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openGl超级宝典学习笔记 (2) 7个主要的几何图元

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点(GL_POINTS):


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点总是正方形的像素,默认情况下,点的大小不受透视除法影响。

即无论与视点的距离怎样,它的大小都不改变。为了获得圆点。必须在抗锯齿模式下绘制点。

能够用glPointSize改变点的大小。

//点
//建立批次
GLBatch	pointBatch;

GLfloat vCoast[24][3] = {{2.80, 1.20, 0.0 }, {2.0,  1.20, 0.0 },
        {2.0,  1.08, 0.0 },  {2.0,  1.08, 0.0 },
        {0.0,  0.80, 0.0 },  {-.32, 0.40, 0.0 },
        {-.48, 0.2, 0.0 },   {-.40, 0.0, 0.0 },
        {-.60, -.40, 0.0 },  {-.80, -.80, 0.0 },
        {-.80, -1.4, 0.0 },  {-.40, -1.60, 0.0 },
        {0.0, -1.20, 0.0 },  { .2, -.80, 0.0 },
        {.48, -.40, 0.0 },   {.52, -.20, 0.0 },
        {.48,  .20, 0.0 },   {.80,  .40, 0.0 },
        {1.20, .80, 0.0 },   {1.60, .60, 0.0 },
        {2.0, .60, 0.0 },    {2.2, .80, 0.0 },
        {2.40, 1.0, 0.0 },   {2.80, 1.0, 0.0 }};

// Load point batch
    pointBatch.Begin(GL_POINTS, 24);
    pointBatch.CopyVertexData3f(vCoast);
    pointBatch.End();

//改变点的大小。提交图形到着色器  下面代码在渲染函数中
glPointSize(4.0f);
pointBatch.Draw();


线段(GL_LINES):

一条线段是在两个顶点之间绘制的,每批线段都应该包括偶数个顶点()。默认情况下宽度为1,唯一改变线段宽度的方法是glLineWidth(Gl float);

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GLBatch	lineBatch;

GLfloat vCoast[24][3] = {{2.80, 1.20, 0.0 }, {2.0,  1.20, 0.0 },
        {2.0,  1.08, 0.0 },  {2.0,  1.08, 0.0 },
        {0.0,  0.80, 0.0 },  {-.32, 0.40, 0.0 },
        {-.48, 0.2, 0.0 },   {-.40, 0.0, 0.0 },
        {-.60, -.40, 0.0 },  {-.80, -.80, 0.0 },
        {-.80, -1.4, 0.0 },  {-.40, -1.60, 0.0 },
        {0.0, -1.20, 0.0 },  { .2, -.80, 0.0 },
        {.48, -.40, 0.0 },   {.52, -.20, 0.0 },
        {.48,  .20, 0.0 },   {.80,  .40, 0.0 },
        {1.20, .80, 0.0 },   {1.60, .60, 0.0 },
        {2.0, .60, 0.0 },    {2.2, .80, 0.0 },
        {2.40, 1.0, 0.0 },   {2.80, 1.0, 0.0 }};

// Load as a bunch of line segments
    lineBatch.Begin(GL_LINES, 24);
    lineBatch.CopyVertexData3f(vCoast);
    lineBatch.End();
<pre name="code" class="cpp">//改变线段的大小,提交图形到着色器  下面代码在渲染函数中
glLineWidth(2.0f);lineBatch.Draw();


线带(GL_LINE_STRIP):

连续从一个顶点到下一个顶点绘制线段。

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GLBatch	lineStripBatch;

GLfloat vCoast[24][3] = {{2.80, 1.20, 0.0 }, {2.0,  1.20, 0.0 },
        {2.0,  1.08, 0.0 },  {2.0,  1.08, 0.0 },
        {0.0,  0.80, 0.0 },  {-.32, 0.40, 0.0 },
        {-.48, 0.2, 0.0 },   {-.40, 0.0, 0.0 },
        {-.60, -.40, 0.0 },  {-.80, -.80, 0.0 },
        {-.80, -1.4, 0.0 },  {-.40, -1.60, 0.0 },
        {0.0, -1.20, 0.0 },  { .2, -.80, 0.0 },
        {.48, -.40, 0.0 },   {.52, -.20, 0.0 },
        {.48,  .20, 0.0 },   {.80,  .40, 0.0 },
        {1.20, .80, 0.0 },   {1.60, .60, 0.0 },
        {2.0, .60, 0.0 },    {2.2, .80, 0.0 },
        {2.40, 1.0, 0.0 },   {2.80, 1.0, 0.0 }};

