reference/shaders/comp/generate_height.comp

#version 310 es
layout(local_size_x = 64, local_size_y = 1, local_size_z = 1) in;

layout(binding = 0, std430) readonly buffer Distribution
{
    vec2 distribution[];
} _137;

layout(binding = 2, std140) uniform UBO
{
    vec4 uModTime;
} _166;

layout(binding = 1, std430) writeonly buffer HeightmapFFT
{
    uint heights[];
} _225;

uvec2 workaround_mix(uvec2 a, uvec2 b, bvec2 sel)
{
    uint _86;
    if (sel.x)
    {
        _86 = b.x;
    }
    else
    {
        _86 = a.x;
    }
    uint _94 = _86;
    uint _97;
    if (sel.y)
    {
        _97 = b.y;
    }
    else
    {
        _97 = a.y;
    }
    return uvec2(_94, _97);
}

vec2 alias(vec2 i, vec2 N)
{
    return mix(i, i - N, greaterThan(i, N * 0.5));
}

vec2 cmul(vec2 a, vec2 b)
{
    vec2 r3 = a.yx;
    vec2 r1 = b.xx;
    vec2 R0 = a * r1;
    vec2 r2 = b.yy;
    vec2 R1 = r2 * r3;
    return R0 + vec2(-R1.x, R1.y);
}

uint pack2(vec2 v)
{
    return packHalf2x16(v);
}

void generate_heightmap()
{
    uvec2 N = uvec2(64u, 1u) * gl_NumWorkGroups.xy;
    uvec2 i = gl_GlobalInvocationID.xy;
    uvec2 param = N - i;
    uvec2 param_1 = uvec2(0u);
    bvec2 param_2 = equal(i, uvec2(0u));
    uvec2 wi = workaround_mix(param, param_1, param_2);
    vec2 a = _137.distribution[(i.y * N.x) + i.x];
    vec2 b = _137.distribution[(wi.y * N.x) + wi.x];
    vec2 param_3 = vec2(i);
    vec2 param_4 = vec2(N);
    vec2 k = _166.uModTime.xy * alias(param_3, param_4);
    float k_len = length(k);
    float w = sqrt(9.81000041961669921875 * k_len) * _166.uModTime.z;
    float cw = cos(w);
    float sw = sin(w);
    vec2 param_5 = a;
    vec2 param_6 = vec2(cw, sw);
    a = cmul(param_5, param_6);
    vec2 param_7 = b;
    vec2 param_8 = vec2(cw, sw);
    b = cmul(param_7, param_8);
    b = vec2(b.x, -b.y);
    vec2 res = a + b;
    vec2 param_9 = res;
    _225.heights[(i.y * N.x) + i.x] = pack2(param_9);
}

void main()
{
    generate_heightmap();
}