Bob Stone / Mbed 2 deprecated Mandelbrot

Mandelbrot viewer for SPI TFT touchscreen

Dependencies:   SPI_TFT TFT_fonts Touch_tft mbed

/media/uploads/RorschachUK/_scaled_p4130004.jpg

A Mandelbrot viewer for Mikroelektronika's "TFT-Proto" 2.8" 320x240 TFT touch panel, which is a pretty inexpensive screen.

I used Peter Drescher's library for it - http://mbed.org/cookbook/SPI-driven-QVGA-TFT and also used his wiring diagram to make an adapter.

main.cpp@1:a9641f372bea, 2013-04-17 (annotated)

Committer:
RorschachUK
Date:
Wed Apr 17 18:14:12 2013 +0000
Revision:
1:a9641f372bea
Parent:
0:a954bd7fd162 
Added a preview rectangle and corrected a calculation.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
RorschachUK 0:a954bd7fd162 1 /* Mandelbrot for mbed - April 2013
RorschachUK 0:a954bd7fd162 2 * Uses Peter Drescher's library for Mikroelektronika's TFT-Proto screen, an inexpensive SPI-driven QVGA touch panel
RorschachUK 0:a954bd7fd162 3 * Library: http://mbed.org/cookbook/SPI-driven-QVGA-TFT
RorschachUK 0:a954bd7fd162 4 * Manufacturer's page for the screen: http://www.mikroe.com/add-on-boards/display/tft-proto/
RorschachUK 0:a954bd7fd162 5 * UK distributor: http://www.mcustore.com/tft-proto-board.html
RorschachUK 0:a954bd7fd162 6 * Partly adapted from Kamil Ondrousek's code for another screen: http://mbed.org/users/JLS/code/Mandelbrot-2/
RorschachUK 0:a954bd7fd162 7 */
RorschachUK 0:a954bd7fd162 8 #include "mbed.h"
RorschachUK 0:a954bd7fd162 9 #include "SPI_TFT.h"
RorschachUK 0:a954bd7fd162 10 #include "Arial12x12.h"
RorschachUK 0:a954bd7fd162 11 #include "touch_tft.h"
RorschachUK 0:a954bd7fd162 12
RorschachUK 0:a954bd7fd162 13 #define WIDTH 320
RorschachUK 0:a954bd7fd162 14 #define HEIGHT 240
RorschachUK 0:a954bd7fd162 15
RorschachUK 0:a954bd7fd162 16 touch_tft tt(p18,p19,p16,p17,p11, p12, p13, p14, p15,"TFT"); // x+,x-,y+,y-,mosi, miso, sclk, cs, reset
RorschachUK 0:a954bd7fd162 17
RorschachUK 0:a954bd7fd162 18 void drawMandelbrot(float centrex, float centrey, float zoom, int maxIter) {
RorschachUK 0:a954bd7fd162 19 float xmin = centrex - 1.0/zoom;
RorschachUK 0:a954bd7fd162 20 float xmax = centrex + 1.0/zoom;
RorschachUK 0:a954bd7fd162 21 float ymin = centrey - HEIGHT / (WIDTH * zoom);
RorschachUK 0:a954bd7fd162 22 float ymax = centrey + HEIGHT / (WIDTH *zoom);
RorschachUK 0:a954bd7fd162 23
RorschachUK 0:a954bd7fd162 24 float dx = (xmax - xmin) / WIDTH;
RorschachUK 0:a954bd7fd162 25 float dy = (ymax - ymin) / HEIGHT;
RorschachUK 0:a954bd7fd162 26
RorschachUK 0:a954bd7fd162 27 float y = ymin;
RorschachUK 0:a954bd7fd162 28
RorschachUK 0:a954bd7fd162 29 float c;
RorschachUK 0:a954bd7fd162 30 unsigned int cr, cg, cb;
RorschachUK 0:a954bd7fd162 31
RorschachUK 0:a954bd7fd162 32 for (int j = 0; j < HEIGHT; j++) {
RorschachUK 0:a954bd7fd162 33 float x = xmin;
RorschachUK 0:a954bd7fd162 34
RorschachUK 0:a954bd7fd162 35 for (int i = 0; i < WIDTH; i++) {
RorschachUK 0:a954bd7fd162 36 float a = x;
RorschachUK 0:a954bd7fd162 37 float b = y;
RorschachUK 0:a954bd7fd162 38 int n = 0;
RorschachUK 0:a954bd7fd162 39
RorschachUK 0:a954bd7fd162 40 while (n < maxIter) {
RorschachUK 0:a954bd7fd162 41 float aa = a * a;
RorschachUK 0:a954bd7fd162 42 float bb = b * b;
RorschachUK 0:a954bd7fd162 43 float twoab = 2.0 * a * b;
