File content as of revision 2:444eeedb41f0:

// ----------------------------------------------------------------------
// SecurityUnlockDemo-Animation.cpp
//
// Fredric L. Rice, June 2019
//
// This module draws a mushroom on the display and then animates it as
// the mushroom moves around "randomly." Every 10 moves or so it will
// "teleport" to a "random" place on the screen.
//
// The random number generator provided by mbed is not very good
// so we attempt to use the analog inputs on PF_3, PF_4, PF_5 to help
// drive some randomness.
//
// ----------------------------------------------------------------------

#include "mbed.h"                           // The mbed operating system
#include "LCD_DISCO_F429ZI.h"               // For controlling the LCD
#include "TS_DISCO_F429ZI.h"                // For controlling the touch screen
#include "SecurityUnlockDemo-Main.h"        // For the main module's prototypes
#include "SecurityUnlockDemo-Animation.h"   // Always include our own header

// ----------------------------------------------------------------------
// Describe data which is defined externally that we may access
//
// ----------------------------------------------------------------------

    // We may be accessing the LCD
    extern LCD_DISCO_F429ZI st_lcd;

    // We may be accessing the touch screen
    extern TS_DISCO_F429ZI st_touchScreen;

// ----------------------------------------------------------------------
// Define local data storage
//
// ----------------------------------------------------------------------

    // We define a "sprite" like entity consisting of a bit map showing
    // the colors of pixes that will display a mushroom which we will
    // move around the screen. The sprite consists of 22 pixes across
    // and 17 pixels down so it's a small graphic. The letters describe
    // the color of each pixel.
    static char * pau8_mushroomMap[SPRITE_HEIGHT_IN_PIXELS] =
    { // 1234567890123456789012
        "wwwwwwwwwbbbbbbwwwwwww",   // 1
        "wwwwwwwbbbwggwbbbwwwww",   // 2
        "wwwwwwbbwwggwwwbbwwwww",   // 3
        "wwwwwbbgwwggggwwbbwwww",   // 4
        "wwwwwbwgggggggggggbwww",   // 5
        "wwwwbbwwggwwwwggwwbbww",   // 6
        "wwwwbwwwgwwwwwwgwwwbww",   // 7
        "wwwwbwwwgwwwwwwgwwwbww",   // 8
        "wwwwbwwggwwwwwwwggwwbw",   // 9
        "wwwwbwwggwwwwwwwggwwbw",   // 10
        "wwwwbgggggwwwwwgggggbw",   // 11
        "wwwwbggbbbbbbbbbbbggbw",   // 12
        "wwwwbbbbwwbwwbwwbbbbbw",   // 13
        "wwwwwwbwwwbwwbwwwwbwww",   // 14
        "wwwwwwbwwwwwwwwwwwbwww",   // 15
        "wwwwwwbbwwwwwwwwwbbwww",   // 16
        "wwwwwwwbbbbbbbbbbbwwww" 
    } ;
    
    // There are 8 different directions that this animation supports,
    // the coordinate offsets to add/subtract from the current pixel
    // position depending upon the direction is mapped here.
    //
    // Directions:
    //      1  2  3     Left up,    Up,     Right Up
    //      4     6     Left,       N/A,    Right
    //      7  8  9     Right Down, Down,   Right Down
    static int8_t i8_movementMatrix[3][6] =
    {
        -1, -1,    -1, 0,   -1, 1,
        -1,  0,     0, 0,    1, 0,
        -1,  1,     0, 1,    1, 1
    } ;
    
    // We maintain local data indicating where the sprite was last drawn
    static uint16_t u16_spriteCurrentX;
    static uint16_t u16_spriteCurrentY;
    static uint8_t  u8_spriteCurrentDirection;

    // When we are first asked to start animation, we launch
    // a thread to continue the animation forever
    static Thread st_animationThread;
    
    // To know whether animation is running, we maintain this boolean
    static bool b_animationThreadRunning;
    
    // After every 10 movements along a given direction, rather than
    // pick a direction and then move toward it we will "teleport"
    // the sprite to a "random" location on the screen and maintain
    // the direction -- unless we're up against a boundary, then a
    // new direction will be selected
    static uint8_t u8_teleportCounter;
    
