Set up the flame build in the flake

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "Wearables";
+  description = "AVR";
 
   inputs = {
     nixpkgs.url = "nixpkgs/nixos-21.11";
@@ -11,12 +11,12 @@
       supportedSystems = [ "x86_64-linux" "avr-none" ];
     in
     {
-      defaultPackage."x86_64-linux" =
+      packages."x86_64-linux"."flame" =
         let
           pkgs = import nixpkgs { system = "x86_64-linux"; };
           avr = pkgs.pkgsCross.avr.buildPackages;
         in pkgs.stdenv.mkDerivation rec {
-          name = "hello";
+          name = "flame";
           src = ./.;
 
           MCU = "attiny85";
@@ -25,8 +25,6 @@
           CFLAGS = ''-O -finline-functions -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Wstrict-prototypes -DF_CPU=${F_CPU} -std=gnu99 -D__${CHIP_SELECT}__=1 -mmcu=${MCU}'';
 
           buildPhase = ''
-            set -x
-
             ${avr.gcc}/bin/avr-gcc ${CFLAGS} -I${src}/base -o base.o -c ${src}/base/base.c
             ${avr.gcc}/bin/avr-gcc ${CFLAGS} -I${src}/base -o sk9822.o -c ${src}/sk9822/sk9822.c
             ${avr.gcc}/bin/avr-gcc ${CFLAGS} -I${src}/base -I${src}/sk9822 -o main.o -c ${src}/flame/main.c
@@ -52,7 +50,7 @@
           ];
         in
         pkgs.mkShell {
-          name = "Wearables-shell";
+          name = "avr-shell";
           buildInputs = avr;
 
           GCC = pkgs.pkgsCross.avr.buildPackages.gcc;

flame/main.c

@@ -4,6 +4,9 @@
 #include <base.h>
 #include <sk9822.h>
 
+#define FPS 60
+#define FRAME_DELAY_MS 1000 / FPS
+
 uint8_t random_step(uint8_t value, uint8_t min, uint8_t max, rng_t *rng) {
     int8_t step = (rng_sample(rng) % 32) - 16;
     uint16_t new_value = value + step;
@@ -16,10 +19,77 @@ uint8_t random_step(uint8_t value, uint8_t min, uint8_t max, rng_t *rng) {
     }
 }
 
+typedef enum {
+    normal,
+    creepy,
+} color_scheme_e;
+
+typedef struct {
+    rgb_t lamp;
+    color_scheme_e color_scheme;
+    
+    int8_t red_step;
+    int8_t green_step;
+    int8_t blue_step;
+
+    uint8_t frame;
+    uint8_t duration;
+} animation_t;
+
+animation_t animation_new() {
+    return (animation_t){
+        .lamp = (rgb_t){ .brightness = 9, .r = 212, .g = 50, .b = 0 },
+        .color_scheme = normal,
+        .red_step = 0,
+        .green_step = 0,
+        .blue_step = 0,
+
+        .frame = 0,
+        .duration = 0,
+    };
+}
+
+void animation_flicker(animation_t *animation, rng_t *rng) {
+    uint8_t rdest;
+    uint8_t gdest;
+    switch (animation->color_scheme) {
+        case normal:
+            rdest = random_step(animation->lamp.r, 180, 255, rng);
+            gdest = random_step(animation->lamp.g, 10, 40, rng);
+            animation->red_step = 60 / (rdest - animation->lamp.r);
+            animation->green_step = 60 / (gdest - animation->lamp.g);
+            animation->duration = 60;
+            break;
+        case creepy:
+            break;
+    }
+}
+
+void animation_step(animation_t *animation, rng_t *rng) {
+    if (animation->duration == 0) {
+        animation_flicker(animation, rng);
+    } else {
+        if (animation->frame == animation->duration) {
+            animation->frame = 0;
+            animation->duration = 0;
+            animation->red_step = 0;
+            animation->green_step = 0;
+            animation->blue_step = 0;
+        } else {
+            animation->frame++;
+            animation->lamp.r += animation->red_step;
+            animation->lamp.g += animation->green_step;
+            animation->lamp.b += animation->blue_step;
+        }
+    }
+}
+
+/*
 void flicker(rgb_t *pixel, rng_t *rng) {
     pixel->r = random_step(pixel->r, 180, 255, rng);
     pixel->g = random_step(pixel->g, 10, 40, rng);
 }
+*/
 
 int main (void) {
     DDRB = _BV(2) | _BV(1) | _BV(0);
@@ -29,23 +99,11 @@ int main (void) {
     io_pin_t data_pin = { .port = &PORTB, .pin = 0 };
     io_pin_t clock_pin = { .port = &PORTB, .pin = 2 };
 
-    rgb_t lamps[2] = { { .brightness =  9, .r = 212, .g =  50, .b =   0 },
-                       { .brightness =  1, .r =   0, .g =   0, .b =   0 } };
-
-    int8_t step_1 = 1;
     rng_t rng = rng_new(0);
+    animation_t animation = animation_new();
     while (1) {
-        send_pixels(data_pin, clock_pin, lamps, 2);
+        animation_step(&animation, &rng);
-
+        send_pixels(data_pin, clock_pin, &animation.lamp, 1);
-        flicker(&lamps[0], &rng);
+        _delay_ms(FRAME_DELAY_MS);
-
-        lamps[1].r += step_1;
-
-        if (lamps[1].r == 255) {
-            step_1 = -1;
-        } else if (lamps[1].r == 0) {
-            step_1 = 1;
-        }
-        _delay_ms(16);
     }
 }