borgware-2d/animations/squares.c

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