怎样理解脚本.docx

理解脚本使用这样一个有限的行为集合，就不再需要复杂的可编译脚本语言了。相反，只需要告诉脚本系统要使用哪些行为，以及这些行为将使用怎样的选项以实现游戏的功能。对于这种方法，最大的好处就是不再需要为指定一个简单的行为而罗列代码行，可以通过编号来引用行为和选项。举个例子，Play Sound行为的编号为4，而且该行为仅要求一个输入，即播放声音的编号。在脚本中只存储两个数值：一个对应于行为，另一个代表了声音。使用数值表示行为（代替文本）的方法可以使这种类型脚本的处理既快速又简单。Mad Lib Scripting系统的设计创建在游戏中想到的行为，可以通过创建或编辑脚本来填充那些空白点（称之为条目entries）。对于每个行为，请明确提供一个可供空白条目填充的选项列表，它的类型可以从一行文本到一串数字。接着将行为和空白条目进行编号，以便脚本系统可以引用它们，以下是一些行为列表的范例：1. Character (*NAME*) takes (*NUMBER*) damage.2. Print (*TEXT*).3. Play sound effect titled (*SOUND_NAME*).4. Play music titled (*MUSIC_NAME*).5. Create object (*OBJECT_NAME*) at coordinates (*XPOS*),(*YPOS*).6. End script processing.在这6种行为中，都有0个或多个空白条目位于括号内，每个空白条目包含了一个文本字符串或者一个数字，这个行为与可能条目（以及条目的类型）的列表被称之为行为模板（action template），如下图所示：一旦使用了行为模板，就可以使用它们的编号而不是行为的文本进行引用（文本的存在只是为了使用户能够更容易理解每个行为所实现的功能）。MLS系统的编写为了使MLS系统功能尽可能强大，需要设计它以便可以支持多重行为的模板，而且每个行为模板都包含不受数量限制的行为。以这种方式，就可以将系统复用到任何想要的项目中。当一个脚本完成时，将脚本读入到引擎中，并处理各自的行为，为每个由脚本编辑器所输入的行为使用指定的条目。一个行为模板需要保存行为的列表，包括文本、条目编号以及每个条目的数据。每个行为按它们在列表中的索引值进行编号，同时每个行为中的空白条目也被加以编号。可以为每个条目指定一种类型（文本型、整数型、浮点型、布尔型、多重选择型），如下所示：0. No entry type1. Text entry2. Boolean value3. Integer number4. Float number5. Multiple choice (a choice from a list of text selections)每个条目类型都有一个独特的特征，字符串类型的长度是可以变化的，数字型可以是两个数字范围之间的任何数值，而布尔值可以是TRUE或者FALSE。至于多重选项型，每个选项都有它自己的文本字符串（脚本从一个列表中获取选项，而且所选选项的索引编号比它的文本更适用）。行为可以采用如下格式:Action #1: Spell targets (*MULTIPLE_CHOICE*).Possible choices for blank entry #1:1. Player character2. Spell caster3. Spell target4. Nobody我们通过创建结构体ENTRY_RULE和ACTION来处理条目规则与行为。enum ENTRY_TYPE ENTRY_NONE = 0, ENTRY_TEXT, ENTRY_BOOL, ENTRY_INT, ENTRY_FLOAT, ENTRY_CHOICE ;typedef char* char_ptr;typedef int BOOL;/=/ Structures to store information about a single blank entry./=typedef struct ENTRY_RULElong type; / type of blank entry (ENTRY_TEXT, ENTRY_BOOL, )/ The following two unions contain the various information about a single blank entry, / from the min/max values (for int and float types), as well as the number of choices / in a multiple choice entry.unionlong long_min; / min value of long typefloat float_min; / min value of float typelong num_choices; / number of choices in list;unionlong long_max; / max value of long typefloat float_max; / max value of float typechar_ptr* choices; / choice text array ;/ structure constructor to clear to default valuesENTRY_RULE()memset(this, 0, sizeof(*this);/ structure destructor to clean up used resourcesENTRY_RULE()/ special case for choice typeif(type = ENTRY_CHOICE & choices != NULL)for(long i = 0; i num_choices; i+) delete choicesi;delete choices; *ENTRY_RULE_PTR;/=/ Structure that store a single action./=typedef struct ACTIONlong index; / action index 0, number of action - 1char text256; / action textshort num_entries_rule; / number of entries in actionENTRY_RULE_PTR entries_rule; / array of entry structuresACTION* next; / next action in linked listACTION()memset(this, 0, sizeof(*this);ACTION()delete entries_rule;delete next; *ACTION_PTR;行为模板被存储为文本文件，同时每个行为的文本被包括在括号中。每个包含条目的行为（标记为文本中的波浪字符）紧跟着是条目数据的列表。每个条目由一个描述条目类型（文本型、布尔型、整型、浮点型或选项型）的单词开始。对于文本类型而言并没有更多的需要信息，对于布尔类型来说也是如此。而作为整数和浮点型，则要求一个最小值和最大值。