OPENGL渲染课后总结

实验二代码

#include <stdlib.h>
#include <stdio.h>
#include <GL/glut.h>
#define MAXN 1000
#define SIZE 500
/*
键盘1,2,3,4对应 白，红，绿，蓝
键盘Q，W,E，R,T对应 线段，矩形，三角形，四边形，五边形
可以通过鼠标右键设置上述属性，同时带有清除功能
shitf+鼠标右键可以选择图形并高亮
点击空白处即可恢复
*/
struct graphic {
	int type;
	GLfloat color[4];
	GLfloat point[5][2];
	GLenum mode;
}list[MAXN];
struct Now {
	//count 当前图形数量 type 当前绘制什么图形
	GLint count, hitsmax, hitsnow, type, last[MAXN], lastcount;//last和lastcount分别用来记录点击的图片和图片数（高亮）
	GLenum mode;
	GLfloat color[4], point[5][2], w, h;//w,h窗口宽高
}now;//现在选择模式
//设置菜单1，绘制什么图形
//now.hitsnow记录当前绘制了几个点 所以要初始化
void setMenu1(int value) {
	if (value == 1) {
		printf("123");
		now.type = 1;
		now.hitsmax = 2;
		now.hitsnow = 0;
	}
	else if (value == 2) {
		now.type = 2;
		now.hitsmax = 2;
		now.hitsnow = 0;
	}
	else if (value == 3) {
		now.type = 3;
		now.hitsmax = 3;
		now.hitsnow = 0;
	}
	else if (value == 4) {
		now.type = 4;
		now.hitsmax = 4;
		now.hitsnow = 0;
	}
	else if (value == 5) {
		now.type = 5;
		now.hitsmax = 5;
		now.hitsnow = 0;
	}
	else {
		now.count = 0;//为了防止drawObject在清除缓存后重新绘制图形（每次调用都会绘制），所以将此设置为0
		printf("123");
		glClear(GL_COLOR_BUFFER_BIT);
		glFlush();
		printf("123");

	}
}
//填充方式
void menu1(int value) {
	if (value == 1)
		now.mode = GL_FILL;
	else if (value == 2) {
		now.mode = GL_LINE;
	}
}
//菜单二 颜色
void menu2(int value) {
	//为了区分高亮，所以设置为0.7
	if (value == 1) {
		now.color[0] = 0.7;
		now.color[1] = 0.7;
		now.color[2] = 0.7;
	}
	else if (value == 2) {
		now.color[0] = 0.5;
		now.color[1] = 0;
		now.color[2] = 0;
	}
	else if(value==3)
	{
		now.color[0] = 0;
		now.color[1] = 0.5;
		now.color[2] = 0;

	}
	else if (value == 4) {
		now.color[0] = 0;
		now.color[1] = 0;
		now.color[2] = 0.5;
	}

}
void init()
{
	//菜单及菜单回调
	int menuBack1, menuBack2;
	now.hitsnow = now.count = now.lastcount = 0;
	now.type = 1;
	now.hitsmax = 2;
	glClearColor(0.0, 0.0, 0.0, 0.0);
	now.color[0] = 0.7; now.color[1] = 0.7; now.color[2] = 0.7;
	now.mode = GL_FILL;
	menuBack1 = glutCreateMenu(menu1);
	glutAddMenuEntry("填充", 1);
	glutAddMenuEntry("勾勒", 2);
	menuBack2 = glutCreateMenu(menu2);
	glutAddMenuEntry("白色", 1);
	glutAddMenuEntry("红色", 2); 
	glutAddMenuEntry("绿色", 3); 
	glutAddMenuEntry("蓝色", 4);
	glutCreateMenu(setMenu1);
	glutAddMenuEntry("创建线段(默认绘制线段)", 1);
	glutAddMenuEntry("创建矩形", 2);
	glutAddMenuEntry("创建三角形", 3);
	glutAddMenuEntry("创建四边形", 4);
	//glutAddMenuEntry("创建五边形", 5);
	glutAddMenuEntry("清屏",6);
	glutAddSubMenu("选择模式(默认填充)", menuBack1);
	glutAddSubMenu("改变颜色(默认白色)", menuBack2);
	glutAttachMenu(GLUT_RIGHT_BUTTON);
}
/*
void drawObjects(GLenum mode)
{
	if(mode == GL_SELECT) glLoadName(1);
	glColor3f(1.0, 0.0, 0.0);
	glRectf(-0.5, -0.5, 1.0, 1.0);
	if(mode == GL_SELECT) glLoadName(2);
	glColor3f(0.0, 0.0, 1.0);
	glRectf(-1.0, -1.0, 0.5, 0.5);
}
*/
void drawObjects(GLenum mode) {
	GLint i;
	for (i = 1; i <= now.count; i++) {
		if (mode == GL_SELECT)
			glLoadName(i);
		glColor3fv(list[i].color);
		glPolygonMode(GL_FRONT_AND_BACK, list[i].mode);
		if (list[i].type == 1)
		{
			glBegin(GL_LINES);
			glVertex2fv(list[i].point[0]);
			glVertex2fv(list[i].point[1]);
			glEnd();
		}
		else if (list[i].type == 2) {
			glRectfv(list[i].point[0], list[i].point[1]);
		}
		else if (list[i].type == 3) {
			glBegin(GL_POLYGON);
			glVertex2fv(list[i].point[0]);
			glVertex2fv(list[i].point[1]);
			glVertex2fv(list[i].point[2]);
			glEnd();
		}
		else if (list[i].type == 4) {
			glBegin(GL_POLYGON);
			glVertex2fv(list[i].point[0]);
			glVertex2fv(list[i].point[1]);
			glVertex2fv(list[i].point[2]);
			glVertex2fv(list[i].point[3]);
			glEnd();
		}
		else {
			glBegin(GL_POLYGON);
			glVertex2fv(list[i].point[0]);
			glVertex2fv(list[i].point[1]);
			glVertex2fv(list[i].point[2]);
			glVertex2fv(list[i].point[3]);
			glVertex2fv(list[i].point[4]);
			glEnd();
		}

	}
}
//高亮
void change(int i) {
	now.lastcount++;
	now.last[now.lastcount] = i;
	if (list[i].color[1] == 0.0)
		list[i].color[0] = 1.0;
	else {
		list[i].color[0] = 1.0;
		list[i].color[1] = 1.0;
		list[i].color[2] = 1.0;
	}
}
//用now.lastcount 记录点击数量，同时用此恢复高亮，此时通过调用drawObject函数绘制颜色
void recover() {
	for (; now.lastcount > 0; now.lastcount--) {
		if (list[now.last[now.lastcount]].color[1] == 0.0)
			list[now.last[now.lastcount]].color[0] = 0.5;
		else {
			list[now.last[now.lastcount]].color[0] = 0.5;
			list[now.last[now.lastcount]].color[1] = 0.5;
			list[now.last[now.lastcount]].color[2] = 0.5;

		}
	}
}
void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	drawObjects(GL_RENDER);
	glFlush();
}

/*  processHits prints out the contents of the
 *  selection array.
 */
void processHits(GLint hits, GLuint buffer[])
{
	unsigned int i, j;
	GLint names, *ptr;

	printf("hits = %d\n", hits);
	ptr = (GLint *)buffer;
	/*for (i = 0; i < hits; i++) {
	   names = *ptr;
	   ptr+=3;
	   for (j = 0; j < names; j++) {
		  if(*ptr==1) printf ("red rectangle\n");
		  else printf ("blue rectangle\n");
		  ptr++;
	   }
	   printf ("\n");
	}*/
	if (hits == 0) {
		recover();
		return;
	}
	//根据点击绘制高亮
	for (i = 0; i < hits; i++) {
		names = *ptr;
		ptr += 3;
		for (j = 0; j < names; j++) {
			change(*ptr);
			ptr++;
		}
	}