    // When we teleport, we display a message indicating that/
    // After about 1 second we want to remove that message from
    // the screen so we maintain this count down timer
    static uint16_t u16_teleportMessageRemovalCountDown;
    
    // In an effort to assist the random number generator we will read
    // vaues from some of the analog inputs which should be near zero
    // but perhaps not entirely
    static AnalogIn st_analog1(PF_3);
    static AnalogIn st_analog2(PF_4);
    static AnalogIn st_analog3(PF_5);

// ----------------------------------------------------------------------
// AnimationDrawSpriteAtThisLocation()
//
// This function will draw or erase the sprite at the X and Y 
// coordinate position passed to it, or it will erase the sprite
// depending upon the argument passed to it.
//
// The colors that are supported are described in the sprite's
// bit mapping.
//
// ----------------------------------------------------------------------
static void AnimationDrawOrEraseSpriteAtThisLocation(uint16_t u16_thisX, uint16_t u16_thisY, bool b_drawSprite)
{
    uint8_t  u8_lineCount    = 0;
    uint16_t u16_currentX    = u16_thisX;
    uint16_t u16_currentY    = u16_thisY;
    uint8_t  u8_currentPixel = 0;
    uint32_t u32thisColor    = LCD_COLOR_BLUE;
    
    // Record where we are placing the sprite this time
    u16_spriteCurrentX = u16_thisX;
    u16_spriteCurrentY = u16_thisY;
    
    // Place the sprite on the screen pixel by pixel
    for (u8_lineCount = 0; u8_lineCount < SPRITE_HEIGHT_IN_PIXELS; u8_lineCount++)
    {
        for (u8_currentPixel = 0; 
            u8_currentPixel < strlen(pau8_mushroomMap[u8_lineCount]); 
                u8_currentPixel++)
        {
            // Are we drawing the sprite rather than erasing it?
            if (true == b_drawSprite)
            {
                // Find out what the color of this pixel should be
                switch(pau8_mushroomMap[u8_lineCount][u8_currentPixel])
                {
                    case 'w':
                    case 'W':
                    {
                        u32thisColor = LCD_COLOR_WHITE;
                        break;
                    }
                    case 'b':
                    case 'B':
                    {
                        u32thisColor = LCD_COLOR_BLUE;
                        break;
                    }
                    case 'g':
                    case 'G':
                    {
                        u32thisColor = LCD_COLOR_GREEN;
                        break;
                    }
                    case 'r':
                    case 'R':
                    {
                        u32thisColor = LCD_COLOR_RED;
                        break;
                    }
                    case 'k':
                    case 'K':
                    {
                        u32thisColor = LCD_COLOR_BLACK;
                        break;
                    }
                    case 'y':
                    case 'Y':
                    {
                        u32thisColor = LCD_COLOR_YELLOW;
                        break;
                    }
                }
            }
            else
            {
                // Since we are erasing the sprite, the color is white
                u32thisColor = LCD_COLOR_WHITE;                
            }
            
            // Place the pixel on the screen with the correct color
            st_lcd.DrawPixel(u16_currentX, u16_currentY, u32thisColor);
            
            // Next pixel
            u16_currentX++;
        }
        
        // Start working on the next line
        u16_currentY++;
        
        u16_currentX = u16_thisX;
    }
}

// ----------------------------------------------------------------------
// AnimationGetANewDirectionToTravel()
//
// We acquire a "random" direction to travel. Note that the mbed random
// number generator is highly flawed, it produces the same numbers
// despite how hard one seeds it. We could utilize an ununsed analog
// input and use the noise that might be found there, but for purposes
// of demonstrating animation, we'll just use what mben provided.
//
// ----------------------------------------------------------------------
static uint8_t AnimationGetANewDirectionToTravel(void)
{
    uint8_t u8_newDirection = 5;
    
    // Keep looking for a "random" number until one is valid
    while(5 == u8_newDirection ||
        u8_newDirection < SPRITE_DIRECTION_LEFT_UP ||
        u8_newDirection > SPRITE_DIRECTION_RIGHT_DOWN)
    {
        // Get a new direction to tavel
        u8_newDirection = (rand() % SPRITE_DIRECTION_RIGHT_DOWN);
    }
    
