/************************************************************************************

Filename    :   CAPI_D3D1X_DistortionRenderer.cpp
Content     :   Experimental distortion renderer
Created     :   November 11, 2013
Authors     :   Volga Aksoy, Michael Antonov, Shariq Hashme

Copyright   :   Copyright 2014 Oculus VR, Inc. All Rights reserved.

Licensed under the Oculus VR Rift SDK License Version 3.1 (the "License"); 
you may not use the Oculus VR Rift SDK except in compliance with the License, 
which is provided at the time of installation or download, or which 
otherwise accompanies this software in either electronic or hard copy form.

You may obtain a copy of the License at

http://www.oculusvr.com/licenses/LICENSE-3.1 

Unless required by applicable law or agreed to in writing, the Oculus VR SDK 
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 "CAPI_D3D1X_DistortionRenderer.h"

#include "../../OVR_CAPI_D3D.h"
#include "../../Kernel/OVR_Color.h"

namespace OVR { namespace CAPI { namespace D3D_NS {

#include "../Shaders/Distortion_vs.h"
#include "../Shaders/Distortion_vs_refl.h"
#include "../Shaders/Distortion_ps.h"
#include "../Shaders/Distortion_ps_refl.h"
#include "../Shaders/DistortionChroma_vs.h"
#include "../Shaders/DistortionChroma_vs_refl.h"
#include "../Shaders/DistortionChroma_ps.h"
#include "../Shaders/DistortionChroma_ps_refl.h"
#include "../Shaders/DistortionTimewarp_vs.h"
#include "../Shaders/DistortionTimewarp_vs_refl.h"
#include "../Shaders/DistortionTimewarpChroma_vs.h"
#include "../Shaders/DistortionTimewarpChroma_vs_refl.h"
    
#include "../Shaders/SimpleQuad_vs.h"
#include "../Shaders/SimpleQuad_vs_refl.h"
#include "../Shaders/SimpleQuad_ps.h"
#include "../Shaders/SimpleQuad_ps_refl.h"

// Distortion pixel shader lookup.
//  Bit 0: Chroma Correction
//  Bit 1: Timewarp

enum {
    DistortionVertexShaderBitMask = 3,
    DistortionVertexShaderCount   = DistortionVertexShaderBitMask + 1,
    DistortionPixelShaderBitMask  = 1,
    DistortionPixelShaderCount    = DistortionPixelShaderBitMask + 1
};

struct PrecompiledShader
{
    const unsigned char* ShaderData;
    size_t ShaderSize;
    const ShaderBase::Uniform* ReflectionData;
    size_t ReflectionSize;
};

// Do add a new distortion shader use these macros (with or w/o reflection)
#define PCS_NOREFL(shader) { shader, sizeof(shader), NULL, 0 }
#define PCS_REFL__(shader) { shader, sizeof(shader), shader ## _refl, sizeof( shader ## _refl )/sizeof(*(shader ## _refl)) }


static PrecompiledShader DistortionVertexShaderLookup[DistortionVertexShaderCount] =
{
    PCS_REFL__(Distortion_vs),
    PCS_REFL__(DistortionChroma_vs),
    PCS_REFL__(DistortionTimewarp_vs),
    PCS_REFL__(DistortionTimewarpChroma_vs),
};

static PrecompiledShader DistortionPixelShaderLookup[DistortionPixelShaderCount] =
{
    PCS_NOREFL(Distortion_ps),
    PCS_REFL__(DistortionChroma_ps)
};

void DistortionShaderBitIndexCheck()
{
    OVR_COMPILER_ASSERT(ovrDistortionCap_Chromatic == 1);
    OVR_COMPILER_ASSERT(ovrDistortionCap_TimeWarp  == 2);
}



struct DistortionVertex
{
    Vector2f ScreenPosNDC;
    Vector2f TanEyeAnglesR;
    Vector2f TanEyeAnglesG;
    Vector2f TanEyeAnglesB;
    Color    Col;
};


// Vertex type; same format is used for all shapes for simplicity.
// Shapes are built by adding vertices to Model.
struct Vertex
{
    Vector3f  Pos;
    Color     C;
    float     U, V;	
    Vector3f  Norm;

    Vertex (const Vector3f& p, const Color& c = Color(64,0,0,255), 
        float u = 0, float v = 0, Vector3f n = Vector3f(1,0,0))
        : Pos(p), C(c), U(u), V(v), Norm(n)
    {}
    Vertex(float x, float y, float z, const Color& c = Color(64,0,0,255),
        float u = 0, float v = 0) : Pos(x,y,z), C(c), U(u), V(v)
    { }

    bool operator==(const Vertex& b) const
    {
        return Pos == b.Pos && C == b.C && U == b.U && V == b.V;
    }
};


//----------------------------------------------------------------------------
// ***** D3D1X::DistortionRenderer

DistortionRenderer::DistortionRenderer(ovrHmd hmd, FrameTimeManager& timeManager,
                                       const HMDRenderState& renderState)
    : CAPI::DistortionRenderer(ovrRenderAPI_D3D11, hmd, timeManager, renderState)
{
    EyeTextureSize[0]    = Sizei(0);
    EyeRenderViewport[0] = Recti();
    EyeTextureSize[1]    = Sizei(0);
    EyeRenderViewport[1] = Recti();
}

DistortionRenderer::~DistortionRenderer()
{
    destroy();
}

// static
CAPI::DistortionRenderer* DistortionRenderer::Create(ovrHmd hmd,
                                                     FrameTimeManager& timeManager,
                                                     const HMDRenderState& renderState)
{
    return new DistortionRenderer(hmd, timeManager, renderState);
}


bool DistortionRenderer::Initialize(const ovrRenderAPIConfig* apiConfig,
                                    unsigned distortionCaps)
{
    const ovrD3D1X(Config)* config = (const ovrD3D1X(Config)*)apiConfig;

    if (!config)
    {
        // Cleanup
        pEyeTextures[0].Clear();
        pEyeTextures[1].Clear();
        memset(&RParams, 0, sizeof(RParams));
        return true;
    }

    if (!config->D3D_NS.pDevice || !config->D3D_NS.pBackBufferRT)
        return false;

