Question

我在OpenGL中遇到纹理映射问题。我正在尝试将不同的纹理应用于场景中的不同对象，但我发现将第二个纹理应用于第二个对象正在改变第一个纹理坐标（我认为）。这两个对象是立方体和圆柱体。

只启用了一个纹理，场景如下所示： enter image description here

如果我然后为一个或多个其他对象启用纹理，我会看到这一点（我现在对“轮子”上的坏纹理映射不太感兴趣）： enter image description here

可能导致这种情况的原因是什么？我的立方体和圆柱的绘图代码如下：

立方体：

    //Alias the values for easier reading
double X = Position().X;
double Y = Position().Y;
double Z = Position().Z;
double W = _fWidth;
double H = _fHeight;
double D = _fDepth;

//Set textures if necessary
if(super._blHasTexture)
{
    super._obTexture.bind(gl);
}

_obTexture.enable(gl);
gl.glColor3f(0.5f, 0.5f, 0.7f);
//Draw

    gl.glBegin(GL2.GL_QUADS);
        //Front
    gl.glNormal3f(0f, 0f, 1f);
    gl.glVertex3d(X, Y, Z);     gl.glTexCoord2f(0f, 0f);
    gl.glVertex3d(X+W, Y, Z);   gl.glTexCoord2f(1f, 0f);
    gl.glVertex3d(X+W, Y-H, Z); gl.glTexCoord2f(1f, 1f);
    gl.glVertex3d(X, Y-H, Z);   gl.glTexCoord2f(0f, 1f);

    //Back
    gl.glNormal3f(0f, 0f, -1f);
    gl.glVertex3d(X, Y, Z-D);   gl.glTexCoord2f(0f, 0f);
    gl.glVertex3d(X+W, Y, Z-D); gl.glTexCoord2f(1f, 0f);
    gl.glVertex3d(X+W, Y-H, Z-D); gl.glTexCoord2f(1f, 1f);
    gl.glVertex3d(X, Y-H, Z-D); gl.glTexCoord2f(0f, 1f);

    //Left
    gl.glNormal3f(-1f, 0f, 0f);
    gl.glVertex3d(X, Y, Z);     gl.glTexCoord2f(0f, 0f);
    gl.glVertex3d(X, Y, Z-D);   gl.glTexCoord2f(1f, 0f);
    gl.glVertex3d(X, Y-H, Z-D); gl.glTexCoord2f(1f, 1f);
    gl.glVertex3d(X, Y-H, Z);   gl.glTexCoord2f(0f, 1f);            

    //Right
    gl.glNormal3f(1f, 0f, 0f);
    gl.glVertex3d(X+W, Y, Z);   gl.glTexCoord2f(0f, 0f);
    gl.glVertex3d(X+W, Y, Z-D); gl.glTexCoord2f(1f, 0f);
    gl.glVertex3d(X+W, Y-H, Z-D); gl.glTexCoord2f(1f, 1f);
    gl.glVertex3d(X+W, Y-H, Z); gl.glTexCoord2f(0f, 1f);

    //Top
    gl.glNormal3f(0f, 1f, 0f);
    gl.glVertex3d(X, Y, Z);     gl.glTexCoord2f(0f, 0f);
    gl.glVertex3d(X+W, Y, Z);   gl.glTexCoord2f(1f, 0f);
    gl.glVertex3d(X+W, Y, Z-D); gl.glTexCoord2f(1f, 1f);
    gl.glVertex3d(X, Y, Z-D);   gl.glTexCoord2f(0f, 1f);

    //Bottom
    gl.glNormal3f(0f, -1f, 0f);
    gl.glVertex3d(X, Y-H, Z);   gl.glTexCoord2f(0f, 0f);
    gl.glVertex3d(X+W, Y-H, Z); gl.glTexCoord2f(1f, 0f);
    gl.glVertex3d(X+W, Y-H, Z-D); gl.glTexCoord2f(1f, 1f);
    gl.glVertex3d(X, Y-H, Z-D); gl.glTexCoord2f(0f, 1f);
gl.glEnd();

_obTexture.disable(gl);

气缸：

GLUquadric quad = glu.gluNewQuadric();
glu.gluQuadricTexture(quad, true);  

_obTexture.bind(gl);
_obTexture.enable(gl);

    //Draw the caps
gl.glBegin(GL2.GL_TRIANGLE_FAN);
    gl.glVertex3f(0f, 0f, 0.01f);
    gl.glTexCoord2f(0f, 0f);
    for(int t = 0; t < 20; t++)
    {
        float X = _fRadius * (float)Math.cos(t);
        float Y = _fRadius * (float)Math.sin(t);
        gl.glVertex3f(X, Y, 0.01f);
    }
    gl.glTexCoord2f(1f, 1f);
gl.glEnd();

gl.glBegin(GL2.GL_TRIANGLE_FAN);
    gl.glVertex3f(0f, 0f, -0.01f + _fHeight);
    gl.glTexCoord2f(0f, 0f);
    for(int t = 0; t < 20; t++)
    {
        float X = _fRadius * (float)Math.cos(t);
        float Y = _fRadius * (float)Math.sin(t);
        gl.glVertex3f(X, Y, -0.01f + _fHeight);
    }
        gl.glTexCoord2f(1f, 1f);
gl.glEnd();         

glu.gluCylinder(quad, _fRadius, _fRadius, _fHeight, 20, 1);
_obTexture.disable(gl);

Answer 1

在每次调用glVertex之前分配纹理坐标，而不是在之后的调用之后分配你应用于以下glVertex调用。

您正在这样做，最后一个坐标集将应用于下一个渲染周期中的第一个顶点（即多维数据集的一个角） - 因此渲染其他对象时会有所不同。

OpenGL纹理坐标问题

1 个答案: