Direct3D11的pData转Buffer时窗口Resize报错问题求助

核心问题 #

你的代码中static unsigned char* buffer = new unsigned char[size];使用了static修饰指针，这意味着buffer只会在第一次执行时分配内存。当窗口放大后，width或height增大，计算出的size会比第一次初始化时更大，但buffer的内存空间还是最初的小尺寸，后续执行memcpy_s时会出现内存越界访问，触发0xC0000005访问冲突错误。

修复代码 #

你需要跟踪buffer的当前容量，每次处理前检查是否足够容纳新的size，不足则重新分配：

int width = frame.width;
int height = frame.height;
int row_pitch = frame.row_pitch;
unsigned char* data = frame.data;

int size = width * height * 4;
int dstRowPitch = width * 4;

// 用静态变量保存buffer和当前容量，避免重复分配
static unsigned char* buffer = nullptr;
static int current_capacity = 0;

// 检查容量是否足够，不足则重新分配
if (buffer == nullptr || current_capacity < size) {
    // 释放旧内存
    delete[] buffer;
    // 分配新内存
    buffer = new unsigned char[size];
    current_capacity = size;
}

std::cout << height << std::endl;
for (int h = 0; h < height; h++) {
    memcpy_s(buffer + h * dstRowPitch, dstRowPitch,
             data + h * row_pitch,
             min(row_pitch, dstRowPitch));
}

额外优化方案 #

如果你的场景允许，推荐使用std::vector<unsigned char>替代手动内存管理，它会自动处理扩容和内存释放，代码更简洁安全：

int width = frame.width;
int height = frame.height;
int row_pitch = frame.row_pitch;
unsigned char* data = frame.data;

int size = width * height * 4;
int dstRowPitch = width * 4;

// 用vector自动管理内存
static std::vector<unsigned char> buffer;

if (buffer.size() < size) {
    buffer.resize(size);
}

std::cout << height << std::endl;
for (int h = 0; h < height; h++) {
    memcpy_s(buffer.data() + h * dstRowPitch, dstRowPitch,
             data + h * row_pitch,
             min(row_pitch, dstRowPitch));
}

内容的提问来源于stack exchange，提问作者gdrfgdrf