    RParams.pDevice		   = config->D3D_NS.pDevice;    
    RParams.pContext       = D3DSELECT_10_11(config->D3D_NS.pDevice, config->D3D_NS.pDeviceContext);
    RParams.pBackBufferRT  = config->D3D_NS.pBackBufferRT;
    RParams.pSwapChain     = config->D3D_NS.pSwapChain;
    RParams.RTSize         = config->D3D_NS.Header.RTSize;
    RParams.Multisample    = config->D3D_NS.Header.Multisample;

	GfxState = *new GraphicsState(RParams.pContext);

    DistortionCaps = distortionCaps;

    //DistortionWarper.SetVsync((hmdCaps & ovrHmdCap_NoVSync) ? false : true);

    pEyeTextures[0] = *new Texture(&RParams, Texture_RGBA, Sizei(0),
                                   getSamplerState(Sample_Linear|Sample_ClampBorder));
    pEyeTextures[1] = *new Texture(&RParams, Texture_RGBA, Sizei(0),
                                   getSamplerState(Sample_Linear|Sample_ClampBorder));

    initBuffersAndShaders();

    // Rasterizer state
    D3D1X_(RASTERIZER_DESC) rs;
    memset(&rs, 0, sizeof(rs));
    rs.AntialiasedLineEnable = true;
    rs.CullMode              = D3D1X_(CULL_BACK);    
    rs.DepthClipEnable       = true;
    rs.FillMode              = D3D1X_(FILL_SOLID);
    Rasterizer = NULL;
    RParams.pDevice->CreateRasterizerState(&rs, &Rasterizer.GetRawRef());

	initOverdrive();

    // TBD: Blend state.. not used?
    // We'll want to turn off blending

#if (OVR_D3D_VERSION == 11)
    GpuProfiler.Init(RParams.pDevice, RParams.pContext);
#endif

    return true;
}

void DistortionRenderer::initOverdrive()
{
	if(RState.DistortionCaps & ovrDistortionCap_Overdrive)
	{
		LastUsedOverdriveTextureIndex = 0;

		for (int i = 0; i < NumOverdriveTextures; i++)
		{
			pOverdriveTextures[i] = *new Texture(&RParams, Texture_RGBA, RParams.RTSize,
				getSamplerState(Sample_Linear|Sample_ClampBorder));

			D3D1X_(TEXTURE2D_DESC) dsDesc;
			dsDesc.Width     = RParams.RTSize.w;
			dsDesc.Height    = RParams.RTSize.h;
			dsDesc.MipLevels = 1;
			dsDesc.ArraySize = 1;
			dsDesc.Format    = DXGI_FORMAT_R8G8B8A8_UNORM;
			dsDesc.SampleDesc.Count = 1;
			dsDesc.SampleDesc.Quality = 0;
			dsDesc.Usage     = D3D1X_(USAGE_DEFAULT);
			dsDesc.BindFlags = D3D1X_(BIND_SHADER_RESOURCE) | D3D1X_(BIND_RENDER_TARGET);
			dsDesc.CPUAccessFlags = 0;
			dsDesc.MiscFlags      = 0;

			HRESULT hr = RParams.pDevice->CreateTexture2D(&dsDesc, NULL, &pOverdriveTextures[i]->Tex.GetRawRef());			
			if (FAILED(hr))
			{
				OVR_DEBUG_LOG_TEXT(("Failed to create overdrive texture."));
				// Remove overdrive flag since we failed to create the texture
				LastUsedOverdriveTextureIndex = -1;	// disables feature
				break;
			}

			RParams.pDevice->CreateShaderResourceView(pOverdriveTextures[i]->Tex, NULL, &pOverdriveTextures[i]->TexSv.GetRawRef());
			RParams.pDevice->CreateRenderTargetView(pOverdriveTextures[i]->Tex, NULL, &pOverdriveTextures[i]->TexRtv.GetRawRef());
		}
	}
	else
	{
		LastUsedOverdriveTextureIndex = -1;
	}
}

void DistortionRenderer::SubmitEye(int eyeId, const ovrTexture* eyeTexture)
{
    const ovrD3D1X(Texture)* tex = (const ovrD3D1X(Texture)*)eyeTexture;

    if (eyeTexture)
    {
        // Use tex->D3D_NS.Header.RenderViewport to update UVs for rendering in case they changed.
        // TBD: This may be optimized through some caching. 
        EyeTextureSize[eyeId]    = tex->D3D_NS.Header.TextureSize;
        EyeRenderViewport[eyeId] = tex->D3D_NS.Header.RenderViewport;

        const ovrEyeRenderDesc& erd = RState.EyeRenderDesc[eyeId];

        ovrHmd_GetRenderScaleAndOffset(erd.Fov,
                                       EyeTextureSize[eyeId], EyeRenderViewport[eyeId],
                                       UVScaleOffset[eyeId]);

		if (RState.DistortionCaps & ovrDistortionCap_FlipInput)
		{
			UVScaleOffset[eyeId][0].y = -UVScaleOffset[eyeId][0].y;
			UVScaleOffset[eyeId][1].y = 1.0f - UVScaleOffset[eyeId][1].y;
		}

        pEyeTextures[eyeId]->UpdatePlaceholderTexture(tex->D3D_NS.pTexture, tex->D3D_NS.pSRView,
                                                      tex->D3D_NS.Header.TextureSize);
    }
}

void DistortionRenderer::renderEndFrame()
{
    renderDistortion(pEyeTextures[0], pEyeTextures[1]);
    
    if(RegisteredPostDistortionCallback)
        RegisteredPostDistortionCallback(RParams.pContext);

