68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/**
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* \defgroup squares Square patterns for the Borg.
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* @{
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*/
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/**
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* @file squares.c
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* @brief Moves layers of translucent checker boards over each other.
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* @author Christian Kroll
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*/
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#include <assert.h>
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#include <stdint.h>
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#include "../config.h"
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#include "../util.h"
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#include "../pixel.h"
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#include "../random/prng.h"
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#include "squares.h"
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#define STEP_WIDTH (NUMPLANE * 2u)
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#define TICK 100
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#define CYCLES 200u
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/**
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* Moves layers of translucent checker boards over each other.
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*/
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void squares(void) {
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// add a rotating color map for smooth transitions
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uint8_t nColorMap[NUMPLANE * 2];
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for (uint8_t i = 0; i < (((NUMPLANE + 1) * 2) - 1); ++i) {
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if (i < (NUMPLANE + 1)) {
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nColorMap[i] = i;
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} else {
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nColorMap[i] = (NUMPLANE * 2) - i;
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}
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}
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uint8_t nOffsets[NUMPLANE] = {0};
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uint8_t nColOffset = 0;
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for (uint8_t nCount = CYCLES; nCount--;) {
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for (uint8_t x = 0; x < NUM_COLS ; ++x) {
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for (uint8_t y = 0; y < NUM_ROWS; ++y) {
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uint8_t nColor = 0;
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for (uint8_t nLayer = 0; nLayer < NUMPLANE; ++nLayer) {
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nColor += (((x + nOffsets[nLayer]) / STEP_WIDTH) + ((y +
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nOffsets[nLayer] + STEP_WIDTH) / STEP_WIDTH)) % 2u;
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}
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setpixel((pixel){x, y},
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nColorMap[(nColOffset + nColor) % (2* NUMPLANE)]);
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}
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}
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// add randomly calculated offsets to each layer starting points
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for (uint8_t i = 0; i < NUMPLANE; ++i) {
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nOffsets[i] = (nOffsets[i] + random8()) % STEP_WIDTH;
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}
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// rotate color map
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nColOffset = (nColOffset + 1) % (NUMPLANE * 2);
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// pause for a moment to ensure that frame transitions are visible
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wait(TICK);
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}
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}
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/*@}*/
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