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OpenGL7-2-快速绘制
添加时间:2013-7-16 点击量:
#include CELLWinApp.hpp
#include <gl/GLU.h>
#include <assert.h>
#include <math.h>
#pragma comment(lib,opengl32.lib)
#pragma comment(lib,glu32.lib)
#pragma comment(lib,winmm.lib)
/
这个例子介绍如何应用
glEnableClientState,
glVertexPointer.
glColorPointer,
glTexCoordPointer,
glDrawArrays
函数进行绘制
接上一个例子,上一个例子中应用了三个缓冲区,定点缓冲区,纹理缓冲区,色彩缓冲
缓冲区多了今后灵活度增长了,然则经管却很麻烦。
OpenGL也支撑一个零丁的缓冲区
/
struct Vertex
{
float x, y, z;
float u,v;
float r, g, b;
};Vertex g_cubeVertices[] =
{
{ -1.0f,-1.0f, 1.0f,0.0f, 0.0f,1.0f, 0.0f, 0.0f },
{ 1.0f,-1.0f, 1.0f,1.0f, 0.0f,1.0f, 0.0f, 0.0f },
{ 1.0f, 1.0f, 1.0f,1.0f, 1.0f,1.0f, 0.0f, 0.0f },
{ -1.0f, 1.0f, 1.0f,0.0f, 1.0f,1.0f, 0.0f, 0.0f },{ -1.0f,-1.0f,-1.0f,1.0f, 0.0f,0.0f, 1.0f, 0.0f },
{ -1.0f, 1.0f,-1.0f,1.0f, 1.0f,0.0f, 1.0f, 0.0f },
{ 1.0f, 1.0f,-1.0f,0.0f, 1.0f,0.0f, 1.0f, 0.0f },
{ 1.0f,-1.0f,-1.0f,0.0f, 0.0f,0.0f, 1.0f, 0.0f },{ -1.0f, 1.0f,-1.0f,0.0f, 1.0f,0.0f, 0.0f, 1.0f },
{ -1.0f, 1.0f, 1.0f,0.0f, 0.0f,0.0f, 0.0f, 1.0f },
{ 1.0f, 1.0f, 1.0f,1.0f, 0.0f,0.0f, 0.0f, 1.0f },
{ 1.0f, 1.0f,-1.0f,1.0f, 1.0f,0.0f, 0.0f, 1.0f },{ -1.0f,-1.0f,-1.0f,1.0f, 1.0f,1.0f, 1.0f, 0.0f },
{ 1.0f,-1.0f,-1.0f,0.0f, 1.0f,1.0f, 1.0f, 0.0f },
{ 1.0f,-1.0f, 1.0f,0.0f, 0.0f,1.0f, 1.0f, 0.0f },
{ -1.0f,-1.0f, 1.0f,1.0f, 0.0f,1.0f, 1.0f, 0.0f },{ 1.0f,-1.0f,-1.0f,1.0f, 0.0f,1.0f, 0.0f, 1.0f },
{ 1.0f, 1.0f,-1.0f,1.0f, 1.0f,1.0f, 0.0f, 1.0f },
{ 1.0f, 1.0f, 1.0f,0.0f, 1.0f,1.0f, 0.0f, 1.0f },
{ 1.0f,-1.0f, 1.0f,0.0f, 0.0f,1.0f, 0.0f, 1.0f },{ -1.0f,-1.0f,-1.0f,0.0f, 0.0f,0.0f, 1.0f, 1.0f },
{ -1.0f,-1.0f, 1.0f,1.0f, 0.0f,0.0f, 1.0f, 1.0f },
{ -1.0f, 1.0f, 1.0f,1.0f, 1.0f,0.0f, 1.0f, 1.0f },
{ -1.0f, 1.0f,-1.0f,0.0f, 1.0f,0.0f, 1.0f, 1.0f }
};
class Tutorial7 :public CELL::Graphy::CELLWinApp
{
public:
Tutorial7(HINSTANCE hInstance)
:CELL::Graphy::CELLWinApp(hInstance)
{
_lbtnDownFlag = false;
_fSpinY = 0;
_fSpinX = 0;
}
virtual void render()
{
do
{
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0f, 0.0f, -5.0f );glRotatef( -_fSpinY, 1.0f, 0.0f, 0.0f );
glRotatef( -_fSpinX, 0.0f, 1.0f, 0.0f );glEnableClientState( GL_VERTEX_ARRAY );
glEnableClientState( GL_COLOR_ARRAY );
glEnableClientState( GL_TEXTURE_COORD_ARRAY );
/
这里大师可以慢慢领会
/
float addrVertex = (float)g_cubeVertices;
float uvAddress = (float)&g_cubeVertices[0].u;float colorAddress = (float)&g_cubeVertices[0].r;
//--------------元素个数---元素类型---元素之间的内存偏移---数据地址
//OpenGL按照元素之间的内存偏移来策画下一个元素的地位。
glVertexPointer( 3, GL_FLOAT, sizeof(Vertex), addrVertex );
glColorPointer( 3, GL_FLOAT, sizeof(Vertex), colorAddress);
glTexCoordPointer( 2, GL_FLOAT, sizeof(Vertex), uvAddress );glDrawArrays( GL_QUADS, 0, 24 );
glDisableClientState( GL_VERTEX_ARRAY );
glDisableClientState( GL_COLOR_ARRAY );
glDisableClientState( GL_TEXTURE_COORD_ARRAY );
SwapBuffers( _hDC );
} while (false);
}/
生成投影矩阵
后面为了重用性,我们会写一个专门的matrix类,完成矩阵的一系列擦做
这个是很有必必要的,当你对Opengl懂得的络续深切,你会发明,很多都是和数学有关的
/
void perspective(float fovy,float aspect,float zNear,float zFar,float matrix[4][4])
{
assert(aspect != float(0));
assert(zFar != zNear);
