Added Big LED strip example

diff --git a/Examples/Big_LED_strip/Big_LED_strip.ino b/Examples/Big_LED_strip/Big_LED_strip.ino
index 168afe7a409c7f4c29bb063b7947ec82382bd023..d95d24bcfe5cea36fa46b9a86c044d2d7784b01a 100644 (file)
--- a/Examples/Big_LED_strip/Big_LED_strip.ino
+++ b/Examples/Big_LED_strip/Big_LED_strip.ino
@@ -1,7 +1,6 @@
 #include <Adafruit_NeoPixel.h>
 #include <inttypes.h>
 
-#define LED_PIN                                12
 #define ROWS                           8
 #define COLS                           32
 #define NUM_PIXELS                     (ROWS * COLS)
@@ -9,8 +8,22 @@
 #define BIG_IMAGE_FILE_SIZE    780
 #define DIMM                           4
 
+/*
+       ATMEGA328P has only 2KiB RAM. The three copies of the color data (const ppm image file,
+       working buffer and NeoPixel library buffer) alone require slightly more than that.
+       When loop() is called, the stack collides with the heap and overrides the library buffer.
+       The resulting visual effect is interesting but in order to actually display the image
+       we must do so directly without allocating a working buffer.
+       Uncomment this to indicate that display_rgb_direct() must be used.
+*/
 #define NEOPIXEL_ATE_MY_RAM
 
+#ifdef NEOPIXEL_ATE_MY_RAM
+#define LED_PIN        12
+#else
+#define LED_PIN        PA2
+#endif
+
 int render_image(uint8_t buff[ROWS][COLS][3], const uint8_t image[]);
 int display_rgb(uint8_t buff[ROWS][COLS][3]);
 int display_rgb_direct(const uint8_t image[]);
@@ -78,28 +91,33 @@ void setup()
 
 void loop()
 {
+       #ifndef NEOPIXEL_ATE_MY_RAM
        uint8_t frame_buffer[ROWS][COLS][3] = {{{0}}};
 
-       #ifdef NEOPIXEL_ATE_MY_RAM
        render_image(frame_buffer, big_image_data);
        display_rgb(frame_buffer);
        #else
        display_rgb_direct(big_image_data);
        #endif
+
 }
 
 int render_image(uint8_t buff[ROWS][COLS][3], const uint8_t image[])
 {
+       size_t row_offset, col_offset;
+
        if (buff == NULL || image == NULL)
                return -1;
 
        for (uint8_t row = 0; row < ROWS; row++)
        {
+               row_offset = row * COLS * 3;
                for (uint8_t col = 0; col < COLS; col++)
                {
+                       col_offset = col * 3;
                        for (uint8_t i = 0; i < 3; i++)
                        {
-                               buff[row][col][i] = image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3 + i];
+                               buff[row][col][i] = image[PPM_HEADER_LENGHT + row_offset + col_offset + i];
                        }
                }
        }
@@ -116,18 +134,20 @@ int display_rgb(uint8_t buff[ROWS][COLS][3])
        {
                for (uint8_t row = 0; row < ROWS; row++)
                {
-                       led_matrix.setPixelColor(col * ROWS + row, led_matrix.Color(buff[row][col][0] / DIMM,
-                                                                                                                                               buff[row][col][1] / DIMM,
-                                                                                                                                               buff[row][col][2] / DIMM));
+                       led_matrix.setPixelColor(col * ROWS + row,
+                               led_matrix.Color(buff[row][col][0] / DIMM,
+                                                                buff[row][col][1] / DIMM,
+                                                                buff[row][col][2] / DIMM));
                }
        }
        for (uint8_t col = 1; col < COLS; col += 2)
        {
                for (uint8_t row = 0; row < ROWS; row++)
                {
-                       led_matrix.setPixelColor((col + 1) * ROWS - row - 1, led_matrix.Color(buff[row][col][0] / DIMM,
-                                                                                                                                                                 buff[row][col][1] / DIMM,
-                                                                                                                                                                 buff[row][col][2] / DIMM));
+                       led_matrix.setPixelColor((col + 1) * ROWS - row - 1,
+                               led_matrix.Color(buff[row][col][0] / DIMM,
+                                                                buff[row][col][1] / DIMM,
+                                                                buff[row][col][2] / DIMM));
                }
        }
        led_matrix.show();
@@ -137,25 +157,33 @@ int display_rgb(uint8_t buff[ROWS][COLS][3])
 
 int display_rgb_direct(const uint8_t image[])
 {
+       size_t row_offset, col_offset;
+
        if (image == NULL)
                return -1;
 
        for (uint8_t col = 0; col < COLS; col += 2)
        {
+               col_offset = col * 3;
                for (uint8_t row = 0; row < ROWS; row++)
                {
-                       led_matrix.setPixelColor(col * ROWS + row, led_matrix.Color(image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3] / DIMM,
-                                                                                                                                               image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3 + 1] / DIMM,
-                                                                                                                                               image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3 + 2] / DIMM));
+                       row_offset = row * COLS * 3;
+                       led_matrix.setPixelColor(col * ROWS + row,
+                               led_matrix.Color(image[PPM_HEADER_LENGHT + row_offset + col_offset] / DIMM,
+                                                                image[PPM_HEADER_LENGHT + row_offset + col_offset + 1] / DIMM,
+                                                                image[PPM_HEADER_LENGHT + row_offset + col_offset + 2] / DIMM));
                }
        }
        for (uint8_t col = 1; col < COLS; col += 2)
        {
+               col_offset = col * 3;
                for (uint8_t row = 0; row < ROWS; row++)
                {
-                       led_matrix.setPixelColor((col + 1) * ROWS - row - 1, led_matrix.Color(image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3] / DIMM,
-                                                                                                                                                                 image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3 + 1] / DIMM,
-                                                                                                                                                                 image[PPM_HEADER_LENGHT + row * COLS * 3 + col * 3 + 2] / DIMM));
+                       row_offset = row * COLS * 3;
+                       led_matrix.setPixelColor((col + 1) * ROWS - row - 1,
+                               led_matrix.Color(image[PPM_HEADER_LENGHT + row_offset + col_offset] / DIMM,
+                                                                image[PPM_HEADER_LENGHT + row_offset + col_offset + 1] / DIMM,
+                                                                image[PPM_HEADER_LENGHT + row_offset + col_offset + 2] / DIMM));
                }
        }
        led_matrix.show();

diff --git a/Examples/Big_LED_strip/Big_LED_strip.png b/Examples/Big_LED_strip/Big_LED_strip.png
new file mode 100644 (file)
index 0000000..5e6805b
Binary files /dev/null and b/Examples/Big_LED_strip/Big_LED_strip.png differ

diff --git a/Examples/Big_LED_strip/tinkercad_link.txt b/Examples/Big_LED_strip/tinkercad_link.txt
new file mode 100644 (file)
index 0000000..3b1f24b
--- /dev/null
+++ b/Examples/Big_LED_strip/tinkercad_link.txt
@@ -0,0 +1 @@
+https://www.tinkercad.com/things/eOSmRi4TA7z-bigledstrip