/*
* cocos2d-x   http://www.cocos2d-x.org
*
* Copyright (c) 2010-2014 - cocos2d-x community
*
* Portions Copyright (c) Microsoft Open Technologies, Inc.
* All Rights Reserved
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and limitations under the License.
*/

#include "OpenGLES.h"
using namespace Platform;
using namespace Windows::UI::Xaml::Controls;
using namespace Windows::Foundation;
using namespace Windows::Foundation::Collections;

OpenGLES::OpenGLES() :
    mEglConfig(nullptr),
    mEglDisplay(EGL_NO_DISPLAY),
    mEglContext(EGL_NO_CONTEXT)
{
    Initialize();
}

OpenGLES::~OpenGLES()
{
    Cleanup();
}

void OpenGLES::Initialize()
{
    const EGLint configAttributes[] = 
    {
        EGL_RED_SIZE, 8,
        EGL_GREEN_SIZE, 8,
        EGL_BLUE_SIZE, 8,
        EGL_ALPHA_SIZE, 8,
        EGL_DEPTH_SIZE, 8,
        EGL_STENCIL_SIZE, 8,
        EGL_NONE
    };

    const EGLint contextAttributes[] = 
    { 
        EGL_CONTEXT_CLIENT_VERSION, 2, 
        EGL_NONE
    };

    const EGLint defaultDisplayAttributes[] =
    {
        // These are the default display attributes, used to request ANGLE's D3D11 renderer.
        // eglInitialize will only succeed with these attributes if the hardware supports D3D11 Feature Level 10_0+.
        EGL_PLATFORM_ANGLE_TYPE_ANGLE, EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE,

        // EGL_ANGLE_DISPLAY_ALLOW_RENDER_TO_BACK_BUFFER is an optimization that can have large performance benefits on mobile devices.
        // Its syntax is subject to change, though. Please update your Visual Studio templates if you experience compilation issues with it.
        EGL_ANGLE_DISPLAY_ALLOW_RENDER_TO_BACK_BUFFER, EGL_TRUE, 
        EGL_NONE,
    };
    
    const EGLint fl9_3DisplayAttributes[] =
    {
        // These can be used to request ANGLE's D3D11 renderer, with D3D11 Feature Level 9_3.
        // These attributes are used if the call to eglInitialize fails with the default display attributes.
        EGL_PLATFORM_ANGLE_TYPE_ANGLE, EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE,
        EGL_PLATFORM_ANGLE_MAX_VERSION_MAJOR_ANGLE, 9,
        EGL_PLATFORM_ANGLE_MAX_VERSION_MINOR_ANGLE, 3,
        EGL_ANGLE_DISPLAY_ALLOW_RENDER_TO_BACK_BUFFER, EGL_TRUE, 
        EGL_NONE,
    };

    const EGLint warpDisplayAttributes[] =
    {
        // These attributes can be used to request D3D11 WARP.
        // They are used if eglInitialize fails with both the default display attributes and the 9_3 display attributes.
        EGL_PLATFORM_ANGLE_TYPE_ANGLE, EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE,
        EGL_PLATFORM_ANGLE_USE_WARP_ANGLE, EGL_TRUE,
        EGL_ANGLE_DISPLAY_ALLOW_RENDER_TO_BACK_BUFFER, EGL_TRUE, 
        EGL_NONE,
    };
    
    EGLConfig config = NULL;

    // eglGetPlatformDisplayEXT is an alternative to eglGetDisplay. It allows us to pass in display attributes, used to configure D3D11.
    PFNEGLGETPLATFORMDISPLAYEXTPROC eglGetPlatformDisplayEXT = reinterpret_cast<PFNEGLGETPLATFORMDISPLAYEXTPROC>(eglGetProcAddress("eglGetPlatformDisplayEXT"));
    if (!eglGetPlatformDisplayEXT)
    {
        throw Exception::CreateException(E_FAIL, L"Failed to get function eglGetPlatformDisplayEXT");
    }

    //
    // To initialize the display, we make three sets of calls to eglGetPlatformDisplayEXT and eglInitialize, with varying 
    // parameters passed to eglGetPlatformDisplayEXT:
    // 1) The first calls uses "defaultDisplayAttributes" as a parameter. This corresponds to D3D11 Feature Level 10_0+.
    // 2) If eglInitialize fails for step 1 (e.g. because 10_0+ isn't supported by the default GPU), then we try again 
    //    using "fl9_3DisplayAttributes". This corresponds to D3D11 Feature Level 9_3.
    // 3) If eglInitialize fails for step 2 (e.g. because 9_3+ isn't supported by the default GPU), then we try again 
    //    using "warpDisplayAttributes".  This corresponds to D3D11 Feature Level 11_0 on WARP, a D3D11 software rasterizer.
    //
    // Note: On Windows Phone, we #ifdef out the first set of calls to eglPlatformDisplayEXT and eglInitialize.
    //       Windows Phones devices only support D3D11 Feature Level 9_3, but the Windows Phone emulator supports 11_0+.
    //       We use this #ifdef to limit the Phone emulator to Feature Level 9_3, making it behave more like
    //       real Windows Phone devices.
    //       If you wish to test Feature Level 10_0+ in the Windows Phone emulator then you should remove this #ifdef.
    //
    
