SGL基本思路讲解

SGL图形库是为Windows图形界面编程服务的，而且一切都是考虑到对新手友好的。在具体介绍提供给用户的函数之前，需要先说明一下应该以什么样的思路来构思我们的SGL程序。

作为C语言程序，main函数总是需要在最开始就了解一下的。在SGL库中，可以将main理解为

void main(){    sgSetup();    while(1){        sgLoop();    }}

其中sgSetup函数和sgLoop函数都是需要由用户来完成的，也就是说我们负责初始化我们的SGL程序然后完成其中的循环逻辑就可以了。其根本思路就是，setup函数里设置与窗口鼠标键盘有关的属性，loop函数绘制每一帧的图案。所以，SGL程序是不会自动结束的，要结束程序的话，可以调用exit(0)这样的函数来实现。

至于loop函数里的逻辑该怎么实现，有两种方法。举个抽象点的例子，比如y = x的平方，我们要依次求出x为1,2,3…的y值，我们既可以每次直接计算x的平方，也可以根据上一次计算的y’来计算当前的y = y’ + 2*x - 1。那么这两种思路也可以应用到我们的SGL程序中。我们既可以直接算出每次loop中需要计算的变量，也可以根据上一次loop的结果进行迭代。两种方法的主要区别在于效率，需要具体情况具体分析。

