void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}


framebuffer-chip.ino

diagram.json

// Wokwi Custom Chip - For information and examples see:
// https://link.wokwi.com/custom-chips-alpha
//
// SPDX-License-Identifier: MIT
// Copyright (C) 2022 Uri Shaked / wokwi.com

#include "wokwi-api.h"
#include <stdio.h>
#include <stdlib.h>

const int MS = 1000; // micros

typedef struct {
  uint8_t r;
  uint8_t g;
  uint8_t b;
  uint8_t a;
} rgba_t;

typedef struct {
  buffer_t framebuffer;
  uint32_t width;
  uint32_t height;
  uint32_t row;
} chip_state_t;

static void chip_timer_event(void *user_data);

void chip_init(void) {
  chip_state_t *chip = malloc(sizeof(chip_state_t));

  chip->row = 0;
  chip->framebuffer = framebuffer_init(&chip->width, &chip->height);
  printf("Framebuffer: width=%d, height=%d\n", chip->width, chip->height);

  const timer_config_t timer_config = {
    .callback = chip_timer_event,
    .user_data = chip,
  };
  timer_t timer = timer_init(&timer_config);
  timer_start(timer, 10 * MS, true);
}

void draw_line(chip_state_t *chip, uint32_t row, rgba_t color) {
  uint32_t offset = chip->width * 4 * row;
  for (int x = 0; x < chip->width * 4; x += 4) {
    buffer_write(chip->framebuffer, offset + x, &color, sizeof(color));
  }
}

void chip_timer_event(void *user_data) {
  chip_state_t *chip = (chip_state_t*)user_data;
  rgba_t deep_green = { .g=0x30, .a = 0xff };
  draw_line(chip, chip->row, deep_green);

  chip->row = (chip->row + 1) % chip->height;
  rgba_t purple = { .r = 0xff, .g=0x00, .b=0xff, .a=0xff };
  draw_line(chip, chip->row, purple);
}
