openglplayground/common.hh

#ifndef __OPENGLPLAYGROUND_COMMON_HH__
#define __OPENGLPLAYGROUND_COMMON_HH__

#include <string>
#include <cstring>
#include <cstdio>
#include <cerrno>
#include <memory>

#include <glbinding/gl/gl.h>

#include <SDL2/SDL.h>
#include <SDL2/SDL_ttf.h>

using namespace gl;
using namespace std::string_literals;

class Exception {
public:
  Exception() : msg_() {
  }

  Exception(std::string msg) : msg_(msg) {
  }
  
  virtual ~Exception() {}

  virtual std::string toString() const {
    return "Exception: "s + msg_;
  }
protected:
  std::string msg_;
};

class POSIXException : public Exception {
public:
  POSIXException(int err): Exception(), err_(err) {
  }

  int getErr() const {return err_;}
  
  std::string toString() const override {
    return "POSIXException: "s + std::strerror(err_);
  }

private:
  int err_;
};
  
class GLException : public Exception {
public:
  GLException(GLenum err) : Exception(), err_(err) {
  }
  
  GLenum getErr() const {return err_;}

  std::string errToString() const {
    std::string ret;
    if (err_ == GL_INVALID_ENUM)
      ret += "GL_INVALID_ENUM ";
    if (err_ == GL_INVALID_VALUE)
      ret += "GL_INVALID_VALUE ";
    if (err_ == GL_INVALID_OPERATION)
      ret += "GL_INVALID_OPERATION ";
    if (err_ == GL_INVALID_FRAMEBUFFER_OPERATION)
      ret += "GL_INVALID_FRAMEBUFFER_OPERATION ";
    if (err_ == GL_OUT_OF_MEMORY)
      ret += "GL_OUT_OF_MEMORY ";
    if (err_ == GL_STACK_UNDERFLOW)
      ret += "GL_STACK_UNDERFLOW ";
    if (err_ == GL_STACK_OVERFLOW)
      ret += "GL_STACK_OVERFLOW ";

    return ret;
  }
  
  std::string toString() const override {
    return "GLException: "s + errToString() + "(" + std::to_string(static_cast<int>(err_)) + ")";
  }
  
private:
  GLenum err_;
};

class SDLException : public Exception {
public:
  SDLException() : Exception(SDL_GetError()) {
  }

  std::string toString() const override {
    return "SDLException: "s + msg_;
  }
};

class TTFException : public Exception {
public:
  TTFException() : Exception(TTF_GetError()) {
  }

  std::string toString() const override {
    return "TTFException: "s + msg_;
  }
};

static void checkGlError() {
  GLenum err;
  if ((err = glGetError()) != GL_NO_ERROR)
    throw GLException(err);
}

static std::string fileToString(std::string const& name) {
  std::FILE *file = std::fopen(name.c_str(), "r");
  if (!file) {
    throw POSIXException(errno);
  }

  std::string ret;
  char buf[512];
  std::size_t p;
  while((p = std::fread(buf, 1, 511, file)) > 0) {
    buf[p] = '\0';
    ret.append(buf);
  }
  if (!std::feof(file)) {
    std::fclose(file);
    throw POSIXException(errno);
  }

  std::fclose(file);
  return ret;
}

enum class VAFormats {
  Vertex,
    VertexTexcoord,
    VertexNormal,
    VertexNormalTexcoord
    };


// Some helpers to C++11-ify SDL

struct SDLSurfaceDeleter {
  void operator()(SDL_Surface* ptr) const
  {
    SDL_FreeSurface(ptr);
  }
};

using SDLSurfaceUPtr = std::unique_ptr<SDL_Surface, SDLSurfaceDeleter>;

class SDLSurfaceScopedLock {
public:
  SDLSurfaceScopedLock(SDL_Surface *surf) : surf_(surf) {
    if (SDL_MUSTLOCK(surf_))
      if (SDL_LockSurface(surf_) != 0)
	throw SDLException{};
  }

  SDLSurfaceScopedLock(SDLSurfaceUPtr& surf) : surf_(surf.get()) {
    if (SDL_MUSTLOCK(surf_))
      if (SDL_LockSurface(surf_) != 0)
	throw SDLException{};
  }

  SDLSurfaceScopedLock(SDLSurfaceScopedLock const& copy) = delete;
  SDLSurfaceScopedLock& operator=(SDLSurfaceScopedLock const& copy) = delete;

  ~SDLSurfaceScopedLock() {
    if (surf_ && SDL_MUSTLOCK(surf_))
      SDL_UnlockSurface(surf_);
  }

  void unlock() {
    if (surf_ && SDL_MUSTLOCK(surf_))
      SDL_UnlockSurface(surf_);
    surf_ = nullptr;
  }
  
private:
  SDL_Surface *surf_;
};

static bool operator==(SDL_Color const& a, SDL_Color const& b) {
  return ((a.r == b.r) && (a.g == b.g) && (a.b == b.b) && (a.a == b.a));
}

static bool operator!=(SDL_Color const& a, SDL_Color const& b) {
  return ((a.r != b.r) || (a.g != b.g) || (a.b != b.b) || (a.a != b.a));
}

// Compatibility with C++11 where make_unique was not in std:: yet
using std::make_unique;

#endif