hoop_pyramid.js

// Jon T <jon@jtutcher.co.uk>

#include "pattern.h"
#include "leds.h"

const uint32_t speed = 50;
const int numberOfColours = 7;
const int16_t maxHeightAbsolute = axis_max[2];
const int16_t minHeightAbsolute = axis_min[2];
const int16_t treeHeightAbsolute = maxHeightAbsolute - minHeightAbsolute;

// the set of colours we will use (in order)
const int colours[numberOfColours] = {0x000000, 0x0000FF, 0xFF8000, 0xFF0020, 0xCC00FF, 0xFFFFFF, 0xFFFFFF};
// relative positions down the tree that we'll draw each colour to (0 means bottom of tree)
const float drawHeightBoundaries[numberOfColours] = {0, 0, 0.2, 0.4, 0.6, 0.8, 1};
// the number of 'frames' per animation - to control speed
const int framesPerTransition[numberOfColours] = {20, 80, 70, 60, 40, 30, 100};

int last_offset = 0;
int state = 0;  // state can be between 0 and colours.length
int frame = 0;

void setup() {}

bool needsRedraw() {
    int offset = (millis() / speed);
    if (offset == last_offset)
        return false;
    last_offset = offset;
    return true;
}

int16_t scaleHeight(float relativeHeight) {
    return (relativeHeight*1.0*treeHeightAbsolute);
}

float getRelativeHeight(int16_t absoluteHeight) {
    return (absoluteHeight-minHeightAbsolute)/(treeHeightAbsolute*1.0);
}

void incrementState() {
    state = (state+1)%(numberOfColours);
}

void incrementFrame() {
    if(frame<framesPerTransition[state]) {
        frame++;
    } else {
        frame = 0;
        incrementState();
    }
}

void sweep(int i) {
    float heightScale = (1 - drawHeightBoundaries[state]);
    float thresholdHeight =  1 - (((frame*1.0)/(framesPerTransition[state]*1.0))*heightScale);
    if(getRelativeHeight(leds[i].z)>thresholdHeight) {
        setPixel(i, colours[state]);
    }
}

void setLeds() {
    for (int i = 0; i < num_leds; i++) {
        sweep(i);
    }
}

void loop() {    
    if(needsRedraw()) {
        incrementFrame();
        setLeds();
        show();
    }
}