#include "vars.h"

// the WindowProc function prototype
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);


// the entry point for any Windows program
int WINAPI WinMain(HINSTANCE hInstance,
                HINSTANCE hPrevInstance,
                LPSTR lpCmdLine,
                int nCmdShow)
{
    HWND hWnd;
    WNDCLASSEX wc;

    ZeroMemory(&wc, sizeof(WNDCLASSEX));

    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.lpszClassName = L"WindowClass";

    RegisterClassEx(&wc);

    RECT wr = {0, 0, SCREEN_WIDTH, SCREEN_HEIGHT};
    AdjustWindowRect(&wr, WS_OVERLAPPEDWINDOW, FALSE);

    hWnd = CreateWindowEx(NULL,
                          L"WindowClass",
                          L"Our First Direct3D Program",
                          WS_OVERLAPPEDWINDOW,
                          300,
                          300,
                          wr.right - wr.left,
                          wr.bottom - wr.top,
                          NULL,
                          NULL,
                          hInstance,
                          NULL);

    ShowWindow(hWnd, nCmdShow);

    // set up and initialize Direct3D
    InitD3D(hWnd);

    // enter the main loop:

    MSG msg;

    while(TRUE)
    {
        if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);

            if(msg.message == WM_QUIT)
                break;
        }

        RenderFrame();
    }

    // clean up DirectX and COM
    CleanD3D();

    return msg.wParam;
}


// this is the main message handler for the program
LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
        case WM_DESTROY:
            {
                PostQuitMessage(0);
                return 0;
            } break;
    }

    return DefWindowProc (hWnd, message, wParam, lParam);
}


// this function initializes and prepares Direct3D for use
void InitD3D(HWND hWnd)
{
   // create a struct to hold information about the swap chain
    DXGI_SWAP_CHAIN_DESC scd;

    // clear out the struct for use
    ZeroMemory(&scd, sizeof(DXGI_SWAP_CHAIN_DESC));

    // fill the swap chain description struct
    scd.BufferCount = 1;                                // one back buffer
    scd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;    // use 32-bit color
    scd.BufferDesc.Width = SCREEN_WIDTH;                // set the back buffer width
    scd.BufferDesc.Height = SCREEN_HEIGHT;              // set the back buffer height
    scd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;  // how swap chain is to be used
    scd.OutputWindow = hWnd;                            // the window to be used
    scd.SampleDesc.Count = 4;                              // how many multisamples
    scd.Windowed = TRUE;                                // windowed/full-screen mode
    scd.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;    // allow full-screen switching

    // create a device, device context and swap chain using the information in the scd struct
    D3D11CreateDeviceAndSwapChain(NULL,
                                  D3D_DRIVER_TYPE_HARDWARE,
                                  NULL,
                                  NULL,
                                  NULL,
                                  NULL,
                                  D3D11_SDK_VERSION,
                                  &scd,
                                  &swapchain,
                                  &dev,
                                  NULL,
                                  &devcon);


    // create the depth buffer texture
    D3D11_TEXTURE2D_DESC texd;
    ZeroMemory(&texd, sizeof(texd));

    texd.Width = SCREEN_WIDTH;
    texd.Height = SCREEN_HEIGHT;
    texd.ArraySize = 1;
    texd.MipLevels = 1;
    texd.SampleDesc.Count = 4;
    texd.Format = DXGI_FORMAT_D32_FLOAT;
    texd.BindFlags = D3D11_BIND_DEPTH_STENCIL;

    ID3D11Texture2D *pDepthBuffer;
    dev->CreateTexture2D(&texd, NULL, &pDepthBuffer);

    // create the depth buffer
    D3D11_DEPTH_STENCIL_VIEW_DESC dsvd;
    ZeroMemory(&dsvd, sizeof(dsvd));

    dsvd.Format = DXGI_FORMAT_D32_FLOAT;
    dsvd.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2DMS;

    dev->CreateDepthStencilView(pDepthBuffer, &dsvd, &zbuffer);
    pDepthBuffer->Release();

    // get the address of the back buffer
    ID3D11Texture2D *pBackBuffer;
    swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);

    // use the back buffer address to create the render target
    dev->CreateRenderTargetView(pBackBuffer, NULL, &backbuffer);
    pBackBuffer->Release();