#define PI 3.14159265358979323ffloat rad = fovy (PI / 180);
float halfFovy = tan(rad / float(2));
matrix[0][0] = float(1) / (aspect halfFovy);
matrix[1][1] = float(1) / (halfFovy);
matrix[2][2] = -(zFar + zNear) / (zFar - zNear);
matrix[2][3] = -float(1);
matrix[3][2] = -(float(2) zFar zNear) / (zFar - zNear);
#undef PI
}
virtual void onInit()
{
/
调用父类的函数。
/
CELL::Graphy::CELLWinApp::onInit();
glMatrixMode( GL_PROJECTION );GLfloat matrix[4][4] =
{
0,0,0,0,
0,0,0,0,
0,0,0,0,
0,0,0,0
};
perspective(45.0f, (GLfloat)_winWidth / (GLfloat)_winHeight, 0.1f, 100.0f,matrix);
glLoadMatrixf((float)matrix);glClearColor(0,0,0,1);
/
增长如下两句话
glEnable(GL_DEPTH_TEST); 启动深度测试,如许,有遮挡策画,被隐瞒的将覆盖
glEnable(GL_TEXTURE_2D); 启动纹理,支撑纹理贴图,如许才可以绘制纹理出来
/
glEnable(GL_DEPTH_TEST);
glEnable(GL_TEXTURE_2D);
/
读一个bmp
/
HBITMAP hBmp = (HBITMAP)LoadImageA(0,1.bmp,IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
/
获取的大小
/
BITMAP bmpInf = {0};
GetObject(hBmp,sizeof(bmpInf),&bmpInf);
/
获取的色彩数据(r,g,b)
/
int size = bmpInf.bmHeight bmpInf.bmWidth 3;
char data = new char[size];BITMAPINFO bi;
bi.bmiHeader.biSize = sizeof(bi.bmiHeader);
bi.bmiHeader.biWidth = bmpInf.bmWidth;
bi.bmiHeader.biHeight = bmpInf.bmHeight;
bi.bmiHeader.biPlanes = 1;
bi.bmiHeader.biBitCount = 24;
bi.bmiHeader.biCompression = BI_RGB;
bi.bmiHeader.biSizeImage = size;
bi.bmiHeader.biClrUsed = 0;
bi.bmiHeader.biClrImportant = 0;
/
获取rgb数据
/
int idata = GetDIBits(_hDC,hBmp,0,bi.bmiHeader.biHeight,data,&bi,DIB_RGB_COLORS);/
产生一个纹理Id,可以认为是纹理句柄,后面的操纵将书用这个纹理id
/
glGenTextures( 1, &_textureId );/
应用这个纹理id,或者叫绑定(接洽关系)
/
glBindTexture( GL_TEXTURE_2D, _textureId );
/
指定纹理的放大,缩小滤波,应用线性体式格式,即当放大的时辰插值体式格式
/
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
/
将的rgb数据上传给opengl.
/
glTexImage2D(
GL_TEXTURE_2D, //! 指定是二维
0, //! 指定为第一级别,纹理可以做mipmap,即lod,离近的就采取级别大的,远则应用较小的纹理
GL_RGB, //! 纹理的应用的存储格局
bmpInf.bmWidth, //! 宽度,老一点的显卡,不支撑不规矩的纹理,即宽度和高度不是2^n。
bmpInf.bmHeight, //! 宽度,老一点的显卡,不支撑不规矩的纹理,即宽度和高度不是2^n。
0, //! 是否的边
GL_BGR_EXT, //! 数据的格局,bmp中,windows,操纵体系中存储的数据是bgr格局
GL_UNSIGNED_BYTE, //! 数据是8bit数据
data
);
[]data;
/
删除
/
DeleteObject(hBmp);
}virtual int events(unsigned msg, unsigned wParam, unsigned lParam)
{
switch(msg)
{
case WM_LBUTTONDOWN:
{
_mousePos.x = LOWORD (lParam);
_mousePos.y = HIWORD (lParam);
_lbtnDownFlag = true;
SetCapture(_hWnd);
}
break;
case WM_LBUTTONUP:
{
_lbtnDownFlag = false;
ReleaseCapture();
}
break;
case WM_MOUSEMOVE:
{
int curX = LOWORD (lParam);
int curY = HIWORD (lParam);if( _lbtnDownFlag )
{
_fSpinX -= (curX - _mousePos.x);
_fSpinY -= (curY - _mousePos.y);
}_mousePos.x = curX;
_mousePos.y = curY;
}
break;
}
return __super::events(msg,wParam,lParam);
}
protected:
unsigned _primitiveType;
/
保存纹理Id
/
unsigned _textureId;float _fSpinX ;
float _fSpinY;
POINT _mousePos;
bool _lbtnDownFlag;
};int CALLBACK _tWinMain(
HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
int nShowCmd
)
{
(void)hInstance;
(void)hPrevInstance;
(void)lpCmdLine;
(void)nShowCmd;Tutorial7 winApp(hInstance);
无论对感情还是对生活,“只要甜不要苦”都是任性而孩子气的,因为我们也不完美,我们也会伤害人。正因为我们都不完美,也因为生活从不是事事如意,所以对这些“瑕疵”的收纳才让我们对生活、对他人的爱变得日益真实而具体。—— 汪冰《世界再亏欠你,也要敢于拥抱幸福》
winApp.start(640,480);
return 0;
}