/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2009 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
*/

#include "OgreGLFBORenderTexture.h"
#include "OgreGLPixelFormat.h"
#include "OgreLogManager.h"
#include "OgreStringConverter.h"
#include "OgreRoot.h"
#include "OgreGLHardwarePixelBuffer.h"
#include "OgreGLFBOMultiRenderTarget.h"

namespace Ogre {

//-----------------------------------------------------------------------------    
    GLFBORenderTexture::GLFBORenderTexture(GLFBOManager *manager, const String &name,
        const GLSurfaceDesc &target, bool writeGamma, uint fsaa):
        GLRenderTexture(name, target, writeGamma, fsaa),
        mFB(manager, fsaa)
    {
        // Bind target to surface 0 and initialise
        mFB.bindSurface(0, target);
        // Get attributes
        mWidth = mFB.getWidth();
        mHeight = mFB.getHeight();
    }

    void GLFBORenderTexture::getCustomAttribute(const String& name, void* pData)
    {
        if(name=="FBO")
        {
            *static_cast<GLFrameBufferObject **>(pData) = &mFB;
        }
    }

	void GLFBORenderTexture::swapBuffers(bool waitForVSync)
	{
		mFB.swapBuffers();
	}
   
/// Size of probe texture
#define PROBE_SIZE 16

/// Stencil and depth formats to be tried
static const GLenum stencilFormats[] =
{
    GL_NONE,                    // No stencil
    GL_STENCIL_INDEX1_EXT,
    GL_STENCIL_INDEX4_EXT,
    GL_STENCIL_INDEX8_EXT,
    GL_STENCIL_INDEX16_EXT
};
static const size_t stencilBits[] =
{
    0, 1, 4, 8, 16
};
#define STENCILFORMAT_COUNT (sizeof(stencilFormats)/sizeof(GLenum))

static const GLenum depthFormats[] =
{
    GL_NONE,
    GL_DEPTH_COMPONENT16,
    GL_DEPTH_COMPONENT24,    // Prefer 24 bit depth
    GL_DEPTH_COMPONENT32,
    GL_DEPTH24_STENCIL8_EXT // packed depth / stencil
};
static const size_t depthBits[] =
{
    0,16,24,32,24
};
#define DEPTHFORMAT_COUNT (sizeof(depthFormats)/sizeof(GLenum))

	GLFBOManager::GLFBOManager(bool atimode):
		mATIMode(atimode)
    {
        detectFBOFormats();
        
        glGenFramebuffersEXT(1, &mTempFBO);
    }

	GLFBOManager::~GLFBOManager()
	{
		if(!mRenderBufferMap.empty())
		{
			LogManager::getSingleton().logMessage("GL: Warning! GLFBOManager destructor called, but not all renderbuffers were released.");
		}
        
        glDeleteFramebuffersEXT(1, &mTempFBO);      
	}

    /** Try a certain FBO format, and return the status. Also sets mDepthRB and mStencilRB.
        @returns true    if this combo is supported
                 false   if this combo is not supported
    */
    GLuint GLFBOManager::_tryFormat(GLenum depthFormat, GLenum stencilFormat)
    {
        GLuint status, depthRB = 0, stencilRB = 0;
        bool failed = false; // flag on GL errors

        if(depthFormat != GL_NONE)
        {
            /// Generate depth renderbuffer
            glGenRenderbuffersEXT(1, &depthRB);
            /// Bind it to FBO
            glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthRB);
            
            /// Allocate storage for depth buffer
            glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, depthFormat,
                                PROBE_SIZE, PROBE_SIZE);
            