    // set the render target as the back buffer
    devcon->OMSetRenderTargets(1, &backbuffer, zbuffer);


    // Set the viewport
    D3D11_VIEWPORT viewport;
    ZeroMemory(&viewport, sizeof(D3D11_VIEWPORT));

    viewport.TopLeftX = 0;    // set the left to 0
    viewport.TopLeftY = 0;    // set the top to 0
    viewport.Width = SCREEN_WIDTH;    // set the width to the window's width
    viewport.Height = SCREEN_HEIGHT;    // set the height to the window's height
    viewport.MinDepth = 0;    // the closest an object can be on the depth buffer is 0.0
    viewport.MaxDepth = 1;    // the farthest an object can be on the depth buffer is 1.0

    devcon->RSSetViewports(1, &viewport);

    InitPipeline();
    InitGraphics();
}


// this is the function used to render a single frame
void RenderFrame(void)
{
  

    D3DXMATRIX matRotate, matView, matProjection;
    D3DXMATRIX matFinal;

    static float Time = 0.0f; Time += 0.0003f;

    // create a world matrices
    D3DXMatrixRotationY(&matRotate, Time);

    // create a view matrix
    D3DXMatrixLookAtLH(&matView,
                        &D3DXVECTOR3(0.0f, 7.0f, 5.0f),    // the camera position
                        &D3DXVECTOR3(0.0f, 0.0f, 0.0f),    // the look-at position
                        &D3DXVECTOR3(0.0f, 1.0f, 0.0f));   // the up direction

    // create a projection matrix
    D3DXMatrixPerspectiveFovLH(&matProjection,
                                (FLOAT)D3DXToRadian(45),                    // field of view
                                (FLOAT)SCREEN_WIDTH / (FLOAT)SCREEN_HEIGHT, // aspect ratio
                                1.0f,                                           // near view-plane
                                1000.0f);                                    // far view-plane

    // load the matrices into the constant buffer
    matFinal = matRotate * matView * matProjection;
    

    // clear the back buffer to a deep blue
    devcon->ClearRenderTargetView(backbuffer, D3DXCOLOR(0.0f, 0.0f, 0.0f, 1.0f));

    // clear the depth buffer
    devcon->ClearDepthStencilView(zbuffer, D3D11_CLEAR_DEPTH, 1.0f, 0);

        // select which vertex buffer to display
        UINT stride = sizeof(VertexType);
        UINT offset = 0;
        devcon->IASetVertexBuffers(0, 1, &pVBuffer, &stride, &offset);
        devcon->IASetIndexBuffer(pIBuffer, DXGI_FORMAT_R32_UINT, 0);

        // select which primtive type we are using
        devcon->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_LINELIST);

                //Draw
        devcon->DrawIndexed(m_indexCount, 0, 0);

    // switch the back buffer and the front buffer
    swapchain->Present(0, 0);
}


// this is the function that cleans up Direct3D and COM
void CleanD3D(void)
{
    swapchain->SetFullscreenState(FALSE, NULL);    // switch to windowed mode

    // close and release all existing COM objects
    zbuffer->Release();
    pLayout->Release();
    pVS->Release();
    pPS->Release();
    pVBuffer->Release();
    pIBuffer->Release();
    swapchain->Release();
    backbuffer->Release();
    dev->Release();
    devcon->Release();
}


// this is the function that creates the shape to render
void InitGraphics()
{
    VertexType* vertices;
        unsigned long* indices;
        int i, j, index;
        float positionX, positionZ;

                // Calculate the number of vertices in the terrain mesh.
        m_vertexCount = (m_terrainWidth - 1) * (m_terrainHeight - 1) * 8;

        // Set the index count to the same as the vertex count.
        m_indexCount = m_vertexCount;

        vertices = new VertexType[m_vertexCount];
        indices = new unsigned long[m_indexCount];

        // Initialize the index to the vertex buffer.
        index = 0;

        // Load the vertex and index array with the terrain data.
        for(j=0; j<(m_terrainHeight-1); j++)
        {
                for(i=0; i<(m_terrainWidth-1); i++)
                {
                        // LINE 1
                        // Upper left.
                        positionX = (float)i;
                        positionZ = (float)(j+1);