    if(LatencyTest2Active)
    {
        renderLatencyPixel(LatencyTest2DrawColor);
    }
}

void DistortionRenderer::EndFrame(bool swapBuffers)
{
    // Don't spin if we are explicitly asked not to
    if (RState.DistortionCaps & ovrDistortionCap_TimeWarp &&
        !(RState.DistortionCaps & ovrDistortionCap_ProfileNoTimewarpSpinWaits))
    {
        if (!TimeManager.NeedDistortionTimeMeasurement())
        {
            // Wait for timewarp distortion if it is time and Gpu idle
            FlushGpuAndWaitTillTime(TimeManager.GetFrameTiming().TimewarpPointTime);

            renderEndFrame();
        }
        else
        {
            // If needed, measure distortion time so that TimeManager can better estimate
            // latency-reducing time-warp wait timing.
            WaitUntilGpuIdle();
            double  distortionStartTime = ovr_GetTimeInSeconds();

            renderEndFrame();

            WaitUntilGpuIdle();
            TimeManager.AddDistortionTimeMeasurement(ovr_GetTimeInSeconds() - distortionStartTime);
        }
    }
    else
    {
        renderEndFrame();
    }

    if(LatencyTestActive)
    {
        renderLatencyQuad(LatencyTestDrawColor);
    }

    if (swapBuffers)
    {
        if (RParams.pSwapChain)
        {
            UINT swapInterval = (RState.EnabledHmdCaps & ovrHmdCap_NoVSync) ? 0 : 1;
#ifndef NO_SCREEN_TEAR_HEALING
            if (TimeManager.ScreenTearingReaction())
            {
                swapInterval = 0;
            }
#endif // NO_SCREEN_TEAR_HEALING
            RParams.pSwapChain->Present(swapInterval, 0);
            
            // Force GPU to flush the scene, resulting in the lowest possible latency.
            // It's critical that this flush is *after* present.
			// With the display driver this flush is obsolete and theoretically should
			// be a no-op.
            // Doesn't need to be done if running through the Oculus driver.
            if (RState.OurHMDInfo.InCompatibilityMode &&
                !(RState.DistortionCaps & ovrDistortionCap_ProfileNoTimewarpSpinWaits))
                WaitUntilGpuIdle();
        }
        else
        {
            // TBD: Generate error - swapbuffer option used with null swapchain.
        }
    }
}


void DistortionRenderer::WaitUntilGpuIdle()
{
    // Flush and Stall CPU while waiting for GPU to complete rendering all of the queued draw calls
    D3D1x_QUERY_DESC queryDesc = { D3D1X_(QUERY_EVENT), 0 };
    Ptr<ID3D1xQuery> query;
    BOOL             done = FALSE;

    if (RParams.pDevice->CreateQuery(&queryDesc, &query.GetRawRef()) == S_OK)
    {
        D3DSELECT_10_11(query->End(),
                        RParams.pContext->End(query));

        // GetData will returns S_OK for both done == TRUE or FALSE.
        // Exit on failure to avoid infinite loop.
        do { }
        while(!done &&
              !FAILED(D3DSELECT_10_11(query->GetData(&done, sizeof(BOOL), 0),
                                      RParams.pContext->GetData(query, &done, sizeof(BOOL), 0)))
             );
    }
}

double DistortionRenderer::FlushGpuAndWaitTillTime(double absTime)
{
    RParams.pContext->Flush();
    return WaitTillTime(absTime);
}

void DistortionRenderer::initBuffersAndShaders()
{
    for ( int eyeNum = 0; eyeNum < 2; eyeNum++ )
    {
        // Allocate & generate distortion mesh vertices.
        ovrDistortionMesh meshData;

//        double startT = ovr_GetTimeInSeconds();

        if (!ovrHmd_CreateDistortionMesh( HMD,
                                          RState.EyeRenderDesc[eyeNum].Eye,
                                          RState.EyeRenderDesc[eyeNum].Fov,
                                          RState.DistortionCaps,
                                          &meshData) )
        {
            OVR_ASSERT(false);
            continue;
        }

//        double deltaT = ovr_GetTimeInSeconds() - startT;
//        LogText("GenerateDistortion time = %f\n", deltaT);

        // Now parse the vertex data and create a render ready vertex buffer from it
        DistortionVertex *   pVBVerts    = (DistortionVertex*)OVR_ALLOC ( sizeof(DistortionVertex) * meshData.VertexCount );
        DistortionVertex *   pCurVBVert  = pVBVerts;
        ovrDistortionVertex* pCurOvrVert = meshData.pVertexData;

        for ( unsigned vertNum = 0; vertNum < meshData.VertexCount; vertNum++ )
        {
            pCurVBVert->ScreenPosNDC.x = pCurOvrVert->ScreenPosNDC.x;
            pCurVBVert->ScreenPosNDC.y = pCurOvrVert->ScreenPosNDC.y;
            pCurVBVert->TanEyeAnglesR  = (*(Vector2f*)&pCurOvrVert->TanEyeAnglesR);
            pCurVBVert->TanEyeAnglesG  = (*(Vector2f*)&pCurOvrVert->TanEyeAnglesG);
            pCurVBVert->TanEyeAnglesB  = (*(Vector2f*)&pCurOvrVert->TanEyeAnglesB);

            // Convert [0.0f,1.0f] to [0,255]
			if (DistortionCaps & ovrDistortionCap_Vignette)
				pCurVBVert->Col.R = (uint8_t)( pCurOvrVert->VignetteFactor * 255.99f );
			else
				pCurVBVert->Col.R = 255;

            pCurVBVert->Col.G = pCurVBVert->Col.R;
            pCurVBVert->Col.B = pCurVBVert->Col.R;
            pCurVBVert->Col.A = (uint8_t)( pCurOvrVert->TimeWarpFactor * 255.99f );;
            pCurOvrVert++;
            pCurVBVert++;
        }