    // Return the new direction of travel
    return u8_newDirection;
}

// ----------------------------------------------------------------------
// AnimationInit()
//
// Initializes any locally-held data and performs all other start-up
// functionality required for the animated functionality, if any.
//
// ----------------------------------------------------------------------
void AnimationInit(void)
{
    // Initialize locally-held data
    u16_spriteCurrentX                  = 0;
    u16_spriteCurrentY                  = 0;
    b_animationThreadRunning            = false;
    u8_spriteCurrentDirection           = AnimationGetANewDirectionToTravel();
    u8_teleportCounter                  = 0;
    u16_teleportMessageRemovalCountDown = 0;
}

// ----------------------------------------------------------------------
// AnimationMoveSprite()
//
// This function is the one that performs the actual move by 1 pixel
// of the sprite. The sprite is erased from the screen and then the
// new location is computed. If that places the sprite outside of the
// boundaries, a new direction is selected and then the proposed
// new location is selected.
//
// Once there is a new sprite location proposed, it gets re-drawn.
//
// ----------------------------------------------------------------------
static void AnimationMoveSprite(void)
{
    uint16_t u16_proposedX      = u16_spriteCurrentX;
    uint16_t u16_proposedY      = u16_spriteCurrentY;
    int8_t   i8_proposedOffsetX = 0;
    int8_t   i8_proposedOffsetY = 0;
    bool     b_haveNewLocation  = false;
    
    // Did we teleport and display a message indicating that we did?
    if (u16_teleportMessageRemovalCountDown > 0)
    {
        // Yes, so count down the timer / counter and see if it expired
        if (0 == --u16_teleportMessageRemovalCountDown)
        {
            // Clear the message line
            st_lcd.ClearStringLine(4);
        }
    }
    
    // Erase the entire sprite from where it currently exists
    AnimationDrawOrEraseSpriteAtThisLocation(u16_spriteCurrentX, u16_spriteCurrentY, false);
    
    // We loop until we have a new location to move the sprite to.
    // We look for a valid location more than once since we may
    // run in to a boundary and have to change our direction of travel
    while(false == b_haveNewLocation)
    {        
        // Compute the new location of the sprite
        switch(u8_spriteCurrentDirection)
        {
            // Extract the proposed offsets for X and Y
            case SPRITE_DIRECTION_LEFT_UP:
            {
                i8_proposedOffsetX = i8_movementMatrix[0][0];
                i8_proposedOffsetY = i8_movementMatrix[0][1];
                break;
            }
            case SPRITE_DIRECTION_UP:
            {
                i8_proposedOffsetX = i8_movementMatrix[0][2];
                i8_proposedOffsetY = i8_movementMatrix[0][3];
                break;
            }
            case SPRITE_DIRECTION_RIGHT_UP:
            {
                i8_proposedOffsetX = i8_movementMatrix[0][4];
                i8_proposedOffsetY = i8_movementMatrix[0][5];
                break;
            }
            case SPRITE_DIRECTION_LEFT:
            {
                i8_proposedOffsetX = i8_movementMatrix[1][0];
                i8_proposedOffsetY = i8_movementMatrix[1][1];
                break;
            }
            case SPRITE_DIRECTION_RIGHT:
            {
                i8_proposedOffsetX = i8_movementMatrix[1][4];
                i8_proposedOffsetY = i8_movementMatrix[1][5];
                break;
            }
            default:
            case SPRITE_DIRECTION_NOT_VALID:
            {
                // We should never be able to get here
                return;
            }
            case SPRITE_DIRECTION_LEFT_DOWN:
            {
                i8_proposedOffsetX = i8_movementMatrix[2][0];
                i8_proposedOffsetY = i8_movementMatrix[2][1];
                break;
            }
            case SPRITE_DIRECTION_DOWN:
            {
                i8_proposedOffsetX = i8_movementMatrix[2][2];
                i8_proposedOffsetY = i8_movementMatrix[2][3];
                break;
            }
            case SPRITE_DIRECTION_RIGHT_DOWN:
            {
                i8_proposedOffsetX = i8_movementMatrix[2][4];
                i8_proposedOffsetY = i8_movementMatrix[2][5];
                break;
            }
        }

