Helios Lyons 201239214

Dependencies:   mbed

Brief

My aim for this project was to create a FRDM K64F adapted version of the classic Space Invaders by Tomohiro Nishikado. The game itself has a number of clear features to implement;

  • Left to right movement for the player 'canon'
  • A fixed amount of player lives
  • Firing mechanics for both canon and invaders (hence collision systems)
  • Random firing from remaining invaders
  • Wave based combat

My own addition to these established ideas was Boss waves, featuring a single, larger sprite which fires at a faster interval than previous waves. The addition of a movement system using a basic for loop, as opposed to a velocity based system, will enhance the nostalgic feel of the game.

https://os.mbed.com/media/uploads/helioslyons/screenshot_2020-05-27_at_06.12.00.png

Gameplay

Movement is controlled with the joystick, moving the canon left or right. Fire by pressing A. Invaders spawn at set positions, but randomly fire at a set interval, which is higher for boss waves. Time is taken during each wave, and displayed at wave intervals, and if the play wins.

Controls are shown on the Gamepad below: (attribution: Craig A. Evans, ELEC2645 University of Leeds)

https://os.mbed.com/media/uploads/helioslyons/screenshot_2020-05-27_at_06.20.18.png

Revision:
1:a3f43007030e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Gamepad2/N5110.cpp	Tue Mar 24 18:02:01 2020 +0000
@@ -0,0 +1,507 @@
+#include "mbed.h"
+#include "N5110.h"
+
+// overloaded constructor includes power pin - LCD Vcc connected to GPIO pin
+// this constructor works fine with LPC1768 - enough current sourced from GPIO
+// to power LCD. Doesn't work well with K64F.
+N5110::N5110(PinName const pwrPin,
+             PinName const scePin,
+             PinName const rstPin,
+             PinName const dcPin,
+             PinName const mosiPin,
+             PinName const sclkPin,
+             PinName const ledPin)
+    :
+    _spi(new SPI(mosiPin,NC,sclkPin)), // create new SPI instance and initialise
+    _led(new DigitalOut(ledPin)),
+    _pwr(new DigitalOut(pwrPin)),
+    _sce(new DigitalOut(scePin)),
+    _rst(new DigitalOut(rstPin)),
+    _dc(new DigitalOut(dcPin))
+{}
+
+// overloaded constructor does not include power pin - LCD Vcc must be tied to +3V3
+// Best to use this with K64F as the GPIO hasn't sufficient output current to reliably
+// drive the LCD.
+N5110::N5110(PinName const scePin,
+             PinName const rstPin,
+             PinName const dcPin,
+             PinName const mosiPin,
+             PinName const sclkPin,
+             PinName const ledPin)
+    :
+    _spi(new SPI(mosiPin,NC,sclkPin)), // create new SPI instance and initialise
+    _led(new DigitalOut(ledPin)),
+    _pwr(NULL), // pwr not needed so null it to be safe
+    _sce(new DigitalOut(scePin)),
+    _rst(new DigitalOut(rstPin)),
+    _dc(new DigitalOut(dcPin))
+{}
+// Second overload contructor uses the New Gamepad (Rev 2.1) pin mappings
+N5110::N5110()
+    :
+    _spi(new SPI(PTD2,NC,PTD1)), // create new SPI instance and initialise
+    _led(new DigitalOut(PTB23)),
+    _pwr(NULL), // pwr not needed so null it to be safe
+    _sce(new DigitalOut(PTB19)),
+    _rst(new DigitalOut(PTC1)),
+    _dc(new DigitalOut(PTB18))
+{}
+
+N5110::~N5110()
+{
+    delete _spi;
+
+    if(_pwr) {
+        delete _pwr;
+    }
+
+    delete _led;
+    delete _sce;
+    delete _rst;
+    delete _dc;
+}
+
+// initialise function - powers up and sends the initialisation commands
+void N5110::init()
+{
+    turnOn();     // power up
+    reset();      // reset LCD - must be done within 100 ms
+    initSPI();    
+    
+    backLightOn();
+    setContrast(0.55);  // this may need tuning (say 0.4 to 0.6)
+    setBias(3);   // datasheet - 48:1 mux - don't mess with if you don't know what you're doing! (0 to 7)
+    setTempCoefficient(0); // datasheet - may need increasing (range 0 to 3) at very low temperatures
+    normalMode();  // normal video mode by default
+    
+    clearRAM();      // RAM is undefined at power-up so clear to be sure
+    clear();   // clear buffer
+}
+
+// sets normal video mode (black on white)
+void N5110::normalMode()
+{
+    sendCommand(0b00100000);   // basic instruction
+    sendCommand(0b00001100);  // normal video mode- datasheet
+}
+
+// sets normal video mode (white on black)
+void N5110::inverseMode()
+{
+    sendCommand(0b00100000);   // basic instruction
