Finish the basic lantern animation

Add some bounding boxes to keep the animation doing something like the right thing

animation/animation.c

@@ -1,6 +1,17 @@
 #include "animation.h"
 #include <stdio.h>
 
+int bound(int value, uint8_t min, uint8_t max) {
+    if (value > max) {
+        return max;
+    } else if (value < min) {
+        return min;
+    } else {
+        return value;
+    }
+}
+
+
 time_line_t time_line_new(int t0, int y0, int t1, int y1) {
     int dt = t1 - t0;
     int dy = y1 - y0;
@@ -15,7 +26,7 @@ time_line_t time_line_new(int t0, int y0, int t1, int y1) {
         error = de + dt;
     }
 
-    return (time_line_t){ .y = y0, .dt = dt, .de = de, .error = error, .inc = inc, .dy = dy };
+    return (time_line_t){ .y = y0, .dt = dt, .de = de, .error = error, .inc = inc, .dy = dy, .y0 = y0, .y1 = y1 };
 }
 
 int time_line_next(time_line_t *self) {
@@ -33,6 +44,12 @@ int time_line_next(time_line_t *self) {
         }
     }
 
+    if (self->y0 < self->y1) {
+        self->y = bound(self->y, self->y0, self->y1);
+    } else {
+        self->y = bound(self->y, self->y1, self->y0);
+    }
+
     self->error = error;
     return self->y;
 }

animation/animation.h

@@ -12,6 +12,8 @@ typedef struct {
     int inc;
     int dt;
     int dy;
+    int y0;
+    int y1;
 } time_line_t;
 
 // Construct a new line object. x1 must be greater than x0, and dy must be less than dx.

lantern/main.c

@@ -20,8 +20,8 @@ You should have received a copy of the GNU General Public License along with thi
 #include <stdio.h>
 
 #define FPS             15
-// #define FRAME_DELAY_MS  1000 / FPS
+#define FRAME_DELAY_MS  1000 / FPS
-#define FRAME_DELAY_MS  1000
+// #define FRAME_DELAY_MS  1000
 #define LIGHT_COUNT     3
 
 typedef enum {
@@ -32,6 +32,16 @@ typedef enum {
     flash
 } color_scheme_e;
 
+uint8_t bound_uint8(int value, uint8_t min, uint8_t max) {
+    if (value > max) {
+        return max;
+    } else if (value < min) {
+        return min;
+    } else {
+        return value;
+    }
+}
+
 uint8_t random_step(uint8_t value, uint8_t min, uint8_t max, rng_t *rng) {
     int8_t step = (rng_sample(rng) % 20) - 10;
     int new_value = value + step;
@@ -81,9 +91,9 @@ void animation_step(animation_t *self) {
         self->duration = 0;
     } else {
         self->frame++;
-        self->color.r = time_line_next(&self->red_line);
+        self->color.r = bound_uint8(time_line_next(&self->red_line), 0, 255);
-        self->color.g = time_line_next(&self->green_line);
+        self->color.g = bound_uint8(time_line_next(&self->green_line), 0, 255);
-        self->color.b = time_line_next(&self->blue_line);
+        self->color.b = bound_uint8(time_line_next(&self->blue_line), 0, 255);
     }
 }
 
@@ -118,19 +128,19 @@ void lantern_start_test(lantern_t *self) {
             255,
             0,
             0,
-            120);
+            15);
     animation_begin(
             &self->animations[1],
             0,
             255,
             0,
-            120);
+            15);
     animation_begin(
             &self->animations[2],
             0,
             0,
             255,
-            120);
+            15);
 }
 
 void lantern_start_normal(lantern_t *self, rng_t *rng) {
@@ -239,7 +249,7 @@ int main(void) {
     rgb_t colors[LIGHT_COUNT];
 
     lantern_t lantern = lantern_new(lights);
-    lantern_set_mode(&lantern, test);
+    lantern_set_mode(&lantern, normal);
 
     rng_t rng = rng_new(15);