// Load as a single line segment
    lineStripBatch.Begin(GL_LINE_STRIP, 24);
    lineStripBatch.CopyVertexData3f(vCoast);
    lineStripBatch.End();
<pre name="code" class="cpp">//改变线段的大小。提交图形到着色器  下面代码在渲染函数中
glLineWidth(2.0f);lineStripBatch.Draw();


线环(GL_LINE_LOOP):

线带的扩展,把一个批次中最后一个点和第一个点连接起来。

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三角形(GL_TRIANGLES):

三角形是OpenGl唯一支持的一种多边图形。

每三个顶点定义一个新三角形。不像线段组成的环,它是实心的,能够填充颜色的。

上一篇我们已经创建了一个三角形。这里我们用四个三角形组成一个金字塔。用方向键能够调整三角形。

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GLBatch    triangleBatch;
<p class="p1"><span class="s1">GLfloat</span><span class="s2"> vGreen[] = { </span><span class="s3">0.0f</span><span class="s2">, </span><span class="s3">1.0f</span><span class="s2">, </span><span class="s3">0.0f</span><span class="s2">, </span><span class="s3">1.0f</span><span class="s2"> };</span></p><p class="p1"><span class="s1">GLfloat</span><span class="s2"> vBlack[] = { </span><span class="s3">0.0f</span><span class="s2">, </span><span class="s3">0.0f</span><span class="s2">, </span><span class="s3">0.0f</span><span class="s2">, </span><span class="s3">1.0f</span><span class="s2"> };</span></p>
// For Triangles, we‘ll make a Pyramid 四个三角形,组成一个金字塔
    GLfloat vPyramid[12][3] = { -2.0f, 0.0f, -2.0f,
        2.0f, 0.0f, -2.0f,
        0.0f, 4.0f, 0.0f,
        
        2.0f, 0.0f, -2.0f,
        2.0f, 0.0f, 2.0f,
        0.0f, 4.0f, 0.0f,
        
        2.0f, 0.0f, 2.0f,
        -2.0f, 0.0f, 2.0f,
        0.0f, 4.0f, 0.0f,
        
        -2.0f, 0.0f, 2.0f,
        -2.0f, 0.0f, -2.0f,
        0.0f, 4.0f, 0.0f};

triangleBatch.Begin(GL_TRIANGLES, 12);
    triangleBatch.CopyVertexData3f(vPyramid);
    triangleBatch.End();

//渲染运行
DrawWireFramedBatch(&triangleBatch);

void DrawWireFramedBatch(GLBatch* pBatch)
{
    // Draw the batch solid green
    shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(), vGreen);
    pBatch->Draw();
    
    //下面部分是为了给图形加入黑色边框
    // Draw black outline
    glPolygonOffset(-1.0f, -1.0f);      // Shift depth values 偏移深度,在同一位置要绘制填充和边线,会产生z冲突,所以要偏移
    glEnable(GL_POLYGON_OFFSET_LINE);
    
    // Draw lines antialiased 反锯齿,让黑边好看些
    glEnable(GL_LINE_SMOOTH);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    
    // Draw black wireframe version of geometry
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);//三种模式。实心,边框,点。能够作用在正面,背面。或者两面
    glLineWidth(2.5f);
    shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(), vBlack);
    pBatch->Draw();
    
    // Put everything back the way we found it //复原原本的设置
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    glDisable(GL_POLYGON_OFFSET_LINE);
    glLineWidth(1.0f);
    glDisable(GL_BLEND);
    glDisable(GL_LINE_SMOOTH);
}

多边模式:

多边形不一定是实心的,我们能够通过glPolygoMode指定将多边形显示为实习。轮廓,点。

glPolygoMode(Glenum face,Glenum mode)

face:GL_FRONT,GL_BACK,GL_FRONT_AND_BACK(默认逆时针的方向为正面)

mode:GL_FILL,GL_LINE,GL_POINT

多边形偏移:

