From: Vladimir Garistov <vl_garistov@gmail.com>
Date: Sun, 3 Oct 2021 21:05:48 +0000 (+0300)
Subject: Added Big LED strip example
X-Git-Url: https://kolegite.com/gitweb/?a=commitdiff_plain;h=15139f3c862007951696102653682d53cc9afb0b;p=vmks.git

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 168afe7..d95d24b 100644
--- 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
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
index 0000000..3b1f24b
--- /dev/null
+++ b/Examples/Big_LED_strip/tinkercad_link.txt
@@ -0,0 +1 @@
+https://www.tinkercad.com/things/eOSmRi4TA7z-bigledstrip