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March 1, 2022 20:57
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Real-time fractals on ESP32 and composite video out
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| /* | |
| Real-time fractals on ESP32 and composite video out | |
| 1 Mar 2022 - @todbot | |
| Basically just combined this sketch: | |
| https://create.arduino.cc/projecthub/picass01/fractal-mandelbrot-with-arduino-72a2b6 | |
| and the "GFX_HelloWorld" sketch from | |
| https://github.com/Roger-random/ESP_8_BIT_composite | |
| Uses ESP_8_BIT_composite color composite video generator library on ESP32. | |
| Connect GPIO25 to signal line, usually the center of composite video plug. | |
| Copyright (c) Roger Cheng | |
| MIT License | |
| Permission is hereby granted, free of charge, to any person obtaining a copy | |
| of this software and associated documentation files (the "Software"), to deal | |
| in the Software without restriction, including without limitation the rights | |
| to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| copies of the Software, and to permit persons to whom the Software is | |
| furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be included in all | |
| copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| SOFTWARE. | |
| */ | |
| #include <ESP_8_BIT_GFX.h> | |
| // A list of 8-bit color values that work well in a cycle. | |
| uint8_t colorCycle[] = { | |
| 0xFF, // White | |
| 0xFE, // Lowering blue | |
| 0xFD, | |
| 0xFC, // No blue | |
| 0xFD, // Raising blue | |
| 0xFE, | |
| 0xFF, // White | |
| 0xF3, // Lowering green | |
| 0xE7, | |
| 0xE3, // No green | |
| 0xE7, // Raising green | |
| 0xF3, | |
| 0xFF, // White | |
| 0x9F, // Lowering red | |
| 0x5F, | |
| 0x1F, // No red | |
| 0x5F, // Raising red | |
| 0x9F, | |
| 0xFF | |
| }; | |
| // Create an instance of the graphics library | |
| ESP_8_BIT_GFX videoOut(true /* = NTSC */, 8 /* = RGB332 color */); | |
| void setup() { | |
| Serial.begin(115200); | |
| // Initial setup of graphics library | |
| videoOut.begin(); | |
| } | |
| double realMin = -2; | |
| double realMax = 1.0; | |
| double imagMin = -1.0; | |
| double imagMax = 1.0; | |
| void loop() { | |
| // Wait for the next frame to minimize chance of visible tearing | |
| videoOut.waitForFrame(); | |
| // Clear screen | |
| videoOut.fillScreen(0); | |
| myMandel( realMin, realMax, imagMin, imagMax, 10, 255, 255); | |
| imagMin += 0.01; | |
| imagMax -= 0.01; | |
| } | |
| long startTime = 0; | |
| void myMandel(double realMin, double realMax, double imagMin, double imagMax, int maxIterations, double ySize, double xSize) { | |
| // http://rosettacode.org/wiki/Mandelbrot_set#AWK | |
| startTime = millis(); | |
| String myString = "\n\n\n\nrealMin=" + String(realMin) + ", realMax=" + String(realMax) + ", imagMin=" + String(imagMin) + ", imagMax=" + String(imagMax) + ", maxIterations=" + String(maxIterations) + ", startTime=" + String((startTime / 1000.0)) + "s"; | |
| Serial.print(myString); | |
| //================================================================ | |
| double xStep = (realMax - realMin) / xSize; | |
| double yStep = (imagMax - imagMin) / ySize; | |
| //char* colorChar[] = {"#", "-", ":", "=", "o"}; // darker to lighter? | |
| uint16_t colors[] = { 0xF800, 0x07E0, 0x07FF, 0xF81F, 0x001F, }; | |
| int colorsLength = (sizeof(colors) / sizeof(colors[0])) - 1; | |
| //int colorsLength = (sizeof(colorCycle) / sizeof(colorCycle[0])) - 1; | |
| int color = 0; | |
| for (int y = 0; y < ySize; y++) { | |
| //Serial.print("\n"); | |
| //switchLED(); | |
| double imagY = imagMin + yStep * y; | |
| for (int x = 0; x < xSize; x++) { | |
| double realX = realMin + xStep * x; | |
| double realZ = realX; | |
| double imagZ = imagY; | |
| for (int n = 0; n <= maxIterations; n++) { | |
| color = n; | |
| double a = realZ * realZ; | |
| double b = imagZ * imagZ; | |
| if (a + b > 4.0) break; | |
| imagZ = 2 * realZ * imagZ + imagY; | |
| realZ = a - b + realX; | |
| } | |
| (color == maxIterations ) ? color = 0 : color = color % colorsLength + 1; | |
| videoOut.fillRect(x,y, 2,2, colors[color]); | |
| //videoOut.fillRect(x,y, 2,2, colorCycle[color]); | |
| } | |
| } | |
| //================================================================ | |
| long elapseTime = millis() - startTime; | |
| myString = "\nelapseTime=" + String((elapseTime / 1000.0)) + "s"; | |
| Serial.print(myString); | |
| } |
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