深度模式下,有意将两个几何图形绘制到同一位置。会发生z-fighting(z冲突)。

glPolygonOffset(GLfloat factor,GLfloat units)能够在不实际改变3d空间中的物理绘制,实现深度值偏移。

Depth Offset = (DZ*factor) + (r*units)

DZ是深度值。r是使深度缓冲区值产生变化的最小值。

还必须启动多边形单独偏移:GL_POLYGON_OFFSET_FILL,GL_POLYGON_OFFSET_LINE,GL_POLYGON_OFFSET_POINT


三角形带(GL_TRIANGLE_STRIP):

绘制一连串的三角形。

长处:

1)指定第一个三角形后,下一个三角形仅仅要再指定一个点。

2)提高运算性能,节省宽带。

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每个三角形都是逆时针顺序。

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GLBatch       triangleStripBatch;
GLfloat vPoints[100][3];    // Scratch array, more than we need


// For triangle strips, a little ring or cylinder segment
    int iCounter = 0;
    GLfloat radius = 3.0f;
    for(GLfloat angle = 0.0f; angle <= (2.0f*M3D_PI); angle += 0.3f)
    {
        GLfloat x = radius * sin(angle);
        GLfloat y = radius * cos(angle);
        
        // Specify the point and move the Z value up a little
        vPoints[iCounter][0] = x;
        vPoints[iCounter][1] = y;
        vPoints[iCounter][2] = -0.5;
        iCounter++;
        
        vPoints[iCounter][0] = x;
        vPoints[iCounter][1] = y;
        vPoints[iCounter][2] = 0.5;
        iCounter++;
    }
    
    // Close up the loop
    vPoints[iCounter][0] = vPoints[0][0];
    vPoints[iCounter][1] = vPoints[0][1];
    vPoints[iCounter][2] = -0.5;
    iCounter++;
    
    vPoints[iCounter][0] = vPoints[1][0];
    vPoints[iCounter][1] = vPoints[1][1];
    vPoints[iCounter][2] = 0.5;
    iCounter++;
    
    // Load the triangle strip
    triangleStripBatch.Begin(GL_TRIANGLE_STRIP, iCounter);
    triangleStripBatch.CopyVertexData3f(vPoints);
    triangleStripBatch.End();


三角形扇(GL_TRIANGLE_FAN):

创建一组环绕中心点的相邻三角形。前三个点构成第一个三角形。兴许的每一个点都和原点以及vn-1行成一个三角形

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GLBatch             triangleFanBatch;
// For a Triangle fan, just a 6 sided hex. Raise the center up a bit
    GLfloat vPoints[100][3];    // Scratch array, more than we need
    int nVerts = 0;
    GLfloat r = 3.0f;
    vPoints[nVerts][0] = 0.0f;
    vPoints[nVerts][1] = 0.0f;
    vPoints[nVerts][2] = 0.0f;
    
    for(GLfloat angle = 0; angle < M3D_2PI; angle += M3D_2PI / 6.0f) {
        nVerts++;
        vPoints[nVerts][0] = float(cos(angle)) * r;
        vPoints[nVerts][1] = float(sin(angle)) * r;
        vPoints[nVerts][2] = -0.5f;
    }
    
    // Close the fan
    nVerts++;
    vPoints[nVerts][0] = r;
    vPoints[nVerts][1] = 0;
    vPoints[nVerts][2] = 0.0f;
    
    // Load it up
    triangleFanBatch.Begin(GL_TRIANGLE_FAN, 8);
    triangleFanBatch.CopyVertexData3f(vPoints);
    triangleFanBatch.End();


完整范例代码:

// Primitieves.cpp
// OpenGL SuperBible, Chapter 2
// Demonstrates the 7 Geometric Primitives
// Program by Richard S. Wright Jr.

