Add libraries, picocalc notes.

libraries/TFT_eSPI/examples/DMA test/boing_ball/boing_ball.ino

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+// 'Boing' ball demo
+
+// STM32F767 55MHz SPI 170 fps without DMA
+// STM32F767 55MHz SPI 227 fps with DMA
+// STM32F446 55MHz SPI 110 fps without DMA
+// STM32F446 55MHz SPI 187 fps with DMA
+// STM32F401 55MHz SPI  56 fps without DMA
+// STM32F401 55MHz SPI 120 fps with DMA
+
+// STM32F767 27MHz SPI  99 fps without DMA
+// STM32F767 27MHz SPI 120 fps with DMA
+// STM32F446 27MHz SPI  73 fps without DMA
+// STM32F446 27MHz SPI  97 fps with DMA
+// STM32F401 27MHz SPI  51 fps without DMA
+// STM32F401 27MHz SPI  90 fps with DMA
+
+// Blue Pill - 36MHz SPI *no* DMA 36 fps
+// Blue Pill - 36MHz SPI with DMA 67 fps
+// Blue Pill overclocked to 128MHz *no* DMA - 32MHz SPI  64 fps
+// Blue Pill overclocked to 128MHz with DMA - 32MHz SPI 116 fps
+
+// ESP32     - 8 bit parallel     110 fps (no DMA)
+// ESP32     - 40MHz SPI *no* DMA  93 fps
+// ESP32     - 40MHz SPI with DMA 112 fps
+
+#define SCREENWIDTH 320
+#define SCREENHEIGHT 240
+
+#include "graphic.h"
+
+#include <TFT_eSPI.h> // Hardware-specific library
+
+TFT_eSPI tft = TFT_eSPI();       // Invoke custom library
+
+#define BGCOLOR    0xAD75
+#define GRIDCOLOR  0xA815
+#define BGSHADOW   0x5285
+#define GRIDSHADOW 0x600C
+#define RED        0xF800
+#define WHITE      0xFFFF
+
+#define YBOTTOM  123  // Ball Y coordinate at bottom
+#define YBOUNCE -3.5  // Upward velocity on ball bounce
+
+// Ball coordinates are stored floating-point because screen refresh
+// is so quick, whole-pixel movements are just too fast!
+float ballx     = 20.0, bally     = YBOTTOM, // Current ball position
+      ballvx    =  0.8, ballvy    = YBOUNCE, // Ball velocity
+      ballframe = 3;                         // Ball animation frame #
+int   balloldx  = ballx, balloldy = bally;   // Prior ball position
+
+// Working buffer for ball rendering...2 scan lines that alternate,
+// one is rendered while the other is transferred via DMA.
+uint16_t renderbuf[2][SCREENWIDTH];
+
+uint16_t palette[16]; // Color table for ball rotation effect
+
+uint32_t startTime, frame = 0; // For frames-per-second estimate
+
+void setup() {
+  Serial.begin(115200);
+//  while(!Serial);
+
+  tft.begin();
+  tft.setRotation(3); // Landscape orientation, USB at bottom right
+  tft.setSwapBytes(false);
+  // Draw initial frame buffer contents:
+  //tft.setBitmapColor(GRIDCOLOR, BGCOLOR);
+  tft.fillScreen(BGCOLOR);
+
+  tft.initDMA();
+
+  tft.drawBitmap(0, 0, (const uint8_t *)background, SCREENWIDTH, SCREENHEIGHT, GRIDCOLOR);
+
+  startTime = millis();
+}
+
+void loop() {
+
+  balloldx = (int16_t)ballx; // Save prior position
+  balloldy = (int16_t)bally;
+  ballx   += ballvx;         // Update position
+  bally   += ballvy;
+  ballvy  += 0.06;          // Update Y velocity
+  if((ballx <= 15) || (ballx >= SCREENWIDTH - BALLWIDTH))
+    ballvx *= -1;            // Left/right bounce
+  if(bally >= YBOTTOM) {     // Hit ground?
+    bally  = YBOTTOM;        // Clip and
+    ballvy = YBOUNCE;        // bounce up
+  }
+
+  // Determine screen area to update.  This is the bounds of the ball's
+  // prior and current positions, so the old ball is fully erased and new
+  // ball is fully drawn.
+  int16_t minx, miny, maxx, maxy, width, height;
+  // Determine bounds of prior and new positions
+  minx = ballx;
+  if(balloldx < minx)                    minx = balloldx;
+  miny = bally;
+  if(balloldy < miny)                    miny = balloldy;
+  maxx = ballx + BALLWIDTH  - 1;
+  if((balloldx + BALLWIDTH  - 1) > maxx) maxx = balloldx + BALLWIDTH  - 1;
+  maxy = bally + BALLHEIGHT - 1;
+  if((balloldy + BALLHEIGHT - 1) > maxy) maxy = balloldy + BALLHEIGHT - 1;
+
+  width  = maxx - minx + 1;
+  height = maxy - miny + 1;
+
+  // Ball animation frame # is incremented opposite the ball's X velocity
+  ballframe -= ballvx * 0.5;
+  if(ballframe < 0)        ballframe += 14; // Constrain from 0 to 13
+  else if(ballframe >= 14) ballframe -= 14;
+
+  // Set 7 palette entries to white, 7 to red, based on frame number.
+  // This makes the ball spin
+  for(uint8_t i=0; i<14; i++) {
+    palette[i+2] = ((((int)ballframe + i) % 14) < 7) ? WHITE : RED;
+    // Palette entries 0 and 1 aren't used (clear and shadow, respectively)
+  }
+
+  // Only the changed rectangle is drawn into the 'renderbuf' array...
+  uint16_t c, *destPtr;
+  int16_t  bx  = minx - (int)ballx, // X relative to ball bitmap (can be negative)
+           by  = miny - (int)bally, // Y relative to ball bitmap (can be negative)
+           bgx = minx,              // X relative to background bitmap (>= 0)
+           bgy = miny,              // Y relative to background bitmap (>= 0)
+           x, y, bx1, bgx1;         // Loop counters and working vars
+  uint8_t  p;                       // 'packed' value of 2 ball pixels
+  int8_t bufIdx = 0;
+
+  // Start SPI transaction and drop TFT_CS - avoids transaction overhead in loop
+  tft.startWrite();
+
+  // Set window area to pour pixels into
+  tft.setAddrWindow(minx, miny, width, height);
+
+  // Draw line by line loop
+  for(y=0; y<height; y++) { // For each row...
+    destPtr = &renderbuf[bufIdx][0];
+    bx1  = bx;  // Need to keep the original bx and bgx values,
+    bgx1 = bgx; // so copies of them are made here (and changed in loop below)
+    for(x=0; x<width; x++) {
+      if((bx1 >= 0) && (bx1 < BALLWIDTH) &&  // Is current pixel row/column
+         (by  >= 0) && (by  < BALLHEIGHT)) { // inside the ball bitmap area?
+        // Yes, do ball compositing math...
+        p = ball[by][bx1 / 2];                // Get packed value (2 pixels)
+        c = (bx1 & 1) ? (p & 0xF) : (p >> 4); // Unpack high or low nibble
+        if(c == 0) { // Outside ball - just draw grid
+          c = background[bgy][bgx1 / 8] & (0x80 >> (bgx1 & 7)) ? GRIDCOLOR : BGCOLOR;
+        } else if(c > 1) { // In ball area...
+          c = palette[c];
+        } else { // In shadow area...
+          c = background[bgy][bgx1 / 8] & (0x80 >> (bgx1 & 7)) ? GRIDSHADOW : BGSHADOW;
+        }
+      } else { // Outside ball bitmap, just draw background bitmap...
+        c = background[bgy][bgx1 / 8] & (0x80 >> (bgx1 & 7)) ? GRIDCOLOR : BGCOLOR;
+      }
+      *destPtr++ = c<<8 | c>>8; // Store pixel colour
+      bx1++;  // Increment bitmap position counters (X axis)
+      bgx1++;
+    }
+
+    tft.pushPixelsDMA(&renderbuf[bufIdx][0], width); // Push line to screen
+
+    // Push line to screen (swap bytes false for STM/ESP32)
+    //tft.pushPixels(&renderbuf[bufIdx][0], width);
+
+    bufIdx = 1 - bufIdx;
+    by++; // Increment bitmap position counters (Y axis)
+    bgy++;
+  }
+  //if (random(100) == 1) delay(2000);
+  tft.endWrite();
+  //delay(5);
+  // Show approximate frame rate
+  if(!(++frame & 255)) { // Every 256 frames...
+    uint32_t elapsed = (millis() - startTime) / 1000; // Seconds
+    if(elapsed) {
+      Serial.print(frame / elapsed);
+      Serial.println(" fps");
+    }
+  }
+}