如何將紋理應用到glutSolidCube

Question

我可以找到有關將紋理映射到指定頂點等的多邊形的教程，但沒有說明如何將紋理應用到用glut（glutSolidCube）繪製的立方體（或其他東西）。

我做喜歡的事：

glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, decal); 
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, repeat); 
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, repeat); 
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, nearest); 
glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, nearest); 

glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 
glTexImage2D(GL_TEXTURE_2D, 0, 4, myImageWidth, myImageHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid *)myImage); 

//... 

glEnable(GL_TEXTURE_2D); 

//now draw the cube 
glutSolidCube(N); 

這樣做我得到的紋理適用於立方體，但整個立方體得到的第一個字節的顏色質感！

使用glutSolidCube時，是否有任何方法將紋理映射到實體立方體（以及其他實體）？

Answer 1

不，因爲glutSolidCube()不生成紋理座標。幸運的是，glutSolidCube()很容易實現並添加紋理座標。這裏的源代碼glutSolidCube()和相關功能，從http://www.opengl.org/resources/libraries/glut/：

/* Copyright (c) Mark J. Kilgard, 1994, 1997. */ 

/**                    
(c) Copyright 1993, Silicon Graphics, Inc.          

ALL RIGHTS RESERVED                

Permission to use, copy, modify, and distribute this software     
for any purpose and without fee is hereby granted, provided      
that the above copyright notice appear in all copies and that     
both the copyright notice and this permission notice appear in     
supporting documentation, and that the name of Silicon       
Graphics, Inc. not be used in advertising or publicity       
pertaining to distribution of the software without specific,      
written prior permission. 

THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU 
"AS-IS" AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR 
OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF 
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. IN NO 
EVENT SHALL SILICON GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE 
ELSE FOR ANY DIRECT, SPECIAL, INCIDENTAL, INDIRECT OR 
CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER, 
INCLUDING WITHOUT LIMITATION, LOSS OF PROFIT, LOSS OF USE, 
SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD PARTIES, WHETHER OR 
NOT SILICON GRAPHICS, INC. HAS BEEN ADVISED OF THE POSSIBILITY 
OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE OR 
PERFORMANCE OF THIS SOFTWARE. 

US Government Users Restricted Rights 

Use, duplication, or disclosure by the Government is subject to 
restrictions set forth in FAR 52.227.19(c)(2) or subparagraph 
(c)(1)(ii) of the Rights in Technical Data and Computer 
Software clause at DFARS 252.227-7013 and/or in similar or 
successor clauses in the FAR or the DOD or NASA FAR 
Supplement. Unpublished-- rights reserved under the copyright 
laws of the United States. Contractor/manufacturer is Silicon 
Graphics, Inc., 2011 N. Shoreline Blvd., Mountain View, CA 
94039-7311. 

OpenGL(TM) is a trademark of Silicon Graphics, Inc. 
*/ 

static void 
drawBox(GLfloat size, GLenum type) 
{ 
    static GLfloat n[6][3] = 
    { 
    {-1.0, 0.0, 0.0}, 
    {0.0, 1.0, 0.0}, 
    {1.0, 0.0, 0.0}, 
    {0.0, -1.0, 0.0}, 
    {0.0, 0.0, 1.0}, 
    {0.0, 0.0, -1.0} 
    }; 
    static GLint faces[6][4] = 
    { 
    {0, 1, 2, 3}, 
    {3, 2, 6, 7}, 
    {7, 6, 5, 4}, 
    {4, 5, 1, 0}, 
    {5, 6, 2, 1}, 
    {7, 4, 0, 3} 
    }; 
    GLfloat v[8][3]; 
    GLint i; 

    v[0][0] = v[1][0] = v[2][0] = v[3][0] = -size/2; 
    v[4][0] = v[5][0] = v[6][0] = v[7][0] = size/2; 
    v[0][1] = v[1][1] = v[4][1] = v[5][1] = -size/2; 
    v[2][1] = v[3][1] = v[6][1] = v[7][1] = size/2; 
    v[0][2] = v[3][2] = v[4][2] = v[7][2] = -size/2; 
    v[1][2] = v[2][2] = v[5][2] = v[6][2] = size/2; 

    for (i = 5; i >= 0; i--) { 
    glBegin(type); 
    glNormal3fv(&n[i][0]); 
    glVertex3fv(&v[faces[i][0]][0]); 
    glVertex3fv(&v[faces[i][1]][0]); 
    glVertex3fv(&v[faces[i][2]][0]); 
    glVertex3fv(&v[faces[i][3]][0]); 
    glEnd(); 
    } 
} 

void APIENTRY 
glutSolidCube(GLdouble size) 
{ 
    drawBox(size, GL_QUADS); 
} 

在一些調用到glTexCoord*家庭的功能只需添加。 NeHe有關於如何開始使用OpenGL進行紋理映射的很好的教程。

Answer 2

按照GLUT API documentation：

[glutSolidCube生成]適合於照明法線但不生成紋理座標（除了茶壺）。

Answer 3

其實，有一個解決方案...

可以用產生的紋理座標這樣

glEnable(GL_TEXTURE_GEN_S); //enable texture coordinate generation 
    glEnable(GL_TEXTURE_GEN_T); 
    glBindTexture(GL_TEXTURE_2D, theTexture[2]); 
    glutSolidCube(2); 
    glDisable(GL_TEXTURE_GEN_S); //enable texture coordinate generation 
    glDisable(GL_TEXTURE_GEN_T);