在没有GL OpenGL矩阵函数的情况下使用矩阵移动三角形

如果没有OpenGL矩阵函数，我不知道如何做到这一点。

通过将每个顶点位置乘以2D来变换三角形仿射缩放、旋转或平移矩阵，如下所述通过键盘输入。

键盘输入：

's' key, scale by 1.1 units in X and Y
'r' key, rotate clockwise (in XY plane) by 2.0 degrees
't' key, translate 0.1 unit in X and Y
'q' key, quit program

您不能使用OpenGL矩阵函数，如glScale、glTranslate或glRotate来执行转换

这就是我目前所拥有的。。。当我构建程序时，三角形不会移动，但按下一些键后我会得到随机数，所以我知道它在做什么：

#include <iostream>
using namespace std;
#include <math.h>
#include <GLUT/glut.h>
void myInit();
void myDraw();
void keyboard( unsigned char, int, int );
float sum;

float theta = 3.14;
int k = 0;
float cVert[3][2]= 
{ 
  -1.0, -1.0, 
  1.0, -1.0,
  0.0, 1.0
};
float triVert[3][2] = 
{
    -1.0, -1.0, 
    1.0, -1.0,
    0.0, 1.0
};
float rotVert[3][3] =
{
  1,0,0,
  0, cos(theta), -sin(theta),
  0, sin(theta), cos(theta)
};
float scaleVert[3][2] =
{
  1.1, 0.0,
  0.0, 1.1, 
  0.0, 0.0
};
int main( int argc, char *argv[] )
{   
  // Initialize window system 
  glutInit( &argc, argv );
  glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
  glutInitWindowSize( 640, 480 );
  glutCreateWindow( "Lab 4" );
  // Initialize graphics 
  myInit();
  // Callbacks
  glutDisplayFunc( myDraw );
    glutKeyboardFunc( keyboard );
    // Event loop 
  glutMainLoop();
}
// Initialize drawing
void myInit()
{
  // Background color 
  glClearColor(0.0, 0.0, 0.0, 1.0);
  // 2D world projection
  glMatrixMode( GL_PROJECTION );
  glLoadIdentity();
  gluOrtho2D( -10.0, 10.0, -10.0, 10.0 );
}
// Display callback 
void myDraw()
{
    // Clear the screen 
  glClearColor(0.0, 0.0, 0.0, 1.0);
  glClear(GL_COLOR_BUFFER_BIT );
  // // Draw triangle in initial position
  // glColor3f( 1.0, 0.0, 0.0 );
  // glBegin( GL_LINE_LOOP );
     //  glVertex2f( triVert[0][0], triVert[0][1] );
        // glVertex2f( triVert[1][0], triVert[1][1] );
        // glVertex2f( triVert[2][0], triVert[2][1] );
  // glEnd();
  // Draw triangle in new position here
  glBegin( GL_LINE_LOOP );
    glColor3f( 0.0, 1.0, 0.0 );
    glVertex2f(cVert[0][0], cVert[0][1]);
    glVertex2f(cVert[1][0], cVert[1][1]);
    glVertex2f(cVert[2][0], cVert[2][1]);
    cout << cVert[3][2] << " ";
  glEnd();
  // Execute draw commands 
  glFlush();
}
// Keyboard callback 
void keyboard( unsigned char key, int x, int y )
{
  // Process keys 
  switch (key)
    {
  case 's': //scale by 1.1 units in X and Y
      for(k=0;k<3;++k)
       {
        cVert[3][2] = cVert[3][2]+(scaleVert[3][2]*triVert[3][2]);
        cout << cVert[3][2]<<" ";
        }
      break;
  case 'r': //rotate clockwise (in XY plane) by 2.0 degrees
       for(k=0;k<3;++k)
       {
        cVert[3][2] = cVert[3][2]+(rotVert[3][3]*triVert[3][2]);
        theta = theta + 2.0;
         cout << cVert[3][2]<<" ";
         cout << theta << " ";
        }
      break;
  case 't': //translate 0.1 unit in X and Y
      break;
    case 'q':                       // exit program
      exit(1);
      break;
    }
  // Redraw the scene 
  glutPostRedisplay();
}