+    sendCommand(0b00001101);   // inverse video mode - datasheet
+}
+
+// function to power up the LCD and backlight - only works when using GPIO to power
+void N5110::turnOn()
+{
+    if (_pwr != NULL) {
+        _pwr->write(1);  // apply power
+    }
+}
+
+// function to power down LCD
+void N5110::turnOff()
+{
+    clear(); // clear buffer
+    refresh();
+    backLightOff(); // turn backlight off
+    clearRAM();   // clear RAM to ensure specified current consumption
+    // send command to ensure we are in basic mode
+    
+    sendCommand(0b00100000); // basic mode
+    sendCommand(0b00001000); // clear display
+    sendCommand(0b00100001); // extended mode
+    sendCommand(0b00100100); // power down
+    
+    // if we are powering the LCD using the GPIO then make it low to turn off
+    if (_pwr != NULL) {
+        wait_ms(10);  // small delay and then turn off the power pin
+        _pwr->write(0);  // turn off power
+    }
+
+}
+
+// function to change LED backlight brightness
+void N5110::backLightOn()
+{
+    _led->write(1);
+}
+
+// function to change LED backlight brightness
+void N5110::backLightOff()
+{
+    _led->write(0);
+}
+
+void N5110::setContrast(float contrast) {
+    
+    // enforce limits
+    if (contrast > 1.0f)
+        contrast = 1.0f;
+    else if (contrast < 0.0f)
+        contrast = 0.0;
+    
+    // convert to char in range 0 to 127 (i.e. 6 bits)
+    char ic = char(contrast*127.0f);
+    
+    sendCommand(0b00100001);  // extended instruction set
+    sendCommand(0b10000000 | ic);   // set Vop (which controls contrast)
+    sendCommand(0b00100000);  // back to basic instruction set
+}
+
+void N5110::setTempCoefficient(char tc) {
+    
+    // enforce limits
+    if (tc>3) {
+        tc=3;
+    }
+    
+    // temperature coefficient may need increasing at low temperatures
+
+    sendCommand(0b00100001);  // extended instruction set
+    sendCommand(0b00000100 | tc);
+    sendCommand(0b00100000);  // back to basic instruction set
+}
+    
+void N5110::setBias(char bias) {
+    
+    // from data sheet
+    // bias      mux rate
+    // 0        1:100
+    // 1        1:80
+    // 2        1:65
+    // 3        1:48   (default)
+    // 4        1:40/1:34
+    // 5        1:24
+    // 6        1:18/1:16
+    // 7        1:10/1:9/1:8
+    
+    // enforce limits
+    if (bias>7) {
+        bias=7;
+    }
+        
+    sendCommand(0b00100001);  // extended mode instruction
+    sendCommand(0b00010000 | bias);  
+    sendCommand(0b00100000); // end of extended mode instruction
+}
+
+// pulse the active low reset line
+void N5110::reset()
+{
+    _rst->write(0);  // reset the LCD
+    _rst->write(1);
+}
+
+// function to initialise SPI peripheral
+void N5110::initSPI()
+{
+    _spi->format(8,1);    // 8 bits, Mode 1 - polarity 0, phase 1 - base value of clock is 0, data captured on falling edge/propagated on rising edge
+    _spi->frequency(4000000);  // maximum of screen is 4 MHz
+}
+
+// send a command to the display
+void N5110::sendCommand(unsigned char command)
+{
+    _dc->write(0);  // set DC low for command
+    _sce->write(0); // set CE low to begin frame
+    _spi->write(command);  // send command
+    _dc->write(1);  // turn back to data by default
+    _sce->write(1); // set CE high to end frame (expected for transmission of single byte)
+}
+
+// send data to the display at the current XY address
+// dc is set to 1 (i.e. data) after sending a command and so should
+// be the default mode.
+void N5110::sendData(unsigned char data)
+{
+    _sce->write(0);   // set CE low to begin frame
+    _spi->write(data);
+    _sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
+}
+
+// this function writes 0 to the 504 bytes to clear the RAM
+void N5110::clearRAM()
+{
+    _sce->write(0);  //set CE low to begin frame
+    for(int i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
+        _spi->write(0x00);  // send 0's
+    }
+    _sce->write(1); // set CE high to end frame
+}
+
+// function to set the XY address in RAM for subsequenct data write
+void N5110::setXYAddress(unsigned int const x,
+                         unsigned int const y)
+{
+    if (x<WIDTH && y<HEIGHT) {  // check within range
+        sendCommand(0b00100000);  // basic instruction
+        sendCommand(0b10000000 | x);  // send addresses to display with relevant mask
+        sendCommand(0b01000000 | y);
+    }
+}
+
+// These functions are used to set, clear and get the value of pixels in the display
