Let the ws2801 fade

src/fader.cpp

@@ -0,0 +1,115 @@
+#include "ws2801.h"
+
+#include "fader.h"
+
+int16_t fadestep = 1;
+
+int somethingChanged = 0; // indicates when a ws2801 update is required
+
+struct Colour {
+	int16_t red, green, blue; // value range is 0 to 255
+};
+
+struct Colour curColour[NUM_MODULES];
+struct Colour targetColour[NUM_MODULES];
+
+void fader_init(void)
+{
+	for(uint32_t i = 0; i < NUM_MODULES; i++) {
+		curColour[i].red   = targetColour[i].red   = 0;
+		curColour[i].green = targetColour[i].green = 0;
+		curColour[i].blue  = targetColour[i].blue  = 0;
+	}
+}
+
+void fader_set_colour(uint32_t module, uint8_t r, uint8_t g, uint8_t b)
+{
+	curColour[module].red   = targetColour[module].red   = r;
+	curColour[module].green = targetColour[module].green = g;
+	curColour[module].blue  = targetColour[module].blue  = b;
+
+	somethingChanged = 1;
+}
+
+void fader_fade_colour(uint32_t module, uint8_t r, uint8_t g, uint8_t b)
+{
+	targetColour[module].red   = r;
+	targetColour[module].green = g;
+	targetColour[module].blue  = b;
+}
+
+void fader_add_colour(uint32_t module, uint8_t r, uint8_t g, uint8_t b)
+{
+	curColour[module].red   += r;
+	curColour[module].green += g;
+	curColour[module].blue  += b;
+
+	if(curColour[module].red > 255) { curColour[module].red = 255; }
+	if(curColour[module].green > 255) { curColour[module].green = 255; }
+	if(curColour[module].blue > 255) { curColour[module].blue = 255; }
+
+	targetColour[module].red   += r;
+	targetColour[module].green += g;
+	targetColour[module].blue  += b;
+
+	if(targetColour[module].red > 255) { targetColour[module].red = 255; }
+	if(targetColour[module].green > 255) { targetColour[module].green = 255; }
+	if(targetColour[module].blue > 255) { targetColour[module].blue = 255; }
+
+	somethingChanged = 1;
+}
+
+void fader_set_fadestep(uint8_t newFadestep)
+{
+	fadestep = newFadestep;
+}
+
+/*!
+ * Fade the colour value in cur towards target.
+ *
+ * \param cur      The colour value to update.
+ * \param target   The target value that should be reached.
+ * \param changed  Output value which is set to 1 if cur was changed.
+ */
+static void fade_colour(int16_t *cur, const int16_t *target, int *changed)
+{
+	int16_t diff;
+	if(*cur > *target) {
+		diff = *cur - *target;
+		if(diff < fadestep) {
+			*cur = *target;
+		} else {
+			*cur -= fadestep;
+		}
+
+		*changed = 1;
+	} else if(*cur < *target) {
+		diff = *target - *cur;
+		if(diff < fadestep) {
+			*cur = *target;
+		} else {
+			*cur += fadestep;
+		}
+
+		*changed = 1;
+	}
+}
+
+void fader_update(void)
+{
+	for(uint32_t i = 0; i < NUM_MODULES; i++) {
+		fade_colour(&(curColour[i].red), &(targetColour[i].red), &somethingChanged);
+		fade_colour(&(curColour[i].green), &(targetColour[i].green), &somethingChanged);
+		fade_colour(&(curColour[i].blue), &(targetColour[i].blue), &somethingChanged);
+
+		ws2801_set_colour(i,
+				(uint8_t)curColour[i].red,
+				(uint8_t)curColour[i].green,
+				(uint8_t)curColour[i].blue);
+	}
+
+	if(somethingChanged) {
+		ws2801_send_update();
+		somethingChanged = 0;
+	}
+}

src/fader.h

@@ -0,0 +1,13 @@
+#ifndef FADER_H
+#define FADER_H
+
+#include <stdint.h>
+
+void fader_init(void);
+void fader_set_colour(uint32_t module, uint8_t r, uint8_t g, uint8_t b);
+void fader_fade_colour(uint32_t module, uint8_t r, uint8_t g, uint8_t b);
+void fader_add_colour(uint32_t module, uint8_t r, uint8_t g, uint8_t b);
+void fader_set_fadestep(uint8_t newFadestep);
+void fader_update(void);
+
+#endif // FADER_H

src/main.cpp

@@ -9,6 +9,8 @@
 
 #include "relais.h"
 #include "wlan.h"
+#include "fader.h"
+#include "ws2801.h"
 
 WiFiUDP udpServer;
 
@@ -22,6 +24,9 @@ const char *favorite_wlans[2*NWLANFAV] = {
 	"franken.freifunk.net", NULL
 };
 
+uint32_t fader_next_update = 0;
+uint32_t fader_loop = 0;
+
 void setup_wifi()
 {
 	bool connected = false;
@@ -55,6 +60,14 @@ void setup()
 
 	relais_setup();
 
+	ws2801_init();
+	fader_init();
+
+	for(int i = 0; i < NUM_MODULES; i++) {
+		fader_set_colour(i, 0, 0, 0);
+		fader_fade_colour(i, 0, 255, 0);
+	}
+
 	Serial.print("starting UDP server on port ");
 	Serial.println(UDP_PORT);
 
@@ -76,6 +89,27 @@ void loop()
 		setup_wifi();
 	}
 
+	uint32_t now = millis();
+	if(now > fader_next_update) {
+		fader_update();
+
+		fader_next_update += 20; // -> 50 FPS
+
+		if((fader_loop % 50) == 0) {
+			if(((fader_loop / 50) % 2) == 0) {
+				for(int i = 0; i < NUM_MODULES; i++) {
+					fader_fade_colour(i, 0, 255, 0);
+				}
+			} else {
+				for(int i = 0; i < NUM_MODULES; i++) {
+					fader_fade_colour(i, 255, 0, 0);
+				}
+			}
+		}
+
+		fader_loop++;
+	}
+
 	/*int n = udpServer.read(buf, 512);
 
 		if(n > 0) {

src/ws2801.cpp

@@ -0,0 +1,29 @@
+#include <SPI.h>
+
+#include "ws2801.h"
+
+uint8_t message[3 * NUM_MODULES];
+
+void ws2801_init(void)
+{
+	SPI.begin();
+}
+
+void ws2801_set_colour(uint32_t module, uint8_t red, uint8_t green, uint8_t blue)
+{
+	message[3*module + 0] = red;
+	message[3*module + 1] = blue;
+	message[3*module + 2] = green;
+}
+
+void ws2801_send_update(void)
+{
+	SPI.beginTransaction(SPISettings(1000000, MSBFIRST, SPI_MODE0));
+
+	for(uint32_t i = 0; i < 3*NUM_MODULES; i++) {
+		SPI.transfer(message[i]);
+	}
+
+	SPI.endTransaction();
+}
+

src/ws2801.h

@@ -0,0 +1,12 @@
+#ifndef WS2801_H
+#define WS2801_H
+
+#include <stdint.h>
+
+#define NUM_MODULES 32
+
+void ws2801_init(void);
+void ws2801_set_colour(uint32_t module, uint8_t red, uint8_t green, uint8_t blue);
+void ws2801_send_update(void);
+
+#endif // WS2801_H