最后，选项类型条目后跟着的是可供选择的编号以及每个选项的文本（包括在引号里）。如下所示： If flag # is thenINT 0 255BOOLElseEndifSet flag # to INT 0 255BOOLPrint TEXTMove character to , , FLOAT 0.0 2048.0FLOAT 0.0 2048.0FLOAT 0.0 2048.0Character pointsCHOICE 3 Main Character Caster TargetCHOICE 2GainsLoosesINT 0 128CHOICE 2HitMagicEngage in battle sequence #INT 0 65535End Script第二篇脚本条目的创建因为ENREY_RULE结构仅包含了行为和条目的规则，所以需要另外的结构数组去存储每个条目的数据。这些新的结构包括了在条目中所使用的文本、布尔值、多重选项，我们使用结构体ENTRY来表示。/=/ structure that store all entries fact information./=typedef struct ENTRYlong type; / type of blank entry (ENTRY_TEXT, ENTRY_BOOL, )unionlong io_value; / used for saving/loadinglong length; / length of text (0 terminator)long selection; / selection in choiceBOOL bool_value; / BOOL valuelong long_value; / long baluefloat float_value; / float value;char* text; / entry text bufferENTRY()memset(this, 0, sizeof(*this);ENTRY()delete text; *ENTRY_PTR;在处理脚本条目的过程中，当一个脚本出现了许多条目时，最麻烦的问题也就接踵而来。脚本中的每个行为都要求一个相匹配的ENTRY_RULE结构，其依次包含了一定数量的ENTRY结构。为了更好地处理一个脚本的结构，还需要其他的结构来记录属于脚本行为的每个条目，我们将它命名为SCRPT。/=/ structure that store all /=typedef struct SCRIPTlong action_index; / 0, number of actions - 1long num_entries; / number of entries in this actionENTRY_PTR entries; / array of entriesSCRIPT* prev; / previous in linked listSCRIPT* next; / next in linked listSCRIPT()memset(this, 0, sizeof(*this);SCRIPT()delete entries;delete next; *SCRIPT_PTR;prev和next维护了整个脚本的连接列表，为了构造SCRIPT结构的连接列表，从代表脚本的第一个行为的根结构开始，然后使用next和prev将SCRIPT结构连接起来，如下图所示： ACTION_TEMPLATE类的整合理解了行为模板所使用的结构以及所容纳的脚本后，现在开始将它们整合到一起创建一个加载并处理脚本的类。/=/ This class encapsulate script save and load./=typedef class ACTION_TEMPLATEprivate:long m_num_actions; / number of actions in templateACTION_PTR m_root_action; / list of template actions public:ACTION_TEMPLATE();ACTION_TEMPLATE();BOOL load_actions(const char* filename);void free();long get_num_actions();ACTION_PTR get_root_action();ACTION_PTR get_action(long act_index);SCRIPT_PTR create_script(long act_index);long get_num_entries_rule(long act_index);ENTRY_RULE_PTR get_entry_rule(long act_index, long entry_rule_index);void expand_default_action_text(char* buffer, ACTION_PTR action);BOOL expand_action_text(char* buffer, SCRIPT_PTR script); *ACTION_TEMPLATE_PTR;实现：/-/ Get quoted line from file./-static BOOL _get_quoted_line(FILE* fp, char* data, long max_data_size)int c;long pos = 0;/ read until a quote is reached (or EOF)while(1)if(c = fgetc(fp) = EOF)return FALSE;if(c = )/ read until next quot (or EOF)while(1)if(c = fgetc(fp) = EOF)return FALSE;/ return text when 2nd quote foundif(c = )datapos = 0;break;/ add acceptable text to lineif(c != 0x0a & c != 0x0d) / if character is not linefeed, not carriage.if(pos max_data_size-1)datapos+ = c;break;return TRUE;/-/ Get word from file./-static BOOL _get_word(FILE* fp, char* data, long max_data_size)int c;long pos = 0;/ reset word to emptydata0 = 0;/ read until an acceptable character foundwhile(1)if(c = fgetc(fp) = EOF)data0 = 0;return FALSE;/ check for start of wordif(c != 32 & c != 0x0a & c != 0x0d) / if character is not blank, not linefeed, not carriage.datapos+ = c;/ loop until