+// Pixels are addressed in the range of 0 to 47 (y) and 0 to 83 (x).  The refresh()
+// function must be called after set and clear in order to update the display
+void N5110::setPixel(unsigned int const x,
+                     unsigned int const y,
+                     bool const         state)
+{
+    if (x<WIDTH && y<HEIGHT) {  // check within range
+        // calculate bank and shift 1 to required position in the data byte
+        if(state) buffer[x][y/8] |= (1 << y%8);
+        else      buffer[x][y/8] &= ~(1 << y%8);
+    }
+}
+
+void N5110::clearPixel(unsigned int const x,
+                       unsigned int const y)
+{
+    if (x<WIDTH && y<HEIGHT) {  // check within range
+        // calculate bank and shift 1 to required position (using bit clear)
+        buffer[x][y/8] &= ~(1 << y%8);
+    }
+}
+
+int N5110::getPixel(unsigned int const x,
+                    unsigned int const y) const
+{
+    if (x<WIDTH && y<HEIGHT) {  // check within range
+        // return relevant bank and mask required bit
+
+        int pixel = (int) buffer[x][y/8] & (1 << y%8);
+
+        if (pixel)
+            return 1;
+        else
+            return 0;
+    }
+
+    return 0;
+
+}
+
+// function to refresh the display
+void N5110::refresh()
+{
+    setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
+    // address auto increments after printing string, so buffer[0][0] will not coincide
+    // with top-left pixel after priting string
+
+    _sce->write(0);  //set CE low to begin frame
+
+    for(int j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
+        for(int i = 0; i < WIDTH; i++) {
+            _spi->write(buffer[i][j]);  // send buffer
+        }
+    }
+    _sce->write(1); // set CE high to end frame
+
+}
+
+// fills the buffer with random bytes.  Can be used to test the display.
+// The rand() function isn't seeded so it probably creates the same pattern everytime
+void N5110::randomiseBuffer()
+{
+    int i,j;
+    for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
+        for(i = 0; i < WIDTH; i++) {
+            buffer[i][j] = rand()%256;  // generate random byte
+        }
+    }
+
+}
+
+// function to print 5x7 font
+void N5110::printChar(char const          c,
+                      unsigned int const  x,
+                      unsigned int const  y)
+{
+    if (y<BANKS) {  // check if printing in range of y banks
+
+        for (int i = 0; i < 5 ; i++ ) {
+            int pixel_x = x+i;
+            if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
+                break;
+            buffer[pixel_x][y] = font5x7[(c - 32)*5 + i];
+            // array is offset by 32 relative to ASCII, each character is 5 pixels wide
+        }
+
+    }
+}
+
+// function to print string at specified position
+void N5110::printString(const char         *str,
+                        unsigned int const  x,
+                        unsigned int const  y)
+{
+    if (y<BANKS) {  // check if printing in range of y banks
+
+        int n = 0 ; // counter for number of characters in string
+        // loop through string and print character
+        while(*str) {
+
+            // writes the character bitmap data to the buffer, so that
+            // text and pixels can be displayed at the same time
+            for (int i = 0; i < 5 ; i++ ) {
+                int pixel_x = x+i+n*6;
+                if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
+                    break;
+                buffer[pixel_x][y] = font5x7[(*str - 32)*5 + i];
+            }
+            str++;  // go to next character in string
+            n++;    // increment index
+        }
+    }
+}
+
+// function to clear the screen buffer
+void N5110::clear()
+{
+    memset(buffer,0,sizeof(buffer));
+}
+
+// function to plot array on display
+void N5110::plotArray(float const array[])
+{
+    for (int i=0; i<WIDTH; i++) {  // loop through array
+        // elements are normalised from 0.0 to 1.0, so multiply
+        // by 47 to convert to pixel range, and subtract from 47
+        // since top-left is 0,0 in the display geometry
+        setPixel(i,47 - int(array[i]*47.0f),true);
+    }
+
+}
+
+// function to draw circle
+void N5110:: drawCircle(unsigned int const x0,
+                        unsigned int const y0,
+                        unsigned int const radius,
+                        FillType const     fill)
+{
+    // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
+    int x = radius;
+    int y = 0;
