init

.gitignore

@@ -0,0 +1,6 @@
+/dist/
+
+*.o
+*.out
+*.swp
+*.swo

.vscode/settings.json

@@ -0,0 +1,13 @@
+{
+    "files.associations": {
+        "*.py": "python",
+        "types.h": "c",
+        "spidev.h": "c",
+        "fcntl.h": "c",
+        "stdlib.h": "c",
+        "math.h": "c",
+        "spi_utils.h": "c",
+        "cstdint": "c",
+        "color_utils.h": "c"
+    }
+}

Makefile

@@ -0,0 +1,24 @@
+CC = gcc
+CFLAGS = -Wall -Wextra -O2
+LDFLAGS = -lm
+
+SRCS = main.c spi_utils.c color_utils.c shader.c
+OBJS = $(SRCS:%.c=dist/%.o)
+TARGET = dist/main
+
+MKDIR_P = mkdir -p
+
+all: $(TARGET)
+
+$(TARGET): $(OBJS)
+	$(MKDIR_P) dist
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+dist/%.o: %.c
+	$(MKDIR_P) dist
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	rm -rf dist
+
+.PHONY: all clean

color_utils.c

@@ -0,0 +1,84 @@
+#include "color_utils.h"
+#include <string.h>
+
+Color hex_to_color(int hex) {
+    Color color;
+
+    color.r = (hex >> 16) % 256;
+    color.g = (hex >> 8) % 256;
+    color.b = hex % 256;
+
+    return color;
+}
+
+Color hsv_to_color(double h, double s, double v) {
+    h = fmod(h, 360);
+    if (s > 1)
+        s = fmod(s, 1);
+    if (v > 1)
+        v = fmod(v, 1);
+
+    double c = v * s;
+    double x = c * (1 - fabs(fmod(h / 60, 2) - 1));
+    double m = v - c;
+
+    double r0, g0, b0;
+
+    if (h >= 0 && h < 60) {
+        r0 = c;
+        g0 = x;
+        b0 = 0;
+    } else if (h >= 60 && h < 120) {
+        r0 = x;
+        g0 = c;
+        b0 = 0;
+    } else if (h >= 120 && h < 180) {
+        r0 = 0;
+        g0 = c;
+        b0 = x;
+    } else if (h >= 180 && h < 240) {
+        r0 = 0;
+        g0 = x;
+        b0 = c;
+    } else if (h >= 240 && h < 300) {
+        r0 = x;
+        g0 = 0;
+        b0 = c;
+    } else {
+        r0 = c;
+        g0 = 0;
+        b0 = x;
+    }
+
+    Color color;
+
+    color.r = (r0 + m) * 255;
+    color.g = (g0 + m) * 255;
+    color.b = (b0 + m) * 255;
+
+    return color;
+}
+
+void set_color(uint8_t* buffer, const Color color) {
+    for (int i = 7; i >= 0; i--)
+        *buffer++ = (color.g & (1 << i)) ? 0b11111000 : 0b10000000;
+
+    for (int i = 7; i >= 0; i--)
+        *buffer++ = (color.r & (1 << i)) ? 0b11111000 : 0b10000000;
+
+    for (int i = 7; i >= 0; i--)
+        *buffer++ = (color.b & (1 << i)) ? 0b11111000 : 0b10000000;
+}
+
+int construct_buffer(uint8_t* buffer,
+                     const Color* colors,
+                     const int num_leds,
+                     const int color_bytes,
+                     const int res_bytes) {
+    const int data_size = num_leds * color_bytes + res_bytes;
+    memset(buffer, 0, data_size);
+    for (int i = 0; i < num_leds; i++) {
+        set_color(buffer + i * color_bytes, colors[i]);
+    }
+    return data_size;
+}

color_utils.h

@@ -0,0 +1,22 @@
+#ifndef COLOR_UTILS_H
+#define COLOR_UTILS_H
+
+#include <math.h>
+#include <stdint.h>
+
+typedef struct Color {
+    uint8_t g;
+    uint8_t r;
+    uint8_t b;
+} Color;
+
+Color hex_to_color(int hex);
+Color hsv_to_color(double h, double s, double v);
+void set_color(uint8_t* buffer, const Color color);
+int construct_buffer(uint8_t* buffer,
+                     const Color* colors,
+                     const int num_leds,
+                     const int color_bytes,
+                     const int res_bytes);
+
+#endif