end of word (or EOF)while(c = fgetc(fp) != EOF)/ break on acceptable word seperatorsif(c = 32 | c = 0x0a | c = 0x0d)break;/ add if enough room leftif(pos next = NULL;if(act_ptr = NULL)m_root_action = act;elseact_ptr-next = act;act_ptr = act;/ copy action textstrcpy(act-text, text);/ store action indexact-index = m_num_actions;/ increase the number of actions loadedm_num_actions+;size_t text_len = strlen(text);/ count the number of entries in the actionfor(size_t i = 0; i num_entries_rule+;/ allocated and read in entries (if any)if(act-num_entries_rule != 0)act-entries_rule = new ENTRY_RULEact-num_entries_rule;for(short entry_index = 0; entry_index num_entries_rule; entry_index+)ENTRY_RULE_PTR entry_rule = &act-entries_ruleentry_index;/ get type of entry_get_word(fp, text, size);if(!stricmp(text, TEXT) / TEXT type, nothing data.entry_rule-type = ENTRY_TEXT;else if(!stricmp(text, INT) / LONG type, get min and max valuesentry_rule-type = ENTRY_INT;/ get min value_get_word(fp, text, size);entry_rule-long_min = atol(text);/ get max value_get_word(fp, text, size);entry_rule-long_max = atol(text);else if(!stricmp(text, FLOAT) / FLOAT type, get min and max valuesentry_rule-type = ENTRY_FLOAT;/ get min value_get_word(fp, text, size);entry_rule-float_min = (float) atof(text);/ get max value_get_word(fp, text, size);entry_rule-float_max = (float) atof(text);else if(!stricmp(text, BOOL) / BOOL type, no options.entry_rule-type = ENTRY_BOOL;else if(!stricmp(text, CHOICE) / CHOICE type, get number of entries and entrys texts.entry_rule-type = ENTRY_CHOICE;/ get the number of choices_get_word(fp, text, size);entry_rule-num_choices = atol(text);entry_rule-choices = new char_ptrentry_rule-num_choices;/ get each entry textfor(long choice_index = 0; choice_index num_choices; choice_index+)_get_quoted_line(fp, text, size);entry_rule-choiceschoice_index = strdup(text);fclose(fp);return TRUE;/-/ Return number of actions in template./-long ACTION_TEMPLATE:get_num_actions()return m_num_actions;/-/ Return root ACTION structure./-ACTION_PTR ACTION_TEMPLATE:get_root_action()return m_root_action;/-/ Return specified ACTION structure./-ACTION_PTR ACTION_TEMPLATE:get_action(long act_index)/ return error if higher than number of actionsif(act_index = m_num_actions)return NULL;ACTION_PTR act_ptr = m_root_action;/ scan listwhile(act_ptr)if(act_ptr-index = act_index)return act_ptr;act_ptr = act_ptr-next;return NULL;/-/ Create script from specified action index./-SCRIPT_PTR ACTION_TEMPLATE:create_script(long act_index)/ make sure it is a valid actionif(act_index = m_num_actions)return NULL;ACTION_PTR act_ptr;/ get pointer to actionif(act_ptr = get_action(act_index) = NULL)return NULL;/ create new SCRIPT structureSCRIPT_PTR script = new SCRIPT;script-action_index = act_index;script-num_entries = act_ptr-num_entries_rule;script-entries = new ENTRYscript-num_entries;/ set up each entryfor(long i = 0; i num_entries; i+)script-entriesi.type = act_ptr-entries_rulei.type;/ set up entry data based on typeswitch(script-entriesi.type)case ENTRY_TEXT:script-entriesi.text = NULL;break;case