ShapeGrammar.h

浏览该文件的文档.

#pragma once
 
#include "procgen/PointSet.h"
 
#include <cstdint>
#include <string>
#include <unordered_map>
#include <vector>
 
namespace eve::procgen {
 
struct ShapeModuleVariant {
    std::string asset;
    float       length = 1.f;
    float       weight = 1.f;
};
 
class EVENGINE_API_DOMAINS ShapeGrammar {
public:
    void clear();
    bool addModule(const std::string& symbol, const std::string& asset, float length,
                   float weight = 1.f);
    bool removeModule(const std::string& symbol);
    bool hasModule(const std::string& symbol) const;
    int  getModuleCount() const;
    std::string getModuleSymbol(int index) const;
    int         getVariantCount(const std::string& symbol) const;
    std::string getVariantAsset(const std::string& symbol, int index) const;
    float       getVariantLength(const std::string& symbol, int index) const;
 
    bool validate(const std::string& grammar);
    PointSet* generate(const std::string& grammar, PointSet* controlPoints, uint32_t seed,
                       bool acceptIncomplete);
    std::string getError() const;
    std::string debugReport() const;
 
private:
    struct Element {
        std::string          symbol;
        std::vector<Element> children;
        int                  repeatMin = 1;
        int                  repeatMax = 1;  // -1 = fill available length
    };
    struct Parser {
        const std::string& text;
        size_t             position = 0;
        std::string        error;
        std::vector<Element> sequence(char terminator = '\0');
        void skipWhitespace();
    };
 
    float elementMinLength(const Element& element) const;
    float sequenceMinLength(const std::vector<Element>& sequence, size_t from = 0) const;
    bool  expandSequence(const std::vector<Element>& sequence, float available,
                         std::vector<std::string>& symbols, float& used) const;
    const ShapeModuleVariant* chooseVariant(const std::string& symbol, uint32_t seed) const;
 
    std::unordered_map<std::string, std::vector<ShapeModuleVariant>> modules_;
    std::vector<std::string> moduleOrder_;
    std::string              error_;
    int                      lastSymbolCount_ = 0;
    float                    lastUsedLength_  = 0.f;
    float                    lastSplineLength_ = 0.f;
};
 
}  // namespace eve::procgen