fft_fragment_program_real.glsl.frag.h

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#include "shaders_common.h"

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

 in vec2 vTex;
 uniform isampler2D sTexture;
 uniform usampler2D sParameterTexture;
 uniform usampler2D sWindow;
 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);

 float window_a = float(texelFetch(sWindow, ivec2(coord.x, 0), 0).r) / float(0x10000);
 float window_b = float(texelFetch(sWindow, ivec2(coord.y, 0), 0).r) / float(0x10000);

 vec2 a = window_a * vec2(texelFetch(sTexture, ivec2(int(coord.x), ycoord), 0).rg) / vec2(0x8000);
 vec2 a_l = vec2(a.x, 0.0);
 vec2 a_r = vec2(a.y, 0.0);
 vec2 b = window_b * vec2(texelFetch(sTexture, ivec2(int(coord.y), ycoord), 0).rg) / vec2(0x8000);
 vec2 b_l = vec2(b.x, 0.0);
 vec2 b_r = vec2(b.y, 0.0);
 b_l = compMul(b_l, twiddle);
 b_r = compMul(b_r, twiddle);

 vec2 res_l = a_l + b_l;
 vec2 res_r = a_r + b_r;
 FragColor = uvec2(packHalf2x16(res_l), packHalf2x16(res_r));
 }
);