#include <GLTools.h>	// OpenGL toolkit
#include <GLMatrixStack.h>
#include <GLFrame.h>
#include <GLFrustum.h>
#include <GLBatch.h>
#include <GLGeometryTransform.h>

#include <math.h>
#ifdef __APPLE__
#include <glut/glut.h>
#else
#define FREEGLUT_STATIC
#include <GL/glut.h>
#endif

/////////////////////////////////////////////////////////////////////////////////
// An assortment of needed classes
GLShaderManager		shaderManager;
GLMatrixStack		modelViewMatrix;
GLMatrixStack		projectionMatrix;
GLFrame				cameraFrame;
GLFrame             objectFrame;
GLFrustum			viewFrustum;

GLBatch				pointBatch;
GLBatch				lineBatch;
GLBatch				lineStripBatch;
GLBatch				lineLoopBatch;
GLBatch				triangleBatch;
GLBatch             triangleStripBatch;
GLBatch             triangleFanBatch;

GLGeometryTransform	transformPipeline;
M3DMatrix44f		shadowMatrix;


GLfloat vGreen[] = { 0.0f, 1.0f, 0.0f, 1.0f };
GLfloat vBlack[] = { 0.0f, 0.0f, 0.0f, 1.0f };


// Keep track of effects step
int nStep = 0;


///////////////////////////////////////////////////////////////////////////////
// This function does any needed initialization on the rendering context.
// This is the first opportunity to do any OpenGL related tasks.
void SetupRC()
{
    // Black background
    glClearColor(0.7f, 0.7f, 0.7f, 1.0f );
    
    shaderManager.InitializeStockShaders();
    
    glEnable(GL_DEPTH_TEST);
    
    transformPipeline.SetMatrixStacks(modelViewMatrix, projectionMatrix);
    
    cameraFrame.MoveForward(-15.0f);
    
    //////////////////////////////////////////////////////////////////////
    // Some points, more or less in the shape of Florida
    GLfloat vCoast[24][3] = {{2.80, 1.20, 0.0 }, {2.0,  1.20, 0.0 },
        {2.0,  1.08, 0.0 },  {2.0,  1.08, 0.0 },
        {0.0,  0.80, 0.0 },  {-.32, 0.40, 0.0 },
        {-.48, 0.2, 0.0 },   {-.40, 0.0, 0.0 },
        {-.60, -.40, 0.0 },  {-.80, -.80, 0.0 },
        {-.80, -1.4, 0.0 },  {-.40, -1.60, 0.0 },
        {0.0, -1.20, 0.0 },  { .2, -.80, 0.0 },
        {.48, -.40, 0.0 },   {.52, -.20, 0.0 },
        {.48,  .20, 0.0 },   {.80,  .40, 0.0 },
        {1.20, .80, 0.0 },   {1.60, .60, 0.0 },
        {2.0, .60, 0.0 },    {2.2, .80, 0.0 },
        {2.40, 1.0, 0.0 },   {2.80, 1.0, 0.0 }};
    
    // Load point batch
    pointBatch.Begin(GL_POINTS, 24);
    pointBatch.CopyVertexData3f(vCoast);
    pointBatch.End();
    
    // Load as a bunch of line segments
    lineBatch.Begin(GL_LINES, 24);
    lineBatch.CopyVertexData3f(vCoast);
    lineBatch.End();
    
    // Load as a single line segment
    lineStripBatch.Begin(GL_LINE_STRIP, 24);
    lineStripBatch.CopyVertexData3f(vCoast);
    lineStripBatch.End();
    
    // Single line, connect first and last points
    lineLoopBatch.Begin(GL_LINE_LOOP, 24);
    lineLoopBatch.CopyVertexData3f(vCoast);
    lineLoopBatch.End();
    
    // For Triangles, we‘ll make a Pyramid
    GLfloat vPyramid[12][3] = { -2.0f, 0.0f, -2.0f,
        2.0f, 0.0f, -2.0f,
        0.0f, 4.0f, 0.0f,
        
        2.0f, 0.0f, -2.0f,
        2.0f, 0.0f, 2.0f,
        0.0f, 4.0f, 0.0f,
        
        2.0f, 0.0f, 2.0f,
        -2.0f, 0.0f, 2.0f,
        0.0f, 4.0f, 0.0f,
        
        -2.0f, 0.0f, 2.0f,
        -2.0f, 0.0f, -2.0f,
        0.0f, 4.0f, 0.0f};
    
    triangleBatch.Begin(GL_TRIANGLES, 12);
    triangleBatch.CopyVertexData3f(vPyramid);
    triangleBatch.End();
    
