cJSON的简单应用——保存/解析 Shader 参数 【代码示例】

自定义的 Shader 程序结构体：

struct ShaderProgram
{
    struct Path
    {
        char *vertex_shader_path;
        char *fragment_shader_path;
    } path;

    struct FragmentShaderUniformlocation
    {
        char *channel_0;
        char *channel_1;
        char *global_time;
        char *resolution;
    } fsul;

};

入口函数：

int main()
{
#ifdef TOFILE
	createObjects();
#else
    parseFile("result.txt");
#endif
    return 0;
}

创建 shader 程序 JSON 对象 并 保存到本地 的函数：

void createObjects()
{
#if MUL
	ShaderProgram sp[2] =
	{
		{
			{ "../Shader/vs_0.glsl","../Shader/fs_0.glsl" },{ "iChannel0","iChannel1","iGlobalTime","iResolution" }
		},// sp[0]

		{
			{ "../Shader/vs_1.glsl","../Shader/fs_1.glsl" },"iResolution" }
		}	// sp[1]
	};
#else
	ShaderProgram sp =
	{
		{ "../Shader/vs_0.glsl","iResolution" }
	};

#endif

	cJSON *root = cJSON_CreateArray();
	cJSON *fld = NULL,*fldd_0 = NULL,*fldd_1;

#if MUL
	for (int i = 0; i < 2; i++)
	{
		cJSON_AddItemToArray(root,fld = cJSON_CreateArray());

		cJSON_AddItemToArray(fld,fldd_0 = cJSON_CreateObject());
		cJSON_AddStringToObject(fldd_0,"Vertex Shader Path",sp[i].path.vertex_shader_path);
		cJSON_AddStringToObject(fldd_0,"Fragment Shader Path",sp[i].path.fragment_shader_path);

		cJSON_AddItemToArray(fld,fldd_1 = cJSON_CreateObject());
		cJSON_AddStringToObject(fldd_1,"Channel 0",sp[i].fsul.channel_0);
		cJSON_AddStringToObject(fldd_1,"Channel 1",sp[i].fsul.channel_1);
		cJSON_AddStringToObject(fldd_1,"Global Time",sp[i].fsul.global_time);
		cJSON_AddStringToObject(fldd_1,"Resolution",sp[i].fsul.resolution);
	}
#else

	cJSON_AddItemToArray(root,fld = cJSON_CreateArray());

	cJSON_AddItemToArray(fld,fldd_0 = cJSON_CreateObject());
	cJSON_AddStringToObject(fldd_0,sp.path.vertex_shader_path);
	cJSON_AddStringToObject(fldd_0,sp.path.fragment_shader_path);

	cJSON_AddItemToArray(fld,fldd_1 = cJSON_CreateObject());
	cJSON_AddStringToObject(fldd_1,sp.fsul.channel_0);
	cJSON_AddStringToObject(fldd_1,sp.fsul.channel_1);
	cJSON_AddStringToObject(fldd_1,sp.fsul.global_time);
	cJSON_AddStringToObject(fldd_1,sp.fsul.resolution);

#endif

	char *out = cJSON_Print(root);
	// 保存信息到文件
	writetoFile("result.txt",out);
	printf("Debug Info: %s",out);
	free(out);

	cJSON_Delete(root);
}

解析本地文本的函数：

void parseFile(char *filename)
{
    FILE *f;
    long len;
    char *data;

    f = fopen(filename,"rb");
    fseek(f,SEEK_END);
    len = ftell(f);
    fseek(f,SEEK_SET);
    data = (char *)malloc(len + 1);
    fread(data,1,len,f);
    fclose(f);

    //easyParse(data);
    itemParse(data);

    free(data);
}

void itemParse(char *text)
{

    cJSON *json;

    json = cJSON_Parse(text);
    if (!json)
    {
        printf("Error before: [%s]\n",cJSON_GetErrorPtr());
    }
    else
    {
        int size_0 = cJSON_GetArraySize(json);
        printf("Shader Program Nums = %d\n",size_0);

        for (int i = 0; i < size_0; i++)
        {
            cJSON *pItem = cJSON_GetArrayItem(json,i);
            if (NULL == pItem)
            {
                continue;
            }
            int size_1 = cJSON_GetArraySize(pItem);
            //printf("Shader Program Item Nums = %d\n",size_1);
            printf("===========================\n");
            for (int j = 0; j < size_1; j++)
            {
                cJSON *ppItem = cJSON_GetArrayItem(pItem,j);

                //printJSON(ppItem);

                int size_2 = cJSON_GetArraySize(ppItem);
                printf("Shader Program Item Size  = %d\n",size_2);
                //printf("---------------------------\n");
                for (int k = 0; k < size_2; k++)
                {
                    cJSON *pppItem = cJSON_GetArrayItem(ppItem,k);

                    printJSON(pppItem);
                }
                printf("===========================\n");
            }
        }
    }

    cJSON_Delete(json);
}

生成的文本内容为：

开启 MUL 的情况下

[[{
			"Vertex Shader Path":	"../Shader/vs_0.glsl","Fragment Shader Path":	"../Shader/fs_0.glsl"
		},{
			"Channel 0":	"iChannel0","Channel 1":	"iChannel1","Global Time":	"iGlobalTime","Resolution":	"iResolution"
		}],[{
			"Vertex Shader Path":	"../Shader/vs_1.glsl","Fragment Shader Path":	"../Shader/fs_1.glsl"
		},"Resolution":	"iResolution"
		}]]

或

未开启 MUL 的情况下

[[{
			"Vertex Shader Path":	"../Shader/vs_0.glsl","Resolution":	"iResolution"
		}]]

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使用 CJSON 在C语言中进行 JSON 的创建和解析的实例讲解