先决条件– OpenGL
OpenGL是一种跨语言，跨平台的API，用于渲染2D和3D矢量图形。使用此功能，我们可以制作很多设计以及动画。下面是一个使用OpenGL制作的简单游戏。
Description(说明)：在这种情况下，球从中间开始移动，并在开始时向左上方移动。但是，然后它与墙壁碰撞并改变方向，但速度保持不变。因此，它到达了向下的方向，在该方向上应该被捕获在一个矩形上(该矩形可以在水平方向上移动)以便继续。
对于在Ubuntu操作系统上工作：
gcc filename.c -lGL -lGLU -lglut -lm
where filename.c is the name of the file
with which this program is saved.
// C program to illustrate OpenGL game
#include
#include
#include
#define pi 3.142857
// Global Declaration
// c and d tracks the number of time 'b' and 'n' pressed respectively
// left and right indicates leftmost and rightmost index of movable rectangle
int c = 0, d = 0, left = 0, right = 0;
int m = 0, j = 1, flag1 = 0, l = 1, flag2 = 0, n = 0, score = 0, count = 1;
// Initialization function
void myInit (void)
{
// Reset background color with white (since all three argument is 1.0)
glClearColor(1.0, 1.0, 1.0, 0.0);
// Set picture color to red (in RGB model)
// as only argument corresponding to R (Red) is 1.0 and rest are 0.0
glColor3f(1.0f, 0.0f, 0.0f);
// Set width of point to one unit
glPointSize(1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
// Set window size in X- and Y- direction
gluOrtho2D(-620.0, 620.0, -340.0, 340.0);
}
// keyboard function : it gets active when button pressed
void keyboard(unsigned char key, int x, int y)
{
left = -200 + 200 * (d - c);
right = 200 + 200 * (d - c);
// if leftmost index of window is hit
// then rectangle will not move to left on furthure pressing of b
// only it will move to right on pressing n
if (left == -600)
{
// '110' -> Ascii value of 'n'
// so d is incremented when n is pressed
if (key == 110)
d++;
}
// if rightmost index of window is hit
// then rectangle will not move to right on furthure pressing of n
// only it will move to left on pressing b
else if (right == 600)
{
// '98' -> Ascii value of 'b'
// so c is incremented when b is pressed
if (key == 98)
c++;
}
// when rectangle is in middle, then it will move into both
// direction depending upon pressed key
else
{
if (key == 98)
c++;
if (key == 110)
d++;
}
glutPostRedisplay();
}
void myDisplay(void)
{
// x and y keeps point on circumference of circle
int x, y, k;
// outer 'for loop' is to for making motion in ball
for (k = 0; k <= 400; k += 5)
{
glClear(GL_COLOR_BUFFER_BIT);
glBegin(GL_LINE_STRIP);
// i keeps track of angle
float i = 0;
// change in m denotes motion in vertical direction and
// change in n denotes motion in horizontal direction
m = m + 6;
n = n + 4;
// drawing of circle centre at (0, 12) iterated up to 2*pi, i.e., 360 degree
while (i <= 2 * pi)
{
y = 12 + 20 * cos(i);
x = 20 * sin(i);
i = i + 0.1;
// flag1 is 0 to show motion in upward direction and is 1 for downward direction
if (m == 288 && flag1 == 0)
{
j = -1;
m = -288;
flag1 = 1;
score++;
}
if (m == 288 && flag1 == 1)
{
j = 1;
m = -288;
flag1 = 0;
}
// flag2 is 0 to show motion in rightward direction and is 1 for leftward direction
if (n == 580 && flag2 == 0)
{
l = -1;
n = -580;
flag2 = 1;
}
if (n == 580 && flag2 == 1)
{
l = 1;
n = -580;
flag2 = 0;
}
// equation for desired motion of ball
glVertex2i((x - l * n), (y - j * m));
}
glEnd();
// these four points draws outer rectangle which determines window
glBegin(GL_LINE_LOOP);
glVertex2i(-600, -320);
glVertex2i(-600, 320);
glVertex2i(600, 320);
glVertex2i(600, -320);
glEnd();
// these four points draws smaller rectangle which is for catching ball
glBegin(GL_LINE_LOOP);
left = -200 + 200 * (d - c);
right = 200 + 200 * (d - c);
glVertex2i(left, -315);
glVertex2i(left, -295);
glVertex2i(right, -295);
glVertex2i(right, -315);
glEnd();
// following condition checks if falling ball is catched on rectangle or not
if ((j * m) == 276)
{
if ((left > ((-1 * l * n) + 20)) || (right < (-1 * l * n) - 20))
{
printf("Game Over !!!\nYour Score is :\t%d\n", score);
exit(0);
}
}
glutSwapBuffers();
}
}
// Driver Program
int main (int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
// Declares window size
glutInitWindowSize(1100, 600);
// Declares window position which is (0, 0)
// means lower left corner will indicate position (0, 0)
glutInitWindowPosition(0, 0);
// Name to window
glutCreateWindow("Game");
// keyboard function
glutKeyboardFunc(keyboard);
// Call to myInit()
myInit();
glutDisplayFunc(myDisplay);
glutMainLoop();
}
以下是动画的屏幕截图。该屏幕快照仅是一个实例。实际上，球会朝不同的方向移动，应该抓住较小的矩形。按下小写b可以向左移动矩形，按下小写n可以向右移动矩形。但是，可以通过更改键盘函数中的代码(其中可以更改键的ASCII值)来更改此代码。
想要从精选的最佳视频中学习和练习问题，请查看《基础知识到高级C的C基础课程》。