+    int radiusError = 1-x;
+
+    while(x >= y) {
+
+        // if transparent, just draw outline
+        if (fill == FILL_TRANSPARENT) {
+            setPixel( x + x0,  y + y0,true);
+            setPixel(-x + x0,  y + y0,true);
+            setPixel( y + x0,  x + y0,true);
+            setPixel(-y + x0,  x + y0,true);
+            setPixel(-y + x0, -x + y0,true);
+            setPixel( y + x0, -x + y0,true);
+            setPixel( x + x0, -y + y0,true);
+            setPixel(-x + x0, -y + y0,true);
+        } else {  // drawing filled circle, so draw lines between points at same y value
+
+            int type = (fill==FILL_BLACK) ? 1:0;  // black or white fill
+
+            drawLine(x+x0,y+y0,-x+x0,y+y0,type);
+            drawLine(y+x0,x+y0,-y+x0,x+y0,type);
+            drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
+            drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
+        }
+
+        y++;
+        if (radiusError<0) {
+            radiusError += 2 * y + 1;
+        } else {
+            x--;
+            radiusError += 2 * (y - x) + 1;
+        }
+    }
+
+}
+
+void N5110::drawLine(unsigned int const x0,
+                     unsigned int const y0,
+                     unsigned int const x1,
+                     unsigned int const y1,
+                     unsigned int const type)
+{
+    // Note that the ranges can be negative so we have to turn the input values
+    // into signed integers first
+    int const y_range = static_cast<int>(y1) - static_cast<int>(y0);
+    int const x_range = static_cast<int>(x1) - static_cast<int>(x0);
+
+    // if dotted line, set step to 2, else step is 1
+    unsigned int const step = (type==2) ? 2:1;
+
+    // make sure we loop over the largest range to get the most pixels on the display
+    // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
+    // or else we'll only end up with 1 pixel in the x column
+    if ( abs(x_range) > abs(y_range) ) {
+
+        // ensure we loop from smallest to largest or else for-loop won't run as expected
+        unsigned int const start = x_range > 0 ? x0:x1;
+        unsigned int const stop =  x_range > 0 ? x1:x0;
+
+        // loop between x pixels
+        for (unsigned int x = start; x<= stop ; x+=step) {
+            // do linear interpolation
+            int const dx = static_cast<int>(x)-static_cast<int>(x0);
+            unsigned int const y = y0 + y_range * dx / x_range;
+
+            // If the line type is '0', this will clear the pixel
+            // If it is '1' or '2', the pixel will be set
+            setPixel(x,y, type);
+        }
+    } else {
+
+        // ensure we loop from smallest to largest or else for-loop won't run as expected
+        unsigned int const start = y_range > 0 ? y0:y1;
+        unsigned int const stop =  y_range > 0 ? y1:y0;
+
+        for (unsigned int y = start; y<= stop ; y+=step) {
+            // do linear interpolation
+            int const dy = static_cast<int>(y)-static_cast<int>(y0);
+            unsigned int const x = x0 + x_range * dy / y_range;
+
+            // If the line type is '0', this will clear the pixel
+            // If it is '1' or '2', the pixel will be set
+            setPixel(x,y, type);
+        }
+    }
+
+}
+
+void N5110::drawRect(unsigned int const x0,
+                     unsigned int const y0,
+                     unsigned int const width,
+                     unsigned int const height,
+                     FillType const     fill)
+{
+    if (fill == FILL_TRANSPARENT) { // transparent, just outline
+        drawLine(x0,y0,x0+(width-1),y0,1);  // top
+        drawLine(x0,y0+(height-1),x0+(width-1),y0+(height-1),1);  // bottom
+        drawLine(x0,y0,x0,y0+(height-1),1);  // left
+        drawLine(x0+(width-1),y0,x0+(width-1),y0+(height-1),1);  // right
+    } else { // filled rectangle
+        int type = (fill==FILL_BLACK) ? 1:0;  // black or white fill
+        for (int y = y0; y<y0+height; y++) {  // loop through rows of rectangle
+            drawLine(x0,y,x0+(width-1),y,type);  // draw line across screen
+        }
+    }
+}
+
+void N5110::drawSprite(int x0,
+                       int y0,
+                       int nrows,
+                       int ncols,
+                       int *sprite)
+{
+    for (int i = 0; i < nrows; i++) {
+        for (int j = 0 ; j < ncols ; j++) {
+
+            int pixel = *((sprite+i*ncols)+j);
+            setPixel(x0+j,y0+i, pixel);
+        }
+    }
+}
\ No newline at end of file