            /// Attach depth
            glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
                                    GL_RENDERBUFFER_EXT, depthRB);
        }

        if(stencilFormat != GL_NONE)
        {
            /// Generate stencil renderbuffer
            glGenRenderbuffersEXT(1, &stencilRB);
            /// Bind it to FBO
            glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, stencilRB);
            glGetError(); // NV hack
            /// Allocate storage for stencil buffer
            glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, stencilFormat,
                                PROBE_SIZE, PROBE_SIZE); 
            if(glGetError() != GL_NO_ERROR) // NV hack
                failed = true;
            /// Attach stencil
            glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
                            GL_RENDERBUFFER_EXT, stencilRB);
            if(glGetError() != GL_NO_ERROR) // NV hack
                failed = true;
        }
        
        status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
        /// If status is negative, clean up
        // Detach and destroy
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, 0);
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, 0);
        if (depthRB)
            glDeleteRenderbuffersEXT(1, &depthRB);
        if (stencilRB)
            glDeleteRenderbuffersEXT(1, &stencilRB);
        
        return status == GL_FRAMEBUFFER_COMPLETE_EXT && !failed;
    }
    
    /** Try a certain packed depth/stencil format, and return the status.
        @returns true    if this combo is supported
                 false   if this combo is not supported
    */
    bool GLFBOManager::_tryPackedFormat(GLenum packedFormat)
    {
        GLuint packedRB;
        bool failed = false; // flag on GL errors

        /// Generate renderbuffer
        glGenRenderbuffersEXT(1, &packedRB);

        /// Bind it to FBO
        glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, packedRB);

        /// Allocate storage for buffer
        glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, packedFormat, PROBE_SIZE, PROBE_SIZE);
        glGetError(); // NV hack

        /// Attach depth
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT,
            GL_RENDERBUFFER_EXT, packedRB);
        if(glGetError() != GL_NO_ERROR) // NV hack
            failed = true;

        /// Attach stencil
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT,
            GL_RENDERBUFFER_EXT, packedRB);
        if(glGetError() != GL_NO_ERROR) // NV hack
            failed = true;

        GLuint status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

        /// Detach and destroy
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, 0);
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, 0);
        glDeleteRenderbuffersEXT(1, &packedRB);

        return status == GL_FRAMEBUFFER_COMPLETE_EXT && !failed;
    }

    /** Detect which internal formats are allowed as RTT
        Also detect what combinations of stencil and depth are allowed with this internal
        format.
    */
    void GLFBOManager::detectFBOFormats()
    {
        // Try all formats, and report which ones work as target
        GLuint fb, tid;
        GLint old_drawbuffer, old_readbuffer;
        GLenum target = GL_TEXTURE_2D;

        glGetIntegerv (GL_DRAW_BUFFER, &old_drawbuffer);
        glGetIntegerv (GL_READ_BUFFER, &old_readbuffer);

        for(size_t x=0; x<PF_COUNT; ++x)
        {
            mProps[x].valid = false;

			// Fetch GL format token
			GLenum fmt = GLPixelUtil::getGLInternalFormat((PixelFormat)x);
            if(fmt == GL_NONE && x!=0)
                continue;

			// No test for compressed formats
			if(PixelUtil::isCompressed((PixelFormat)x))
				continue;

			// Buggy ATI cards *crash* on non-RGB(A) formats
			int depths[4];
			PixelUtil::getBitDepths((PixelFormat)x, depths);
			if(fmt!=GL_NONE && mATIMode && (!depths[0] || !depths[1] || !depths[2]))
				continue;

            // Create and attach framebuffer
            glGenFramebuffersEXT(1, &fb);
            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
            if (fmt!=GL_NONE)
            {
				// Create and attach texture
				glGenTextures(1, &tid);
				glBindTexture(target, tid);
				
                // Set some default parameters so it won't fail on NVidia cards         
				if (GLEW_VERSION_1_2)
					glTexParameteri(target, GL_TEXTURE_MAX_LEVEL, 0);
                glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
                glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
                glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
                glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
                            
				glTexImage2D(target, 0, fmt, PROBE_SIZE, PROBE_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
				glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
                                target, tid, 0);
            }
			else
			{
				// Draw to nowhere -- stencil/depth only
				glDrawBuffer(GL_NONE);
				glReadBuffer(GL_NONE);
			}
            // Check status
            GLuint status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);

			// Ignore status in case of fmt==GL_NONE, because no implementation will accept
			// a buffer without *any* attachment. Buffers with only stencil and depth attachment
			// might still be supported, so we must continue probing.
            if(fmt == GL_NONE || status == GL_FRAMEBUFFER_COMPLETE_EXT)
            {
                mProps[x].valid = true;
				StringUtil::StrStreamType str;
				str << "FBO " << PixelUtil::getFormatName((PixelFormat)x) 
					<< " depth/stencil support: ";

