两天学会DirectX 3D之入门

环境配置以及背景知识

环境
Windows 8.1 64bit
VS2013
Microsoft DirectX SDK (June 2010)
NVDIA Geforce GT755

环境的配置參考VS2008整合DirectX9.0开发环境

一些背景知识 

DirectX的和应用层与硬件层的关系例如以下

REF设备同意开发者測试那些Direct3D提供了但未被图形设备所实现的功能。

COM（Component Object Model）是一项可使DirectX独立于编程语言，并具备向下兼容的技术。基本思想是将大而复杂的应用软件分为一系列的可现行实现，易于开发，理解复用和调整的软件单元。

COM组件是遵循COM规范编写，以Win32动态链接库（dll）或者可执行文件形式公布的可执行二进制代码（exe）。

COM的长处：

• 与开发语言无关
• 通过接口有效保证了组件的复用性
• 组件执行效率高。便于使用和管理

以下能够正式開始今天的学习了。

绘制一个三角形

用到的DxUtility类在VS2008整合DirectX9.0开发环境已经实现了。能够直接去看。主要改动一下渲染的几个函数。

#include "dxutility.h"
#include <windows.h>
#include <iostream>

//
// Globals
//

IDirect3DDevice9* Device = 0;
D3DXMATRIX World;
IDirect3DVertexBuffer9 * VB = 0;

const int Width = 800;
const int Height = 600;

struct Vertex{
    Vertex(){};
    Vertex(float _x, float _y, float _z)
    {
        x = _x;
        y = _y;
        z = _z;
    }

    float x, y, z;
    static const DWORD FVF;
};

const DWORD Vertex::FVF = D3DFVF_XYZ;

//
// Framework Functions
//

bool Setup()
{
    Device->CreateVertexBuffer(
        3 * sizeof(Vertex),
        D3DUSAGE_WRITEONLY,
        Vertex::FVF,
        D3DPOOL_MANAGED,
        &VB,
        0);

    Vertex* vertices;
    VB->Lock(0, 0, (void**)&vertices, 0);

    vertices[0] = Vertex(-1.0f, 0.0f, 2.0f);
    vertices[1] = Vertex(0.0f, 1.0f, 2.0f);
    vertices[2] = Vertex(1.0f, 0.0f, 2.0f);

    VB->Unlock();

    D3DXMATRIX proj;
    D3DXMatrixPerspectiveFovLH(
        &proj,                        // result
        D3DX_PI * 0.5f,               // 90 - degrees
        (float)Width / (float)Height, // aspect ratio
        1.0f,                         // near plane
        1000.0f);                     // far plane
    Device->SetTransform(D3DTS_PROJECTION, &proj);

    Device->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME);

    return true;
}

void Cleanup()
{
    Dx::Release<IDirect3DVertexBuffer9*>(VB);
}

bool Display(float timeDelta)
{
    if (Device) // Only use Device methods if we have a valid device.
    {
        Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);
        Device->BeginScene();

        Device->SetStreamSource(0, VB, 0, sizeof(Vertex));
        Device->SetFVF(Vertex::FVF);

        // Draw one triangle.
        Device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);

        Device->EndScene();
        Device->Present(0, 0, 0, 0);
    }

    return true;
}

//
// WndProc
//
LRESULT CALLBACK Dx::WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
    case WM_DESTROY:
        ::PostQuitMessage(0);
        break;

    case WM_KEYDOWN:
        if (wParam == VK_ESCAPE)
            ::DestroyWindow(hwnd);
        break;
    }
    return ::DefWindowProc(hwnd, msg, wParam, lParam);
}

//
// WinMain
//
int WINAPI WinMain(HINSTANCE hinstance,
    HINSTANCE prevInstance,
    PSTR cmdLine,
    int showCmd)
{
    if (!Dx::InitDx(hinstance,
        Width, Height, true, D3DDEVTYPE_HAL, &Device))
    {
        ::MessageBox(0, "InitD3D() - FAILED", 0, 0);
        return 0;
    }

    if (!Setup())
    {
        ::MessageBox(0, "Setup() - FAILED", 0, 0);
        return 0;
    }
    Dx::EnterMsgLoop(Display);