RorschachUK 0:a954bd7fd162 44
RorschachUK 0:a954bd7fd162 45 a = aa - bb + x;
RorschachUK 0:a954bd7fd162 46 b = twoab + y;
RorschachUK 0:a954bd7fd162 47
RorschachUK 0:a954bd7fd162 48 if(aa + bb > 16.0) {
RorschachUK 0:a954bd7fd162 49 break;
RorschachUK 0:a954bd7fd162 50 }
RorschachUK 0:a954bd7fd162 51 n++;
RorschachUK 0:a954bd7fd162 52 }
RorschachUK 0:a954bd7fd162 53
RorschachUK 0:a954bd7fd162 54 if (n == maxIter) {
RorschachUK 0:a954bd7fd162 55 //It's in the set - Black
RorschachUK 0:a954bd7fd162 56 tt.pixel(i,j,Black);
RorschachUK 0:a954bd7fd162 57 } else {
RorschachUK 0:a954bd7fd162 58 //Not in the set - pick a colour
RorschachUK 0:a954bd7fd162 59 c = 3.0 * (maxIter-n)/maxIter;
RorschachUK 0:a954bd7fd162 60 cr = ((c < 1.0) ? 255 * ( 1.0 - c) : (c > 2.0) ? 255 * (c - 2.0) : 0);
RorschachUK 0:a954bd7fd162 61 cg = ((c < 1.0) ? 255 * c : (c > 2.0) ? 0 : 255 * (2.0 - c));
RorschachUK 0:a954bd7fd162 62 cb = ((c < 1.0) ? 0 : (c > 2.0) ? 255 * (3.0 - c) : 255 * (c - 1.0));
RorschachUK 0:a954bd7fd162 63 tt.pixel(i,j, RGB(cr,cg,cb));
RorschachUK 0:a954bd7fd162 64 }
RorschachUK 0:a954bd7fd162 65 x += dx;
RorschachUK 0:a954bd7fd162 66 }
RorschachUK 0:a954bd7fd162 67 y += dy;
RorschachUK 0:a954bd7fd162 68 }
RorschachUK 0:a954bd7fd162 69 }
RorschachUK 0:a954bd7fd162 70
RorschachUK 0:a954bd7fd162 71 int main()
RorschachUK 0:a954bd7fd162 72 {
RorschachUK 0:a954bd7fd162 73 //Setup screen
RorschachUK 0:a954bd7fd162 74 tt.claim(stdout); // send stdout to the TFT display
RorschachUK 0:a954bd7fd162 75 tt.background(Black); // set background to black
RorschachUK 0:a954bd7fd162 76 tt.foreground(White); // set chars to white
RorschachUK 0:a954bd7fd162 77 tt.cls(); // clear the screen
RorschachUK 0:a954bd7fd162 78 tt.set_font((unsigned char*) Arial12x12); // select the font
RorschachUK 0:a954bd7fd162 79 tt.set_orientation(1);
RorschachUK 0:a954bd7fd162 80 tt.calibrate(); // calibrate the touch
RorschachUK 0:a954bd7fd162 81 point p;
RorschachUK 0:a954bd7fd162 82
RorschachUK 0:a954bd7fd162 83 tt.locate(0,0);
RorschachUK 0:a954bd7fd162 84
RorschachUK 0:a954bd7fd162 85 //Setup base Mandelbrot
RorschachUK 0:a954bd7fd162 86 float centrex = -0.5;
RorschachUK 0:a954bd7fd162 87 float centrey = 0.0;
RorschachUK 0:a954bd7fd162 88 float zoom=0.5;
RorschachUK 0:a954bd7fd162 89 int maxiterations = 150;
RorschachUK 0:a954bd7fd162 90
RorschachUK 0:a954bd7fd162 91 while(true) {
RorschachUK 0:a954bd7fd162 92 //Draw it
RorschachUK 0:a954bd7fd162 93 drawMandelbrot(centrex, centrey, zoom, maxiterations);
RorschachUK 0:a954bd7fd162 94
RorschachUK 0:a954bd7fd162 95 //Wait for a touch
RorschachUK 0:a954bd7fd162 96 p=tt.get_touch();
RorschachUK 0:a954bd7fd162 97 while(!tt.is_touched(p)) {
RorschachUK 0:a954bd7fd162 98 p=tt.get_touch();
RorschachUK 0:a954bd7fd162 99 }
RorschachUK 0:a954bd7fd162 100 //Set new centre and zoom
RorschachUK 0:a954bd7fd162 101 p = tt.to_pixel(p);
RorschachUK 0:a954bd7fd162 102 centrex += (2.0 * p.x - WIDTH) / (zoom * WIDTH);
RorschachUK 1:a9641f372bea 103 centrey += (2.0 * p.y - HEIGHT) / (zoom * WIDTH);
RorschachUK 0:a954bd7fd162 104 zoom *= 4.0;
RorschachUK 1:a9641f372bea 105 tt.rect(p.x - WIDTH / 8.0, p.y - HEIGHT / 8.0, p.x + WIDTH / 8.0, p.y + HEIGHT / 8.0, Yellow);
RorschachUK 0:a954bd7fd162 106 }
RorschachUK 0:a954bd7fd162 107 }