opengl - texture - Cómo aplicar textura a glutSolidCube

texture in opengl c++

Question

Puedo encontrar tutoriales sobre el mapeo de texturas a polígonos especificando vértices, etc., pero nada sobre cómo aplicar una textura a un cubo (u otro material) dibujado con exceso (glutSolidCube).

Estoy haciendo algo como:

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);

Al hacer esto obtengo la textura para aplicar al cubo, ¡pero todo el cubo obtiene el color del primer byte en la textura!

¿Hay alguna manera de mapear una textura en un cubo sólido (y otros sólidos) cuando se utiliza glutSolidCube?

Answer 1

De acuerdo con la documentación de API GLUT :

[glutSolidCube genera] normales apropiadas para iluminación pero no generan coordenadas de textura (excepto para la tetera).

Answer 2

No, ya que glutSolidCube() no genera coordenadas de textura. Afortunadamente, sin embargo, glutSolidCube() es fácil de implementar y agrega coordenadas de textura. Aquí está el código fuente de glutSolidCube() y las funciones asociadas, de http://www.opengl.org/resources/libraries/glut/ :

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

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(c) Copyright 1993, Silicon Graphics, Inc.                                      

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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,
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NOT SILICON GRAPHICS, INC.  HAS BEEN ADVISED OF THE POSSIBILITY
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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);
}

Solo agregue algunas llamadas a la familia de funciones glTexCoord * . NeHe tiene un buen tutorial sobre cómo comenzar a mapear texturas con OpenGL.

Answer 3

En realidad, hay una solución ...

puedes usar generar coordenadas de textura como esta

    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);