三角形渲染

OpenGL正方形渲染與移動(dòng)

渲染

1. 將正方形頂點(diǎn)存儲(chǔ)在全局?jǐn)?shù)組

   GLfloat vVerts[] = {
          -blockSize,-blockSize,0.0f,
          blockSize,-blockSize,0.0f,
          blockSize,blockSize,0.0f,
          -blockSize,blockSize,0.0f
   };
   

2. 初始化

   void setupRC()
   {
      //設(shè)置清屏顏色（背景顏色）
      glClearColor(0.98f, 0.40f, 0.7f, 1);
      shaderManager.InitializeStockShaders();
      //修改為GL_TRIANGLE_FAN 鏈接方式，4個(gè)頂點(diǎn)
      triangleBatch.Begin(GL_TRIANGLE_FAN, 4);
      triangleBatch.CopyVertexData3f(vVerts);
      triangleBatch.End();
    }
   

3. 重塑函數(shù)（glutReshapeFunc回調(diào)）

   /*
    在窗口大小改變時(shí)，接收新的寬度&高度课幕。
   */
   void changeSize(int w,int h)
   {
      /*
       x,y 參數(shù)代表窗口中視圖的左下角坐標(biāo)，而寬度座柱、高度是像素為表示，通常x,y 都是為0
      */
     glViewport(0, 0, w, h);
   
    }
   

4. 渲染函數(shù)（glutDisplayFunc回調(diào)）

   void RenderScene(void)
   {
      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
      GLfloat vRed[] = {1.0,0.0,0.0,1.0f};
   //傳遞到存儲(chǔ)著色器，即GLT_SHADER_IDENTITY著色器，這個(gè)著色器只是使    用指定顏色以默認(rèn)笛卡爾坐標(biāo)第在屏幕上渲染幾何圖形
    shaderManager.UseStockShader(GLT_SHADER_IDENTITY,vRed);
    //提交著色器
     triangleBatch.Draw();
      //在開(kāi)始的設(shè)置openGL 窗口的時(shí)候斋配，我們指定要一個(gè)雙緩沖區(qū)的渲染環(huán)  境。這就意味著將在后臺(tái)緩沖區(qū)進(jìn)行渲染孵稽，渲染結(jié)束后交換給前臺(tái)许起。這種方式可以防止觀察者看到可能伴隨著動(dòng)畫(huà)幀與動(dòng)畫(huà)幀之間的閃爍的渲染過(guò)程十偶。緩沖區(qū)交換平臺(tái)將以平臺(tái)特定的方式進(jìn)行菩鲜。
   //將后臺(tái)緩沖區(qū)進(jìn)行渲染，然后結(jié)束后交換給前臺(tái)
     glutSwapBuffers();
    }
   
   

監(jiān)聽(tīng)鍵盤(pán)函數(shù)

GLUT提供了另一個(gè)回調(diào)函數(shù)glutSpecialFunc惦积，監(jiān)聽(tīng)了特殊按鍵被調(diào)用的函數(shù)接校，例如功能鍵或方向鍵。

在Main函數(shù)中加入以下代碼，注冊(cè)SpecialKeys回調(diào)函數(shù)

glutSpecialFunc(SpecialKeys)

• 通過(guò)點(diǎn)更新坐標(biāo)的方式移動(dòng)正方形蛛勉，并增加碰撞檢測(cè)

  triangleBatch.CopyVertexData3f(vVerts);復(fù)制頂點(diǎn)數(shù)據(jù)更新批次位置鹿寻；

  glutPostRedisplay();告知GLUT需要更新內(nèi)容

  void SpecialKeys(int key, int x, int y){
  
      GLfloat stepSize = 0.025f;
  
      GLfloat blockX = vVerts[0];
      GLfloat blockY = vVerts[10];
  
      printf("v[0] = %f\n",blockX);
      printf("v[10] = %f\n",blockY);
  
     if (key == GLUT_KEY_UP) {
  
    blockY += stepSize;
    }
  
    if (key == GLUT_KEY_DOWN) {
  
    blockY -= stepSize;
    }
  
   if (key == GLUT_KEY_LEFT) {
    blockX -= stepSize;
    }
  
   if (key == GLUT_KEY_RIGHT) {
    blockX += stepSize;
   }
  
   //觸碰到邊界（4個(gè)邊界）的處理
  
  //當(dāng)正方形移動(dòng)超過(guò)最左邊的時(shí)候
  if (blockX < -1.0f) {
    blockX = -1.0f;
  }
  
