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