47 lines
1.7 KiB
C++
47 lines
1.7 KiB
C++
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#include "ws2812b.h"
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#include "spectrum.h"
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static uint8_t saturate (const unsigned k, const unsigned ofs = 0x100u) {
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if (k < ofs) return 0u; // začátek je třeba trochu posunout
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const unsigned x = k - ofs; // jinak ledky trochu svítí - žárovka tuto vlastnost nemá
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if (x >= (1u << 16)) return 0xffu; // zasarutuj
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unsigned w, y = 0xffu; // aproximaci začneme od 255
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for (unsigned n=0u; n<6u; n++) { // končí cca za 3-4 iterace, max. 6
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w = (y + x/y) >> 1; // Newtonova metoda sqrt
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if (y == w) break; // konec iterace - lepší už to nebude
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else y = w;
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}
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return y; // výsledek
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}
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unsigned int Spectrum::Send(uint16_t * const ptr, const unsigned int len) {
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led << true;
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// procesor je rychlý, zvládne FFT i s kosinovým oknem v přerušení
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CopyToComplex (buffer, ptr, len);
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ifft.Forward (buffer);
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// vyhodnotí barvy pro basy, středy a výšky
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unsigned qa = 0u;
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for (unsigned n=1u; n<blow; n++) qa += buffer[n].norm();
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cred = saturate (qa >> 0, 0x200u);
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qa = 0u;
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for (unsigned n=blow; n<bmiddle; n++) qa += buffer[n].norm();
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cgreen = saturate (qa >> 4);
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qa = 0u;
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for (unsigned n=bmiddle; n<bhigh; n++) qa += buffer[n].norm();
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cblue = saturate (qa >> 2);
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// uloží barvy do ledek
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Entry l0(0), l1(0), l2(0), l3(0);
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l0.ws.order = 0; l0.ws.r = cred;
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l1.ws.order = 1; l1.ws.g = cgreen;
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l2.ws.order = 2; l2.ws.b = cblue;
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l3.ws.order = 3; l3.ws.r = 0xffu - cred; l3.ws.g = 0xffu - cgreen; l3.ws.b = 0xffu - cblue;
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// a frontou pošle na výstup
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ring.Write (l0.number);
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ring.Write (l1.number);
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ring.Write (l2.number);
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ring.Write (l3.number);
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// změří čas výpočtu (pod 0.5ms, rámec je 32ms)
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led << false;
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return len;
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}
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