c++ - 嵌套名称说明符中使用的不完整类型 'TextureLoader'

Question

我有这门课

#ifndef WRAPPED_TEXTURE_H
#define WRAPPED_TEXTURE_H

#include <SDL2/SDL.h>
#include "../ui/utils/texture.h"

// color keying - CHROMA KEY!!!!

class WrappedTexture {

public:
    WrappedTexture() {
        raw_texture = NULL;
        width = 0;
        height = 0;
        bound_renderer = NULL;
    }
    WrappedTexture(SDL_Renderer* bound_renderer) {
        raw_texture = NULL;
        width = 0;
        height = 0;
        this->bound_renderer = bound_renderer;
    }
    ~WrappedTexture() {
        printf("Freeing resources!");
        free();
    }
    void free() {
        if (raw_texture != NULL) {
            SDL_DestroyTexture(raw_texture);
            raw_texture = NULL;
            width = 0;
            height = 0;
        }
    }
    void load_from_file(std::string path) {
        free();
        TextureLoader::load_texture_chroma(path, bound_renderer, NULL, std::vector<Uint8> { 0, 0xFF, 0xFF}, *this);
    }
    void render(int x, int y) {
        SDL_Rect render_frame = { x, y, width, height };
        SDL_RenderCopy(bound_renderer, raw_texture, NULL, &render_frame);
    }

    int get_width() {
        return width;
    }
    int get_height() {
        return height;
    }
    void set_width_height(int width, int height) {
        this->width = width;
        this->height = height;
    }
    void set_raw_texture(SDL_Texture* raw_texture) {
        this->raw_texture = raw_texture;
    }

private:
    SDL_Texture* raw_texture;
    int width;
    int height;
    SDL_Renderer* bound_renderer;
};

#endif

而且我有实用程序类，其中包含对我有用的功能。

#ifndef TEXTURE_H
#define TEXTURE_H

#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <vector>

#include "image.h"

#include "../../domain/WrappedTexture.h"

class TextureLoader {
public:
    static WrappedTexture *create_wrapped_texture(int width, int height, SDL_Texture* raw, SDL_Renderer* render) {
        WrappedTexture* wt = new WrappedTexture(render);
        wt->set_width_height(width, height);
        wt->set_raw_texture(raw);
        return wt;
    }
    static SDL_Texture* load_texture_chroma(std::string path,
            SDL_Renderer* renderer, SDL_Surface* screen_surface,
            std::vector<Uint8> pixelColor, WrappedTexture& output) {
        int width = -1;
        int height = -1;

        SDL_Texture* new_texture = NULL;
        SDL_Surface* loaded_surface = ImageLoader::load_image(path,
                screen_surface);
        if (loaded_surface == NULL) {
            printf("Unable to load image %s! SDL_image Error: %s\n",
                    path.c_str(), IMG_GetError());
        } else {
            SDL_SetColorKey(loaded_surface, SDL_TRUE,
                    SDL_MapRGB(loaded_surface->format, pixelColor[0],
                            pixelColor[1], pixelColor[2]));
            new_texture = SDL_CreateTextureFromSurface(renderer,
                    loaded_surface);
            if (new_texture == NULL) {
                printf("Unable to create texture %s! SDL Error: %s\n",
                        path.c_str(), SDL_GetError());
            } else {
                width = loaded_surface->w;
                height = loaded_surface->h;
            }
            SDL_FreeSurface(loaded_surface);
        }

        if (width != -1 && height != -1 && &output != NULL) {
            output = *TextureLoader::create_wrapped_texture(width, height, new_texture, renderer);
        }
        return new_texture;
    }
};

#endif

但我在行 incomplete type 'TextureLoader' used in nested name specifier

中遇到错误

void load_from_file(std::string path) {
    free();
    TextureLoader::load_texture_chroma(path, bound_renderer, NULL, std::vector<Uint8> { 0, 0xFF, 0xFF}, *this); // error
}

我试图在 WrappedTexture 类中声明 class TextureLoader 并尝试在 TextureLoader 中声明 class WrappedTexture 但它没有'帮助。

有什么问题？

Answer 1

问题可能出在你对类的引用，在它被完全声明之前:

output = *TextureLoader::create_wrapped_texture(width, height, new_texture, renderer);

此时 TextureLoader 类还没有完全声明。尝试将函数定义移至 .cpp 文件。您的所有功能都在 header 中实现是否有原因？