#version 460 core

layout(rgba32f, binding = 0) uniform writeonly image2D outputImage;

layout(std430, binding = 3) buffer layoutName
{
  vec2 o_Points[];
};

// 1 -> 1
// 2 -> 3
// 3 -> 9
// 4 -> 27
// 5 -> 81
// 6 -> 243
// ...

// 4  27
// 1 + 3 + 9 = 13

// Sn = ((3^n)-1)/2
// S3 = 3^3 - 1 / 2
// 3^4

// gl_NumWorkGroups : This variable contains the number of work groups passed to the dispatch function.
// gl_WorkGroupID : This is the current work group for this shader invocation. Each of the XYZ components will be on the half-open range [0, gl_NumWorkGroups.XYZ).
// gl_LocalInvocationID : This is the current invocation of the shader within the work group. Each of the XYZ components will be on the half-open range [0, gl_WorkGroupSize.XYZ).

layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
void main()
{
    uint triangleCount = gl_NumWorkGroups.x;
    uint currentPoint = gl_WorkGroupID.x;

    uint offset = (triangleCount - 1) / 2;

    uint firstPointIndex = offset * 3 + 1;
    o_Points[firstPointIndex + currentPoint * 3 ] = o_Points[offset + currentPoint] / 2 + vec2(0, 0.36);
    o_Points[firstPointIndex + currentPoint * 3 + 1] = o_Points[offset + currentPoint] / 2 + vec2(-0.5, -0.5);
    o_Points[firstPointIndex + currentPoint * 3 + 2] = o_Points[offset + currentPoint] / 2 + vec2(0.5, -0.5);
}