Added Software

Software/libraries/Adafruit_ILI9341/examples/mandelbrot/mandelbrot.ino

@@ -0,0 +1,97 @@
+#include <Adafruit_ILI9341.h>
+
+#ifdef ADAFRUIT_PYPORTAL
+  #define TFT_D0        34 // Data bit 0 pin (MUST be on PORT byte boundary)
+  #define TFT_WR        26 // Write-strobe pin (CCL-inverted timer output)
+  #define TFT_DC        10 // Data/command pin
+  #define TFT_CS        11 // Chip-select pin
+  #define TFT_RST       24 // Reset pin
+  #define TFT_RD         9 // Read-strobe pin
+  #define TFT_BACKLIGHT 25
+  // ILI9341 with 8-bit parallel interface:
+  Adafruit_ILI9341 tft = Adafruit_ILI9341(tft8bitbus, TFT_D0, TFT_WR, TFT_DC, TFT_CS, TFT_RST, TFT_RD);
+  #define USE_BUFFER   // buffer all 155 KB of data for bliting - uses passive ram but looks nicer?
+#else
+  // Use SPI
+  #define STMPE_CS 6
+  #define TFT_CS   9
+  #define TFT_DC   10
+  #define SD_CS    5
+  Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);
+#endif
+
+
+const int16_t
+  bits        = 20,   // Fractional resolution
+  pixelWidth  = 320,  // TFT dimensions
+  pixelHeight = 240,
+  iterations  = 128;  // Fractal iteration limit or 'dwell'
+float
+  centerReal  = -0.6, // Image center point in complex plane
+  centerImag  =  0.0,
+  rangeReal   =  3.0, // Image coverage in complex plane
+  rangeImag   =  3.0;
+
+#if defined(USE_BUFFER)
+  uint16_t buffer[pixelWidth * pixelHeight];
+#endif
+
+void setup(void) {
+  Serial.begin(115200);
+  Serial.print("Mandelbrot drawer!");
+
+  tft.begin();
+  tft.setRotation(1);
+  tft.fillScreen(ILI9341_BLACK);
+
+  // Turn on backlight (required on PyPortal)
+#if defined(TFT_BACKLIGHT)
+  pinMode(TFT_BACKLIGHT, OUTPUT);
+  digitalWrite(TFT_BACKLIGHT, HIGH);
+#endif
+}
+
+void loop() {
+  int64_t       n, a, b, a2, b2, posReal, posImag;
+  uint32_t      startTime,elapsedTime;
+
+
+  int32_t
+    startReal   = (int64_t)((centerReal - rangeReal * 0.5)   * (float)(1 << bits)),
+    startImag   = (int64_t)((centerImag + rangeImag * 0.5)   * (float)(1 << bits)),
+    incReal     = (int64_t)((rangeReal / (float)pixelWidth)  * (float)(1 << bits)),
+    incImag     = (int64_t)((rangeImag / (float)pixelHeight) * (float)(1 << bits));
+  
+  startTime = millis();
+  posImag = startImag;
+  for (int y = 0; y < pixelHeight; y++) {
+    posReal = startReal;
+    for (int x = 0; x < pixelWidth; x++) {
+      a = posReal;
+      b = posImag;
+      for (n = iterations; n > 0 ; n--) {
+        a2 = (a * a) >> bits;
+        b2 = (b * b) >> bits;
+        if ((a2 + b2) >= (4 << bits)) 
+          break;
+        b  = posImag + ((a * b) >> (bits - 1));
+        a  = posReal + a2 - b2;
+      }
+      #if defined(USE_BUFFER)
+        buffer[y * pixelWidth + x] = (n * 29)<<8 | (n * 67);
+      #else
+        tft.drawPixel(x, y, (n * 29)<<8 | (n * 67)); // takes 500ms with individual pixel writes
+      #endif
+      posReal += incReal;
+    }
+    posImag -= incImag;
+  }
+  #if defined(USE_BUFFER)
+    tft.drawRGBBitmap(0, 0, buffer, pixelWidth, pixelHeight); // takes 169 ms
+  #endif
+  elapsedTime = millis()-startTime;
+  Serial.print("Took "); Serial.print(elapsedTime); Serial.println(" ms");
+
+  rangeReal *= 0.95;
+  rangeImag *= 0.95;
+}