将地球纹理贴图应用到 Sphere
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【中文标题】将地球纹理贴图应用到 Sphere【英文标题】：Applying map of the earth texture a Sphere 【发布时间】：2015-08-04 02:21:47 【问题描述】：到目前为止，我一直在尝试在太阳系的 openGL（使用 JOGL）中实现 3D 动画，但我有 5 个不同大小的行星，但我似乎遇到的问题是我无法在Sphere 谁能帮我看看它是怎么做的？
这是我的 Display 方法中的代码：
@Override
public void display(GLAutoDrawable drawable)
GL2 gl = drawable.getGL().getGL2();
GLU glu = new GLU();
gl.glClear(GL.GL_COLOR_BUFFER_BIT);
//make sure we are in model_view mode
gl.glMatrixMode(GL2.GL_MODELVIEW);
gl.glLoadIdentity();
glu.gluLookAt(10,20,20,0,3,0,0, 20, 0);
//gl.glMatrixMode(GL2.GL_PROJECTION);
//glu.gluPerspective(45,1,1,25);
//render ground plane
gl.glPushMatrix();
gl.glTranslatef(-10.75f, 3.0f, -1.0f);
gl.glColor3f(0.3f, 0.5f, 1f);
GLUquadric earth = glu.gluNewQuadric();
glu.gluQuadricDrawStyle(earth, GLU.GLU_FILL);
glu.gluQuadricNormals(earth, GLU.GLU_FLAT);
glu.gluQuadricOrientation(earth, GLU.GLU_OUTSIDE);
final float radius = 3.378f;
final int slices = 89;
final int stacks = 16;
glu.gluSphere(earth, radius, slices, stacks);
glu.gluDeleteQuadric(earth);
Texture earths;
try
earths = TextureIO.newTexture(new File("earth.png"), true);
catch (IOException e)
javax.swing.JOptionPane.showMessageDialog(null, e);
gl.glPopMatrix();
//gl.glEnd();
gl.glPushMatrix();
gl.glTranslatef(2.75f, 3.0f, -0.0f);
gl.glColor3f(0.3f, 0.5f, 1f);
GLUquadric earth1 = glu.gluNewQuadric();
glu.gluQuadricDrawStyle(earth1, GLU.GLU_FILL);
glu.gluQuadricNormals(earth1, GLU.GLU_FLAT);
glu.gluQuadricOrientation(earth1, GLU.GLU_OUTSIDE);
final float radius1 = 3.378f;
final int slices1 = 90;
final int stacks1 = 63;
glu.gluSphere(earth1, radius1, slices1, stacks1);
glu.gluDeleteQuadric(earth1);
gl.glPopMatrix();
gl.glPushMatrix();
gl.glTranslatef(3.75f, 6.0f, -7.20f);
gl.glColor3f(0.3f, 0.5f, 1f);
GLUquadric earth3 = glu.gluNewQuadric();
glu.gluQuadricDrawStyle(earth3, GLU.GLU_FILL);
glu.gluQuadricNormals(earth3, GLU.GLU_FLAT);
glu.gluQuadricOrientation(earth1, GLU.GLU_OUTSIDE);
final float radius3 = 1.878f;
final int slices3 = 89;
final int stacks3 = 16;
glu.gluSphere(earth3, radius3, slices3, stacks3);
glu.gluDeleteQuadric(earth3);
gl.glPopMatrix();
gl.glPushMatrix();
gl.glTranslatef(12.75f, 2.0f, -7.20f);
gl.glColor3f(0.3f, 0.5f, 1f);
GLUquadric earth4 = glu.gluNewQuadric();
glu.gluQuadricDrawStyle(earth4, GLU.GLU_FILL);
glu.gluQuadricNormals(earth4, GLU.GLU_FLAT);
glu.gluQuadricOrientation(earth4, GLU.GLU_OUTSIDE);
final float radius4 = 1.078f;
