基于图形之能动起来的语法基础
操纵矩阵堆栈
-
矩阵堆栈的操作
- 入栈（保存当前矩阵）
- 出栈（恢复上一次保存的矩阵）
-
一切变换操作，都通过矩阵来完成的
-
入栈
- 保存当前变换效果
- 实现函数：
glPushMatrix
-
出栈
- 恢复上一次保存的矩阵
- 实现函数：
glPopMatrix
-
入栈
void glPushMatrix() -
功能：
- 保存当前变换矩阵
-
函数：无
-
返回值：无
-
备注：
- 将当前矩阵压入栈顶
-
出栈
-
void glPopMatrix() -
功能：
- 恢复上一次保存的矩阵
-
函数：无
-
返回值：无
-
备注：
- 将栈顶矩阵恢复成当前矩阵
- 如果矩阵堆栈中只有一个矩阵，将导致错误
1.左右平移（按左右键）：
#include
#include
#include
GLfloat step = 0.0f;//！！！！
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glPushMatrix();
glTranslated(step, 0.0f, 0.0f);//平移
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_TRIANGLES);
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glEnd();
glPopMatrix();
glFlush();
}
void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_LEFT)
step -= 0.1f;
if(key == GLUT_KEY_RIGHT)
step += 0.1f;
glutPostRedisplay();
}
int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( "OpenGL Examples!" );
glutSpecialFunc(SpecialKeys);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
-
平移
void glTranslatef(GLfloat x, GLfloat y, GLfloat z) -
功能：
- 场景平移
-
参数：
- x: X轴方向平移的距离
- y: Y轴方向平移的距离
- z: Z轴方向平移的距离
-
返回值:无
2.缩放
-
void glScalef(GLfloat x, GLfloat y, GLfloat z) -
功能：
- 场景缩放
-
参数：
- x: X轴方向的缩放因子
- y: Y轴方向的缩放因子
- z: Z轴方向的缩放因子
-
返回值:无
-
备注：无
#include
#include
#includeGLfloat step = 1.0f;//！！！！！
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glPushMatrix();glScalef(step, step, step);//缩放
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_TRIANGLES);
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glEnd();glPopMatrix();
glFlush();
}
void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_LEFT)
step -= 0.1f;
if(key == GLUT_KEY_RIGHT)
step += 0.1f;glutPostRedisplay();
}int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( “OpenGL Examples!” );
glutSpecialFunc(SpecialKeys);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
3.旋转
#include
#include
#include
GLfloat step = 0.0f;
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glPushMatrix();
glRotatef(step, 0.0f, 0.0f, 1.0f);
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_TRIANGLES);
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glEnd();
glPopMatrix();
glFlush();
}
void SpecialKeys(int key, int x, int y)//键盘控制
{
if(key == GLUT_KEY_UP)
step += 30.0f;
if(key == GLUT_KEY_DOWN)
step -= 30.0f;
step = (GLfloat)((int)step % 360);
glutPostRedisplay();
}
int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( "OpenGL Examples!" );
glutSpecialFunc(SpecialKeys);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
-
void glRotatef(GLfloat angle, GLfloat x, GLfloat y, GLfloat z) -
功能：
- 场景旋转
-
参数：
- angle: 旋转的角度
- x，y，z: 用于指定旋转轴
-
备注：
- 绕原点（0,0,0）到（x,y,z）的直线逆时针旋转angle个角度
#include
#include
#includeGLfloat step = 0.0f;
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glColor3f(1.0, 1.0, 0.0);
glPointSize(10);
glBegin( GL_POINTS );
glVertex2f( 0.0, 0.0 );
glEnd();glPushMatrix();
glTranslatef(0.2f,0.2f,0.0f);
glRotatef(step, 0.0f, 0.0f, 1.0f);
//glTranslatef(0.2f,0.2f,0.0f);
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_POLYGON );
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glVertex2f( 0.2, -0.2 );
glEnd();glPopMatrix();
glFlush();}
void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_UP)
step += 1.0f;
if(key == GLUT_KEY_DOWN)
step -=1.0f;
glutPostRedisplay();
}int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( “OpenGL Examples!” );
glutSpecialFunc(SpecialKeys);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
…
#include
#include
#include
#include
GLfloat step = 0.0f;
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glPushMatrix();
GLfloat rotateYMatrix[]=
{
cos(step),sin(step),0.0f,0.0f,
-sin(step),cos(step),0.0f,0.0f,
0.0f,0.0f,1.0f,0.0f,
0.0f,0.0f,0.0f,1.0f
};
glMultMatrixf(rotateYMatrix);
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_TRIANGLES);
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glEnd();
glPopMatrix();
glFlush();
}
void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_UP)
step += 0.2f;
if(key == GLUT_KEY_DOWN)
step -= 0.2f;
glutPostRedisplay();
}
int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( "OpenGL Examples!" );
glutSpecialFunc(SpecialKeys);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
…
平移+旋转
#include
#include
#include
#include
GLfloat step = 0.0f;
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glColor3f(1.0, 1.0, 0.0);
glPointSize(10);
glBegin( GL_POINTS );
glVertex2f( 0.0, 0.0 );
glEnd();
glPushMatrix();
glTranslatef(step,0.2f,0.0f);
glRotatef((step*100), 0.0f, 0.0f, 1.0f);
//glTranslatef(0.2f,0.2f,0.0f);
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_POLYGON );
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glVertex2f( 0.2, -0.2 );
glEnd();
glPopMatrix();
glFlush();
}
void SpecialKeys(int key, int x, int y)
{
if(key == GLUT_KEY_UP)
step += 0.1f;
if(key == GLUT_KEY_DOWN)
step -= 0.1f;
glutPostRedisplay();
}
int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( "OpenGL Examples!" );
glutSpecialFunc(SpecialKeys);
glutDisplayFunc( display );
glutMainLoop();
return 0;
}
…
-
先旋转再平移
glRotatef(step, 0.0f, 0.0f, 1.0f);
glTranslatef(0.2f,0.2f,0.0f);
先旋转后平移，相当于旋转中心点为（0,0,0）
4.键盘操控：用ad控制
#include
#include
#include
GLfloat step = 0.0f;
void display()
{
glClear( GL_COLOR_BUFFER_BIT );
glColor3f(1.0, 1.0, 0.0);
glPointSize(10);
glBegin( GL_POINTS );
glVertex2f( 0.0, 0.0 );
glEnd();
glPushMatrix();
glTranslatef(0.2f,0.2f,0.0f);
glRotatef(step, 0.0f, 0.0f, 1.0f);
//glTranslatef(0.2f,0.2f,0.0f);
glColor3f( 0.0, 1.0, 0.0 );
glBegin( GL_POLYGON );
glVertex2f( -0.2, -0.2 );
glVertex2f( -0.2, 0.2 );
glVertex2f( 0.2, 0.2 );
glVertex2f( 0.2, -0.2 );
glEnd();
glPopMatrix();
glFlush();
}
void NormalKeys(unsigned char key, int x, int y)//键盘
{
if(key == 'a')
step += 5.0f;
if(key == 'd')
step -= 5.0f;
step = (GLfloat)((int)step % 360);
glutPostRedisplay();
}
int main( int argc, char ** argv )
{
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowPosition( 100, 100 );
glutInitWindowSize( 400, 400 );
glutCreateWindow( "OpenGL Examples!" );
//glutSpecialFunc(SpecialKeys);
glutKeyboardFunc(NormalKeys);//！！！！！！！！！！
glutDisplayFunc( display );
glutMainLoop();
return 0;
}