  //當(dāng)正方形移動(dòng)到最右邊時(shí)
  //1.0 - blockSize * 2 = 總邊長(zhǎng) - 正方形的邊長(zhǎng) = 最左邊點(diǎn)的位置
  if (blockX > (1.0 - blockSize * 2)) {
    blockX = 1.0f - blockSize * 2;
  }
  
  //當(dāng)正方形移動(dòng)到最下面時(shí)
  //-1.0 - blockSize * 2 = Y（負(fù)軸邊界） - 正方形邊長(zhǎng) = 最下面點(diǎn)的位置
  if (blockY < -1.0f + blockSize * 2 ) {
  
    blockY = -1.0f + blockSize * 2;
  }
  
  //當(dāng)正方形移動(dòng)到最上面時(shí)
  if (blockY > 1.0f) {
  
      blockY = 1.0f;
  
  }
  
  printf("blockX = %f\n",blockX);
  printf("blockY = %f\n",blockY);
  
  // Recalculate vertex positions
  vVerts[0] = blockX;
  vVerts[1] = blockY - blockSize*2;
  printf("(%f,%f)\n",vVerts[0],vVerts[1]);
  
  vVerts[3] = blockX + blockSize*2;
  vVerts[4] = blockY - blockSize*2;
  printf("(%f,%f)\n",vVerts[3],vVerts[4]);
  
  vVerts[6] = blockX + blockSize*2;
  vVerts[7] = blockY;
  printf("(%f,%f)\n",vVerts[6],vVerts[7]);
  
  vVerts[9] = blockX;
  vVerts[10] = blockY;
  printf("(%f,%f)\n",vVerts[9],vVerts[10]);
  
  triangleBatch.CopyVertexData3f(vVerts);
  
  glutPostRedisplay();
  }
  
  

• 通過(guò)矩陣更新坐標(biāo)的方式移動(dòng)正方形，并增加碰撞檢測(cè)

  設(shè)置矩陣渲染

  void RenderScene(void)
  {
  
      glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
  
      GLfloat vRed[] = {1.0f,0.0f,0.0f,0.0f};
  
      M3DMatrix44f mFinalTransform,mTransfromMatrix,mRotationMartix;
  
      //平移
      m3dTranslationMatrix44(mTransfromMatrix, xPos, yPos, 0.0f);
  
      //每次平移時(shí)诽凌，旋轉(zhuǎn)5度
      static float yRot = 0.0f;
      yRot += 5.0f;
      m3dRotationMatrix44(mRotationMartix, m3dDegToRad(yRot), 0.0f, 0.0f, 1.0f);
  
      //將旋轉(zhuǎn)和移動(dòng)的矩陣結(jié)果 合并到mFinalTransform （矩陣相乘）
      m3dMatrixMultiply44(mFinalTransform, mTransfromMatrix, mRotationMartix);
  
      //將矩陣結(jié)果 提交給固定著色器（平面著色器）中繪制
      shaderManager.UseStockShader(GLT_SHADER_FLAT,mFinalTransform,vRed);
      triangleBatch.Draw();
  
      //執(zhí)行交換緩存區(qū)
      glutSwapBuffers();
  
  }
  

  更新x與y坐標(biāo)移動(dòng)

  void SpecialKeys(int key, int x, int y){
  
     GLfloat stepSize = 0.025f;
  
     if (key == GLUT_KEY_UP) {
  
         yPos += stepSize;
     }
  
     if (key == GLUT_KEY_DOWN) {
         yPos -= stepSize;
     }
  
     if (key == GLUT_KEY_LEFT) {
         xPos -= stepSize;
     }
  
     if (key == GLUT_KEY_RIGHT) {
         xPos += stepSize;
     }
  
     //碰撞檢測(cè)
     if (xPos < (-1.0f + blockSize)) {
  
         xPos = -1.0f + blockSize;
     }
  
     if (xPos > (1.0f - blockSize)) {
         xPos = 1.0f - blockSize;
     }
  
     if (yPos < (-1.0f + blockSize)) {
         yPos = -1.0f + blockSize;
     }
  
     if (yPos > (1.0f - blockSize)) {
         yPos = 1.0f - blockSize;
     }
  
     glutPostRedisplay();
  
  }