glut生成opengl反弹小方块效果

利用opengl实现了反弹小方块的效果，蓝宝书代码并不全，所以自己实现了没有缺少的部分。

#include "../../shared/gltools.h"

GLfloat x1 = 0.0f;

GLfloat y1 = 0.0f;

GLfloat rSize = 50.0f;

GLfloat xStep = 5.0f;

GLfloat yStep = 5.0f;

GLfloat windowWidth = 400;

GLfloat windowHeight = 300;

void RenderScene(void){

glClear(GL_COLOR_BUFFER_BIT);

glColor3f(1.0f,0.0f,0.0f);

glRectf(x1,y1,x1+rSize,y1-rSize);

glutSwapBuffers();

}

void Change(GLsizei w,GLsizei h){

GLfloat aspectRatio;

if(h==0)

h=1;

glViewport(0,0,w,h);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

aspectRatio = (GLfloat)w/(GLfloat)h;

if(w<=h){

glOrtho(-h/2,h/2,-w/2*aspectRatio,w/2*aspectRatio,1.0,-1.0);

windowWidth = w/2*aspectRatio;

windowHeight = h/2;

}

else{

glOrtho(-h/2*aspectRatio,h/2*aspectRatio,-w/2,w/2,1.0,-1.0);

windowWidth = h/2*aspectRatio;

windowHeight = w/2;

}

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

}

void SetClearColor(void){

glClearColor(0.0f,0.0f,1.0f,1.0f);

}

void TimerFunction(int value){

if(x1>windowWidth - rSize || x1< -windowWidth)

xStep = -xStep;

if(y1>windowHeight || y1<-windowHeight+rSize)

yStep = -yStep;

x1+=xStep;

y1+=yStep;

if(x1>(windowWidth-rSize+xStep))

x1=windowWidth - rSize -1;

else if(x1<-(windowWidth+xStep))

x1=-windowWidth -1;

if(y1>(windowHeight+yStep))

y1=windowHeight - 1;

else if(y1<-(windowHeight-rSize+yStep))

y1=-windowHeight+rSize-1;

glutPostRedisplay();

glutTimerFunc(33,TimerFunction,1);

}

int main(int argc,char* argv[]){

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);

glutInitWindowSize(800,600);

glutCreateWindow("lqwang");

glutDisplayFunc(RenderScene);

glutReshapeFunc(Change);

glutTimerFunc(33,TimerFunction,1);

SetClearColor();

glutMainLoop();

return 0;

}