下面给大家贴一个用SGL实现的简单小游戏，可以简单了解一下程序的结构，里面函数的具体用法后续文章会讨论。

#include "winsgl.h"#define inRect(x, y, x1, y1, x2, y2) ((x>=x1&&x<=x2)&&(y>=y1&&y<=y2))#define speedUp(e) (e+=e>0?2:-2)void movePlayer(int x, int y);void moveEnemy();int hasCollision();struct _player {vecTwo pos;bitMap *oldImage;}player;struct _enemy {vecTwo pos;vecTwo vel;bitMap *oldImage;}enemy1, enemy2, enemy3, enemy4;int liveTime = 0;void sgSetup() {initWindow(640, 640, "Collision --SGL Sample Game", BIT_MAP);initMouse(SG_COORDINATE);player.oldImage = (bitMap*)malloc(sizeof(bitMap));enemy1.oldImage = (bitMap*)malloc(sizeof(bitMap));enemy2.oldImage = (bitMap*)malloc(sizeof(bitMap));enemy3.oldImage = (bitMap*)malloc(sizeof(bitMap));enemy4.oldImage = (bitMap*)malloc(sizeof(bitMap));}void sgLoop() {static int first = 1, cont = 0, drag = 0;vecTwo position;int press;if (first) {loadBmp(0, 0, "Source\\collision\\background.bmp");player.pos.x = player.pos.y = 290;enemy1.pos.x = 120;enemy1.pos.y = 100;enemy2.pos.x = 432;enemy2.pos.y = 120;enemy3.pos.x = 100;enemy3.pos.y = 432;enemy4.pos.x = 480;enemy4.pos.y = 480;enemy1.vel.x = enemy1.vel.y = enemy2.vel.y = enemy3.vel.x = 4;enemy4.vel.x = enemy4.vel.y = enemy3.vel.y = enemy2.vel.x = -4;getImage(player.pos.x, player.pos.y, player.pos.x + 59, player.pos.y + 59, player.oldImage);getImage(enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63, enemy1.oldImage);getImage(enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31, enemy2.oldImage);getImage(enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95, enemy3.oldImage);getImage(enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51, enemy4.oldImage);setColor(255, 0, 0);putQuad(player.pos.x, player.pos.y, player.pos.x + 59, player.pos.y + 59, SOLID_FILL);setColor(0, 0, 255);putQuad(enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63, SOLID_FILL);putQuad(enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31, SOLID_FILL);putQuad(enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95, SOLID_FILL);putQuad(enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51, SOLID_FILL);first = 0;}press = mouseStatus(SG_LEFT_BUTTON);position = mousePos();setColor(0, 0, 0);putQuad(0, 0, 639, 39, SOLID_FILL);setColor(255, 255, 0);putNumber(liveTime, 640, 0, 'r');if (hasCollision()) {first = 1;cont = 0;drag = 0;return;}if (press==SG_BUTTON_DOWN&&(inRect(position.x, position.y, player.pos.x, player.pos.y, player.pos.x+59, player.pos.y+59)||drag)) {if(!cont)liveTime = 0;cont = drag = 1;movePlayer(position.x - 29, position.y - 29);}if (press == SG_BUTTON_UP && inRect(position.x, position.y, player.pos.x, player.pos.y, player.pos.x + 59, player.pos.y + 59))drag = 0;if (!cont)return;else {moveEnemy();delayEnd(20);delayBegin();liveTime += 24;}}void movePlayer(int x, int y) {putImage(player.pos.x, player.pos.y, player.oldImage, COPY_PUT);setColor(255, 0, 0);player.pos.x = x;player.pos.y = y;free(player.oldImage->data);getImage(player.pos.x, player.pos.y, player.pos.x + 83, player.pos.y + 63, player.oldImage);putQuad(player.pos.x, player.pos.y, player.pos.x + 59, player.pos.y + 59, SOLID_FILL);}void moveEnemy() {putImage(enemy1.pos.x, enemy1.pos.y, enemy1.oldImage, COPY_PUT);putImage(enemy2.pos.x, enemy2.pos.y, enemy2.oldImage, COPY_PUT);putImage(enemy3.pos.x, enemy3.pos.y, enemy3.oldImage, COPY_PUT);putImage(enemy4.pos.x, enemy4.pos.y, enemy4.oldImage, COPY_PUT);if (liveTime % 10000 < 24) {speedUp(enemy1.vel.x);speedUp(enemy1.vel.y);speedUp(enemy2.vel.x);speedUp(enemy2.vel.y);speedUp(enemy3.vel.x);speedUp(enemy3.vel.y);speedUp(enemy4.vel.x);speedUp(enemy4.vel.y);}enemy1.pos.x += enemy1.vel.x;enemy1.pos.y += enemy1.vel.y;enemy2.pos.x += enemy2.vel.x;enemy2.pos.y += enemy2.vel.y;enemy3.pos.x += enemy3.vel.x;enemy3.pos.y += enemy3.vel.y;enemy4.pos.x += enemy4.vel.x;enemy4.pos.y += enemy4.vel.y;if (enemy1.pos.x < 0) {enemy1.pos.x = -enemy1.pos.x;enemy1.vel.x = -enemy1.vel.x;}if (enemy1.pos.x > 555) {enemy1.pos.x = 1110-enemy1.pos.x;enemy1.vel.x = -enemy1.vel.x;}if (enemy1.pos.y < 0) {enemy1.pos.y = -enemy1.pos.y;enemy1.vel.y = -enemy1.vel.y;}if (enemy1.pos.y > 575) {enemy1.pos.y = 1150 - enemy1.pos.y;enemy1.vel.y = -enemy1.vel.y;}if (enemy2.pos.x < 0) {enemy2.pos.x = -enemy2.pos.x;enemy2.vel.x = -enemy2.vel.x;}if (enemy2.pos.x > 503) {enemy2.pos.x = 1006 - enemy2.pos.x;enemy2.vel.x = -enemy2.vel.x;}if (enemy2.pos.y < 0) {enemy2.pos.y = -enemy2.pos.y;enemy2.vel.y = -enemy2.vel.y;}if (enemy2.pos.y > 607) {enemy2.pos.y = 1214 - enemy2.pos.y;enemy2.vel.y = -enemy2.vel.y;}if (enemy3.pos.x < 0) {enemy3.pos.x = -enemy3.pos.x;enemy3.vel.x = -enemy3.vel.x;}if (enemy3.pos.x > 579) {enemy3.pos.x = 1158 - enemy3.pos.x;enemy3.vel.x = -enemy3.vel.x;}if (enemy3.pos.y < 0) {enemy3.pos.y = -enemy3.pos.y;enemy3.vel.y = -enemy3.vel.y;}if (enemy3.pos.y > 543) {enemy3.pos.y = 1086 - enemy3.pos.y;enemy3.vel.y = -enemy3.vel.y;}if (enemy4.pos.x < 0) {enemy4.pos.x = -enemy4.pos.x;enemy4.vel.x = -enemy4.vel.x;}if (enemy4.pos.x > 575) {enemy4.pos.x = 1150 - enemy4.pos.x;enemy4.vel.x = -enemy4.vel.x;}if (enemy4.pos.y < 0) {enemy4.pos.y = -enemy4.pos.y;enemy4.vel.y = -enemy4.vel.y;}if (enemy4.pos.y > 588) {enemy4.pos.y = 1176 - enemy4.pos.y;enemy4.vel.y = -enemy4.vel.y;}free(enemy1.oldImage->data);free(enemy2.oldImage->data);free(enemy3.oldImage->data);free(enemy4.oldImage->data);getImage(enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63, enemy1.oldImage);getImage(enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31, enemy2.oldImage);getImage(enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95, enemy3.oldImage);getImage(enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51, enemy4.oldImage);setColor(0, 0, 255);putQuad(enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63, SOLID_FILL);putQuad(enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31, SOLID_FILL);putQuad(enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95, SOLID_FILL);putQuad(enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51, SOLID_FILL);}int hasCollision() {if (inRect(player.pos.x, player.pos.y, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x, player.pos.y + 29, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x, player.pos.y + 59, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x + 29, player.pos.y, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x + 29, player.pos.y + 59, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x + 59, player.pos.y, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x + 59, player.pos.y + 29, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x + 59, player.pos.y + 59, enemy1.pos.x, enemy1.pos.y, enemy1.pos.x + 83, enemy1.pos.y + 63))return 1;if (inRect(player.pos.x, player.pos.y, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x, player.pos.y + 29, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x, player.pos.y + 59, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x + 29, player.pos.y, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x + 29, player.pos.y + 59, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x + 59, player.pos.y, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x + 59, player.pos.y + 29, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x + 59, player.pos.y + 59, enemy2.pos.x, enemy2.pos.y, enemy2.pos.x + 135, enemy2.pos.y + 31))return 1;if (inRect(player.pos.x, player.pos.y, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x, player.pos.y + 29, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x, player.pos.y + 59, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x + 29, player.pos.y, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x + 29, player.pos.y + 59, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x + 59, player.pos.y, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x + 59, player.pos.y + 29, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x + 59, player.pos.y + 59, enemy3.pos.x, enemy3.pos.y, enemy3.pos.x + 59, enemy3.pos.y + 95))return 1;if (inRect(player.pos.x, player.pos.y, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x, player.pos.y + 29, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x, player.pos.y + 59, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x + 29, player.pos.y, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x + 29, player.pos.y + 59, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x + 59, player.pos.y, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x + 59, player.pos.y + 29, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (inRect(player.pos.x + 59, player.pos.y + 59, enemy4.pos.x, enemy4.pos.y, enemy4.pos.x + 63, enemy4.pos.y + 51))return 1;if (!inRect(player.pos.x, player.pos.y, 40, 40, 539, 539))return 1;return 0;}

代码是很久很久之前写的了，看起来冗余程度很高，不过我也懒得优化了。

里面用到的背景图片我上传了，可以根据自己的审美p图，让这个程序看起来好看一点。需要注意的一点就是四周那个黑框是有作用的，需要保留，中间的空白可以换成自己喜欢的图片。但是，我没换过背景图片，不保证没有bug。