main.c

@@ -0,0 +1,68 @@
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include "spi_utils.h"
+#include "color_utils.h"
+#include "shader.h"
+
+#define RES_BYTES 40
+#define COLOR_BYTES 24
+
+volatile sig_atomic_t stop = 0;
+
+void handle_sigint(int sig) {
+    stop = 1;
+}
+
+int main() {
+    signal(SIGINT, handle_sigint);
+
+    const char* device = "/dev/spidev1.0";
+    const uint8_t spi_mode = SPI_MODE_0;
+    const uint8_t spi_bits = 8;
+    const uint32_t spi_speed = 6400000;
+
+    int fd = init_device(device, spi_mode, spi_bits, spi_speed);
+    if (fd < 0)
+        return -1;
+
+    const int num_leds = 60;
+    const int data_size = COLOR_BYTES * num_leds + RES_BYTES;
+
+    uint8_t* buffer = malloc(data_size);
+    Color* colors = malloc(sizeof(Color) * num_leds);
+
+    struct timeval start_time;
+    gettimeofday(&start_time, NULL);
+
+    while (!stop) {
+        struct timeval current_time;
+        gettimeofday(&current_time, NULL);
+
+        double time_elapsed =
+            (current_time.tv_sec - start_time.tv_sec) +
+            (current_time.tv_usec - start_time.tv_usec) / 1000000.0;
+
+        for (int i = 0; i < num_leds; i++) {
+            colors[i] = shader(i, time_elapsed);
+        }
+
+        construct_buffer(buffer, colors, num_leds, COLOR_BYTES, RES_BYTES);
+        send_buffer(fd, buffer, data_size, spi_speed, spi_bits);
+    }
+
+    for (int i = 0; i < num_leds; i++) {
+        colors[i] = hex_to_color(0x000000);
+    }
+
+    construct_buffer(buffer, colors, num_leds, COLOR_BYTES, RES_BYTES);
+    send_buffer(fd, buffer, data_size, spi_speed, spi_bits);
+
+    free(buffer);
+    free(colors);
+    close(fd);
+
+    return 0;
+}

shader.c

@@ -0,0 +1,5 @@
+#include "shader.h"
+
+Color shader(int index, double time) {
+    return hsv_to_color(time * 120 + index * 6, 1, 1);
+}

shader.h

@@ -0,0 +1,8 @@
+#ifndef SHADER_H
+#define SHADER_H
+
+#include "color_utils.h"
+
+Color shader(int index, double time);
+
+#endif

spi_utils.c

@@ -0,0 +1,43 @@
+#include "spi_utils.h"
+
+int init_device(const char* device,
+                uint8_t spi_mode,
+                uint8_t spi_bits,
+                uint32_t spi_speed) {
+    int fd;
+
+    if ((fd = open(device, O_RDWR)) < 0) {
+        perror("SPI 设备打开失败");
+        close(fd);
+        return -1;
+    }
+
+    ioctl(fd, SPI_IOC_WR_MODE, &spi_mode);
+    ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &spi_bits);
+    ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &spi_speed);
+
+    return fd;
+}
+
+int send_buffer(int fd,
+                uint8_t* buffer,
+                const int data_size,
+                uint32_t spi_speed,
+                uint8_t spi_bits) {
+    int ret;
+
+    struct spi_ioc_transfer tr = {
+        .tx_buf = (unsigned long)buffer,
+        .len = data_size,
+        .speed_hz = spi_speed,
+        .bits_per_word = spi_bits,
+    };
+
+    ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
+
+    if (ret < 0) {
+        perror("SPI 信息发送失败");
+    }
+
+    return ret;
+}

spi_utils.h

@@ -0,0 +1,23 @@
+#ifndef SPI_UTILS_H
+#define SPI_UTILS_H
+
+#include <fcntl.h>
+#include <linux/spi/spidev.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+typedef unsigned char uint8_t;
+typedef unsigned int uint32_t;
+
+int init_device(const char* device,
+                uint8_t spi_mode,
+                uint8_t spi_bits,
+                uint32_t spi_speed);
+int send_buffer(int fd,
+                uint8_t* buffer,
+                const int data_size,
+                uint32_t spi_speed,
+                uint8_t spi_bits);
+
+#endif