Cómo aplicar textura a glutSolidCube
Pregunta
Puedo encontrar tutoriales sobre el mapeo de texturas a polígonos que especifican vértices, etc., pero nada sobre cómo aplicar una textura a un cubo (u otro material) dibujado con glut (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 forma de mapear una textura a un cubo sólido (y otros sólidos) cuando se usa glutSolidCube?
Solución
No, ya que glutSolidCube ()
no genera coordenadas de textura. Afortunadamente, sin embargo, glutSolidCube ()
es fácil de implementar y agregar coordenadas de textura. Aquí está el código fuente de glutSolidCube ()
y funciones asociadas, desde http://www.opengl.org/resources/libraries/glut/ :
/* Copyright (c) Mark J. Kilgard, 1994, 1997. */
/**
(c) Copyright 1993, Silicon Graphics, Inc.
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ELSE FOR ANY DIRECT, SPECIAL, INCIDENTAL, INDIRECT OR
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NOT SILICON GRAPHICS, INC. HAS BEEN ADVISED OF THE POSSIBILITY
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Use, duplication, or disclosure by the Government is subject to
restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
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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);
}
Simplemente agregue algunas llamadas al glTexCoord * familia de funciones. NeHe tiene un buen tutorial sobre cómo comenzar con el mapeo de texturas con OpenGL.
Otros consejos
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);
De acuerdo con la documentación de la API GLUT :
[glutSolidCube genera] normales apropiadas para la iluminación pero no generan coordenadas de textura (excepto la tetera).