        DistortionMeshVBs[eyeNum] = *new Buffer(&RParams);
		DistortionMeshVBs[eyeNum]->Data(Buffer_Vertex | Buffer_ReadOnly, pVBVerts, sizeof(DistortionVertex)* meshData.VertexCount);
        DistortionMeshIBs[eyeNum] = *new Buffer(&RParams);
		DistortionMeshIBs[eyeNum]->Data(Buffer_Index | Buffer_ReadOnly, meshData.pIndexData, (sizeof(INT16)* meshData.IndexCount));

        OVR_FREE ( pVBVerts );
        ovrHmd_DestroyDistortionMesh( &meshData );
    }

    // Uniform buffers
    for(int i = 0; i < Shader_Count; i++)
    {
        UniformBuffers[i] = *new Buffer(&RParams);
        //MaxTextureSet[i] = 0;
    }

    initShaders();
}

void DistortionRenderer::renderDistortion(Texture* leftEyeTexture, Texture* rightEyeTexture)
{

#if (OVR_D3D_VERSION == 10)
	RParams.pContext->GSSetShader(NULL);
#else // d3d 11
	RParams.pContext->HSSetShader(NULL, NULL, 0);
	RParams.pContext->DSSetShader(NULL, NULL, 0);
	RParams.pContext->GSSetShader(NULL, NULL, 0);
#endif

    RParams.pContext->RSSetState(Rasterizer);

	bool overdriveActive = IsOverdriveActive();
	int currOverdriveTextureIndex = -1;

	if(overdriveActive)
	{
		currOverdriveTextureIndex = (LastUsedOverdriveTextureIndex + 1) % NumOverdriveTextures;
        ID3D1xRenderTargetView* distortionRtv = pOverdriveTextures[currOverdriveTextureIndex]->TexRtv.GetRawRef();
        ID3D1xRenderTargetView* mrtRtv[2] = {distortionRtv, RParams.pBackBufferRT};
        RParams.pContext->OMSetRenderTargets(2, mrtRtv, 0);

        RParams.pContext->ClearRenderTargetView(distortionRtv, RState.ClearColor);
    }
    else
    {
        RParams.pContext->OMSetRenderTargets(1, &RParams.pBackBufferRT, 0);
    }

    // Not affected by viewport.
    RParams.pContext->ClearRenderTargetView(RParams.pBackBufferRT, RState.ClearColor);

    setViewport(Recti(0,0, RParams.RTSize.w, RParams.RTSize.h));


    for(int eyeNum = 0; eyeNum < 2; eyeNum++)
    {
		ShaderFill distortionShaderFill(DistortionShader);
        distortionShaderFill.SetTexture(0, eyeNum == 0 ? leftEyeTexture : rightEyeTexture);

        if(RState.DistortionCaps & ovrDistortionCap_HqDistortion)
        {
            static float aaDerivMult = 0.5f;
            DistortionShader->SetUniform1f("AaDerivativeMult", aaDerivMult);
        }
        else
        {
            // 0.0 disables high quality anti-aliasing
            DistortionShader->SetUniform1f("AaDerivativeMultOffset", -1.0f);
        }

		if(overdriveActive)
		{
            distortionShaderFill.SetTexture(1, pOverdriveTextures[LastUsedOverdriveTextureIndex]);
            
            static float overdriveScaleRegularRise = 0.1f;
			static float overdriveScaleRegularFall = 0.05f;	// falling issues are hardly visible            
			DistortionShader->SetUniform2f("OverdriveScales", overdriveScaleRegularRise, overdriveScaleRegularFall);
		}
        else
        {
            // -1.0f disables PLO            
            DistortionShader->SetUniform2f("OverdriveScales", -1.0f, -1.0f);
        }

        distortionShaderFill.SetInputLayout(DistortionVertexIL);

        DistortionShader->SetUniform2f("EyeToSourceUVScale",  UVScaleOffset[eyeNum][0].x, UVScaleOffset[eyeNum][0].y);
        DistortionShader->SetUniform2f("EyeToSourceUVOffset", UVScaleOffset[eyeNum][1].x, UVScaleOffset[eyeNum][1].y);
        
		if (DistortionCaps & ovrDistortionCap_TimeWarp)
		{                       
            ovrMatrix4f timeWarpMatrices[2];
            ovrHmd_GetEyeTimewarpMatrices(HMD, (ovrEyeType)eyeNum,
                                          RState.EyeRenderPoses[eyeNum], timeWarpMatrices);

            // Can feed identity like matrices incase of concern over timewarp calculations
			DistortionShader->SetUniform4x4f("EyeRotationStart", Matrix4f(timeWarpMatrices[0]));
			DistortionShader->SetUniform4x4f("EyeRotationEnd",   Matrix4f(timeWarpMatrices[1]));

            renderPrimitives(&distortionShaderFill, DistortionMeshVBs[eyeNum], DistortionMeshIBs[eyeNum],
                            NULL, 0, (int)DistortionMeshIBs[eyeNum]->GetSize()/2, Prim_Triangles);
		}
        else
        {
            renderPrimitives(&distortionShaderFill, DistortionMeshVBs[eyeNum], DistortionMeshIBs[eyeNum],
                            NULL, 0, (int)DistortionMeshIBs[eyeNum]->GetSize()/2, Prim_Triangles);
        }
    }

    LastUsedOverdriveTextureIndex = currOverdriveTextureIndex;

    // Re-activate to only draw on back buffer
    if(overdriveActive)
    {
        RParams.pContext->OMSetRenderTargets(1, &RParams.pBackBufferRT, 0);
    }
}

void DistortionRenderer::createDrawQuad()
{
    const int numQuadVerts = 4;
    LatencyTesterQuadVB = *new Buffer(&RParams);
    if(!LatencyTesterQuadVB)
    {
        return;
    }

