use bitmask for direction

democode.c

@@ -24,7 +24,6 @@
 
 struct dm001data {
     uint8_t pos;
-    uint8_t dir;
     uint16_t ramp;
     uint8_t decay[16][3];
 };
@@ -36,7 +35,6 @@ struct dm002data {
 struct dm003data {
     uint8_t step;
     uint8_t pos[3];
-    uint8_t dir[3];
 };
 
 union demodata {
@@ -56,13 +54,14 @@ static uint16_t demomode001(void)
 {
     struct dm001data *dm = &demo.dm001;
 
-    dm->pos  = sequence_chase(dm->pos, &dm->dir, nvram_data.channels);
-    dm->ramp = color_ramp(dm->ramp +8, chan_value[dm->pos]);
-    color_div(chan_value[dm->pos], 4, dm->decay[dm->pos]);
+    dm->pos  = sequence_chase(dm->pos, nvram_data.channels);
+    uint8_t pos = dm->pos & POS_MASK;
+    dm->ramp = color_ramp(dm->ramp +8, chan_value[pos]);
+    color_div(chan_value[pos], 4, dm->decay[pos]);
 
     uint8_t chan;
     for (chan = 0; chan < 16; chan++) {
-        if (chan != dm->pos) {
+        if (chan != pos) {
             color_sub(chan_value[chan], dm->decay[chan], chan_value[chan]);
         }
     }
@@ -100,12 +99,12 @@ static uint16_t demomode003(void)
 
     for (color = 0; color < 3; color++) {
         if (dm->step == 0) {
-            dm->pos[color] = sequence_chase(dm->pos[color], &dm->dir[color], nvram_data.channels);
+            dm->pos[color] = sequence_chase(dm->pos[color], nvram_data.channels);
         }
 
         uint8_t chan;
         for (chan = 0; chan < 16; chan++) {
-            if (chan == dm->pos[color]) {
+            if (chan == (dm->pos[color] & POS_MASK)) {
                 chan_value[chan][color] = 0xFF;
             } else if (chan_value[chan][color] > 16) {
                 chan_value[chan][color] -= 16;
@@ -134,7 +133,7 @@ void demomode_init(uint8_t mode)
 
         case 0x01:
             /* rgb chase */
-            demo.dm001.dir = 1;
+            demo.dm001.pos = DIR_UP | 0;
             demomode_run = demomode001;
             break;
 
@@ -145,12 +144,9 @@ void demomode_init(uint8_t mode)
 
         case 0x03:
             /* three color chaser */
-            demo.dm003.pos[COLOR_RED]   = 0;
-            demo.dm003.pos[COLOR_GREEN] = 9;
-            demo.dm003.pos[COLOR_BLUE]  = 9;
-            demo.dm003.dir[COLOR_RED]   = 1;
-            demo.dm003.dir[COLOR_GREEN] = 1;
-            demo.dm003.dir[COLOR_BLUE]  = 0;
+            demo.dm003.pos[COLOR_RED]   = DIR_UP | 0;
+            demo.dm003.pos[COLOR_GREEN] = DIR_UP | 9;
+            demo.dm003.pos[COLOR_BLUE]  = DIR_DOWN | 9;
             demomode_run = demomode003;
             break;
 

demohelper.c

@@ -22,21 +22,22 @@
 #include <string.h>
 #include "rgb16mpm.h"
 
-uint8_t sequence_chase(uint8_t old_value, uint8_t *dir, uint16_t mask)
+uint8_t sequence_chase(uint8_t old_pos, uint16_t mask)
 {
-    uint8_t value = old_value;
+    uint8_t pos = (old_pos & POS_MASK);
+    uint8_t dir = (old_pos & DIR_MASK);
 
     do {
-        value = (*dir) ? value +1 : value -1;
-        value &= 0x0F;
+        pos = (dir == DIR_DOWN) ? pos -1 : pos +1;
+        pos &= 0x0F;
 
-        if (value == 0x00 || value == 0x0F) {
-            *dir = (value == 0x00);
+        if (pos == 0x00 || pos == 0x0F) {
+            dir = (pos == 0x00) ? DIR_UP : DIR_DOWN;
         }
 
-    } while (!((1<<value) & mask) || value == old_value);
+    } while (!((1<<pos) & mask) || pos == (old_pos & ~(DIR_MASK)));
 
-    return value;
+    return dir | pos;
 }
 
 uint16_t color_ramp(uint16_t value, uint8_t *color)

rgb16mpm.h

@@ -58,8 +58,14 @@ void demomode_init(uint8_t mode);
 extern uint16_t (*demomode_run)(void);
 
 /* demohelper.c funcs */
-uint8_t sequence_chase(uint8_t old_value, uint8_t *dir, uint16_t mask);
-uint16_t color_ramp(uint16_t value, uint8_t *color);
+uint8_t sequence_chase(uint8_t old_value, uint16_t mask);
+
+#define POS_MASK            0x7F
+#define DIR_MASK            0x80
+#define DIR_UP              0x80
+#define DIR_DOWN            0x00
+uint16_t color_ramp(uint16_t pos, uint8_t *color);
+
 void color_add(uint8_t *color1, uint8_t *color2, uint8_t *output);
 void color_sub(uint8_t *color1, uint8_t *color2, uint8_t *output);
 void color_div(uint8_t *color, uint8_t div, uint8_t *output);
@@ -73,10 +79,10 @@ extern uint8_t chan_value[16][3];
 
 /* rgbctrl.c funcs */
 void rgb_init(void);
-uint8_t rgb_update(uint8_t dirty_mask, uint8_t update_mode);
 
 #define UPDATE_NONE         0x00
 #define UPDATE_PARTIAL      0x01
 #define UPDATE_BLOCKING     0x02
+uint8_t rgb_update(uint8_t dirty_mask, uint8_t update_mode);
 
 #endif /* _RGB16MPM_H_ */