ENTRY_INT:script-entriesi.long_value = act_ptr-entries_rulei.long_min;break;case ENTRY_FLOAT:script-entriesi.float_value = act_ptr-entries_rulei.float_min;break; case ENTRY_BOOL:script-entriesi.bool_value = TRUE;break; case ENTRY_CHOICE:script-entriesi.selection = 0;break;return script;/-/ Return number of entries rule in the specified action./-long ACTION_TEMPLATE:get_num_entries_rule(long act_index)/ get pointer to specified actionACTION_PTR act_ptr = get_action(act_index);/ return 0 if on errorif(act_ptr = NULL)return 0;return act_ptr-num_entries_rule;/-/ Return specified entry rule in specified action./-ENTRY_RULE_PTR ACTION_TEMPLATE:get_entry_rule(long act_index, long entry_rule_index)ACTION_PTR act_ptr = get_action(act_index);if(act_ptr = NULL | entry_rule_index = act_ptr-num_entries_rule)return NULL;return &(act_ptr-entries_ruleentry_rule_index);/-/ Expand action text using min/first/TRUE choice values./-void ACTION_TEMPLATE:expand_default_action_text(char* buffer, ACTION_PTR action)/ copy action text into buffer if no entries ruleif(action-num_entries_rule = 0)strcpy(buffer, action-text);return;/ expand entry types into action textsize_t buf_pos = 0;long rule_index = 0;size_t text_len = strlen(action-text);const size_t mem_size = 256;for(size_t i = 0; i texti = )if(action-entries_rulerule_index.type = ENTRY_TEXT)memcpy(&bufferbuf_pos, (*TEXT*), 8);buf_pos += 8;else if(action-entries_rulerule_index.type = ENTRY_INT)sprintf(memory, (*%lu*), action-entries_rulerule_index.long_min);memcpy(&bufferbuf_pos, memory, strlen(memory);buf_pos += strlen(memory);else if(action-entries_rulerule_index.type = ENTRY_FLOAT)sprintf(memory, (*%lf*), action-entries_rulerule_index.float_min);memcpy(&bufferbuf_pos, memory, strlen(memory);buf_pos += strlen(memory);else if(action-entries_rulerule_index.type = ENTRY_BOOL)memcpy(&bufferbuf_pos, (*TRUE*), 8);buf_pos += 8;else if(action-entries_rulerule_index.type = ENTRY_CHOICE)memcpy(&bufferbuf_pos, (*, 2);buf_pos += 2;char* choice = action-entries_rulerule_index.choices0;size_t choice_len = strlen(choice);memcpy(&bufferbuf_pos, choice, choice_len);buf_pos += choice_len;memcpy(&bufferbuf_pos, *), 2);buf_pos += 2;rule_index+;elsebufferbuf_pos+ = action-texti;bufferbuf_pos = 0;/-/ Expand action text using selections./-BOOL ACTION_TEMPLATE:expand_action_text(char* buffer, SCRIPT_PTR script)/ get a pointer to the specified actionACTION_PTR act_ptr = get_action(script-action_index);if(act_ptr = NULL)return FALSE;/ copy action text into buffer if no entriesif(act_ptr-num_entries_rule = 0)strcpy(buffer, act_ptr-text);return TRUE;/ expand entry types into action textsize_t buf_pos = 0;size_t entry_index = 0;char memory256;size_t memory_length; size_t act_text_length = strlen(act_ptr-text);for(size_t i = 0; i texti = )if(act_ptr-entries_ruleentry_index.type = ENTRY_TEXT & script-entriesentry_index.type = ENTRY_TEXT) memcpy(&bufferbuf_pos, (*, 2);buf_pos += 2;if(script-entriesentry_index.text)for(long j = 0; j entriesentry_index.textj = 0)break;bufferbuf_pos+ = script-entriesentry_index.textj;memcpy(&bufferbuf_pos, *)