final int slices4 = 89;
final int stacks4 = 16;
glu.gluSphere(earth4, radius4, slices4, stacks4);
glu.gluDeleteQuadric(earth4);
gl.glPopMatrix();
gl.glPushMatrix();
gl.glTranslatef(2.75f, -6.0f, -0.0f);
gl.glColor3f(0.3f, 0.5f, 1f);
GLUquadric earth5 = glu.gluNewQuadric();
glu.gluQuadricDrawStyle(earth5, GLU.GLU_FILL);
glu.gluQuadricNormals(earth5, GLU.GLU_FLAT);
glu.gluQuadricOrientation(earth5, GLU.GLU_OUTSIDE);
final float radius5 = 3.778f;
final int slices5 = 90;
final int stacks5 = 63;
glu.gluSphere(earth5, radius5, slices5, stacks5);
glu.gluDeleteQuadric(earth5);
gl.glPopMatrix();
【问题讨论】：
为什么要在显示循环中加载纹理？所有的初始化必须在显示循环之前完成，因为显示循环被称为 60>次/秒。关于你问的问题，你能在其他模型上看到纹理吗？如果不是，那么我会建议您更改您的 png 图像。您可以使用 GIMP 等软件。 宁可调用 GLU.createGLU(GL) 以创建功能更强大的 GLU 实例：jogamp.org/deployment/jogamp-next/javadoc/jogl/javadoc/com/… 如果不这样做，您可能会收到 UnsupportedOperationException，这取决于您调用的方法， GLU 实现的方法比 GLUgl2 少。 您的网格中缺少纹理坐标 谢谢你们的时间和帮助我让它工作 您好，您应该避免弃用 opengl 以支持着色器。我刚写完Hello Triangle，如果你想看看:) 【参考方案1】：创建自己的球体网格
简单的2D循环通过2个角度（球坐标系2笛卡尔）。如果您想要更高的精度，可以轻松添加椭球体属性（地球不是球体）。如果没有，那么您可以对所有行星使用单球体网格，并在使用前对其进行缩放...
设a 为经度，b 为纬度，所以循环a 从0 到2*PI [rad] 和b 从-0.5*PI 到+0.5*PI [rad] 其中@987654337 @ 是 Pi（在 C++ math.h 中称为 M_PI）。如果您的数学 api 使用度数，则转换为度数 PI [rad] = 180.0 [deg]
为每个顶点添加必要的信息
光照法线
// just unit sphere
nx=cos(b)*cos(a);
ny=cos(b)*sin(a);
nz=sin(b);
纹理坐标（假设矩形无失真图像）
// just convert a,b to <0,1> range
tx=a/(2.0*PI)
ty=(b/PI)+0.5;
顶点位置
// just sphere(rx=ry=rz=r) or ellipsoid (rx=ry=equatorial and rz=polar radius)
// can also use rx*nx,ry*ny,rz*nz instead ...
x=rx*cos(b)*cos(a);
y=ry*cos(b)*sin(a);
z=rz*sin(b);
将所有这些发送到 OpenGL
所以以上所有内容都存储在一些内存空间（CPU 或 GPU）中，然后发送到渲染。您可以使用旧版glBegin(QUAD_STRIP); ... glEnd(); 或 displaylist/VBO/VAO。在每个行星/物体之前绑定正确的纹理，不要忘记更新ModelView 矩阵。这是我的坐标系的样子：
还可以查看这些相关的 Q/As：
realistic n-body solar system sphere mesh by subdivision[edit1] C++ 示例
//---------------------------------------------------------------------------
const int nb=15; // slices
const int na=nb<<1; // points per equator
class planet
public:
bool _init; // has been initiated ?
GLfloat x0,y0,z0; // center of planet [GCS]
GLfloat pos[na][nb][3]; // vertex
GLfloat nor[na][nb][3]; // normal
GLfloat txr[na][nb][2]; // texcoord
GLuint txrid; // texture id
GLfloat t; // dayly rotation angle [deg]
planet() _init=false; txrid=0; x0=0.0; y0=0.0; z0=0.0; t=0.0;
~planet() if (_init) glDeleteTextures(1,&txrid);
void init(GLfloat r,AnsiString texture); // call after OpenGL is already working !!!
