我试图在按下键时绘制一个六边形棱镜，但我遇到了一个大问题:默认情况下，它在屏幕上绘制为随机形状。这是我的代码。当我按下p时，它显示为一个金字塔，当按下c时，我可以看到一个立方体，但是默认情况下它是随机形状的，我不明白为什么...这是我的代码和示例照片:
#include <stdlib.h>
#include <math.h>
#include "dependente\freeglut\freeglut.h"
#include "dependente\glfw\glfw3.h"
#include <stdio.h> //incluziuni librarii
#define RADDEG 57.29577951f //constanta
float XUP[3] = { 1,0,0 }, XUN[3] = { -1, 0, 0 }, //vector coordonate
YUP[3] = { 0,1,0 }, YUN[3] = { 0,-1, 0 },
ZUP[3] = { 0,0,1 }, ZUN[3] = { 0, 0,-1 },
ORG[3] = { 0,0,0 };
GLfloat viewangle = 0, tippangle = 0, traj[120][3]; //variabila pentru unghi camera
GLfloat d[3] = { 0.1, 0.1, 0.1 }; //vector directie
GLfloat xAngle = 0.0, yAngle = 0.0, zAngle = 0.0;
bool draw_pyramid = false; //variabila desenat figuri
bool draw_box = false;
bool draw_prism = false;
// Use arrow keys to rotate entire scene !!!
void Special_Keys(int key, int x, int y) //functie ptr taste sus jos stanga dreapta
{
switch (key) {
case GLUT_KEY_LEFT: viewangle -= 5; break;
case GLUT_KEY_RIGHT: viewangle += 5; break;
case GLUT_KEY_UP: tippangle -= 5; break;
case GLUT_KEY_DOWN: tippangle += 5; break;
default: printf("Special key %c == %d", key, key);
}
glutPostRedisplay();
}
void Pyramid(void) //draw the pyramid shape
{
glBegin(GL_TRIANGLE_FAN);//triangles have a common vertex, which is the central vertex
glColor3f(1.0f, 0.0f, 0.0f); glVertex3f(0.0f, 1.0f, 0.0f); //V0(red)
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f); //V1(green)
glColor3f(0.0f, 0.0f, 1.0f); glVertex3f(1.0f, -1.0f, 1.0f); //V2(blue)
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(1.0f, -1.0f, -1.0f); //V3(green)
glColor3f(0.0f, 0.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f); //V4(blue)
glColor3f(0.0f, 1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f); //V1(green)
glEnd();
}
void Draw_Box(void) //functie desenat cub
{
glBegin(GL_QUADS);//// Draw A Quad
glColor3f(0.0, 0.7, 0.1); // Front - green
glVertex3f(-1.0, 1.0, 1.0);
glVertex3f(1.0, 1.0, 1.0);
glVertex3f(1.0, -1.0, 1.0);
glVertex3f(-1.0, -1.0, 1.0);
glColor3f(0.9, 1.0, 0.0); // Back - yellow
glVertex3f(-1.0, 1.0, -1.0);
glVertex3f(1.0, 1.0, -1.0);
glVertex3f(1.0, -1.0, -1.0);
glVertex3f(-1.0, -1.0, -1.0);
glColor3f(0.2, 0.2, 1.0); // Top - blue
glVertex3f(-1.0, 1.0, 1.0);
glVertex3f(1.0, 1.0, 1.0);
glVertex3f(1.0, 1.0, -1.0);
glVertex3f(-1.0, 1.0, -1.0);
glColor3f(0.7, 0.0, 0.1); // Bottom - red
glVertex3f(-1.0, -1.0, 1.0);
glVertex3f(1.0, -1.0, 1.0);
glVertex3f(1.0, -1.0, -1.0);
glVertex3f(-1.0, -1.0, -1.0);
glEnd();
}
void hexagonalPrism()
{
glBegin(GL_QUADS);
glVertex3f(0.5, 0, 0.5);
glVertex3f(0.5, 0, -0.5);
glVertex3f(-0.5, 0, -0.5);
glVertex3f(-0.5, 0, 0.5);
glVertex3f(0.5, 0, -0.5);
glVertex3f(0.5, 1, -0.5);
glVertex3f(-0.5, 1, -0.5);
glVertex3f(-0.5, 0, -0.5);
glVertex3f(0.5, 1, -0.5);
glVertex3f(-0.5, 1, -0.5);
glVertex3f(-0.5, 0, 0.5);
glVertex3f(0.5, 0, 0.5);
glEnd();
glBegin(GL_TRIANGLES);
glVertex3f(0.5, 0, 0.5);
glVertex3f(0.5, 1, -0.5);
glVertex3f(0.5, 0, -0.5);
glVertex3f(-0.5, 0, 0.5);
glVertex3f(-0.5, 1, -0.5);
glVertex3f(-0.5, 0, -0.5);
glEnd();
}
void Keyboard(unsigned char key, int x, int y) //press a key to perform actions
{
switch (key) {
case 'd': d[0] += 0.1; break; //camera right
case 'a': d[0] -= 0.1; break; //camera left
case 'w': d[1] += 0.1; break; //camera up
case 's': d[1] -= 0.1; break; //camera down
case 'm': d[2] += 0.1; break; //magnify
