first commit

README.md

@@ -0,0 +1,12 @@
+<<<     a bunch of classic demoscene effects running on an esp32     >>>
+___.   .__         __  .__         .___               __                 
+\_ |__ |__|_______/  |_|  |__    __| _/____  ___.__._/  |________  ____  
+ | __ \|  \_  __ \   __\  |  \  / __ |\__  \<   |  |\   __\_  __ \/  _ \ 
+ | \_\ \  ||  | \/|  | |   Y  \/ /_/ | / __ \\___  | |  |  |  | \(  <_> )
+ |___  /__||__|   |__| |___|  /\____ |(____  / ____| |__|  |__|   \____/ 
+     \/                     \/      \/     \/\/                          
+ +-----  - -  --- - - --- - -- - - - --- - - - --- --- -- - - - -- -- --+
+ :         reliving some teenage coding on a lazy summer day            .
+ .   oldskool effects running on an ESP32 with a monochrome display     :
+ :                    http://www.derfunke.net                           .
+ +-- (( 2022 )) ------ -- - -------------- -- --- ---------------- -- --+

include/README

@@ -0,0 +1,39 @@
+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

lib/README

@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

platformio.ini

@@ -0,0 +1,22 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:lolin32]
+platform = espressif32
+board = lolin32
+framework = arduino
+
+monitor_speed = 115200
+
+;   NeoGPS=slashdevin/NeoGPS@^4.2.9
+
+lib_deps =
+  SSD1306=adafruit/Adafruit SSD1306@^2.5.6
+  Time=paulstoffregen/Time@^1.6.1

src/main.cpp

@@ -0,0 +1,157 @@
+#include <Arduino.h>
+
+#include <SPI.h>
+#include <Wire.h>
+#include <Adafruit_GFX.h>
+#include <Adafruit_SSD1306.h>
+
+#define DEG2RAD 0.01745329f
+
+#define SCREEN_WIDTH 128
+#define SCREEN_HEIGHT 64
+
+#define OLED_RESET     -1
+#define SCREEN_ADDRESS 0x3C
+Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
+
+#define STAR_COUNT 300
+
+#define TEXT_COUNT 17
+int textIdx = 0;
+unsigned long lastText = 0;
+const char *texts[] = {
+  "REMEMBER WHERE YOU ARE",
+  "THIS\nSPECK\nOF MATTER",
+  "YOU ARE\nSTARDUST",
+  "THAT WILL\nWALK HERE",
+  "ONLY\nONCE",
+  "GO FIND\nOTHERS",
+  "8000\nLIGHT\nYEARS",
+  "ISN'T\nFAR",
+  "WHEN YOU\nTRAVEL",
+  "IN YOUR\nMIND",
+  "",
+  "",
+  "",
+  "HAPPY\nBIRTHDAY",
+  "HAPPY\nBIRTHDAY",
+  "",
+  "",
+};
+
+struct Star {
+  int angle;
+  int age;
+  int speed;
+};
+
+Star sfield[STAR_COUNT];
+
+void init_display() {
+  Wire.begin(5, 4);
+
+  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS, false, false)) {
+    Serial.println(F("SSD1306 allocation failed"));
+    while(true) ; // do not proceed
+  }
+
+  display.clearDisplay();
+}
+
+void star_reset(int which) {
+  sfield[which].angle = random(360);
+  sfield[which].speed = random(1, 6);
+}
+
+void init_starfield() {
+  for (int i = 0; i < STAR_COUNT; i++) {
+    sfield[i].age = random(0, 100); 
+    star_reset( i );
+  }
+}
+
+void setup() {
+  Serial.begin(115200);
+  init_display();
+  init_starfield(); 
+  Serial.println("Kicking off starfield");
+}
+
+void draw_starfield() {
+  int xstar, ystar;
+
+  // compute center of screen
+  int xc = SCREEN_WIDTH >> 1;
+  int yc = SCREEN_HEIGHT >> 1;
+
+  display.clearDisplay(); 
+
+  for (int i = 0; i < STAR_COUNT; i++) {  
+
+    if (sfield[i].age > 100) { 
+      sfield[i].age = sfield[i].age - 100;
+      star_reset(i);
+    } else {    
+      sfield[i].age = sfield[i].age + sfield[i].speed; 
+    }
+
+    xstar = (xc + (sin(sfield[i].angle * DEG2RAD) * sfield[i].age )); 
+    ystar = (yc + (cos(sfield[i].angle * DEG2RAD) * sfield[i].age )); 
+    display.drawPixel(xstar, ystar, WHITE);  
+  }
+}
+
+void draw_moire() {
+  float t = millis() * 0.001;
+
+  float cx1 = sin(t / 2) * SCREEN_WIDTH  / 3 + SCREEN_WIDTH / 2;
+  float cy1 = sin(t / 4) * SCREEN_HEIGHT / 3 + SCREEN_HEIGHT / 2;
+  float cx2 = cos(t / 3) * SCREEN_WIDTH  / 3 + SCREEN_WIDTH / 2;
+  float cy2 = cos(t)     * SCREEN_HEIGHT / 3 + SCREEN_HEIGHT / 2;
+
+  for(int y = 0; y < SCREEN_HEIGHT; y++) {
+    float dy = (y - cy1) * (y - cy1);
+    float dy2 = (y - cy2) * (y - cy2);
+    for(int x = 0; x < SCREEN_WIDTH; x++) {
+      float dx = (x - cx1) * (x - cx1);
+      float dx2 = (x - cx2) * (x - cx2);
+      int ic = (int)ceil(sqrt(dx + dy));
+      int ic2 = (int)ceil(sqrt(dx2 + dy2));
+      int shade = ((( ic ^ ic2 ) >> 3) & 1) * 255;
+      
+      if(shade > 128) { 
+        display.drawPixel(x, y, WHITE);  
+      } else {
+        display.drawPixel(x, y, BLACK);
+      }
+
+    }
+  }
+}
+
+void draw_text1() {
+  if( (millis() - lastText) >= 3200 ) { 
+    textIdx++;
+    lastText = millis(); 
+    if(textIdx >= TEXT_COUNT) textIdx = 0; 
+  }
+  display.setTextSize(2);
+  display.setTextColor(SSD1306_WHITE);
+  display.setCursor(10, 12);
+  display.println(F( texts[textIdx] ));
+  // display.setCursor(10, 32);
+  // display.setTextSize(2);
+  // display.println(F("WHERE YOU ARE"));
+}
+
+void loop() {
+  if( (textIdx > 9) && (textIdx <= 12) ) {
+    draw_moire();
+  } else {
+    draw_starfield();
+  }
+  draw_text1();
+
+  // draw_moire();
+  display.display();
+}