From: R. Steve McKown <rsmckown@gmail.com>
Date: Tue, 6 Dec 2011 01:48:06 +0000 (-0700)
Subject: Fix fading
X-Git-Tag: 1.0~62
X-Git-Url: https://oss.titaniummirror.com/gitweb?p=rgblamp.git;a=commitdiff_plain;h=3f7701b78ad4ba8d930cbcf6b17f429290606c25

Fix fading
---

diff --git a/main.c b/main.c
index 71693c5..4086fec 100644
--- a/main.c
+++ b/main.c
@@ -12,30 +12,34 @@
 #include "buttons.h"
 #include "rgb.h"
 
-#define STEP_SIZE               64             /* ms */
-#define MIN_INCOLOR_STEPS       16
+#define STEP_SIZE               32             /* ms */
+#if 0
+#define MIN_INCOLOR_STEPS       320
 #define MAX_INCOLOR_STEPS       57600
+#define MIN_FADE_STEPS          32
 #define MAX_FADE_STEPS          480
-#define reset_steps()           do { incolor_steps = 1; fade_steps = 0; } while (0)
-#define rand_u8()               (rand() >> 7)
-#define rand_u16()              (rand() << 8 + rand() >> 7)
-#if 1
-#define rand_incolor_steps()    MIN_INCOLOR_STEPS * 2
-#define rand_fade_steps()       16
 #else
+#define MIN_INCOLOR_STEPS       32
+#define MAX_INCOLOR_STEPS       160
+#define MIN_FADE_STEPS          32
+#define MAX_FADE_STEPS          160
+#endif
+#define reset_steps()           do { incolor_steps = 1; fade_steps = 0; } while (0)
+#define rand_u8()               (rand() & 0xff)
+#define rand_u16()              ((rand() << 8) + (rand() & 0xff))
 #define rand_incolor_steps()    (MIN_INCOLOR_STEPS + rand_u16() % \
                                     (MAX_INCOLOR_STEPS - MIN_INCOLOR_STEPS))
-#define rand_fade_steps()       (1 + rand_u16() % MAX_FADE_STEPS)
-#endif
-#define leds_set(r,g,b,w)       rgb_set((r).value >> 8, \
-                                    (g).value >> 8, \
-                                    (b).value >> 8, \
-                                    (w).value >> 8)
+#define rand_fade_steps()       (MIN_FADE_STEPS + rand() % \
+                                    (MAX_FADE_STEPS - MIN_FADE_STEPS))
+#define leds_set(r,g,b,w)       rgb_set((r).value >> 7, \
+                                    (g).value >> 7, \
+                                    (b).value >> 7, 0)
+//                                    (w).value >> 7)
 
 typedef struct {
-  unsigned value;
-  unsigned increment;
-  unsigned char remainder;
+  int value;
+  int increment;
+  int remainder;
 } led_t;
 #define INIT_LED { 0, 0, 0 }
 
@@ -47,7 +51,7 @@ int main(void)
     led_t wht = INIT_LED;
     unsigned char fast = 0;
     unsigned incolor_steps;
-    unsigned fade_steps;
+    int fade_steps;
 
     pic_init();
     buttons_init();
@@ -84,14 +88,19 @@ int main(void)
               }
               leds_set(red, grn, blu, wht);
             } else if (--incolor_steps == 0) {
-              unsigned newr, newg, newb, neww;
+              int newr, newg, newb, neww, tmp;
 
               /* Next led color.  All off is not a valid option. */
               do {
-                newr = rand() << 8;
-                newg = rand() << 8;
-                newb = rand() << 8;
-                neww = rand() << 8;
+                /* RGB values are processed 15-bit values.  This allows for
+                 * signedness when fading to a lesser value.  The actual PWM
+                 * values are set from the most significant 8 bits, so
+                 * leds_set() does >> 7.
+                 */
+                newr = rand();
+                newg = rand();
+                newb = rand();
+                neww = rand();
               } while (newr == 0 && newg == 0 && newb == 0 && neww == 0);
 
               /* Next incolor and fade steps */
@@ -104,14 +113,14 @@ int main(void)
               }
 
               /* Compute increment and remainder for each led */
-              red.increment = newr / fade_steps;
-              red.remainder = newr - red.increment * fade_steps;
-              grn.increment = newg / fade_steps;
-              grn.remainder = newg - grn.increment * fade_steps;
-              blu.increment = newb / fade_steps;
-              blu.remainder = newb - blu.increment * fade_steps;
-              wht.increment = neww / fade_steps;
-              wht.remainder = neww - wht.increment * fade_steps;
+              red.increment = (newr - red.value) / fade_steps;
+              red.remainder = newr - (red.value + red.increment * fade_steps);
+              grn.increment = (newg - grn.value) / fade_steps;
+              grn.remainder = newg - (grn.value + grn.increment * fade_steps);
+              blu.increment = (newb - blu.value) / fade_steps;
+              blu.remainder = newb - (blu.value + blu.increment * fade_steps);
+              wht.increment = (neww - wht.value) / fade_steps;
+              wht.remainder = neww - (wht.value + wht.increment * fade_steps);
             }
             __delay_ms(STEP_SIZE); /* step should be start to start... */
         } else {