//

// File:       terrain_simulator.h

//

// Abstract:   This example shows how OpenCL can be used to create a procedural field of 

//             grass on a generated terrain model which is then rendered with OpenGL.  

//             Because OpenGL buffers are shared with OpenCL, the data can remain on the 

//             graphics card, thus eliminating the API overhead of creating and submitting 

//             the vertices from the host.

//

//             All geometry is generated on the compute device, and outputted into

//             a shared OpenGL buffer.  The terrain gets generated only within the 

//             visible arc covering the camera's view frustum to avoid the need for 

//             culling.  A page of grass is computed on the surface of the terrain as

//             bezier patches, and flow noise is applied to the angle of the blades

//             to simulate wind.  Multiple instances of grass are rendered at jittered

//             offsets to add more grass coverage without having to compute new pages.

//             Finally, a physically based sky shader (via OpenGL) is applied to 

//             the background to provide an environment for the grass.

//

// Version:    <1.0>

//

// Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Inc. ("Apple")

//             in consideration of your agreement to the following terms, and your use,

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//

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//

//             The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

//             WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

//             WARRANTIES OF NON - INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A

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//             IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

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//             INTERRUPTION ) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION

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//

// Copyright ( C ) 2008 Apple Inc. All Rights Reserved.

//

////////////////////////////////////////////////////////////////////////////////////////////////////

#ifndef __TERRAIN_SIMULATOR__

#define __TERRAIN_SIMULATOR__ 

#include "compute_engine.h"

/////////////////////////////////////////////////////////////////////////////

class TerrainSimulator

{

public:

    TerrainSimulator();

    ~TerrainSimulator();

    bool reset(ComputeEngine &rkCompute);

    bool setup(ComputeEngine &rkCompute, uint uiSizeX, uint uiSizeY);

    bool update(ComputeEngine &rkCompute, uint uiIteration);

    bool compute(ComputeEngine &rkCompute, uint uiIteration);

public:

    void setProjectedCorners(const float4 afCorners[4]);

    void setRangeMatrix(const float16 &rkM){ m_kRangeMatrix = rkM; }

    void setInverseModelViewProjectionMatrix(const float16 &rkM) { m_kInverseModelViewProjectionMatrix = rkM; }

    void setFalloffDistance(float fV)      { m_fFalloff = fV; }

    void setCameraFov(float fV)            { m_fCameraFov = fV;    }

    void setCameraPosition(float4 fV)      { m_kCameraPosition = fV;    }

    void setCameraRotation(float4 fV)      { m_kCameraRotation = fV; }

    void setCameraFrame(float4 fUp, float4 fView, float4 fLeft)

                                           { m_kCameraUp = fUp;

                                             m_kCameraView = fView;

                                             m_kCameraLeft = fLeft; }

    void setNoiseBias(float2 fV)           { m_kNoiseBias = fV; }

    void setNoiseScale(float2 fV)          { m_kNoiseScale = fV; }

    void setNoiseAmplitude(float fV)       { m_fNoiseAmplitude = fV; }

    void setProjectedRange(float4 fV)      { m_kProjectedRange = fV;    }

    void setVertexBufferAttachment(uint uiId, bool bCopy)    { m_uiVertexBufferId = uiId; m_bCopyVertexData = bCopy; }

    void setNormalBufferAttachment(uint uiId, bool bCopy)    { m_uiNormalBufferId = uiId; m_bCopyNormalData = bCopy; }

    void setTexCoordBufferAttachment(uint uiId, bool bCopy)  { m_uiTexCoordBufferId = uiId; m_bCopyTexCoordData = bCopy; }

public:

    float getFalloffDistance()             { return m_fFalloff;         }

    float getCameraFov()                   { return m_fCameraFov;       }

    const float4& getCameraPosition(float4 fV)      { return m_kCameraPosition;    }

    const float2& getNoiseBias()           { return m_kNoiseBias; }

    const float2& getNoiseScale()          { return m_kNoiseScale; }

    float getNoiseAmplitude()              { return m_fNoiseAmplitude; }

    float* getVertexData()                  { return m_afVertexData;   }

    uint getVertexCount()                   { return m_uiVertexCount;  }

    uint getVertexBytes()                   { return m_uiVertexBytes;  }

    uint getVertexComponentCount()          { return m_uiVertexComponents; }

    uint getVertexBufferAttachment()        { return m_uiVertexBufferId; }

    float* getNormalData()                  { return m_afNormalData;   }

    uint getNormalCount()                   { return m_uiNormalCount;     }

    uint getNormalBytes()                   { return m_uiNormalBytes;  }

    uint getNormalComponentCount()          { return m_uiNormalComponents; }

    uint getNormalBufferAttachment()        { return m_uiNormalBufferId; }

    float* getTexCoordData()                { return m_afTexCoordData;    }

    uint getTexCoordCount()                 { return m_uiTexCoordCount;     }

    uint getTexCoordBytes()                 { return m_uiTexCoordBytes;   }

    uint getTexCoordComponentCount()        { return m_uiTexCoordComponents; }

    uint getTexCoordBufferAttachment()      { return m_uiTexCoordBufferId; }

    uint getRequiredVertexBufferSize(uint uiSizeX, uint uiSizeZ);

    uint getRequiredNormalBufferSize(uint uiSizeX, uint uiSizeZ);

    uint getRequiredTexCoordBufferSize(uint uiSizeX, uint uiSizeZ);

protected:

    virtual void destroy();

    virtual bool allocate(uint uiSizeX, uint uiSizeY);

    void attachMemory(ComputeEngine &rkCompute);

    void detachMemory(ComputeEngine &rkCompute);

    void clearMemory(ComputeEngine &rkCompute);

    void updateOutputs(ComputeEngine &rkCompute);

protected:

    bool m_bInitialized;

    uint m_uiKernelArgCount;

    uint m_auiLocalDim[2];

    uint m_auiGlobalDim[2];

    void** m_apvKernelArgValues;

    size_t* m_atKernelArgSizes;

    uint m_uiSizeX;

    uint m_uiSizeY;

    float m_fJitterAmount;

    float m_fCameraFov;

    float4 m_kCameraPosition;

    float4 m_kCameraRotation;

    float4 m_kCameraUp;

    float4 m_kCameraView;

    float4 m_kCameraLeft;

    float4 m_kProjectedRange;

    float4 m_akProjectedCorners[4];

    float2 m_kNoiseBias;

    float2 m_kNoiseScale;

    float m_fNoiseAmplitude;

    float *m_afVertexData;

    uint m_uiVertexBytes;

    uint m_uiVertexCount;

    uint m_uiVertexComponents;

    uint m_uiVertexBufferId;

    bool m_bCopyVertexData;

    float *m_afNormalData;

    uint m_uiNormalBytes;

    uint m_uiNormalCount;

    uint m_uiNormalComponents;

    uint m_uiNormalBufferId;

    bool m_bCopyNormalData;

    float *m_afTexCoordData;

    uint m_uiTexCoordBytes;

    uint m_uiTexCoordCount;

    uint m_uiTexCoordComponents;

    uint m_uiTexCoordBufferId;

    bool m_bCopyTexCoordData;

    float2 m_kClipRange;

    float m_fFalloff;

    float16 m_kRangeMatrix;

    float16 m_kInverseModelViewProjectionMatrix;

};

/////////////////////////////////////////////////////////////////////////////

#endif