void draw();
;
void planet::init(GLfloat r,AnsiString texture)
if (!_init) _init=true; glGenTextures(1,&txrid);
GLfloat x,y,z,a,b,da,db;
GLfloat tx0,tdx,ty0,tdy;// just correction if CLAMP_TO_EDGE is not available
int ia,ib;
// a,b to texture coordinate system
tx0=0.0;
ty0=0.5;
tdx=0.5/M_PI;
tdy=1.0/M_PI;
// load texture to GPU memory
if (texture!="")
Byte q;
unsigned int *pp;
int xs,ys,x,y,adr,*txr;
union unsigned int c32; Byte db[4]; c;
Graphics::TBitmap *bmp=new Graphics::TBitmap; // new bmp
bmp->LoadFromFile(texture); // load from file
bmp->HandleType=bmDIB; // allow direct access to pixels
bmp->PixelFormat=pf32bit; // set pixel to 32bit so int is the same size as pixel
xs=bmp->Width; // resolution should be power of 2
ys=bmp->Height;
txr=new int[xs*ys];
for(adr=0,y=0;y<ys;y++)
pp=(unsigned int*)bmp->ScanLine[y];
for(x=0;x<xs;x++,adr++)
// rgb2bgr and copy bmp -> txr[]
c.c32=pp[x];
q =c.db[2];
c.db[2]=c.db[0];
c.db[0]=q;
txr[adr]=c.c32;
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D,txrid);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,GL_MODULATE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, xs, ys, 0, GL_RGBA, GL_UNSIGNED_BYTE, txr);
glDisable(GL_TEXTURE_2D);
delete bmp;
delete[] txr;
// texture coordinates by 1 pixel from each edge (GL_CLAMP_TO_EDGE)
tx0+=1.0/GLfloat(xs);
ty0+=1.0/GLfloat(ys);
tdx*=GLfloat(xs-2)/GLfloat(xs);
tdy*=GLfloat(ys-2)/GLfloat(ys);
// correct texture coordinate system (invert x)
tx0=1.0-tx0; tdx=-tdx;
da=(2.0*M_PI)/GLfloat(na-1);
db= M_PI /GLfloat(nb-1);
for (ib=0,b=-0.5*M_PI;ib<nb;ib++,b+=db)
for (ia=0,a= 0.0 ;ia<na;ia++,a+=da)
x=cos(b)*cos(a);
y=cos(b)*sin(a);
z=sin(b);
nor[ia][ib][0]=x;
nor[ia][ib][1]=y;
nor[ia][ib][2]=z;
pos[ia][ib][0]=r*x;
pos[ia][ib][1]=r*y;
pos[ia][ib][2]=r*z;
txr[ia][ib][0]=tx0+(a*tdx);
txr[ia][ib][1]=ty0+(b*tdy);
void planet::draw()
if (!_init) return;
int ia,ib0,ib1;
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glTranslatef(x0,y0,z0);
glRotatef(90.0,1.0,0.0,0.0); // rotate planets z axis (North) to OpenGL y axis (Up)
glRotatef(-t,0.0,0.0,1.0); // rotate planets z axis (North) to OpenGL y axis (Up)
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D,txrid);
glColor3f(1.0,1.0,1.0);
for (ib0=0,ib1=1;ib1<nb;ib0=ib1,ib1++)
glBegin(GL_QUAD_STRIP);
for (ia=0;ia<na;ia++)
glNormal3fv (nor[ia][ib0]);
glTexCoord2fv(txr[ia][ib0]);
glVertex3fv (pos[ia][ib0]);
glNormal3fv (nor[ia][ib1]);
glTexCoord2fv(txr[ia][ib1]);
glVertex3fv (pos[ia][ib1]);
glEnd();
glDisable(GL_TEXTURE_2D);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
//---------------------------------------------------------------------------
用法：
// variable to store planet (global)
planet earth;
// init after OpenGL initialisation
earth.init(1.0,"earth.bmp");
// position update
earth.x0= 0.0;
earth.y0= 0.0;
earth.z0=-20.0;
// add this to render loop
earth.draw(); // draws the planet
earth.t+=2.5; // just rotate planet by 2.5 deg each frame...
我知道它很丑，但它不使用任何有趣的东西，只是使用旧的 OpenGL 和 Math.h (cos(),sin(),M_PI) 和 VCL 来加载位图。所以重写你的环境，你会没事的。不要忘记每个行星都有自己的纹理，因此每个行星需要有一个 txrid，因此要么将每个行星作为单独的 planet 变量，要么重写...
【讨论】：
感谢 Spektre 的所有帮助，我让它工作了以上是关于将地球纹理贴图应用到 Sphere的主要内容，如果未能解决你的问题，请参考以下文章