    
    // For a Triangle fan, just a 6 sided hex. Raise the center up a bit
    GLfloat vPoints[100][3];    // Scratch array, more than we need
    int nVerts = 0;
    GLfloat r = 3.0f;
    vPoints[nVerts][0] = 0.0f;
    vPoints[nVerts][1] = 0.0f;
    vPoints[nVerts][2] = 0.0f;
    
    for(GLfloat angle = 0; angle < M3D_2PI; angle += M3D_2PI / 6.0f) {
        nVerts++;
        vPoints[nVerts][0] = float(cos(angle)) * r;
        vPoints[nVerts][1] = float(sin(angle)) * r;
        vPoints[nVerts][2] = -0.5f;
    }
    
    // Close the fan
    nVerts++;
    vPoints[nVerts][0] = r;
    vPoints[nVerts][1] = 0;
    vPoints[nVerts][2] = 0.0f;
    
    // Load it up
    triangleFanBatch.Begin(GL_TRIANGLE_FAN, 8);
    triangleFanBatch.CopyVertexData3f(vPoints);
    triangleFanBatch.End();
    
    // For triangle strips, a little ring or cylinder segment
    int iCounter = 0;
    GLfloat radius = 3.0f;
    for(GLfloat angle = 0.0f; angle <= (2.0f*M3D_PI); angle += 0.3f)
    {
        GLfloat x = radius * sin(angle);
        GLfloat y = radius * cos(angle);
        
        // Specify the point and move the Z value up a little
        vPoints[iCounter][0] = x;
        vPoints[iCounter][1] = y;
        vPoints[iCounter][2] = -0.5;
        iCounter++;
        
        vPoints[iCounter][0] = x;
        vPoints[iCounter][1] = y;
        vPoints[iCounter][2] = 0.5;
        iCounter++;
    }
    
    // Close up the loop
    vPoints[iCounter][0] = vPoints[0][0];
    vPoints[iCounter][1] = vPoints[0][1];
    vPoints[iCounter][2] = -0.5;
    iCounter++;
    
    vPoints[iCounter][0] = vPoints[1][0];
    vPoints[iCounter][1] = vPoints[1][1];
    vPoints[iCounter][2] = 0.5;
    iCounter++;
    
    // Load the triangle strip
    triangleStripBatch.Begin(GL_TRIANGLE_STRIP, iCounter);
    triangleStripBatch.CopyVertexData3f(vPoints);
    triangleStripBatch.End();
}


/////////////////////////////////////////////////////////////////////////
void DrawWireFramedBatch(GLBatch* pBatch)
{
    // Draw the batch solid green
    shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(), vGreen);
    pBatch->Draw();
    
    // Draw black outline
    glPolygonOffset(-1.0f, -1.0f);      // Shift depth values
    glEnable(GL_POLYGON_OFFSET_LINE);
    
    // Draw lines antialiased
    glEnable(GL_LINE_SMOOTH);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    
    // Draw black wireframe version of geometry
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    glLineWidth(2.5f);
    shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(), vBlack);
    pBatch->Draw();
    
    // Put everything back the way we found it
    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    glDisable(GL_POLYGON_OFFSET_LINE);
    glLineWidth(1.0f);
    glDisable(GL_BLEND);
    glDisable(GL_LINE_SMOOTH);
}


///////////////////////////////////////////////////////////////////////////////
// Called to draw scene
void RenderScene(void)
{
    // Clear the window with current clearing color
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    
    modelViewMatrix.PushMatrix();
    M3DMatrix44f mCamera;
    cameraFrame.GetCameraMatrix(mCamera);
    modelViewMatrix.MultMatrix(mCamera);
    
