![](/media/cache/profiles/851fd85e0c2baf63f6042123c2b4aac7.50x50_q85.jpg)
Mandelbrot viewer for SPI TFT touchscreen
Dependencies: SPI_TFT TFT_fonts Touch_tft mbed
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.
Diff: main.cpp
- Revision:
- 0:a954bd7fd162
- Child:
- 1:a9641f372bea
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Sat Apr 13 19:27:43 2013 +0000 @@ -0,0 +1,106 @@ +/* Mandelbrot for mbed - April 2013 + * Uses Peter Drescher's library for Mikroelektronika's TFT-Proto screen, an inexpensive SPI-driven QVGA touch panel + * Library: http://mbed.org/cookbook/SPI-driven-QVGA-TFT + * Manufacturer's page for the screen: http://www.mikroe.com/add-on-boards/display/tft-proto/ + * UK distributor: http://www.mcustore.com/tft-proto-board.html + * Partly adapted from Kamil Ondrousek's code for another screen: http://mbed.org/users/JLS/code/Mandelbrot-2/ + */ +#include "mbed.h" +#include "SPI_TFT.h" +#include "Arial12x12.h" +#include "touch_tft.h" + +#define WIDTH 320 +#define HEIGHT 240 + +touch_tft tt(p18,p19,p16,p17,p11, p12, p13, p14, p15,"TFT"); // x+,x-,y+,y-,mosi, miso, sclk, cs, reset + +void drawMandelbrot(float centrex, float centrey, float zoom, int maxIter) { + float xmin = centrex - 1.0/zoom; + float xmax = centrex + 1.0/zoom; + float ymin = centrey - HEIGHT / (WIDTH * zoom); + float ymax = centrey + HEIGHT / (WIDTH *zoom); + + float dx = (xmax - xmin) / WIDTH; + float dy = (ymax - ymin) / HEIGHT; + + float y = ymin; + + float c; + unsigned int cr, cg, cb; + + for (int j = 0; j < HEIGHT; j++) { + float x = xmin; + + for (int i = 0; i < WIDTH; i++) { + float a = x; + float b = y; + int n = 0; + + while (n < maxIter) { + float aa = a * a; + float bb = b * b; + float twoab = 2.0 * a * b; + + a = aa - bb + x; + b = twoab + y; + + if(aa + bb > 16.0) { + break; + } + n++; + } + + if (n == maxIter) { + //It's in the set - Black + tt.pixel(i,j,Black); + } else { + //Not in the set - pick a colour + c = 3.0 * (maxIter-n)/maxIter; + cr = ((c < 1.0) ? 255 * ( 1.0 - c) : (c > 2.0) ? 255 * (c - 2.0) : 0); + cg = ((c < 1.0) ? 255 * c : (c > 2.0) ? 0 : 255 * (2.0 - c)); + cb = ((c < 1.0) ? 0 : (c > 2.0) ? 255 * (3.0 - c) : 255 * (c - 1.0)); + tt.pixel(i,j, RGB(cr,cg,cb)); + } + x += dx; + } + y += dy; + } +} + +int main() +{ + //Setup screen + tt.claim(stdout); // send stdout to the TFT display + tt.background(Black); // set background to black + tt.foreground(White); // set chars to white + tt.cls(); // clear the screen + tt.set_font((unsigned char*) Arial12x12); // select the font + tt.set_orientation(1); + tt.calibrate(); // calibrate the touch + point p; + + tt.locate(0,0); + + //Setup base Mandelbrot + float centrex = -0.5; + float centrey = 0.0; + float zoom=0.5; + int maxiterations = 150; + + while(true) { + //Draw it + drawMandelbrot(centrex, centrey, zoom, maxiterations); + + //Wait for a touch + p=tt.get_touch(); + while(!tt.is_touched(p)) { + p=tt.get_touch(); + } + //Set new centre and zoom + p = tt.to_pixel(p); + centrex += (2.0 * p.x - WIDTH) / (zoom * WIDTH); + centrey += (2.0 * p.y - HEIGHT) / (zoom * HEIGHT); + zoom *= 4.0; + } +} \ No newline at end of file