        // Apply the proposed offsets to the proposed new coordinates
        u16_proposedX += i8_proposedOffsetX;
        u16_proposedY += i8_proposedOffsetY;
    
        // Are the proposed coordinates within the bounds of where we 
        // want the sprite to move within?
        if (u16_proposedX < SPRITE_MINIMUM_X || u16_proposedX > SPRITE_MAXIMUM_X ||
            u16_proposedY < SPRITE_MINIMUM_Y || u16_proposedY > SPRITE_MAXIMUM_Y)
        {
            // We have encountered a boundary so we must choose
            // a new location and then try again
            u8_spriteCurrentDirection = AnimationGetANewDirectionToTravel();
            
            // Increment the teleport counter and see if it's time to teleport
            if (++u8_teleportCounter == 10)
            {
                // It is time to teleport, pick a new "random" location
                u16_proposedX = (rand() % LCD_WIDTH);
                u16_proposedY = (rand() % LCD_HEIGHT);
        
                // Start counting for the next teleport
                u8_teleportCounter = 0;
                
                // Report that we teleported!
                st_lcd.DisplayStringAt(1, LINE(4), (uint8_t *)"Teleported!", CENTER_MODE);
                
                // After a while we will remove that message so this is a timer/counter
                u16_teleportMessageRemovalCountDown = 40;
            }
            else
            {
                // Start over from where we currently are
                u16_proposedX = u16_spriteCurrentX;
                u16_proposedY = u16_spriteCurrentY;                
            }

            // Try for a new location
            continue;
        }
        
        // We have a new proposed location
        b_haveNewLocation = true;
    }
    
    // Place the sprite at the new location
    AnimationDrawOrEraseSpriteAtThisLocation(u16_proposedX, u16_proposedY, true);
}

// ----------------------------------------------------------------------
// AnimationThread()
//
// This is the main thread for the animation functionality. The thread
// usually runs forever however there is a mechanism for terminating
// it provided in this module.
//
// The thread wakes up about 40 times a second so that the animation
// can move fairly quickly and smoothly.
//
// ----------------------------------------------------------------------
void AnimationThread(void)
{
    // This thread will run until it gets terminated upon request
    while(true)
    {
        // Wake up 40 times a second
        wait(0.025);
        
        // Move ths sprite in the cirrent direction of travel
        AnimationMoveSprite();
    }
}

// ----------------------------------------------------------------------
// AnimationPerformAnimation()
//
// This function is called when it is time to start animating the
// sprite. It checks to make sure that the animation thread is not
// yet started before it starts the animation.
//
// ----------------------------------------------------------------------
void AnimationPerformAnimation(uint32_t u32_randomSeeder)
{
    // Are we currently not running the animation?
    if (false == b_animationThreadRunning)
    {
        // Place the sprite on to the screen
        AnimationDrawOrEraseSpriteAtThisLocation(LCD_WIDTH / 2, LCD_HEIGHT / 2, true);
    
        // Start the animation thread
        st_animationThread.start(AnimationThread);
    
        // Flag the fact that the thread is running
        b_animationThreadRunning = true;
        
        // In an effort to add more "randomness," read some of the
        // analog inputs and add their values, if any, to the seed
        u32_randomSeeder = (st_analog1 * 100) + (st_analog2 * 100) + (st_analog3 * 100);
    
        // In order to "seed" the random number generator, we acquire
        // and discard up to 2000 random numbers
        u32_randomSeeder %= 2000;
    
        // Acquire up to 2000 random numbers
        while (u32_randomSeeder-- > 0)
        {
            // Acquire the number and then discard it
            (void)AnimationGetANewDirectionToTravel();
        }
    }
}

// ----------------------------------------------------------------------
// AnimationStopAnimation()
//
// In the event the animation thread needs to be stopped, this function
// may be called to terminate the animation thread.
//
// ----------------------------------------------------------------------
void AnimationStopAnimation(void)
{
    // Is the animation thread running?
    if (true == b_animationThreadRunning)
    {
        // Stop the animation thread
        st_animationThread.terminate();
        
        // Flag the fact that animation is no longer running
        b_animationThreadRunning = false;
    }
}

// End of file