95 lines
2.2 KiB
C++
95 lines
2.2 KiB
C++
// Mandlebrot
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// This will run quite slowly due to the large number of floating point calculations per pixel
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#include <TFT_eSPI.h> // Hardware-specific library
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#include <SPI.h>
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TFT_eSPI tft = TFT_eSPI(); // Invoke custom library
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#define TFT_GREY 0x7BEF
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unsigned long runTime = 0;
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float sx = 0, sy = 0;
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uint16_t x0 = 0, x1 = 0, yy0 = 0, yy1 = 0;
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void setup()
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{
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Serial.begin(250000);
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//randomSeed(analogRead(A0));
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Serial.println();
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// Setup the LCD
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tft.init();
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tft.setRotation(3);
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}
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void loop()
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{
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runTime = millis();
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tft.fillScreen(TFT_BLACK);
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tft.startWrite();
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for (int px = 1; px < 320; px++)
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{
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for (int py = 0; py < 240; py++)
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{
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float x0 = (map(px, 0, 320, -250000/2, -242500/2)) / 100000.0; //scaled x coordinate of pixel (scaled to lie in the Mandelbrot X scale (-2.5, 1))
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float yy0 = (map(py, 0, 240, -75000/4, -61000/4)) / 100000.0; //scaled y coordinate of pixel (scaled to lie in the Mandelbrot Y scale (-1, 1))
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float xx = 0.0;
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float yy = 0.0;
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int iteration = 0;
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int max_iteration = 128;
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while ( ((xx * xx + yy * yy) < 4) && (iteration < max_iteration) )
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{
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float xtemp = xx * xx - yy * yy + x0;
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yy = 2 * xx * yy + yy0;
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xx = xtemp;
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iteration++;
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}
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int color = rainbow((3*iteration+64)%128);
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yield();tft.drawPixel(px, py, color);
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}
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}
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tft.endWrite();
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Serial.println(millis()-runTime);
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while(1) yield();
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}
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unsigned int rainbow(int value)
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{
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// Value is expected to be in range 0-127
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// The value is converted to a spectrum colour from 0 = blue through to red = blue
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byte red = 0; // Red is the top 5 bits of a 16 bit colour value
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byte green = 0;// Green is the middle 6 bits
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byte blue = 0; // Blue is the bottom 5 bits
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byte quadrant = value / 32;
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if (quadrant == 0) {
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blue = 31;
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green = 2 * (value % 32);
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red = 0;
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}
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if (quadrant == 1) {
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blue = 31 - (value % 32);
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green = 63;
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red = 0;
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}
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if (quadrant == 2) {
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blue = 0;
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green = 63;
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red = value % 32;
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}
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if (quadrant == 3) {
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blue = 0;
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green = 63 - 2 * (value % 32);
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red = 31;
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}
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return (red << 11) + (green << 5) + blue;
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}
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