    LatencyTesterQuadVB->Data(Buffer_Vertex, NULL, numQuadVerts * sizeof(Vertex));
    Vertex* vertices = (Vertex*)LatencyTesterQuadVB->Map(0, numQuadVerts * sizeof(Vertex), Map_Discard);
    if(!vertices)
    {
        OVR_ASSERT(false); // failed to lock vertex buffer
        return;
    }

    const float left   = -1.0f;
    const float top    = -1.0f;
    const float right  =  1.0f;
    const float bottom =  1.0f;

    vertices[0] = Vertex(Vector3f(left,  top,    0.0f), Color(255, 255, 255, 255));
    vertices[1] = Vertex(Vector3f(left,  bottom, 0.0f), Color(255, 255, 255, 255));
    vertices[2] = Vertex(Vector3f(right, top,    0.0f), Color(255, 255, 255, 255));
    vertices[3] = Vertex(Vector3f(right, bottom, 0.0f), Color(255, 255, 255, 255));

    LatencyTesterQuadVB->Unmap(vertices);
}

void DistortionRenderer::renderLatencyQuad(unsigned char* latencyTesterDrawColor)
{
    const int numQuadVerts = 4;

    if(!LatencyTesterQuadVB)
    {
        createDrawQuad();
    }
       
    ShaderFill quadFill(SimpleQuadShader);
    quadFill.SetInputLayout(SimpleQuadVertexIL);

    setViewport(Recti(0,0, RParams.RTSize.w, RParams.RTSize.h));

    SimpleQuadShader->SetUniform2f("Scale", 0.3f, 0.3f);
    SimpleQuadShader->SetUniform4f("Color", (float)latencyTesterDrawColor[0] / 255.99f,
                                            (float)latencyTesterDrawColor[0] / 255.99f,
                                            (float)latencyTesterDrawColor[0] / 255.99f,
                                            1.0f);

    for(int eyeNum = 0; eyeNum < 2; eyeNum++)
    {
        SimpleQuadShader->SetUniform2f("PositionOffset", eyeNum == 0 ? -0.5f : 0.5f, 0.0f);    
        renderPrimitives(&quadFill, LatencyTesterQuadVB, NULL, NULL, 0, numQuadVerts, Prim_TriangleStrip);
    }
}

void DistortionRenderer::renderLatencyPixel(unsigned char* latencyTesterPixelColor)
{
    const int numQuadVerts = 4;

    if(!LatencyTesterQuadVB)
    {
        createDrawQuad();
    }
    
    ShaderFill quadFill(SimpleQuadShader);
    quadFill.SetInputLayout(SimpleQuadVertexIL);

    setViewport(Recti(0,0, RParams.RTSize.w, RParams.RTSize.h));

#ifdef OVR_BUILD_DEBUG
    SimpleQuadShader->SetUniform4f("Color", (float)latencyTesterPixelColor[0] / 255.99f,
                                            (float)latencyTesterPixelColor[1] / 255.99f,
                                            (float)latencyTesterPixelColor[2] / 255.99f,
                                            1.0f);

    Vector2f scale(20.0f / RParams.RTSize.w, 20.0f / RParams.RTSize.h); 
#else
    SimpleQuadShader->SetUniform4f("Color", (float)latencyTesterPixelColor[0] / 255.99f,
                                            (float)latencyTesterPixelColor[0] / 255.99f,
                                            (float)latencyTesterPixelColor[0] / 255.99f,
                                            1.0f);

    Vector2f scale(1.0f / RParams.RTSize.w, 1.0f / RParams.RTSize.h); 
#endif
    SimpleQuadShader->SetUniform2f("Scale", scale.x, scale.y);
    SimpleQuadShader->SetUniform2f("PositionOffset", 1.0f-scale.x, 1.0f-scale.y);
    renderPrimitives(&quadFill, LatencyTesterQuadVB, NULL, NULL, 0, numQuadVerts, Prim_TriangleStrip);
}

void DistortionRenderer::renderPrimitives(
                          const ShaderFill* fill,
                          Buffer* vertices, Buffer* indices,
                          Matrix4f* viewMatrix, int offset, int count,
                          PrimitiveType rprim)
{
    OVR_ASSERT(fill->GetInputLayout() != 0);    
    RParams.pContext->IASetInputLayout((ID3D1xInputLayout*)fill->GetInputLayout());    

    if (indices)
    {
        RParams.pContext->IASetIndexBuffer(indices->GetBuffer(), DXGI_FORMAT_R16_UINT, 0);
    }

    ID3D1xBuffer* vertexBuffer = vertices->GetBuffer();
    UINT          vertexStride = sizeof(Vertex);
    UINT          vertexOffset = offset;
    RParams.pContext->IASetVertexBuffers(0, 1, &vertexBuffer, &vertexStride, &vertexOffset);

    ShaderSet* shaders = ((ShaderFill*)fill)->GetShaders();

    ShaderBase*     vshader = ((ShaderBase*)shaders->GetShader(Shader_Vertex));
    unsigned char*  vertexData = vshader->UniformData;
    if (vertexData)
    {
		// TODO: some VSes don't start with StandardUniformData!
		if ( viewMatrix )
		{
			StandardUniformData* stdUniforms = (StandardUniformData*) vertexData;
			stdUniforms->View = viewMatrix->Transposed();
			stdUniforms->Proj = StdUniforms.Proj;
		}
		UniformBuffers[Shader_Vertex]->Data(Buffer_Uniform, vertexData, vshader->UniformsSize);
		vshader->SetUniformBuffer(UniformBuffers[Shader_Vertex]);
    }

    for(int i = Shader_Vertex + 1; i < Shader_Count; i++)
    {
        if (shaders->GetShader(i))
        {
            ((ShaderBase*)shaders->GetShader(i))->UpdateBuffer(UniformBuffers[i]);
            ((ShaderBase*)shaders->GetShader(i))->SetUniformBuffer(UniformBuffers[i]);
        }
    }