    Cleanup();

    Device->Release();

    return 0;
}

终于效果 

给三角形加上颜色
数据结构定义

struct ColorVertex{
    ColorVertex(float _x, float _y, float _z, D3DCOLOR c)
    {
        x = _x;
        y = _y;
        z = _z;
        color = c;
    }
    float x, y, z;
    D3DCOLOR color;
    static const DWORD FVF;
};
const DWORD ColorVertex::FVF = D3DFVF_XYZ | D3DFVF_DIFFUSE;

创建Buffer

    Device->CreateVertexBuffer(
        3 * sizeof(ColorVertex),
        D3DUSAGE_WRITEONLY,
        ColorVertex::FVF,
        D3DPOOL_MANAGED,
        &VB,
        0);

    ColorVertex *v;
    VB->Lock(0, 0, (void**)&v, 0);
    v[0] = ColorVertex(-1.0f, 0.0f, 2.0f, D3DCOLOR_XRGB(255, 0, 0));
    v[1] = ColorVertex(0.0f, 1.0f, 2.0f, D3DCOLOR_XRGB(0, 255, 0));
    v[2] = ColorVertex(1.0f, 0.0f, 2.0f, D3DCOLOR_XRGB(0, 0, 255));

    VB->Unlock();

在绘制函数中设置使用Ground插值进行三角形绘制

bool Display(float timeDelta)
{
    if (Device) // Only use Device methods if we have a valid device.
    {
        std::cout << "Display" << std::endl;
        Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);
        Device->BeginScene();

        Device->SetStreamSource(0, VB, 0, sizeof(ColorVertex));
        Device->SetFVF(ColorVertex::FVF);

        Device->SetRenderState(D3DRS_SHADEMODE, D3DSHADE_GOURAUD);
        Device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);

        Device->EndScene();
        Device->Present(0, 0, 0, 0);
    }

    return true;
}

渲染结果

绘制一个旋转的正方体

生成Vertex Buffer和Index Buffer

   Device->CreateVertexBuffer(
        8 * sizeof(ColorVertex),
        D3DUSAGE_WRITEONLY,
        ColorVertex::FVF,
        D3DPOOL_MANAGED,
        &VB,
        0);
    Device->CreateIndexBuffer(
        36 * sizeof(WORD),
        D3DUSAGE_WRITEONLY,
        D3DFMT_INDEX16,
        D3DPOOL_MANAGED,
        &IB,
        0);

    ColorVertex *v;
    VB->Lock(0, 0, (void**)&v, 0);
    v[0] = ColorVertex(-1.0f, -1.0f, -1.0f, D3DCOLOR_XRGB(255, 0, 0));
    v[1] = ColorVertex(-1.0f, 1.0f, -1.0f, D3DCOLOR_XRGB(0, 255, 0));
    v[2] = ColorVertex(1.0f, 1.0f, -1.0f, D3DCOLOR_XRGB(0, 0, 255));
    v[3] = ColorVertex(1.0f, -1.0f, -1.0f, D3DCOLOR_XRGB(255, 255, 0));
    v[4] = ColorVertex(-1.0f, -1.0f, 1.0f, D3DCOLOR_XRGB(0, 255, 0));
    v[5] = ColorVertex(-1.0f, 1.0f, 1.0f, D3DCOLOR_XRGB(0, 0, 255));
    v[6] = ColorVertex(1.0f, 1.0f, 1.0f, D3DCOLOR_XRGB(255, 0, 255));
    v[7] = ColorVertex(1.0f, -1.0f, 1.0f, D3DCOLOR_XRGB(0, 255, 0));

    VB->Unlock();

    WORD* indices = 0;
    IB->Lock(0, 0, (void**)&indices, 0);
    // front side
    indices[0] = 0; indices[1] = 1; indices[2] = 2;
    indices[3] = 0; indices[4] = 2; indices[5] = 3;

