acidportal

- 😈 Worlds smallest Evil Portal on a LilyGo T-QT
git clone git://git.acid.vegas/acidportal.git
Sprite_image_4bit.ino (3448B)
      1 /*
      2 
      3   Sketch to show how a Sprite can use a four-bit image with
      4   a palette to change the appearance of an image while rendering
      5   it only once.
      6 
      7   Example for library:
      8   https://github.com/Bodmer/TFT_eSPI
      9 
     10   A Sprite is notionally an invisible graphics screen that is
     11   kept in the processors RAM. Graphics can be drawn into the
     12   Sprite just as it can be drawn directly to the screen. Once
     13   the Sprite is completed it can be plotted onto the screen in
     14   any position. If there is sufficient RAM then the Sprite can
     15   be the same size as the screen and used as a frame buffer.
     16 
     17   A 16 bit Sprite occupies (2 * width * height) bytes in RAM.
     18 
     19   On a ESP8266 Sprite sizes up to 126 x 160 can be accommodated,
     20   this size requires 40kBytes of RAM for a 16 bit color depth.
     21   
     22   When 8 bit color depth sprites are created they occupy
     23   (width * height) bytes in RAM, so larger sprites can be
     24   created, or the RAM required is halved.
     25 
     26 */
     27 
     28 
     29 // Set delay after plotting the sprite
     30 #define DELAY 30
     31 
     32 // Width and height of sprite
     33 #define WIDTH  164
     34 #define HEIGHT 164
     35 
     36 #include "sample_images.h"
     37 
     38 TFT_eSPI    tft = TFT_eSPI();         // Declare object "tft"
     39 
     40 TFT_eSprite spr = TFT_eSprite(&tft);  // Declare Sprite object "spr" with pointer to "tft" object
     41 
     42 byte red = 31; // Red is the top 5 bits of a 16 bit colour value
     43 byte green = 0;// Green is the middle 6 bits
     44 byte blue = 0; // Blue is the bottom 5 bits
     45 byte state = 0;
     46 
     47 int rloop = 0;
     48 int incr = 1;
     49 
     50 uint16_t cmap[16];
     51 
     52 void setup()
     53 {
     54   Serial.begin(9600);
     55   Serial.println();
     56 
     57   delay(50);
     58 
     59   // Initialise the TFT registers
     60   tft.init();
     61   
     62   spr.setColorDepth(4);
     63 
     64   // Create a sprite of defined size
     65   spr.createSprite(WIDTH, HEIGHT);
     66 
     67   // Clear the TFT screen to black
     68   tft.fillScreen(TFT_BLACK);
     69   
     70   // push the image - only need to do this once.
     71   spr.pushImage(2, 2, 160, 160, (uint16_t *)stars);
     72 
     73   for (int i = 0; i < 16; i++)
     74     cmap[i] = rainbow();
     75 }
     76 
     77 void loop(void)
     78 {
     79   // create a palette with the defined colors and push it.  
     80   spr.createPalette(cmap, 16);
     81   spr.pushSprite(tft.width() / 2 - WIDTH / 2, tft.height() / 2 - HEIGHT / 2);
     82   
     83   // update the colors
     84   for (int i = 0; i < 15; i++) {
     85     cmap[i] = cmap[i + 1];
     86   }
     87   if (incr == 2) {
     88     (void)rainbow();  // skip alternate steps to go faster
     89   }
     90   cmap[15] = rainbow();
     91   rloop += incr;
     92   if (rloop > 0xc0) {
     93     incr = incr == 2 ? 1 : 2;
     94     rloop = 0;
     95     
     96   }
     97   delay(DELAY);
     98 
     99 }
    100 
    101 // #########################################################################
    102 // Return a 16 bit rainbow colour
    103 // #########################################################################
    104 unsigned int rainbow()
    105 {
    106     switch (state) {
    107       case 0:
    108         green ++;
    109         if (green == 64) {
    110           green = 63;
    111           state = 1;
    112         }
    113         break;
    114       case 1:
    115         red--;
    116         if (red == 255) {
    117           red = 0;
    118           state = 2;
    119         }
    120         break;
    121       case 2:
    122         blue ++;
    123         if (blue == 32) {
    124           blue = 31;
    125           state = 3;
    126         }
    127         break;
    128       case 3:
    129         green --;
    130         if (green == 255) {
    131           green = 0;
    132           state = 4;
    133         }
    134         break;
    135       case 4:
    136         red ++;
    137         if (red == 32) {
    138           red = 31;
    139           state = 5;
    140         }
    141         break;
    142       case 5:
    143         blue --;
    144         if (blue == 255) {
    145           blue = 0;
    146           state = 0;
    147         }
    148         break;
    149     }
    150     return red << 11 | green << 5 | blue;
    151 }
    152