    D3D1X_(PRIMITIVE_TOPOLOGY) prim;
    switch(rprim)
    {
    case Prim_Triangles:
        prim = D3D1X_(PRIMITIVE_TOPOLOGY_TRIANGLELIST);
        break;
    case Prim_Lines:
        prim = D3D1X_(PRIMITIVE_TOPOLOGY_LINELIST);
        break;
    case Prim_TriangleStrip:
        prim = D3D1X_(PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);
        break;
    default:
        OVR_ASSERT(0);
        return;
    }
    RParams.pContext->IASetPrimitiveTopology(prim);

    fill->Set(rprim);

    if (indices)
    {
        RParams.pContext->DrawIndexed(count, 0, 0);
    }
    else
    {
        RParams.pContext->Draw(count, 0);
    }
}

void DistortionRenderer::setViewport(const Recti& vp)
{
    D3D1x_VIEWPORT d3dvp;

    d3dvp.Width    = D3DSELECT_10_11(vp.w, (float)vp.w);
    d3dvp.Height   = D3DSELECT_10_11(vp.h, (float)vp.h);
    d3dvp.TopLeftX = D3DSELECT_10_11(vp.x, (float)vp.x);
    d3dvp.TopLeftY = D3DSELECT_10_11(vp.y, (float)vp.y);
    d3dvp.MinDepth = 0;
    d3dvp.MaxDepth = 1;
    RParams.pContext->RSSetViewports(1, &d3dvp);
}




static D3D1X_(INPUT_ELEMENT_DESC) DistortionMeshVertexDesc[] =
{
    {"Position", 0, DXGI_FORMAT_R32G32_FLOAT,   0, 0,   D3D1X_(INPUT_PER_VERTEX_DATA), 0},
    {"TexCoord", 0, DXGI_FORMAT_R32G32_FLOAT,   0, 8,   D3D1X_(INPUT_PER_VERTEX_DATA), 0},
    {"TexCoord", 1, DXGI_FORMAT_R32G32_FLOAT,   0, 16,	D3D1X_(INPUT_PER_VERTEX_DATA), 0},
    {"TexCoord", 2, DXGI_FORMAT_R32G32_FLOAT,   0, 24,	D3D1X_(INPUT_PER_VERTEX_DATA), 0},
    {"Color",    0, DXGI_FORMAT_R8G8B8A8_UNORM, 0, 32,  D3D1X_(INPUT_PER_VERTEX_DATA), 0},
};

static D3D1X_(INPUT_ELEMENT_DESC) SimpleQuadMeshVertexDesc[] =
{
    {"Position", 0, DXGI_FORMAT_R32G32_FLOAT,   0, 0,   D3D1X_(INPUT_PER_VERTEX_DATA), 0},
};

// TODO: this is D3D specific
void DistortionRenderer::initShaders()
{  
    {
        PrecompiledShader vsShaderByteCode = DistortionVertexShaderLookup[DistortionVertexShaderBitMask & DistortionCaps];
        Ptr<D3D_NS::VertexShader> vtxShader = *new D3D_NS::VertexShader(
            &RParams,
            (void*)vsShaderByteCode.ShaderData, vsShaderByteCode.ShaderSize,
            vsShaderByteCode.ReflectionData, vsShaderByteCode.ReflectionSize);

        DistortionVertexIL = NULL;
        ID3D1xInputLayout** objRef = &DistortionVertexIL.GetRawRef();

        HRESULT validate = RParams.pDevice->CreateInputLayout(
            DistortionMeshVertexDesc, sizeof(DistortionMeshVertexDesc) / sizeof(DistortionMeshVertexDesc[0]),
            vsShaderByteCode.ShaderData, vsShaderByteCode.ShaderSize, objRef);
        OVR_UNUSED(validate);

        DistortionShader = *new ShaderSet;
        DistortionShader->SetShader(vtxShader);

        PrecompiledShader psShaderByteCode = DistortionPixelShaderLookup[DistortionPixelShaderBitMask & DistortionCaps];

        Ptr<D3D_NS::PixelShader> ps  = *new D3D_NS::PixelShader(
            &RParams,
            (void*)psShaderByteCode.ShaderData, psShaderByteCode.ShaderSize,
            psShaderByteCode.ReflectionData, psShaderByteCode.ReflectionSize);

        DistortionShader->SetShader(ps);
    }

    {
        Ptr<D3D_NS::VertexShader> vtxShader = *new D3D_NS::VertexShader(
            &RParams,
            (void*)SimpleQuad_vs, sizeof(SimpleQuad_vs),
            SimpleQuad_vs_refl, sizeof(SimpleQuad_vs_refl) / sizeof(SimpleQuad_vs_refl[0]));
            //NULL, 0);

        SimpleQuadVertexIL = NULL;
        ID3D1xInputLayout** objRef   = &SimpleQuadVertexIL.GetRawRef();

        HRESULT validate = RParams.pDevice->CreateInputLayout(
            SimpleQuadMeshVertexDesc, sizeof(SimpleQuadMeshVertexDesc) / sizeof(SimpleQuadMeshVertexDesc[0]),
            (void*)SimpleQuad_vs, sizeof(SimpleQuad_vs), objRef);
        OVR_UNUSED(validate);

        SimpleQuadShader = *new ShaderSet;
        SimpleQuadShader->SetShader(vtxShader);

        Ptr<D3D_NS::PixelShader> ps  = *new D3D_NS::PixelShader(
            &RParams,
            (void*)SimpleQuad_ps, sizeof(SimpleQuad_ps),
            SimpleQuad_ps_refl, sizeof(SimpleQuad_ps_refl) / sizeof(SimpleQuad_ps_refl[0]));

        SimpleQuadShader->SetShader(ps);
    }
}



ID3D1xSamplerState* DistortionRenderer::getSamplerState(int sm)
{
    if (SamplerStates[sm])    
        return SamplerStates[sm];

