opengl中的纹理映射错误（具有多个纹理）

Question

我在Opengl中使用多个纹理时遇到了麻烦。我写了一个测试程序，绘制了两个正方形，一个比另一个大。当我只对其中一个进行纹理化时，一切正常，但当我同时纹理时，结果就是这样：

这就是我用来初始化纹理的代码：

unsigned int grass_height, grass_width, wall_height, wall_width;
unsigned char *grass = loadBMP("./minegrama.bmp", &grass_height, &grass_width);
unsigned char *wall = loadBMP("./mineleaves.bmp", &wall_height, &wall_width);

glShadeModel(GL_SMOOTH);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);

glGenTextures(2, tex);

glBindTexture(GL_TEXTURE_2D, tex[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, grass_width, grass_height, 0, GL_BGR, GL_UNSIGNED_BYTE, grass);
gluBuild2DMipmaps(tex[0], GL_RGB, grass_width, grass_height, GL_RGB, GL_UNSIGNED_BYTE, grass);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

glBindTexture(GL_TEXTURE_2D, tex[1]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, wall_width, wall_height, 0, GL_BGR, GL_UNSIGNED_BYTE, wall);
gluBuild2DMipmaps(tex[1], GL_RGB, grass_width, grass_height, GL_RGB, GL_UNSIGNED_BYTE, wall);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

这是图纸的代码：

//Seta o MatrixMode pra usar texturas
glMatrixMode(GL_TEXTURE);
//INICIO DO CHAO
glPushMatrix();
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, tex[0]);
//Desenhar o chao;
glColor3f(0, 0.39, 0);
glBegin(GL_QUADS);
glVertex3f(-30, -30, -0.001);
glTexCoord3f(-30, -30, -0.001);

glVertex3f(30, -30, -0.001);
glTexCoord3f(30, -30, -0.001);

glVertex3f(30, 30, -0.001);
glTexCoord3f(30, 30, -0.001);

glVertex3f(-30, 30, -0.001);
glTexCoord3f(-30, 30, -0.001);
glEnd();
glDisable(GL_TEXTURE_2D);
glPopMatrix();
//FIM DO CHAO


glPushMatrix();
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, tex[1]);
glTranslatef(0, 0, 10);
glBegin(GL_QUADS);
glVertex3f(-1, -1, 0); glTexCoord3f(-1, -1, 0); //Especifica cada vértice
glVertex3f(1, -1, 0); glTexCoord3f(1, -1, 0);
glVertex3f(1, 1, 0); glTexCoord3f(1, 1, 0);
glVertex3f(-1, 1, 0); glTexCoord3f(-1, 1, 0);
glDisable(GL_TEXTURE_2D);
glEnd();
glPopMatrix();

Answer 1

gluBuild2DMipmaps的第一个参数是错误的。 target参数的documentation表示：

  

指定目标纹理。必须是GLU_TEXTURE_2D。

此外，您的纹理坐标看起来不太好。使用当前值，大矩形上的纹理将重复60次。另外，纹理坐标的z值应为0，而不是0.01。更好的是：将glTexCoord2f用于二维纹理。