切换到freeglut后不渲染的线条
lines not rendering after switching to freeglut
本文关键字：freeglut 更新时间：2023-10-16
我在一个项目中使用了glut -但是我去了free glut以便能够使用
glutBitmapCharacter
然而，当我这样做时，我用来绘制网格的东西不再起作用
//This creates the grid
for(float f = -1;f<1; f+=0.05){
glBegin(GL_LINE_STRIP);
glVertex2f(f,-1);
glVertex2f(f,1);
glEnd();
glBegin(GL_LINE_STRIP);
glVertex2f(-1,f);
glVertex2f(1,f);
glEnd();
}
全类:
#include<stdlib.h>
#include<windows.h>
#include<GL/glut.h>
#include<GL/freeglut.h>
#include<iostream>
#include <vector>
#include "include/Block.h"
#include <string>
using namespace std;
void drawBitmapText(char *string, float x, float y, float z);
void reshape(int w, int h);
void render(void);
void keyboard(unsigned char c,int x,int y);
void mouse(int button,int state, int x, int y);
vector <Block> blockList;
int screenXSize=800;
int screenYSize=800;
int selectedBlockType = 0;
int main(int argc, char ** argv){
blockList.push_back(*new Block(0,1,1));
Block Test = blockList.at(0);
string s = Test.getName();
glutInit(&argc,argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowPosition(100,100);
glutInitWindowSize(screenXSize,screenYSize);
glutCreateWindow("TITLE");
glutDisplayFunc(render);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutMouseFunc(mouse);
glutMainLoop();
}
void mouse(int button,int state, int x, int y){
if(button==GLUT_RIGHT_BUTTON){
}
if(button==GLUT_LEFT_BUTTON){
}
}
void keyboard(unsigned char c,int x,int y){
if (c==27){
exit(0);
}
}
void reshape(int w, int h)
{
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity (); ...
gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h);
}
void drawBitmapText(char *string, float x, float y, float z)
{
char *c;
glRasterPos3f(x, y, z);
for (c=string; *c != ' '; c++)
{
glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, *c);
}
}
void render(void){
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
drawBitmapText("CAN YOU READ ME?",200,200,0);
//This creates the grid
for(float f = -1;f<1; f+=0.05){
glBegin(GL_LINE_STRIP);
glVertex3f(f,-1);
glVertex3f(f,1);
glEnd();
glBegin(GL_LINE_STRIP);
glVertex2f(-1,f);
glVertex2f(1,f);
glEnd();
}
任何帮助都是非常感谢的
glutSwapBuffers();
glFlush();
}
但是我能够运行示例项目
/*
* GLUT Shapes Demo
*
* Written by Nigel Stewart November 2003
*
* This program is test harness for the sphere, cone
* and torus shapes in GLUT.
*
* Spinning wireframe and smooth shaded shapes are
* displayed until the ESC or q key is pressed. The
* number of geometry stacks and slices can be adjusted
* using the + and - keys.
*/
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#include <stdlib.h>
static int slices = 16;
static int stacks = 16;
/* GLUT callback Handlers */
static void resize(int width, int height)
{
const float ar = (float) width / (float) height;
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glFrustum(-ar, ar, -1.0, 1.0, 2.0, 100.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity() ;
}
static void display(void)
{
const double t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
const double a = t*90.0;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glColor3d(1,0,0);
glPushMatrix();
glTranslated(-2.4,1.2,-6);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutSolidSphere(1,slices,stacks);
glPopMatrix();
glPushMatrix();
glTranslated(0,1.2,-6);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutSolidCone(1,1,slices,stacks);
glPopMatrix();
glPushMatrix();
glTranslated(2.4,1.2,-6);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutSolidTorus(0.2,0.8,slices,stacks);
glPopMatrix();
glPushMatrix();
glTranslated(-2.4,-1.2,-6);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutWireSphere(1,slices,stacks);
glPopMatrix();
glPushMatrix();
glTranslated(0,-1.2,-6);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutWireCone(1,1,slices,stacks);
glPopMatrix();
glPushMatrix();
glTranslated(2.4,-1.2,-6);
glRotated(60,1,0,0);
glRotated(a,0,0,1);
glutWireTorus(0.2,0.8,slices,stacks);
glPopMatrix();
glutSwapBuffers();
}
static void key(unsigned char key, int x, int y)
{
switch (key)
{
case 27 :
case 'q':
exit(0);
break;
case '+':
slices++;
stacks++;
break;
case '-':
if (slices>3 && stacks>3)
{
slices--;
stacks--;
}
break;
}
glutPostRedisplay();
}
static void idle(void)
{
glutPostRedisplay();
}
const GLfloat light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };
const GLfloat mat_ambient[] = { 0.7f, 0.7f, 0.7f, 1.0f };
const GLfloat mat_diffuse[] = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };
/* Program entry point */
int main(int argc, char *argv[])
{
glutInit(&argc, argv);
glutInitWindowSize(640,480);
glutInitWindowPosition(10,10);
glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow("GLUT Shapes");
glutReshapeFunc(resize);
glutDisplayFunc(display);
glutKeyboardFunc(key);
glutIdleFunc(idle);
glClearColor(1,1,1,1);
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glEnable(GL_LIGHT0);
glEnable(GL_NORMALIZE);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_LIGHTING);
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);
glutMainLoop();
return EXIT_SUCCESS;
}
问题是你的网格正在被OpenGL剪切(丢弃)，因为它在观看锥体之外。
在reshape函数中，通过调用gluOrtho2D将对象的区域设置为x方向的(0, width)和y方向的(0, height)。这本身不是问题，但您使用的网格坐标是(-1,1)。如果你仔细观察你的窗口，你会看到左下角的像素点被点亮了。
你需要做的最基本的事情是弄清楚你想要画到哪个空间。与gluOrtho2D你有，你有效地渲染窗口坐标，所以如果你更新你的网格从[0，宽度]相比[-1,1]渲染，你的网格将出现以及文本。相反，如果您想使用网格的坐标空间，则将gluOrtho2D函数更新为gluOrtho2D( -1, 1, -1, 1 )，并将您呈现文本的位置更新为在该正方形内。
还有一点，有一个名为GL_LINES的基本类型，它将在每两个顶点之间绘制一条线段。在网格渲染循环中，可以将循环写成
glBegin( GL_LINES );
for ( float f = -1; f < 1; f += 0.05 ) {
glVertex2f( f, -1 );
glVertex2f( f , 1 );
glVertex2f( -1, f );
glVertex2f( 1, f );
}
glEnd();
(哦，在你的例子中，你混合了glVertex2f和glVertex3f[这是完全合法的OpenGL]，除了在你使用glVertex3f时，你只提供了两个参数导致语法错误)
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