main.cpp

// include the basic windows header files and the Direct3D header files
#include <windows.h>
#include <windowsx.h>
#include <d3d9.h>
#include <d3d10.h>
#include <d3d11.h>
#include <dxgi.h>
#include <d3dcompiler.h>

#include <iostream>
#include <fstream>
using namespace std;

// include the Direct3D Library file
#pragma comment (lib, "d3d9.lib")
#pragma comment (lib, "d3d10.lib")
#pragma comment (lib, "d3d11.lib")

// define the screen resolution
#define SCREEN_WIDTH  800
#define SCREEN_HEIGHT 600

// global declarations
IDXGISwapChain *swapchain;             // the pointer to the swap chain interface
ID3D11Device *dev;                     // the pointer to our Direct3D device interface
ID3D11DeviceContext *devcon;           // the pointer to our Direct3D device context
ID3D11RenderTargetView *backbuffer;    // the pointer to our back buffer
ID3D11InputLayout *pLayout;            // the pointer to the input layout
ID3D11VertexShader *pVS;               // the pointer to the vertex shader
ID3D11PixelShader *pPS;                // the pointer to the pixel shader
ID3D11Buffer *pVBuffer;                // the pointer to the vertex buffer

// a struct to define a single vertex
struct VERTEX{FLOAT X, Y, Z; float Color[4];};

// function prototypes
void InitD3D(HWND hWnd);    // sets up and initializes Direct3D
void RenderFrame(void);     // renders a single frame
void CleanD3D(void);        // closes Direct3D and releases memory
void InitGraphics(void);    // creates the shape to render
void InitPipeline(void);    // loads and prepares the shaders

// 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 = "WindowClass";

    RegisterClassEx(&wc);

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

    hWnd = CreateWindowEx(0,
                          "WindowClass",
                          "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,
                                  0,
                                  NULL,
                                  0,
                                  D3D11_SDK_VERSION,
                                  &scd,
                                  &swapchain,
                                  &dev,
                                  NULL,
                                  &devcon);


    // 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, NULL);


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

    viewport.TopLeftX = 0;
    viewport.TopLeftY = 0;
    viewport.Width = SCREEN_WIDTH;
    viewport.Height = SCREEN_HEIGHT;

    devcon->RSSetViewports(1, &viewport);

    InitPipeline();
    InitGraphics();
}


// this is the function used to render a single frame
void RenderFrame(void)
{
    float color[4] = {0.0f, 0.2f, 0.4f, 1.0f};
    // clear the back buffer to a deep blue
    devcon->ClearRenderTargetView(backbuffer, color);

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

    // select which primtive type we are using
    devcon->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

    // draw the vertex buffer to the back buffer
    devcon->Draw(3, 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
    pLayout->Release();
    pVS->Release();
    pPS->Release();
    pVBuffer->Release();
    swapchain->Release();
    backbuffer->Release();
    dev->Release();
    devcon->Release();
}


// this is the function that creates the shape to render
void InitGraphics()
{
    // create a triangle using the VERTEX struct
    VERTEX OurVertices[] =
            {
                    {0.0f, 0.5f, 0.0f, {1.0f, 0.0f, 0.0f, 1.0f}},
                    {0.45f, -0.5, 0.0f, {0.0f, 1.0f, 0.0f, 1.0f}},
                    {-0.45f, -0.5f, 0.0f, {0.0f, 0.0f, 1.0f, 1.0f}}
            };


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

    bd.Usage = D3D11_USAGE_DYNAMIC;                // write access access by CPU and GPU
    bd.ByteWidth = sizeof(VERTEX) * 3;             // size is the VERTEX struct * 3
    bd.BindFlags = D3D11_BIND_VERTEX_BUFFER;       // use as a vertex buffer
    bd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;    // allow CPU to write in buffer

    dev->CreateBuffer(&bd, NULL, &pVBuffer);       // create the buffer


    // copy the vertices into the buffer
    D3D11_MAPPED_SUBRESOURCE ms;
    devcon->Map(pVBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &ms);    // map the buffer
    memcpy(ms.pData, OurVertices, sizeof(OurVertices));                 // copy the data
    devcon->Unmap(pVBuffer, 0);                                      // unmap the buffer
}

void WINAPI D3DCompileFromFile(const char *filename,
                       const D3D_SHADER_MACRO *defines, ID3DInclude *include, const char *entrypoint,
                       const char *target, UINT sflags, UINT eflags, ID3DBlob **shader, ID3DBlob **error_messages) {

    SIZE_T data_size;
    char* buffer;

    ifstream infile;
    infile.open(filename, ios::binary);
    infile.seekg(0, ios::end);
    data_size = infile.tellg();
    infile.seekg(0, ios::beg);
    buffer = new char[data_size];
    infile.read(buffer, data_size);
    infile.close();

    D3DCompile(buffer, data_size,filename,
                           defines, include,entrypoint,
                           target, sflags, eflags, shader, error_messages);
}
// this function loads and prepares the shaders
void InitPipeline()
{
    // load and compile the two shaders
    ID3D10Blob *VS, *PS;
    D3DCompileFromFile("Z://shaders.shader", 0, 0, "VShader", "vs_4_0", 0, 0, &VS, 0);
    D3DCompileFromFile("Z://shaders.shader", 0, 0, "PShader", "ps_4_0", 0, 0, &PS, 0);

    // encapsulate both shaders into 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 layout 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, 12, D3D11_INPUT_PER_VERTEX_DATA, 0},
            };

    dev->CreateInputLayout(ied, 2, VS->GetBufferPointer(), VS->GetBufferSize(), &pLayout);
    devcon->IASetInputLayout(pLayout);
}