                // For each depth/stencil formats
                for (size_t depth = 0; depth < DEPTHFORMAT_COUNT; ++depth)
                {
                    if (depthFormats[depth] != GL_DEPTH24_STENCIL8_EXT)
                    {
                        // General depth/stencil combination

                        for (size_t stencil = 0; stencil < STENCILFORMAT_COUNT; ++stencil)
                        {
                            //StringUtil::StrStreamType l;
                            //l << "Trying " << PixelUtil::getFormatName((PixelFormat)x) 
                            //	<< " D" << depthBits[depth] 
                            //	<< "S" << stencilBits[stencil];
                            //LogManager::getSingleton().logMessage(l.str());

                            if (_tryFormat(depthFormats[depth], stencilFormats[stencil]))
                            {
                                /// Add mode to allowed modes
                                str << "D" << depthBits[depth] << "S" << stencilBits[stencil] << " ";
                                FormatProperties::Mode mode;
                                mode.depth = depth;
                                mode.stencil = stencil;
                                mProps[x].modes.push_back(mode);
                            }
                        }
                    }
                    else
                    {
                        // Packed depth/stencil format

// #if OGRE_PLATFORM == OGRE_PLATFORM_LINUX
// It now seems as if this workaround now *breaks* nvidia cards on Linux with the 169.12 drivers on Linux
#if 0
                        // Only query packed depth/stencil formats for 32-bit
                        // non-floating point formats (ie not R32!) 
                        // Linux nVidia driver segfaults if you query others
                        if (PixelUtil::getNumElemBits((PixelFormat)x) != 32 ||
                            PixelUtil::isFloatingPoint((PixelFormat)x))
                        {
                            continue;
                        }
#endif

                        if (_tryPackedFormat(depthFormats[depth]))
                        {
                            /// Add mode to allowed modes
                            str << "Packed-D" << depthBits[depth] << "S" << 8 << " ";
                            FormatProperties::Mode mode;
                            mode.depth = depth;
                            mode.stencil = 0;   // unuse
                            mProps[x].modes.push_back(mode);
                        }
                    }
                }

                LogManager::getSingleton().logMessage(str.str());

            }
            // Delete texture and framebuffer
            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
            glDeleteFramebuffersEXT(1, &fb);
			
			// Workaround for NVIDIA / Linux 169.21 driver problem
			// see http://www.ogre3d.org/phpBB2/viewtopic.php?t=38037&start=25
			glFinish();
			
            if (fmt!=GL_NONE)
                glDeleteTextures(1, &tid);
        }

        // It seems a bug in nVidia driver: glBindFramebufferEXT should restore
        // draw and read buffers, but in some unclear circumstances it won't.
        glDrawBuffer(old_drawbuffer);
        glReadBuffer(old_readbuffer);

		String fmtstring;
        for(size_t x=0; x<PF_COUNT; ++x)
        {
            if(mProps[x].valid)
                fmtstring += PixelUtil::getFormatName((PixelFormat)x)+" ";
        }
        LogManager::getSingleton().logMessage("[GL] : Valid FBO targets " + fmtstring);
    }
    void GLFBOManager::getBestDepthStencil(GLenum internalFormat, GLenum *depthFormat, GLenum *stencilFormat)
    {
        const FormatProperties &props = mProps[internalFormat];
        /// Decide what stencil and depth formats to use
        /// [best supported for internal format]
        size_t bestmode=0;
        int bestscore=-1;
        for(size_t mode=0; mode<props.modes.size(); mode++)
        {
#if 0
            /// Always prefer D24S8
            if(stencilBits[props.modes[mode].stencil]==8 &&
                depthBits[props.modes[mode].depth]==24)
            {
                bestmode = mode;
                break;
            }
#endif
            int desirability = 0;
            /// Find most desirable mode
            /// desirability == 0            if no depth, no stencil
            /// desirability == 1000...2000  if no depth, stencil
            /// desirability == 2000...3000  if depth, no stencil
            /// desirability == 3000+        if depth and stencil
            /// beyond this, the total numer of bits (stencil+depth) is maximised
            if(props.modes[mode].stencil)
                desirability += 1000;
            if(props.modes[mode].depth)
                desirability += 2000;
            if(depthBits[props.modes[mode].depth]==24) // Prefer 24 bit for now
                desirability += 500;
			if(depthFormats[props.modes[mode].depth]==GL_DEPTH24_STENCIL8_EXT) // Prefer 24/8 packed 
				desirability += 5000;
            desirability += stencilBits[props.modes[mode].stencil] + depthBits[props.modes[mode].depth];
            
