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#include "Qt3DSRendererUtil.h"
#include "Qt3DSRenderResourceBufferObjects.h"
#include "Qt3DSRenderResourceTexture2D.h"

using namespace qt3ds::render;

void CRendererUtil::ResolveMutisampleFBOColorOnly(IResourceManager &inManager,
                                                  CResourceTexture2D &ioResult,
                                                  NVRenderContext &inRenderContext, QT3DSU32 inWidth,
                                                  QT3DSU32 inHeight,
                                                  NVRenderTextureFormats::Enum inColorFormat,
                                                  NVRenderFrameBuffer &inSourceFBO)
{
    // create resolve FBO
    CResourceFrameBuffer theResolveFB(inManager);
    // Allocates the frame buffer which has the side effect of setting the current render target to
    // that frame buffer.
    theResolveFB.EnsureFrameBuffer();
    // set copy flags
    qt3ds::render::NVRenderClearFlags copyFlags(NVRenderClearValues::Color);

    // get / create resolve targets and attach
    ioResult.EnsureTexture(inWidth, inHeight, inColorFormat);
    theResolveFB->Attach(NVRenderFrameBufferAttachments::Color0, *ioResult);
    // CN - I don't believe we have to resolve the depth.
    // The reason is we render the depth texture specially unresolved.  So there is no need to
    // resolve
    // the depth prepass texture to anything else.

    // 1. Make resolve buffer be the render target ( already happend )
    // 2. Make the current layer FBO the current read target
    // 3. Do the blit from MSAA to non MSAA

    // 2.
    inRenderContext.SetReadTarget(&inSourceFBO);
    inRenderContext.SetReadBuffer(NVReadFaces::Color0);
    // 3.
    inRenderContext.BlitFramebuffer(0, 0, inWidth, inHeight, 0, 0, inWidth, inHeight, copyFlags,
                                    NVRenderTextureMagnifyingOp::Nearest);
}

void CRendererUtil::ResolveSSAAFBOColorOnly(IResourceManager &inManager,
                                            CResourceTexture2D &ioResult, QT3DSU32 outWidth,
                                            QT3DSU32 outHeight, NVRenderContext &inRenderContext,
                                            QT3DSU32 inWidth, QT3DSU32 inHeight,
                                            NVRenderTextureFormats::Enum inColorFormat,
                                            NVRenderFrameBuffer &inSourceFBO)
{
    // create resolve FBO
    CResourceFrameBuffer theResolveFB(inManager);
    // Allocates the frame buffer which has the side effect of setting the current render target to
    // that frame buffer.
    theResolveFB.EnsureFrameBuffer();
    // set copy flags
    qt3ds::render::NVRenderClearFlags copyFlags(NVRenderClearValues::Color);

    // get / create resolve targets and attach
    ioResult.EnsureTexture(outWidth, outHeight, inColorFormat);
    theResolveFB->Attach(NVRenderFrameBufferAttachments::Color0, *ioResult);
    // CN - I don't believe we have to resolve the depth.
    // The reason is we render the depth texture specially unresolved.  So there is no need to
    // resolve
    // the depth prepass texture to anything else.

    // 1. Make resolve buffer be the render target ( already happend )
    // 2. Make the current layer FBO the current read target
    // 3. Do the blit from High res to low res buffer

    // 2.
    inRenderContext.SetReadTarget(&inSourceFBO);
    inRenderContext.SetReadBuffer(NVReadFaces::Color0);
    // 3.
    inRenderContext.BlitFramebuffer(0, 0, inWidth, inHeight, 0, 0, outWidth, outHeight, copyFlags,
                                    NVRenderTextureMagnifyingOp::Linear);
}

void CRendererUtil::GetSSAARenderSize(QT3DSU32 inWidth, QT3DSU32 inHeight, QT3DSU32 &outWidth,
                                      QT3DSU32 &outHeight)
{
    // we currently double width and height
    outWidth = inWidth * 2;
    outHeight = inHeight * 2;

    // keep aspect ration?
    // clamp to max
    if (outWidth > MAX_SSAA_DIM)
        outWidth = MAX_SSAA_DIM;
    if (outHeight > MAX_SSAA_DIM)
        outHeight = MAX_SSAA_DIM;
}