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我画了一个圆圈并尝试添加鼠标事件,这改变了圆圈的颜色我找不到好的来源
这是整个代码:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define window_width 1080
#define window_height 720
void drawFilledSun() {
//static float angle;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0, 0, -10);
int i, x, y;
double radius = 0.30;
//glColor3ub(253, 184, 19);
glColor3ub(255, 0, 0);
double twicePi = 2.0 * 3.142;
x = 0, y = 0;
glBegin(GL_TRIANGLE_FAN); //BEGIN CIRCLE
glVertex2f(x, y); // center of circle
for (i = 0; i <= 20; i++) {
glVertex2f(
(x + (radius * cos(i * twicePi / 20))), (y + (radius * sin(i * twicePi / 20)))
);
}
glEnd(); //END
}
void main_loop_function() {
int c;
drawFilledSun();
glutSwapBuffers();
c = getchar();
}
void GL_Setup(int width, int height) {
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glEnable(GL_DEPTH_TEST);
gluPerspective(45, (float)width / height, .1, 100);
glMatrixMode(GL_MODELVIEW);
}
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitWindowSize(window_width, window_height);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
glutCreateWindow("GLUT Example!!!");
glutIdleFunc(main_loop_function);
GL_Setup(window_width, window_height);
glutMainLoop();
}
最佳答案
为太阳的红色绿色和蓝色分量添加一个数组和一个颜色索引:
int color_i = 0;
GLubyte color[][3] = { {255, 0, 0 }, {253, 184, 19} };
使用颜色数组设置颜色属性
void drawFilledSun() {
// [...]
glColor3ubv(color[color_i]);
摆脱
getchar
在 main_loop_function
,它会阻止窗口响应。但请调用 glutPostRedisplay
持续更新窗口:void main_loop_function() {
drawFilledSun();
glutSwapBuffers();
glutPostRedisplay();
}
使用
glutDisplayFunc
而不是 glutIdleFunc
并添加 glutMouseFunc
打回来:int main(int argc, char** argv) {
// [...]
glutDisplayFunc(main_loop_function);
glutMouseFunc( mouseFunc );
在鼠标回调中更改颜色索引:
void mouseFunc(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
color_i = (color_i == 0) ? 1 : 0;
}
}
请参阅示例:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define window_width 1080
#define window_height 720
int color_i = 0;
GLubyte color[][3] = { {255, 0, 0 }, {253, 184, 19} };
void drawFilledSun() {
//static float angle;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glTranslatef(0, 0, -10);
int i, x, y;
double radius = 0.30;
glColor3ubv(color[color_i]);
double twicePi = 2.0 * 3.142;
x = 0, y = 0;
glBegin(GL_TRIANGLE_FAN); //BEGIN CIRCLE
glVertex2f(x, y); // center of circle
for (i = 0; i <= 20; i++) {
glVertex2f(
(x + (radius * cos(i * twicePi / 20))), (y + (radius * sin(i * twicePi / 20)))
);
}
glEnd(); //END
}
void main_loop_function() {
drawFilledSun();
glutSwapBuffers();
glutPostRedisplay();
}
void GL_Setup(int width, int height) {
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glEnable(GL_DEPTH_TEST);
gluPerspective(45, (float)width / height, .1, 100);
glMatrixMode(GL_MODELVIEW);
}
void mouseFunc(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
color_i = (color_i == 0) ? 1 : 0;
}
}
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitWindowSize(window_width, window_height);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
glutCreateWindow("GLUT Example!!!");
glutDisplayFunc(main_loop_function);
glutMouseFunc( mouseFunc );
GL_Setup(window_width, window_height);
glutMainLoop();
}
关于c++ - 添加鼠标事件来改变简单圆圈的颜色,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/61491993/