Adding a backBuffer to avoid flickering. Color improvements.

3 files changed, 43 insertions, 13 deletions

diff --git a/main/InovaLedDisplay.cpp b/main/InovaLedDisplay.cpp
index f579043..0d8d7e8 100644
--- a/main/InovaLedDisplay.cpp
+++ b/main/InovaLedDisplay.cpp
@@ -48,12 +48,32 @@ InovaLedDisplay::InovaLedDisplay(uint8_t r0, uint8_t g0, uint8_t clk, uint8_t cs
 
 
 void InovaLedDisplay::drawPixel(int16_t x, int16_t y, uint16_t color) {
-    displayBuffer[y][x / 8] = displayBuffer[y][x / 8] & ~(0b0000000000000011 << (14 - (2 * (x % 8)))); // clear this column (note the bitwise inversion)
-    displayBuffer[y][x / 8] = displayBuffer[y][x / 8] | (color << (14 - (2 * (x % 8)))); // write color to column
+
+    if(x < 0 || x >= _width || y < 0 || y >= _height) return;
+
+    // Adafruit GFX color is 16-bit 5-6-5 rgb
+    // We store only 2-bit rg, so we assume any amount of red or green wants that color
+    uint8_t r, g;
+    r = color >> 11; // RRRRRggggggbbbbb
+    g = (color >> 5) & 0x3F; // rrrrrGGGGGGbbbbb
+
+    color = 0;
+    if(g > 0) color += 1;
+    if(r > 0) color += 2;
+
+    uint8_t i = backBufferIndex;
+    displayBuffer[i][y][x / 8] = displayBuffer[i][y][x / 8] & ~(0b0000000000000011 << (14 - (2 * (x % 8)))); // clear this column (note the bitwise inversion)
+    displayBuffer[i][y][x / 8] = displayBuffer[i][y][x / 8] | (color << (14 - (2 * (x % 8)))); // write color to column
 }
 
 
-void InovaLedDisplay::updateDisplay(void) {}
+void InovaLedDisplay::swapBuffer(void) {
+    shouldSwapBuffer = true;
+
+    while(shouldSwapBuffer) {
+        vTaskDelay(1 / portTICK_PERIOD_MS);
+    }
+}
 
 
 void InovaLedDisplay::runDisplay(void) {
@@ -73,7 +93,7 @@ void InovaLedDisplay::runDisplay(void) {
             spi_transaction_t t;
             memset(&t, 0, sizeof(t));
             t.length = 16;
-            data = SPI_SWAP_DATA_TX(displayBuffer[current_row][i], 16);
+            data = SPI_SWAP_DATA_TX(displayBuffer[1 - backBufferIndex][current_row][i], 16);
             t.tx_buffer = &data;
             t.flags = SPI_TRANS_MODE_DIO;  // output on two data lines. Even bits go to GREEN, odd to RED
             ret = spi_device_polling_transmit(spi, &t);
@@ -92,6 +112,12 @@ void InovaLedDisplay::runDisplay(void) {
 
         if(++current_row == NUM_ROW) {
             current_row = 0;
+
+            if(shouldSwapBuffer) {
+                backBufferIndex++;
+                backBufferIndex = backBufferIndex % 2;
+                shouldSwapBuffer = false;
+            }
         }
     }
 }
diff --git a/main/InovaLedDisplay.h b/main/InovaLedDisplay.h
index b394708..a1d9ad9 100644
--- a/main/InovaLedDisplay.h
+++ b/main/InovaLedDisplay.h
@@ -16,16 +16,18 @@ class InovaLedDisplay : public virtual Adafruit_GFX {
 
         void drawPixel(int16_t x, int16_t y, uint16_t c);
 
-        void updateDisplay(void);
+        void swapBuffer(void);
 
         void runDisplay(void);
 
         void stopDisplay(void);
 
     private:
-        uint16_t displayBuffer[NUM_ROW][NUM_COL / 8]; // each column is two bits, so 8 can fit in 16-bit integer
+        uint16_t displayBuffer[2][NUM_ROW][NUM_COL / 8]; // each column is two bits, so 8 can fit in 16-bit integer
         spi_device_handle_t spi;
         bool run = true;
+        bool shouldSwapBuffer = false;
+        uint8_t backBufferIndex = 0;
         gpio_num_t latch, oe, addr0, addr1, addr2;
 };
 
diff --git a/main/main.cpp b/main/main.cpp
index 1d64d95..7555410 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -10,9 +10,10 @@
 
 #define CHAR_HEIGHT          8
 #define CHAR_WIDTH           8
-#define RED                  1
-#define GREEN                2
-#define ORANGE               3
+#define BLACK                0x0000
+#define RED                  0xF800
+#define GREEN                0x07E0
+#define ORANGE               0xFFE0
 
 #define PIN_NUM_MISO         12
 #define PIN_NUM_MOSI         13
@@ -55,19 +56,19 @@ extern "C" void runDisplayTask(void* taskParams) {
 extern "C" void app_main(void)
 {
     InovaLedDisplay display = InovaLedDisplay(PIN_NUM_MISO, PIN_NUM_MOSI, PIN_NUM_CLK, PIN_NUM_CS, PIN_NUM_R_LATCH, PIN_NUM_R_CLK, PIN_NUM_R_ADDR_0, PIN_NUM_R_ADDR_1, PIN_NUM_R_ADDR_2);
-    
+
     display.fillScreen(0);
 
     display.setCursor(0, 0);
-    display.setTextColor(2);
+    display.setTextColor(RED);
     display.setTextWrap(false);
     display.print("Adafruit GFX 0123456789");
 
     TaskHandle_t taskHandle;
     xTaskCreate(runDisplayTask, "updateDisplay", STACK_SIZE, &display, tskIDLE_PRIORITY, &taskHandle);
-    
+
     //runDisplayTask(&display);
-    
+
     //while(true) {
     //    vTaskDelay(100 / portTICK_PERIOD_MS);
     //}
@@ -80,6 +81,7 @@ extern "C" void app_main(void)
         display.fillScreen(0);
         display.setCursor(j, 0);
         display.print(hello);
+        display.swapBuffer();
 
         if(--j == min_x) {
             j = display.width();