#include "fluid_common_render.hlsli"

//	Vertex
//	A full-screen edge detection pass to locate artifacts
VS_OUTPUT_EDGE main(VS_INPUT input)
{
    VS_OUTPUT_EDGE output = (VS_OUTPUT_EDGE)0;
    output.position = float4(input.pos, 1);

    float2 texelSize = 1.0 / float2(RTWidth, RTHeight);
    float2 center = float2((input.pos.x + 1) / 2.0, 1.0 - (input.pos.y + 1) / 2.0);

    // Eight nearest neighbours needed for Sobel.
    output.textureUV00 = center + float2(-texelSize.x, -texelSize.y);
    output.textureUV01 = center + float2(-texelSize.x, 0);
    output.textureUV02 = center + float2(-texelSize.x, texelSize.y);

    output.textureUV10 = center + float2(0, -texelSize.y);
    output.textureUV12 = center + float2(0, texelSize.y);

    output.textureUV20 = center + float2(texelSize.x, -texelSize.y);
    output.textureUV21 = center + float2(texelSize.x, 0);
    output.textureUV22 = center + float2(texelSize.x, texelSize.y);

    return output;
}