case 'n': d[2] -= 0.1; break; //minify
case 'p': draw_pyramid = true; draw_box = false; break; //draw pyramid when key is pressed
case 'c': draw_box = true; draw_pyramid = false; break; //draw cube when key is pressed
case 't': draw_box = false; draw_pyramid = false; draw_prism = true; break; //draw prism when key is pressed
case 'x': xAngle += 5; break; //modify x axis angle
case 'y': yAngle += 5; break; //modify y axis angle
case 'z': zAngle += 5; break; //modify z axis angle
default: printf(" Keyboard %c == %d", key, key); //see what key it's pressed
}
glutPostRedisplay();
}
void Triad(void)
{
glColor3f(1.0, 1.0, 1.0); //set the dark grey color
glBegin(GL_LINES);
glVertex3fv(ORG); glVertex3fv(XUP);
glVertex3fv(ORG); glVertex3fv(YUP);
glVertex3fv(ORG); glVertex3fv(ZUP);
glEnd();
glRasterPos3f(1.1, 0.0, 0.0);
glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, 'X'); //draw the x axis
glRasterPos3f(0.0, 1.1, 0.0);
glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, 'Y'); //draw the y axis
glRasterPos3f(0.0, 0.0, 1.1);
glutBitmapCharacter(GLUT_BITMAP_HELVETICA_18, 'Z'); //draw the z axis
}
void redraw(void)
{
int v;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
glLoadIdentity();
glTranslatef(0, 0, -3);
glRotatef(tippangle, 1, 0, 0); // Up and down arrow keys 'tip' view.
glRotatef(viewangle, 0, 1, 0); // Right/left arrow keys 'turn' view.
glDisable(GL_LIGHTING);
Triad();
glPushMatrix();
glTranslatef(d[0], d[1], d[2]); // Move box down X axis.
glScalef(0.2, 0.2, 0.2);
glRotatef(zAngle, 0, 0, 1);
glRotatef(yAngle, 0, 1, 0);
glRotatef(xAngle, 1, 0, 0);
if ( draw_pyramid )
Pyramid();
if (hexagonalPrism)
hexagonalPrism();
if ( draw_box )
Draw_Box();
glPopMatrix();
glutSwapBuffers();
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitWindowSize(900, 600);
glutInitWindowPosition(300, 300);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE);
glutCreateWindow("Big HW1");
glutDisplayFunc(redraw);
glutKeyboardFunc(Keyboard);
glutSpecialFunc(Special_Keys);
glClearColor(0.1, 0.0, 0.1, 1.0);
glMatrixMode(GL_PROJECTION);//specify which matrix is the current matrix, matrix that represents your camera's lens (aperture, far-field, near-field, etc).
gluPerspective(60, 1.5, 1, 10); //set up a perspective projection matrix
glMatrixMode(GL_MODELVIEW); //specify which matrix is the current matrix,matrix that represents your camera (position, pointing, and up vector).
glutMainLoop();
return 1;
}
最佳答案
当然，一个六边形有6个边，但是在hexagonalPrism函数中，您只为边画3个四边形，为顶部和底部画2个三角形。
为Hexagon的拐角点定义6个点:
x: 0.866, 0.0, -0.866, -0.866, 0.0, 0.866
y: 0.5, 1.0, 0.5, -0.5, -1.0, -0.5
使用该点为侧面绘制6个四边形，并为顶部和底部绘制多边形。例如。:
void hexagonalPrism()
{
float x[] = { 0.866f, 0.0f, -0.866f, -0.866f, 0.0f, 0.866f };
float y[] = { 0.5f, 1.0f, 0.5f, -0.5f, -1.0f, -0.5f };
glBegin(GL_QUADS);
for (int i1 = 0; i1 < 6; ++i1)
{
glColor4f(
i1 < 2 || i1 > 4 ? 1.0f : 0.0f,
i1 > 0 && i1 < 5 ? 1.0f : 0.0f,
i1 > 2 ? 1.0f : 0.0f,
1.0f
);
int i2 = (i1 + 1) % 6;
glVertex3f(x[i1], 0.0f, y[i1]);
glVertex3f(x[i2], 0.0f, y[i2]);
glVertex3f(x[i2], 1.0f, y[i2]);
glVertex3f(x[i1], 1.0f, y[i1]);
}
glEnd();
glColor4f( 1, 1, 1, 1 );
glBegin(GL_POLYGON);
for (int i = 0; i < 6; ++i)
glVertex3f(x[i], 0.0f, y[i]);
glEnd();
glBegin(GL_POLYGON);
for (int i = 0; i < 6; ++i)
glVertex3f(x[i], 1.0f, y[i]);
glEnd();
}
关于c++ - 当我在OpenGL中按下键时无法绘制六边形棱镜，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/58318862/