Hi,
I'm rewriting my Processing simulation code for Arduino + FastLED. The animation runs fine and looks as expected - but is way slower than I'd expect on a small 16x16 matrix. I guess I made a silly mistake and I#m too blind to see it.
My guess was: Is it possible, that sinf() gets really slow with (very) large angles? I tryed to avoid it by using fmodf() before, but no change.
The (in my eyes) critical part of the code is here, it gets called for every single pixel:
It runs on a Teensy 3.6 with 256 LEDs at the beginning @240fps and drops within minutes down to 45fps with only 3 animation layers. Both numbers feel just not right. I suspect I do something stupid I'm not aware of. I use no lookup table for the polar data, because later I want to move the polar origin during runtime, too.Code:// calculate distance and angle of the point relative to // the origin described by center_x & center_y void get_polar_values() { // calculate the cartesian distances (deltas) from polar origin point // aka visual rotation center float dx = x - center_x; float dy = y - center_y; // calculate distance between current point & polar origin // it's hypotf(), length of the origin vector, pytharorean theroem dist = hypotf(dx, dy); // calculate the angle // (where around the polar origin is the current point?) angle = atan2f(dy, dx); } // convert polar coordinates back to cartesian // & render noise value there uint8_t render_pixel() { // convert polar coordinates back to cartesian ones float newx = (offset_x + center_x - (cosf(newangle) * newdist)) * scale_x; float newy = (offset_y + center_y - (sinf(newangle) * newdist)) * scale_y; // render noisevalue at this new cartesian point uint16_t noise_field_value = inoise16(newx, newy, z); // A) enhance histogram (improve contrast) by setting the black and white point // B) scale the result to a 0-255 range // it's the contrast boosting & the "colormapping" (technically brightness mapping) if (noise_field_value<30000) noise_field_value = 30000; if (noise_field_value>50000) noise_field_value = 50000; uint8_t value = map(noise_field_value, 30000, 50000, 0, 255); return value; }
Here the complete code for context what I'm doing:
Any hint, comment or roast is appreciated! I'm a bit lost.Code:// (c) by Stefan Petrick 2023 #include <FastLED.h> #define WIDTH 16 #define HEIGHT 16 #define NUM_LEDS ((WIDTH) * (HEIGHT)) CRGB leds[WIDTH*HEIGHT]; float c, d, e, f, time; // some timedependant counters float newdist, newangle; // parameters for reconstruction float z; // 3d dimension for the 3d noise function float offset_x, offset_y; // wanna shift the cartesians during runtime? float scale_x, scale_y; // cartesian scaling in 2 dimensions float dist, angle; // the actual polar coordinates int x, y; // the cartesian coordiantes int num_x = WIDTH; // horizontal pixel count int num_y = HEIGHT; // vertical pixel count float center_x = (num_x / 2) - 0.5; // the reference point for polar coordinates float center_y = (num_y / 2) - 0.5; // (can also be outside of the actual xy matrix) void setup() { Serial.begin(115200); FastLED.addLeds<APA102, 33, 32, BGR, DATA_RATE_MHZ(12)>(leds, 256); } void loop() { // set timers time = millis(); // save the current running time time = time * 0.5 ; // global anaimation speed (higher value = faster) c = time / 400; // speeds of the subtimers (smaller value = faster) d = time / 800; e = time / 600; // calculate whats constant in the current frame center_x = (num_x / 2) - 0.5; // the reference point for polar coordinates center_y = (num_y / 2) - 0.5; for (x = 0; x < num_x; x++) { for (y = 0; y < num_y; y++) { // layer No 1: RED------------------------------------------------------------- // calculate distance and angle of the point relative to // the origin described by center_x & center_y get_polar_values(); // set all parameters for the first layer (red) scale_x = 5000; scale_y = 5000; newangle = angle * 3 + c - dist/4; newdist = dist; z = c * 10000; offset_x = 0; offset_y = c*5; // convert polar coordinates back to cartesian // & render noise value there byte show1 = render_pixel(); // layer 2: Green scale_x = 6000; scale_y = 6000; newangle = angle * 3 + c*1.1 - dist/4; newdist = dist; z = c * 12000; offset_x = 0; offset_y = d*5; // convert polar coordinates back to cartesian // & render noise value there byte show2 = render_pixel(); // layer 3: blue scale_x = 7000; scale_y = 7000; newangle = angle * 3 + c*1.2 - dist/4; newdist = dist; z = c * 13000; offset_x = 0; offset_y = e*5; // convert polar coordinates back to cartesian // & render noise value there byte show3 = render_pixel(); CRGB color = CRGB(show1,show2,show3); leds[XY(x, y)] = color; } } adjust_gamma(); FastLED.show(); EVERY_N_MILLIS(100) Serial.println(FastLED.getFPS()); } void get_polar_values() { // calculate the cartesian distances (deltas) from polar origin point // aka visual rotation center float dx = x - center_x; float dy = y - center_y; // calculate distance between current point & polar origin // it's hypotf(), length of the origin vector, pytharorean theroem //dist = sqrt((dx*dx)+(dy*dy)); dist = hypotf(dx, dy); // calculate the angle // (where around the polar origin is the current point?) angle = atan2f(dy, dx); // done, that's all we need } uint8_t render_pixel() { // convert polar coordinates back to cartesian ones fmodf(newangle, 2 * PI); // no solution to the fps decline, but slower to begin with float newx = (offset_x + center_x - (cosf(newangle) * newdist)) * scale_x; float newy = (offset_y + center_y - (sinf(newangle) * newdist)) * scale_y; // render noisevalue at this new cartesian point uint16_t noise_field_value = inoise16(newx, newy, z); // A) enhance histogram (improve contrast) by setting the black and white point // B) scale the result to a 0-255 range // it's the contrast boosting & the "colormapping" (technically brightness mapping) // #################### not sure if the following 3 lines are unperformant?! // #################### do the datatypes make sense? if (noise_field_value<30000) noise_field_value = 30000; if (noise_field_value>50000) noise_field_value = 50000; uint8_t value = map(noise_field_value, 30000, 50000, 0, 255); return value; // done, we've just rendered one color value for one single pixel } uint16_t XY(uint8_t x, uint8_t y) { //if (x >= WIDTH) return NUM_LEDS; //if (y >= HEIGHT) return NUM_LEDS; if (y & 1) return (y + 1) * WIDTH - 1 - x; else return y * WIDTH + x; } void adjust_gamma() { for (uint16_t i = 0; i < NUM_LEDS; i++) { leds[i].r = dim8_video(leds[i].r); leds[i].g = dim8_video(leds[i].g); leds[i].b = dim8_video(leds[i].b); } }
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