    D3D1X_(SAMPLER_DESC) ss;
    memset(&ss, 0, sizeof(ss));
    if (sm & Sample_Clamp)    
        ss.AddressU = ss.AddressV = ss.AddressW = D3D1X_(TEXTURE_ADDRESS_CLAMP);    
    else if (sm & Sample_ClampBorder)    
        ss.AddressU = ss.AddressV = ss.AddressW = D3D1X_(TEXTURE_ADDRESS_BORDER);    
    else    
        ss.AddressU = ss.AddressV = ss.AddressW = D3D1X_(TEXTURE_ADDRESS_WRAP);

    if (sm & Sample_Nearest)
    {
        ss.Filter = D3D1X_(FILTER_MIN_MAG_MIP_POINT);
    }
    else if (sm & Sample_Anisotropic)
    {
        ss.Filter = D3D1X_(FILTER_ANISOTROPIC);
        ss.MaxAnisotropy = 8;
    }
    else
    {
        ss.Filter = D3D1X_(FILTER_MIN_MAG_MIP_LINEAR);
    }
    ss.MaxLOD = 15;
    RParams.pDevice->CreateSamplerState(&ss, &SamplerStates[sm].GetRawRef());
    return SamplerStates[sm];
}


void DistortionRenderer::destroy()
{
	for(int eyeNum = 0; eyeNum < 2; eyeNum++)
	{
		DistortionMeshVBs[eyeNum].Clear();
		DistortionMeshIBs[eyeNum].Clear();
	}

	DistortionVertexIL.Clear();

	if (DistortionShader)
    {
        DistortionShader->UnsetShader(Shader_Vertex);
	    DistortionShader->UnsetShader(Shader_Pixel);
	    DistortionShader.Clear();
    }

    LatencyTesterQuadVB.Clear();
}


DistortionRenderer::GraphicsState::GraphicsState(ID3D1xDeviceContext* c)
: context(c)
, rasterizerState(NULL)
, inputLayoutState(NULL)
, depthStencilViewState(NULL)
, omBlendState(NULL)
, omSampleMaskState(0xffffffff)
, iaIndexBufferPointerState(NULL)
, memoryCleared(TRUE)
, currentPixelShader(NULL)
, currentVertexShader(NULL)
, currentGeometryShader(NULL)
#if (OVR_D3D_VERSION == 11)
, currentHullShader(NULL)
, currentDomainShader(NULL)
#endif
{
	for (int i = 0; i < D3D1x_COMMONSHADER_SAMPLER_SLOT_COUNT; ++i)
		samplerStates[i] = NULL;

	for (int i = 0; i < D3D1x_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT; i++)
	{
		psShaderResourceState[i] = NULL;
		vsShaderResourceState[i] = NULL;
	}

	for (int i = 0; i < D3D1x_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT; i++)
	{
		psConstantBuffersState[i] = NULL;
		vsConstantBuffersState[i] = NULL;
	}

	for (int i = 0; i < D3D1x_SIMULTANEOUS_RENDER_TARGET_COUNT; i++)
		renderTargetViewState[i] = NULL;

	for (int i = 0; i < 4; i++)
		omBlendFactorState[i] = NULL;

	for (int i = 0; i < D3D1x_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT; i++)
		iaVertexBufferPointersState[i] = NULL;
}

void DistortionRenderer::GraphicsState::clearMemory()
{
	if (rasterizerState != NULL)
	{
		rasterizerState->Release();
		rasterizerState = NULL;
	}

	for (int i = 0; i < D3D1x_COMMONSHADER_SAMPLER_SLOT_COUNT; ++i)
	{
		if (samplerStates[i] == NULL)
			continue;
		samplerStates[i]->Release();
		samplerStates[i] = NULL;
	}

	if (inputLayoutState != NULL)
	{
		inputLayoutState->Release();
		inputLayoutState = NULL;
	}

	for (int i = 0; i < D3D1x_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT; i++)
	{
		if (psShaderResourceState[i] != NULL)
		{
			psShaderResourceState[i]->Release();
			psShaderResourceState[i] = NULL;
		}
		if (vsShaderResourceState[i] != NULL)
		{
			vsShaderResourceState[i]->Release();
			vsShaderResourceState[i] = NULL;
		}
	}

	for (int i = 0; i < D3D1x_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT; i++)
	{
		if (psConstantBuffersState[i] != NULL)
		{
			psConstantBuffersState[i]->Release();
			psConstantBuffersState[i] = NULL;
		}
		if (vsConstantBuffersState[i] != NULL)
		{
			vsConstantBuffersState[i]->Release();
			vsConstantBuffersState[i] = NULL;
		}
	}

	for (int i = 0; i < D3D1x_SIMULTANEOUS_RENDER_TARGET_COUNT; i++)
	{
		if (renderTargetViewState[i] != NULL)
		{
			renderTargetViewState[i]->Release();
			renderTargetViewState[i] = NULL;
		}
	}

	if (depthStencilViewState != NULL)
	{
		depthStencilViewState->Release();
		depthStencilViewState = NULL;
	}

	if (omBlendState != NULL)
	{
		omBlendState->Release();
		omBlendState = NULL;
	}

	if (iaIndexBufferPointerState != NULL)
	{
		iaIndexBufferPointerState->Release();
		iaIndexBufferPointerState = NULL;
	}

	for (int i = 0; i < D3D1x_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT; i++)
	{
		if (iaVertexBufferPointersState[i] == NULL)
			continue;
		iaVertexBufferPointersState[i]->Release();
		iaVertexBufferPointersState[i] = NULL;
	}

	if (currentPixelShader != NULL)
	{
		currentPixelShader->Release();
		currentPixelShader = NULL;
	}

	if (currentVertexShader != NULL)
	{
		currentVertexShader->Release();
		currentVertexShader = NULL;
	}

	if (currentGeometryShader != NULL)
	{
		currentGeometryShader->Release();
		currentGeometryShader = NULL;
	}

