fft_fragment_program_complex.glsl.frag.h

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#include "shaders_common.h"

static const char *fft_fragment_program_complex = GLSL_300(
 precision mediump float;
 precision highp int;
 precision highp usampler2D;
 precision highp isampler2D;

 in vec2 vTex;
 uniform usampler2D sTexture;
 uniform usampler2D sParameterTexture;
 uniform int uViewportOffset;
 out uvec2 FragColor;

 vec2 compMul(vec2 a, vec2 b) { return vec2(a.x * b.x - a.y * b.y, a.x * b.y + a.y * b.x); }

 void main() {
 uvec2 params = texture(sParameterTexture, vec2(vTex.x, 0.5)).rg;
 uvec2 coord = uvec2((params.x >> 16u) & 0xffffu, params.x & 0xffffu);
 int ycoord = int(gl_FragCoord.y) - uViewportOffset;
 vec2 twiddle = unpackHalf2x16(params.y);

 uvec2 x = texelFetch(sTexture, ivec2(int(coord.x), ycoord), 0).rg;
 uvec2 y = texelFetch(sTexture, ivec2(int(coord.y), ycoord), 0).rg;
 vec4 a = vec4(unpackHalf2x16(x.x), unpackHalf2x16(x.y));
 vec4 b = vec4(unpackHalf2x16(y.x), unpackHalf2x16(y.y));
 b.xy = compMul(b.xy, twiddle);
 b.zw = compMul(b.zw, twiddle);

 vec4 res = a + b;
 FragColor = uvec2(packHalf2x16(res.xy), packHalf2x16(res.zw));
 }
);