}
void mouse(int button, int state, int x, int y)
{
	GLuint selectBuf[SIZE];
	GLint hits, i, j;
	GLint viewport[4];
	glGetIntegerv(GL_VIEWPORT, viewport);
	if (glutGetModifiers() == GLUT_ACTIVE_SHIFT && button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
		recover();
		glSelectBuffer(SIZE, selectBuf);
		glRenderMode(GL_SELECT);
		glInitNames();
		glPushName(0);
		glMatrixMode(GL_PROJECTION);
		glPushMatrix();
		glLoadIdentity();
		gluPickMatrix((GLdouble)x, (GLdouble)(viewport[3] - y), 5.0, 5.0, viewport);
		gluOrtho2D(0, now.w, 0, now.h);
		drawObjects(GL_SELECT);
		glMatrixMode(GL_PROJECTION);
		glPopMatrix();
		glFlush();
		hits = glRenderMode(GL_RENDER);
		processHits(hits, selectBuf);
	}
	else if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
		now.point[now.hitsnow][0] = (GLdouble)x;
		now.point[now.hitsnow][1] = (GLdouble)(viewport[3] - y);
		now.hitsnow++;
		if (now.hitsnow == now.hitsmax) {
			now.count++;
			/*for (i = 0; i <= 3; i++) {
				list[now.count].color[i] = now.color[i];
				for (j = 0; j < 2; j++) {
					list[now.count].point[i][j] = now.point[i][j];
				}
			}*/
			for (i = 0; i < 3; i++) {
				list[now.count].color[i] = now.color[i];
			}
			for (i = 0; i < now.hitsmax; i++) {
				for (j = 0; j < 2; j++) {
					list[now.count].point[i][j] = now.point[i][j];
				}
			}
			list[now.count].type = now.type;
			list[now.count].mode = now.mode;
			now.hitsnow = 0;



		}
	}
	/* if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
	 {
	 glGetIntegerv (GL_VIEWPORT, viewport);

	 glSelectBuffer (SIZE, selectBuf);
	 glRenderMode(GL_SELECT);

	 glInitNames();
	 glPushName(0);

	 glMatrixMode (GL_PROJECTION);
	 glPushMatrix ();
	 glLoadIdentity ();
	 gluPickMatrix ((GLdouble) x, (GLdouble) (viewport[3] - y),
					5.0, 5.0, viewport);
	 gluOrtho2D (-2.0, 2.0, -2.0, 2.0);
	 drawObjects(GL_SELECT);


	 glMatrixMode (GL_PROJECTION);
	 glPopMatrix ();
	 glFlush ();

	 hits = glRenderMode (GL_RENDER);
	 processHits (hits, selectBuf);

	 glutPostRedisplay();
	 }*/
	glutPostRedisplay();
}


void reshape(int w, int h)
{
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0, w, 0, h);
	now.w = w;
	now.h = h;
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
	switch (key) {
	case 27:
		exit(0);
		break;
	case '1':
		now.color[0] = 0.7;
		now.color[1] = 0.7;
		now.color[2] = 0.7;
		break;
	case '2':
		now.color[0] = 0.5;
		now.color[1] = 0;
		now.color[2] = 0;
		break;
	case '3':
		now.color[0] = 0;
		now.color[1] = 0.5;
		now.color[2] = 0;
		break;
	case '4':
		now.color[0] = 0;
		now.color[1] = 0;
		now.color[2] = 0.5;
		break;
	case 'q':
		now.type = 1;
		now.hitsmax = 2;
		now.hitsnow = 0;
		break;
	case 'w':
		now.type = 2;
		now.hitsmax = 2;
		now.hitsnow = 0;
		break;
	case 'e':
		now.type = 3;
		now.hitsmax = 3;
		now.hitsnow = 0;
		break;
	case 'r':
		now.type = 4;
		now.hitsmax = 4;
		now.hitsnow = 0;
		break;
	case 't':
		now.type = 5;
		now.hitsmax = 5;
		now.hitsnow = 0;
		break;
	}
}

/* Main Loop */
int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(500, 500);
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);
	init();
	glutReshapeFunc(reshape);
	glutDisplayFunc(display);
	glutMouseFunc(mouse);
	glutKeyboardFunc(keyboard);
	glutMainLoop();
	return 0;
}