#if (OVR_D3D_VERSION == 11)

	if (currentHullShader != NULL)
	{
		currentHullShader->Release();
		currentHullShader = NULL;
	}

	if (currentDomainShader != NULL)
	{
		currentDomainShader->Release();
		currentDomainShader = NULL;
	}

#endif

	memoryCleared = TRUE;
}

DistortionRenderer::GraphicsState::~GraphicsState()
{
	clearMemory();
}


void DistortionRenderer::GraphicsState::Save()
{
	if (!memoryCleared)
		clearMemory();

	memoryCleared = FALSE;

	context->RSGetState(&rasterizerState);
	context->PSGetSamplers(0, D3D1x_COMMONSHADER_SAMPLER_SLOT_COUNT, samplerStates);
	context->IAGetInputLayout(&inputLayoutState);

	context->PSGetShaderResources(0, D3D1x_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT, psShaderResourceState);
	context->VSGetShaderResources(0, D3D1x_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT, vsShaderResourceState);

	context->PSGetConstantBuffers(0, D3D1x_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT, psConstantBuffersState);
	context->VSGetConstantBuffers(0, D3D1x_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT, vsConstantBuffersState);

	context->OMGetRenderTargets(D3D1x_SIMULTANEOUS_RENDER_TARGET_COUNT, renderTargetViewState, &depthStencilViewState);

	context->OMGetBlendState(&omBlendState, omBlendFactorState, &omSampleMaskState);

	context->IAGetPrimitiveTopology(&primitiveTopologyState);

	context->IAGetIndexBuffer(&iaIndexBufferPointerState, &iaIndexBufferFormatState, &iaIndexBufferOffsetState);

	context->IAGetVertexBuffers(0, D3D1x_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT, iaVertexBufferPointersState, iaVertexBufferStridesState, iaVertexBufferOffsetsState);

#if (OVR_D3D_VERSION == 10)
	context->PSGetShader(&currentPixelShader);
	context->VSGetShader(&currentVertexShader);
	context->GSGetShader(&currentGeometryShader);
#else // Volga says class instance interfaces are very new and almost no one uses them
	context->PSGetShader(&currentPixelShader, NULL, NULL);
	context->VSGetShader(&currentVertexShader, NULL, NULL);
	context->GSGetShader(&currentGeometryShader, NULL, NULL);
	context->HSGetShader(&currentHullShader, NULL, NULL);
	context->DSGetShader(&currentDomainShader, NULL, NULL);
	/* maybe above doesn't work; then do something with this (must test on dx11)
	ID3D11ClassInstance* blank_array[0];
	UINT blank_uint = 0;
	context->PSGetShader(&currentPixelShader, blank_array, blank_uint);
	context->VSGetShader(&currentVertexShader, blank_array, blank_uint);
	context->GSGetShader(&currentGeometryShader, blank_array, blank_uint);
	context->HSGetShader(&currentHullShader, blank_array, blank_uint);
	context->DSGetShader(&currentDomainShader, blank_array, blank_uint);
	*/
#endif
}


void DistortionRenderer::GraphicsState::Restore()
{
	if (rasterizerState != NULL)
		context->RSSetState(rasterizerState);

	context->PSSetSamplers(0, D3D1x_COMMONSHADER_SAMPLER_SLOT_COUNT, samplerStates);

	if (inputLayoutState != NULL)
		context->IASetInputLayout(inputLayoutState);

	if (psShaderResourceState != NULL)
		context->PSSetShaderResources(0, D3D1x_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT, psShaderResourceState);

	if (vsShaderResourceState != NULL)
		context->VSSetShaderResources(0, D3D1x_COMMONSHADER_INPUT_RESOURCE_SLOT_COUNT, vsShaderResourceState);

	if (psConstantBuffersState != NULL)
		context->PSSetConstantBuffers(0, D3D1x_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT, psConstantBuffersState);

	if (vsConstantBuffersState != NULL)
		context->VSSetConstantBuffers(0, D3D1x_COMMONSHADER_CONSTANT_BUFFER_API_SLOT_COUNT, vsConstantBuffersState);

	if (depthStencilViewState != NULL || renderTargetViewState != NULL)
		context->OMSetRenderTargets(D3D1x_SIMULTANEOUS_RENDER_TARGET_COUNT, renderTargetViewState, depthStencilViewState);

	if (omBlendState != NULL)
		context->OMSetBlendState(omBlendState, omBlendFactorState, omSampleMaskState);

	context->IASetPrimitiveTopology(primitiveTopologyState);

	if (iaIndexBufferPointerState != NULL)
		context->IASetIndexBuffer(iaIndexBufferPointerState, iaIndexBufferFormatState, iaIndexBufferOffsetState);

	if (iaVertexBufferPointersState != NULL)
		context->IASetVertexBuffers(0, D3D1x_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT, iaVertexBufferPointersState, iaVertexBufferStridesState, iaVertexBufferOffsetsState);

#if (OVR_D3D_VERSION == 10)
	if (currentPixelShader != NULL)
		context->PSSetShader(currentPixelShader);
	if (currentVertexShader != NULL)
		context->VSSetShader(currentVertexShader);
	if (currentGeometryShader != NULL)
		context->GSSetShader(currentGeometryShader);
#else
	if (currentPixelShader != NULL)
		context->PSSetShader(currentPixelShader, NULL, 0);
	if (currentVertexShader != NULL)
		context->VSSetShader(currentVertexShader, NULL, 0);
	if (currentGeometryShader != NULL)
		context->GSSetShader(currentGeometryShader, NULL, 0);
	if (currentHullShader != NULL)
		context->HSSetShader(currentHullShader, NULL, 0);
	if (currentDomainShader != NULL)
		context->DSSetShader(currentDomainShader, NULL, 0);
#endif
	clearMemory();
}

}}} // OVR::CAPI::D3D1X