Add new example for Julia set

2025-08-01 03:34:43 +02:00 · 2023-04-26 01:59:08 +01:00
parent 4e2f2edd58
commit 18e37ca026
1 changed files with 83 additions and 0 deletions
--- a/examples/Generic/Julia_Set/Julia_Set.ino
+++ b/examples/Generic/Julia_Set/Julia_Set.ino
@@ -0,0 +1,83 @@
+// Based on sketch here:
+// https://github.com/OpenHDZ/Arduino-experimentation
+// Adapted for TFT_eSPI library
+
+// Note: a high number of floating point calculations are needed
+// for each pixel so rendering will be quite slow.
+// For best performance use a Teensy 4.x (600MHz CPU clock).
+
+#include <TFT_eSPI.h>       // Hardware-specific library
+
+TFT_eSPI tft = TFT_eSPI();  // Invoke custom library
+
+const uint16_t MAX_ITERATION = 300; // Nombre de couleurs
+
+#define SCREEN_WIDTH  tft.width()  // 
+#define SCREEN_HEIGHT tft.height() // Taille de l'écran
+
+static float zoom = 0.5;
+
+/* Fonction setup */
+void setup() {
+/* Initialise l'écran LCD */
+  tft.begin();
+  tft.setRotation(1);
+  tft.fillScreen(TFT_BLACK);
+  tft.setFreeFont(&FreeMono9pt7b);
+}
+
+/* Fonction loop() */
+void loop() {
+  /* Dessine la fractale */
+  draw_Julia(-0.8,+0.156,zoom);
+  tft.fillRect(0, 0, 150, 20, TFT_BLACK);
+  tft.setCursor(0,15);
+  tft.setTextColor(TFT_WHITE);
+  tft.print(" Zoom = ");
+  tft.println(zoom);
+  delay(2000);
+  zoom *= 1.5;
+  if (zoom > 100) zoom = 0.5;
+}
+
+/* 
+  Dessine une fractale de Julia
+ */
+
+void draw_Julia(float c_r, float c_i, float zoom) {
+
+  tft.setCursor(0,0);
+  float new_r = 0.0, new_i = 0.0, old_r = 0.0, old_i = 0.0;
+
+  /* Pour chaque pixel en X */
+
+  for(int16_t x = SCREEN_WIDTH/2 - 1; x >= 0; x--) { // Rely on inverted symettry
+    /* Pour chaque pixel en Y */
+    for(uint16_t y = 0; y < SCREEN_HEIGHT; y++) {      
+      old_r = 1.5 * (x - SCREEN_WIDTH / 2) / (0.5 * zoom * SCREEN_WIDTH);
+      old_i = (y - SCREEN_HEIGHT / 2) / (0.5 * zoom * SCREEN_HEIGHT);
+      uint16_t i = 0;
+
+      while ((old_r * old_r + old_i * old_i) < 4.0 && i < MAX_ITERATION) {
+        new_r = old_r * old_r - old_i * old_i ;
+        new_i = 2.0 * old_r * old_i;
+
+        old_r = new_r+c_r;
+        old_i = new_i+c_i;
+        
+        i++;
+      }
+      /* Affiche le pixel */
+      if (i < 100){
+        tft.drawPixel(x,y,tft.color565(255,255,map(i,0,100,255,0)));
+        tft.drawPixel(SCREEN_WIDTH - x - 1,SCREEN_HEIGHT - y - 1,tft.color565(255,255,map(i,0,100,255,0)));
+      }if(i<200){
+        tft.drawPixel(x,y,tft.color565(255,map(i,100,200,255,0),0));
+        tft.drawPixel(SCREEN_WIDTH - x - 1,SCREEN_HEIGHT - y - 1,tft.color565(255,map(i,100,200,255,0),0));
+      }else{
+        tft.drawPixel(x,y,tft.color565(map(i,200,300,255,0),0,0));
+        tft.drawPixel(SCREEN_WIDTH - x - 1,SCREEN_HEIGHT - y - 1,tft.color565(map(i,200,300,255,0),0,0));
+      }
+    }
+  }
+}