6.texture, coords.prev6).b*/;
   
   return  saturate(tex2D(s0, coords.tex) + 0.4 * float4(
      saturate(red_result - 7.0 * tex2D(s0, coords.tex).r),
      saturate(green_result - 7.0 * tex2D(s0, coords.tex).g),
      saturate(blue_result - 7.0 * tex2D(s0, coords.tex).b),
      1.0));
}