daedalus/Source/SysGL/Graphics/GraphicsContextGL.cpp

#include "Base/Types.h"

#include <stdio.h>

#include "SysGL/GL.h"
#include <SDL2/SDL_ttf.h>
#include <iostream>

#include "Graphics/GraphicsContext.h"

#include "Graphics/ColourValue.h"
#include "UI/DrawText.h"

#include "UI/Menu.h"

SDL_Window * gWindow = nullptr;
SDL_Renderer * gSdlRenderer = nullptr;
SDL_GLContext gContext = nullptr;

extern void HandleEndOfFrame();

class GraphicsContextGL : public CGraphicsContext
{
public:
	virtual ~GraphicsContextGL();


	virtual bool Initialise();
	virtual bool IsInitialised() const { return true; }

	virtual void ClearAllSurfaces();
	virtual void ClearZBuffer();
	virtual void ClearColBuffer(const c32 & colour);
	virtual void ClearToBlack();
	virtual void ClearColBufferAndDepth(const c32 & colour);
	virtual	void BeginFrame();
	virtual void EndFrame();
	virtual void UpdateFrame( bool wait_for_vbl );

	virtual void GetScreenSize(u32 * width, u32 * height) const;
	virtual void ViewportType(u32 * width, u32 * height) const;

	virtual void SetDebugScreenTarget( ETargetSurface buffer [[maybe_unused]] ) {}
	virtual void DumpNextScreen() {}
	virtual void DumpScreenShot() {}
	virtual void UItoGL();
};

template<> bool CSingleton< CGraphicsContext >::Create()
{
	DAEDALUS_ASSERT_Q(mpInstance == nullptr);

	mpInstance = std::make_shared<GraphicsContextGL>();
	return mpInstance->Initialise();
}


GraphicsContextGL::~GraphicsContextGL()
{
	SDL_DestroyWindow(gWindow);
	gWindow = NULL;
	SDL_Quit();
}


extern bool initgl();
bool GraphicsContextGL::Initialise()
{

	//Initialize SDL
	if( SDL_Init( SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_EVENTS | SDL_INIT_GAMECONTROLLER ) < 0 )
	{
		printf( "SDL could not initialize! SDL Error: %s\n", SDL_GetError() );
		return false;
	}

	if (TTF_Init() < 0)
	{
		printf( "SDL could not initialize TTF Font! SDL Error: %s\n", SDL_GetError() );
		return false;
	}


    // Decide GL+GLSL versions

#if defined(__APPLE__)
    // GL 3.2 Core + GLSL 150
    const char* glsl_version = "#version 150";
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_FORWARD_COMPATIBLE_FLAG); // Always required on Mac
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
#else
       // Simplified context creation
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_COMPATIBILITY);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
#endif

	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);


	//Create window
	gWindow = SDL_CreateWindow( "Daedalus", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL | SDL_WINDOW_ALLOW_HIGHDPI);

	//Create context
	gContext = SDL_GL_CreateContext( gWindow );

	SDL_GL_MakeCurrent(gWindow, gContext);

	SDL_GL_SetSwapInterval(1);

	GLenum err = glewInit();
	if (err != GLEW_OK || !GLEW_VERSION_3_2)
	{
		SDL_DestroyWindow(gWindow);
		gWindow = NULL;
		//SDL_Quit();
		return false;
	}

	CDrawText::Initialise();

	//ClearColBufferAndDepth(0,0,0,0);
	UpdateFrame(false);
	return initgl();
}

void GraphicsContextGL::UItoGL()
{
    if (gSdlRenderer != nullptr)
    {
        SDL_RenderPresent(gSdlRenderer);
        SDL_RenderFlush(gSdlRenderer);
        SDL_DestroyRenderer(gSdlRenderer);
        gSdlRenderer = nullptr;

        // If you destroyed the window, re-initialize context
        if (gWindow)
        {
            SDL_DestroyWindow(gWindow);
            SDL_GL_DeleteContext(gContext);
            gContext = nullptr;
            gWindow = nullptr;
        }
        GraphicsContextGL::Initialise();
    }
}

void GraphicsContextGL::GetScreenSize(u32 * width, u32 * height) const
{
	int window_width, window_height;
	SDL_GL_GetDrawableSize(gWindow, &window_width, &window_height);

	*width  = window_width;
	*height = window_height;
}

void GraphicsContextGL::ViewportType(u32 * width, u32 * height) const
{
	GetScreenSize(width, height);
}

void GraphicsContextGL::ClearAllSurfaces()
{
	// FIXME: this should clear/flip a couple of times to ensure the front and backbuffers are cleared.
	// Not sure if it's necessary...
	GraphicsContextGL::UItoGL();
	ClearToBlack();
}

void GraphicsContextGL::ClearToBlack()
{
	glDepthMask(GL_TRUE);
	glClearDepth( 1.0f );
	glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
}

void GraphicsContextGL::ClearZBuffer()
{
	glDepthMask(GL_TRUE);
	glClearDepth( 1.0f );
	glClear( GL_DEPTH_BUFFER_BIT );
}

void GraphicsContextGL::ClearColBuffer(const c32 & colour)
{
	glClearColor( colour.GetRf(), colour.GetGf(), colour.GetBf(), colour.GetAf() );
	glClear( GL_COLOR_BUFFER_BIT );
}

void GraphicsContextGL::ClearColBufferAndDepth(const c32 & colour)
{
	glDepthMask(GL_TRUE);
	glClearDepth( 1.0f );
	glClearColor( colour.GetRf(), colour.GetGf(), colour.GetBf(), colour.GetAf() );
	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
}

void GraphicsContextGL::BeginFrame()
{
	// Get window size (may be different than the requested size)
	u32 width, height;
	GetScreenSize(&width, &height);

	// Special case: avoid division by zero below
	height = height > 0 ? height : 1;

	glViewport( 0, 0, width, height );
	glScissor( 0, 0, width, height );
}

void GraphicsContextGL::EndFrame()
{
	HandleEndOfFrame();
}

void GraphicsContextGL::UpdateFrame( bool wait_for_vbl [[maybe_unused]] )
{
	glBindFramebuffer(GL_FRAMEBUFFER, 0);

	if (gSdlRenderer == nullptr) {
		SDL_GL_SwapWindow(gWindow);
	}

	
//	if( gCleanSceneEnabled ) //TODO: This should be optional
//	{
	//	ClearColBuffer( c32(0xff000000) ); // ToDo : Use gFillColor instead?
	//}
}