    M3DMatrix44f mObjectFrame;
    objectFrame.GetMatrix(mObjectFrame);
    modelViewMatrix.MultMatrix(mObjectFrame);
    
    shaderManager.UseStockShader(GLT_SHADER_FLAT, transformPipeline.GetModelViewProjectionMatrix(), vBlack);
    
    switch(nStep) {
        case 0:
            glPointSize(4.0f);
            pointBatch.Draw();
            glPointSize(1.0f);
            break;
        case 1:
            glLineWidth(2.0f);
            lineBatch.Draw();
            glLineWidth(1.0f);
            break;
        case 2:
            glLineWidth(2.0f);
            lineStripBatch.Draw();
            glLineWidth(1.0f);
            break;
        case 3:
            glLineWidth(2.0f);
            lineLoopBatch.Draw();
            glLineWidth(1.0f);
            break;
        case 4:
            DrawWireFramedBatch(&triangleBatch);
            break;
        case 5:
            DrawWireFramedBatch(&triangleStripBatch);
            break;
        case 6:
            DrawWireFramedBatch(&triangleFanBatch);
            break;
    }
    
    modelViewMatrix.PopMatrix();
    
    // Flush drawing commands
    glutSwapBuffers();
}


// Respond to arrow keys by moving the camera frame of reference
void SpecialKeys(int key, int x, int y)
{
    if(key == GLUT_KEY_UP)
        objectFrame.RotateWorld(m3dDegToRad(-5.0f), 1.0f, 0.0f, 0.0f);
    
    if(key == GLUT_KEY_DOWN)
        objectFrame.RotateWorld(m3dDegToRad(5.0f), 1.0f, 0.0f, 0.0f);
    
    if(key == GLUT_KEY_LEFT)
        objectFrame.RotateWorld(m3dDegToRad(-5.0f), 0.0f, 1.0f, 0.0f);
    
    if(key == GLUT_KEY_RIGHT)
        objectFrame.RotateWorld(m3dDegToRad(5.0f), 0.0f, 1.0f, 0.0f);
    
    glutPostRedisplay();
}




///////////////////////////////////////////////////////////////////////////////
// A normal ASCII key has been pressed.
// In this case, advance the scene when the space bar is pressed
void KeyPressFunc(unsigned char key, int x, int y)
{
    if(key == 32)
    {
        nStep++;
        
        if(nStep > 6)
            nStep = 0;
    }
    
    switch(nStep)
    {
        case 0:
            glutSetWindowTitle("GL_POINTS");
            break;
        case 1:
            glutSetWindowTitle("GL_LINES");
            break;
        case 2:
            glutSetWindowTitle("GL_LINE_STRIP");
            break;
        case 3:
            glutSetWindowTitle("GL_LINE_LOOP");
            break;
        case 4:
            glutSetWindowTitle("GL_TRIANGLES");
            break;
        case 5:
            glutSetWindowTitle("GL_TRIANGLE_STRIP");
            break;
        case 6:
            glutSetWindowTitle("GL_TRIANGLE_FAN");
            break;
    }
    
    glutPostRedisplay();
}

///////////////////////////////////////////////////////////////////////////////
// Window has changed size, or has just been created. In either case, we need
// to use the window dimensions to set the viewport and the projection matrix.
void ChangeSize(int w, int h)
{
    glViewport(0, 0, w, h);
    viewFrustum.SetPerspective(35.0f, float(w) / float(h), 1.0f, 500.0f);
    projectionMatrix.LoadMatrix(viewFrustum.GetProjectionMatrix());
    modelViewMatrix.LoadIdentity();
}

///////////////////////////////////////////////////////////////////////////////
// Main entry point for GLUT based programs
int main(int argc, char* argv[])
{
    gltSetWorkingDirectory(argv[0]);
    
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);
    glutInitWindowSize(800, 600);
    glutCreateWindow("GL_POINTS");
    glutReshapeFunc(ChangeSize);
    glutKeyboardFunc(KeyPressFunc);
    glutSpecialFunc(SpecialKeys);
    glutDisplayFunc(RenderScene);
    
    GLenum err = glewInit();
    if (GLEW_OK != err) {
        fprintf(stderr, "GLEW Error: %s\n", glewGetErrorString(err));
        return 1;
    }
    
    
    SetupRC();
    
    glutMainLoop();
    return 0;
}


openGl超级宝典学习笔记 (2) 7个主要的几何图元