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // Upper right.
                        positionX = (float)(i+1);
                        positionZ = (float)(j+1);

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // LINE 2
                        // Upper right.
                        positionX = (float)(i+1);
                        positionZ = (float)(j+1);

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // Bottom right.
                        positionX = (float)(i+1);
                        positionZ = (float)j;

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // LINE 3
                        // Bottom right.
                        positionX = (float)(i+1);
                        positionZ = (float)j;

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // Bottom left.
                        positionX = (float)i;
                        positionZ = (float)j;

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // LINE 4
                        // Bottom left.
                        positionX = (float)i;
                        positionZ = (float)j;

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;

                        // Upper left.
                        positionX = (float)i;
                        positionZ = (float)(j+1);

                        vertices[index].position = D3DXVECTOR3(positionX, 0.0f, positionZ);
                        vertices[index].color = D3DXVECTOR4(1.0f, 1.0f, 1.0f, 1.0f);
                        indices[index] = index;
                        index++;                        
                }
        }

    // create the vertex buffer
    D3D11_BUFFER_DESC bd;
    ZeroMemory(&bd, sizeof(bd));

    bd.Usage = D3D11_USAGE_DYNAMIC;
    bd.ByteWidth = sizeof(VertexType) * m_vertexCount;
    bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;
    bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;

    dev->CreateBuffer(&bd, NULL, &pVBuffer);

    // copy the vertices into the buffer
    D3D11_MAPPED_SUBRESOURCE ms;
    devcon->Map(pVBuffer, NULL, D3D11_MAP_WRITE_DISCARD, NULL, &ms);    // map the buffer
    memcpy(ms.pData, vertices, sizeof(vertices));               // copy the data
    devcon->Unmap(pVBuffer, NULL);

    // create the index buffer
    bd.Usage = D3D11_USAGE_DYNAMIC;
    bd.ByteWidth = sizeof(unsigned long) * m_indexCount;
    bd.BindFlags = D3D11_BIND_INDEX_BUFFER;
    bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
    bd.MiscFlags = 0;

    dev->CreateBuffer(&bd, NULL, &pIBuffer);

    devcon->Map(pIBuffer, NULL, D3D11_MAP_WRITE_DISCARD, NULL, &ms);    // map the buffer
    memcpy(ms.pData, indices, sizeof(indices));                 // copy the data
    devcon->Unmap(pIBuffer, NULL);
        /*
    D3DX11CreateShaderResourceViewFromFile(dev,        // the Direct3D device
                                        L"Wood.png",    // load Wood.png in the local folder
                                        NULL,           // no additional information
                                        NULL,           // no multithreading
                                        &pTexture,      // address of the shader-resource-view
                                        NULL);          // no multithreading
                                                                       */
                                                                       

    delete [] vertices;
        vertices = 0;

        delete [] indices;
        indices = 0;
}




// this function loads and prepares the shaders
void InitPipeline()
{
    // compile the shaders
    ID3D10Blob *VS, *PS;
    D3DX11CompileFromFile(L"shaders.hlsl", 0, 0, "VShader", "vs_5_0", 0, 0, 0, &VS, 0, 0);
    D3DX11CompileFromFile(L"shaders.hlsl", 0, 0, "PShader", "ps_5_0", 0, 0, 0, &PS, 0, 0);

    // create the shader objects
    dev->CreateVertexShader(VS->GetBufferPointer(), VS->GetBufferSize(), NULL, &pVS);
    dev->CreatePixelShader(PS->GetBufferPointer(), PS->GetBufferSize(), NULL, &pPS);

    // set the shader objects
    devcon->VSSetShader(pVS, 0, 0);
    devcon->PSSetShader(pPS, 0, 0);

    // create the input element object
        D3D11_INPUT_ELEMENT_DESC ied[] =
    {
        {"POSITION", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0},
        {"COLOR", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0, D3D10_APPEND_ALIGNED_ELEMENT, D3D11_INPUT_PER_VERTEX_DATA, 0},
    };

    // use the input element descriptions to create the input layout
    dev->CreateInputLayout(ied, 3, VS->GetBufferPointer(), VS->GetBufferSize(), &pLayout);
    devcon->IASetInputLayout(pLayout);

   
}