我希望能得到一个由四个三角形组成的小动画。我写了几个版本的代码,但是没有一个版本能够正常运行。结果就是我只看到了一个黑色的空白屏幕。 我的代码:
#define GLUT_DISABLE_ATEXIT_HACK
#define TIMERSECS 20
#include <windows.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <GL/GL.H>
#include <stdlib.h>
float arc = 0.0f;
void draw_traingle(float x0, float y0, float x1, float y1, float x2, float y2) {
glColor4f(0.0f, 0.0f, 1.0f, 1.0f); //Blue
glVertex2f(x0, y0);
glVertex2f(x1, y1);
glVertex2f(x2, y2);
}
void draw(void) {
glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT);
glRotatef(arc, 1.0f,0.0f,0.0f);
glBegin(GL_POLYGON);
float center_x = 300.0f;
float center_y = 300.0f;
float up_x = center_x;
float up_y = 250.0f;
float down_x = center_x;
float down_y = 350.0f;
float right_x = 350.0f;
float right_y = center_y;
float left_x = 250.0f;
float left_y = center_y;
glPushMatrix();
draw_traingle(up_x, up_y, right_x, right_y, center_x, center_y);
draw_traingle(right_x, right_y, down_x, down_y, center_x, center_y);
draw_traingle(down_x, down_y, left_x, left_y, center_x, center_y);
draw_traingle(left_x, left_y, up_x, up_y, center_x, center_y);
glPopMatrix();
glEnd();
glFlush();
glutSwapBuffers();
}
void handleKeypress(unsigned char key, int x, int y) {
switch (key) {
case 27:
exit(0);
}
}
void init(void) {
glClearColor(0.0, 0.0, 0.0, 0.0);
glViewport(0, 0, 600, 600);
glMatrixMode(GL_PROJECTION);
glLoadIdentity(); //=1
gluOrtho2D(0.0, 600.0, 0.0, 600.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity(); //=1
}
void update(int value) {
arc += 2.0f;
if (arc > 360.f) {
arc -= 360;
}
glutPostRedisplay();
glutTimerFunc(TIMERSECS, update, 0);
}
int main(int argc, char** argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //single buffer and RGBA
glutInitWindowSize(600, 600);
glutInitWindowPosition(100, 100);
glutCreateWindow("Window");
init();
glutDisplayFunc(draw);
glutTimerFunc(TIMERSECS, update, 0);
glutKeyboardFunc(handleKeypress);
glutMainLoop();
return 0;
}
我想创建一个动画,其中我的矩形由三角形构建,每个小时间内旋转2度。我希望像钟表一样旋转它。 我知道问题不在时间(不是太小),而是在glRotatef-我不知道它应该使用什么参数才能给我一个合适的效果。
提前感谢!:)