            if(desirability>bestscore)
            {
                bestscore = desirability;
                bestmode = mode;
            }
        }
        *depthFormat = depthFormats[props.modes[bestmode].depth];
        *stencilFormat = stencilFormats[props.modes[bestmode].stencil];
    }

    GLFBORenderTexture *GLFBOManager::createRenderTexture(const String &name, 
		const GLSurfaceDesc &target, bool writeGamma, uint fsaa)
    {
        GLFBORenderTexture *retval = new GLFBORenderTexture(this, name, target, writeGamma, fsaa);
        return retval;
    }
	MultiRenderTarget *GLFBOManager::createMultiRenderTarget(const String & name)
	{
		return new GLFBOMultiRenderTarget(this, name);
	}

    void GLFBOManager::bind(RenderTarget *target)
    {
        /// Check if the render target is in the rendertarget->FBO map
        GLFrameBufferObject *fbo = 0;
        target->getCustomAttribute("FBO", &fbo);
        if(fbo)
            fbo->bind();
        else
            // Old style context (window/pbuffer) or copying render texture
            glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
    }
    
    GLSurfaceDesc GLFBOManager::requestRenderBuffer(GLenum format, size_t width, size_t height, uint fsaa)
    {
        GLSurfaceDesc retval;
        retval.buffer = 0; // Return 0 buffer if GL_NONE is requested
        if(format != GL_NONE)
        {
            RBFormat key(format, width, height, fsaa);
            RenderBufferMap::iterator it = mRenderBufferMap.find(key);
            if(it != mRenderBufferMap.end())
            {
                retval.buffer = it->second.buffer;
                retval.zoffset = 0;
				retval.numSamples = fsaa;
                // Increase refcount
                ++it->second.refcount;
            }
            else
            {
                // New one
                GLRenderBuffer *rb = new GLRenderBuffer(format, width, height, fsaa);
                mRenderBufferMap[key] = RBRef(rb);
                retval.buffer = rb;
                retval.zoffset = 0;
				retval.numSamples = fsaa;
            }
        }
        //std::cerr << "Requested renderbuffer with format " << std::hex << format << std::dec << " of " << width << "x" << height << " :" << retval.buffer << std::endl;
        return retval;
    }
    //-----------------------------------------------------------------------
    void GLFBOManager::requestRenderBuffer(const GLSurfaceDesc &surface)
    {
        if(surface.buffer == 0)
            return;
        RBFormat key(surface.buffer->getGLFormat(), surface.buffer->getWidth(), surface.buffer->getHeight(), surface.numSamples);
        RenderBufferMap::iterator it = mRenderBufferMap.find(key);
        assert(it != mRenderBufferMap.end());
        if (it != mRenderBufferMap.end())   // Just in case
        {
            assert(it->second.buffer == surface.buffer);
            // Increase refcount
            ++it->second.refcount;
        }
    }
    //-----------------------------------------------------------------------
    void GLFBOManager::releaseRenderBuffer(const GLSurfaceDesc &surface)
    {
        if(surface.buffer == 0)
            return;
        RBFormat key(surface.buffer->getGLFormat(), surface.buffer->getWidth(), surface.buffer->getHeight(), surface.numSamples);
        RenderBufferMap::iterator it = mRenderBufferMap.find(key);
        if(it != mRenderBufferMap.end())
		{
			// Decrease refcount
			--it->second.refcount;
			if(it->second.refcount==0)
			{
				// If refcount reaches zero, delete buffer and remove from map
				delete it->second.buffer;
				mRenderBufferMap.erase(it);
				//std::cerr << "Destroyed renderbuffer of format " << std::hex << key.format << std::dec
				//        << " of " << key.width << "x" << key.height << std::endl;
			}
		}
    }
}