    // back side
    indices[6] = 4; indices[7] = 6; indices[8] = 5;
    indices[9] = 4; indices[10] = 7; indices[11] = 6;

    // left side
    indices[12] = 4; indices[13] = 5; indices[14] = 1;
    indices[15] = 4; indices[16] = 1; indices[17] = 0;

    // right side
    indices[18] = 3; indices[19] = 2; indices[20] = 6;
    indices[21] = 3; indices[22] = 6; indices[23] = 7;

    // top
    indices[24] = 1; indices[25] = 5; indices[26] = 6;
    indices[27] = 1; indices[28] = 6; indices[29] = 2;

    // bottom
    indices[30] = 4; indices[31] = 0; indices[32] = 3;
    indices[33] = 4; indices[34] = 3; indices[35] = 7;

    IB->Unlock();

绘制函数。让正方体旋转起来

       // spin the cube:
        //
        D3DXMATRIX Rx, Ry;

        // rotate 45 degrees on x-axis
        D3DXMatrixRotationX(&Rx, 3.14f / 4.0f);

        // incremement y-rotation angle each frame
        static float y = 0.0f;
        D3DXMatrixRotationY(&Ry, y);
        y += timeDelta;

        // reset angle to zero when angle reaches 2*PI
        if (y >= 6.28f)
            y = 0.0f;

        // combine x- and y-axis rotation transformations.
        D3DXMATRIX p = Rx * Ry;

        Device->SetTransform(D3DTS_WORLD, &p);

        Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);
        Device->BeginScene();

        Device->SetStreamSource(0, VB, 0, sizeof(ColorVertex));
        Device->SetIndices(IB);
        Device->SetFVF(ColorVertex::FVF);

        Device->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, 8, 0, 12);

        Device->EndScene();
        Device->Present(0, 0, 0, 0);

在屏幕上显示FPS信息
首先初始化文字

    D3DXFONT_DESC d3dFont;

    memset(&d3dFont, 0, sizeof(d3dFont));
    d3dFont.Height = 25; // in logical units
    d3dFont.Width = 12; // in logical units
    d3dFont.Weight = 500;// boldness, range 0(light) - 1000(bold)
    d3dFont.Italic = FALSE;
    d3dFont.CharSet = DEFAULT_CHARSET;
    strcpy_s(d3dFont.FaceName, "Times New Roman");
    if (FAILED(D3DXCreateFontIndirect(Device, &d3dFont, &font)))
    {
        ::MessageBox(0, "D3DXCreateFontIndirect() - FAILED", 0, 0);
        ::PostQuitMessage(0);
    }

声明几个变量

ID3DXFont* font = 0;
DWORD FrameCnt = 0;
float TimeElapsed = 0;
float FPS = 0;
char FPSString[16];

FPS的计算 

FrameCnt++;
TimeElapsed += timeDelta;
if (TimeElapsed >= 1.0f)
{
    FPS = (float)FrameCnt / TimeElapsed;
    sprintf_s(FPSString, "FPS:%f", FPS);
    FPSString[15] = '\0'; // mark end of string
    TimeElapsed = 0.0f;
    FrameCnt = 0;
}

文字的渲染

Device->BeginScene();
RECT rect = { 0, 0, Width, Height };
font->DrawText(
    m_pSprite,
    FPSString,
    -1, // size of string or -1 indicates null terminating string
    &rect, // rectangle text is to be formatted to in windows coords
    DT_TOP | DT_LEFT, // draw in the top left corner of the viewport
    0xff000000);      // black text

Device->EndScene();

记住最后要Clear掉COM对象

void Cleanup()
{
    Dx::Release<IDirect3DVertexBuffer9*>(VB);
    Dx::Release<IDirect3DIndexBuffer9*>(IB);
    Dx::Release<ID3DXFont*>(font);
}

执行结果

參考

Introduction to 3D Game Programming with DirectX® 9.0