1. 实验目的
练习OpenGL基础编程，实现OpenGL的颜色混合和渐变效果。
2. 实验内容和要求
按要求完成以下两个绘图，提交纸质实验报告，同时提交实验报告和代码的电子版。
I). 利用OpenGL对下面的图形进行七种颜色的渐变填充，实现彩虹效果。
II). 利用OpenGL绘制如下图形，颜色利用随机函数随机设定，实现颜色混合的效果。
3.实验结果
第一题：
源代码：
#include"pch.h" //因为我下载的是visual stdio 2017所以必须加这个头文件
#include<GL/glut.h>
#include<math.h>
#define PI 3.1415926
void init(void) {
glClearColor(1.0, 1.0, 1.0, 1.0);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(-200.0, 200.0, -200.0, 200.0);
}
void lineSegment(void) {
glClear(GL_COLOR_BUFFER_BIT);
int i;
float t, t1;
for (i = 0; i < 100; i++) {
t = PI / 100 * i;
t1 = PI / 100 * (i + 1);
glShadeModel(GL_SMOOTH);
glBegin(GL_POLYGON);
glColor3f(0, 0, 0); glVertex2f(32 * cos(t), 32 * sin(t));
glColor3f(0, 0, 0); glVertex2f(32 * cos(t1), 32 * sin(t1));
glColor3f(0, 0, 0); glVertex2f(35 * cos(t1), 35 * sin(t1));
glColor3f(0, 0, 0); glVertex2f(35 * cos(t), 35 * sin(t));
glEnd();
glBegin(GL_POLYGON);
glColor3f(0.6, 0.125, 0.94); glVertex2f(35 * cos(t), 35 * sin(t));
glColor3f(0.6, 0.125, 0.94); glVertex2f(35 * cos(t1), 35 * sin(t1));
glColor3f(0, 0, 1); glVertex2f(45 * cos(t1), 45 * sin(t1));
glColor3f(0, 0, 1); glVertex2f(45 * cos(t), 45 * sin(t));
glEnd();
glBegin(GL_POLYGON);
glColor3f(0, 0, 1); glVertex2f(45 * cos(t1), 45 * sin(t1));
glColor3f(0, 0, 1); glVertex2f(45 * cos(t), 45 * sin(t));
glColor3f(0, 1, 1); glVertex2f(55 * cos(t), 55 * sin(t));
glColor3f(0, 1, 1); glVertex2f(55 * cos(t1), 55 * sin(t1));
glEnd();
glBegin(GL_POLYGON);
glColor3f(0, 1, 1); glVertex2f(55 * cos(t), 55 * sin(t));
glColor3f(0, 1, 1); glVertex2f(55 * cos(t1), 55 * sin(t1));
glColor3f(0, 1, 0); glVertex2f(65 * cos(t1), 65 * sin(t1));
glColor3f(0, 1, 0); glVertex2f(65 * cos(t), 65 * sin(t));
glEnd();
glBegin(GL_POLYGON);
glColor3f(0, 1, 0); glVertex2f(65 * cos(t1), 65 * sin(t1));
glColor3f(0, 1, 0); glVertex2f(65 * cos(t), 65 * sin(t));
glColor3f(1, 1, 0); glVertex2f(75 * cos(t), 75 * sin(t));
glColor3f(1, 1, 0); glVertex2f(75 * cos(t1), 75 * sin(t1));
glEnd();
glBegin(GL_POLYGON);
glColor3f(1, 1, 0); glVertex2f(75 * cos(t), 75 * sin(t));
glColor3f(1, 1, 0); glVertex2f(75 * cos(t1), 75 * sin(t1));
glColor3f(1, 0.38, 0); glVertex2f(85 * cos(t1), 85 * sin(t1));
glColor3f(1, 0.38, 0); glVertex2f(85 * cos(t), 85 * sin(t));
glEnd();
glBegin(GL_POLYGON);
glColor3f(1, 0.38, 0); glVertex2f(85 * cos(t1), 85 * sin(t1));
glColor3f(1, 0.38, 0); glVertex2f(85 * cos(t), 85 * sin(t));
glColor3f(1, 0, 0); glVertex2f(95 * cos(t), 95 * sin(t));
glColor3f(1, 0, 0); glVertex2f(95 * cos(t1), 95 * sin(t1));
glEnd();
glBegin(GL_POLYGON);
glColor3f(0, 0, 0); glVertex2f(95 * cos(t1), 95 * sin(t1));
glColor3f(0, 0, 0); glVertex2f(95 * cos(t), 95 * sin(t));
glColor3f(0, 0, 0); glVertex2f(98 * cos(t), 98 * sin(t));
glColor3f(0, 0, 0); glVertex2f(98 * cos(t1), 98 * sin(t1));
glEnd();
}
glColor3f(0, 0, 0);
glLineWidth(3);
glBegin(GL_LINES);
glVertex2i(32 * cos(0), 32 * sin(0));
glVertex2i(98 * cos(0), 98 * sin(0));
glVertex2i(32 * cos(PI), 32 * sin(PI));
glVertex2i(98 * cos(PI), 98 * sin(PI));
glEnd();
glFlush();
}
void main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition(100, 100);
glutInitWindowSize(600, 600);
glutCreateWindow("彩虹");
init();
glutDisplayFunc(lineSegment);
glutMainLoop();
}
运行结果
第二题
源代码
#include"pch.h" //因为我下载的是visual stdio 2017所以必须加这个头文件
#include<GL/glut.h>
#include<math.h>
#include<stdlib.h>
#define PI 3.1415926
void init(void) {
glClearColor(1.0, 1.0, 1.0, 1.0);
glEnable(GL_BLEND);
//glBlendFunc(GL_ONE, GL_ZERO);// sFactor, dFactor
//glBlendFunc(GL_ZERO, GL_ONE);// sFactor, dFactor
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//glBlendFunc(GL_ONE, GL_ONE);
glMatrixMode(GL_PROJECTION);
gluOrtho2D(-200.0, 200.0, -200.0, 200.0);
}
void lineSegment(void) {
float a,b,c;
float t,t1;
glClear(GL_COLOR_BUFFER_BIT);
for (int i = 0; i < 10; i++) {
t = 2 * PI / 10 * i;
a = rand() % 256 / 255.0;
b = rand() % 256 / 255.0;
c = rand() % 256 / 255.0;
glColor4f(a, b, c , 0.5);
glBegin(GL_POLYGON);
for (int j = 0; j < 2000; j++) {
t1 = 2 * PI / 2000 * j;
glVertex2f(35 * cos(t) + 35 * cos(t1), 35 * sin(t)+ 35 * sin(t1));
}
glEnd();
}
glFlush();
}
void main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition(100, 100);
glutInitWindowSize(600, 600);
glutCreateWindow("扇形图");
init();
glutDisplayFunc(lineSegment);
glutMainLoop();
}
运行结果
