Comment appliquer une texture à glutSolidCube

Question

Je peux trouver des tutoriels sur la cartographie de textures sur des polygones spécifiant des sommets, etc., mais rien sur la manière d'appliquer une texture à un cube (ou à un autre élément) dessiné avec glut (glutSolidCube).

Je fais quelque chose comme:

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);

Ce faisant, je reçois la texture à appliquer au cube mais tout le cube obtient la couleur du premier octet de la texture!

Est-il possible de mapper une texture sur un cube solide (et d'autres solides) lors de l'utilisation de glutSolidCube?

Answer 1

Non, car glutSolidCube () ne génère pas de coordonnées de texture. Heureusement, glutSolidCube () est facile à mettre en oeuvre et à ajouter des coordonnées de texture. Voici le code source de glutSolidCube () et des fonctions associées, à partir de http://www.opengl.org/resources/libraries/glut/ :

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

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*/

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);
}

Ajoutez simplement quelques appels à la glTexCoord * famille de fonctions. NeHe propose un bon tutoriel sur la mise en route du mappage de texture. avec OpenGL.

Answer 2

En fait, il y a une solution ...

vous pouvez utiliser générer des coordonnées de texture comme ceci

    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);

Answer 3

Selon la documentation de l'API GLUT :

  

[glutSolidCube génère] des normales appropriées pour l'éclairage, mais ne génère pas de coordonnées de texture (sauf pour la théière).