#if (WINAPI_FAMILY != WINAPI_FAMILY_PHONE_APP)
    // This tries to initialize EGL to D3D11 Feature Level 10_0+. See above comment for details.
    mEglDisplay = eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, defaultDisplayAttributes);
    if (mEglDisplay == EGL_NO_DISPLAY)
    {
        throw Exception::CreateException(E_FAIL, L"Failed to get EGL display");
    }

    if (eglInitialize(mEglDisplay, NULL, NULL) == EGL_FALSE)
#endif    
    {
        // This tries to initialize EGL to D3D11 Feature Level 9_3, if 10_0+ is unavailable (e.g. on Windows Phone, or certain Windows tablets).
        mEglDisplay = eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, fl9_3DisplayAttributes);
        if (mEglDisplay == EGL_NO_DISPLAY)
        {
            throw Exception::CreateException(E_FAIL, L"Failed to get EGL display");
        }

        if (eglInitialize(mEglDisplay, NULL, NULL) == EGL_FALSE)
        {
            // This initializes EGL to D3D11 Feature Level 11_0 on WARP, if 9_3+ is unavailable on the default GPU (e.g. on Surface RT).
            mEglDisplay = eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE, EGL_DEFAULT_DISPLAY, warpDisplayAttributes);
            if (mEglDisplay == EGL_NO_DISPLAY)
            {
                throw Exception::CreateException(E_FAIL, L"Failed to get EGL display");
            }

            if (eglInitialize(mEglDisplay, NULL, NULL) == EGL_FALSE)
            {
                // If all of the calls to eglInitialize returned EGL_FALSE then an error has occurred.
                throw Exception::CreateException(E_FAIL, L"Failed to initialize EGL");
            }
        }
    }

    EGLint numConfigs = 0;
    if ((eglChooseConfig(mEglDisplay, configAttributes, &mEglConfig, 1, &numConfigs) == EGL_FALSE) || (numConfigs == 0))
    {
        throw Exception::CreateException(E_FAIL, L"Failed to choose first EGLConfig");
    }

    mEglContext = eglCreateContext(mEglDisplay, mEglConfig, EGL_NO_CONTEXT, contextAttributes);
    if (mEglContext == EGL_NO_CONTEXT)
    {
        throw Exception::CreateException(E_FAIL, L"Failed to create EGL context");
    }
}

void OpenGLES::Cleanup()
{
    if (mEglDisplay != EGL_NO_DISPLAY && mEglContext != EGL_NO_CONTEXT)
    {
        eglDestroyContext(mEglDisplay, mEglContext);
        mEglContext = EGL_NO_CONTEXT;
    }

    if (mEglDisplay != EGL_NO_DISPLAY)
    {
        eglTerminate(mEglDisplay);
        mEglDisplay = EGL_NO_DISPLAY;
    }
}

void OpenGLES::Reset()
{
    Cleanup();
    Initialize();
}

EGLSurface OpenGLES::CreateSurface(SwapChainPanel^ panel, const Size* renderSurfaceSize)
{
    if (!panel)
    {
        throw Exception::CreateException(E_INVALIDARG, L"SwapChainPanel parameter is invalid");
    }

    EGLSurface surface = EGL_NO_SURFACE;

    const EGLint surfaceAttributes[] =
    {
        // EGL_ANGLE_SURFACE_RENDER_TO_BACK_BUFFER is part of the same optimization as EGL_ANGLE_DISPLAY_ALLOW_RENDER_TO_BACK_BUFFER (see above).
        // If you have compilation issues with it then please update your Visual Studio templates.
        EGL_ANGLE_SURFACE_RENDER_TO_BACK_BUFFER, EGL_TRUE,
        EGL_NONE
    };
    
    // Create a PropertySet and initialize with the EGLNativeWindowType.
    PropertySet^ surfaceCreationProperties = ref new PropertySet();
    surfaceCreationProperties->Insert(ref new String(EGLNativeWindowTypeProperty), panel);

    // If a render surface size is specified, add it to the surface creation properties
    if (renderSurfaceSize != nullptr)
    {
        surfaceCreationProperties->Insert(ref new String(EGLRenderSurfaceSizeProperty), PropertyValue::CreateSize(*renderSurfaceSize));
    }

    surface = eglCreateWindowSurface(mEglDisplay, mEglConfig, reinterpret_cast<IInspectable*>(surfaceCreationProperties), surfaceAttributes);
    if (surface == EGL_NO_SURFACE)
    {
        throw Exception::CreateException(E_FAIL, L"Failed to create EGL surface");
    }

    return surface;
}

void OpenGLES::DestroySurface(const EGLSurface surface)
{
    if (mEglDisplay != EGL_NO_DISPLAY && surface != EGL_NO_SURFACE)
    {
        eglDestroySurface(mEglDisplay, surface);
    }
}

void OpenGLES::MakeCurrent(const EGLSurface surface)
{
    if (eglMakeCurrent(mEglDisplay, surface, surface, mEglContext) == EGL_FALSE)
    {
        throw Exception::CreateException(E_FAIL, L"Failed to make EGLSurface current");
    }
}

EGLBoolean OpenGLES::SwapBuffers(const EGLSurface surface)
{
    return (eglSwapBuffers(mEglDisplay, surface));
}