Question

如果我评论DrawGLScene()，我会看到一个大的阴影三角形，如果我注释掉drawtri()，我会看到一个方形纹理。但是我无法将两者结合起来 - 当两个func都被调用时，我只看到三角形 outline ，并且应用强红色滤镜渲染纹理。

可能是什么问题？

void DrawGLScene()
{
    int x, y;
    float float_x, float_y, float_xb, float_yb;
    float x0=0,y0=0,x1=10,y1=10,z=-3;

    // glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);      // Clear The Screen And The Depth Buffer
glEnable(GL_TEXTURE_2D);
    glLoadIdentity();               // Reset The View
    glTranslatef(0.0f,0.0f,-12.0f);              // move 12 units into the screen.

    glBindTexture(GL_TEXTURE_2D, texture[0]);   // choose the texture to use.

    glPolygonMode(GL_BACK, GL_FILL);
    glPolygonMode(GL_FRONT, GL_LINE);


    glBegin(GL_QUADS);

        glTexCoord2f( 0,0);
        glVertex3f( x0, y0, z );

        glTexCoord2f( 0, 1 );
        glVertex3f( x0, y1, z );

        glTexCoord2f( 1, 1);
        glVertex3f( x1, y1, z );

        glTexCoord2f( 1, 0 );
        glVertex3f( x1, y0,z );
    glEnd();
   glDisable(GL_TEXTURE_2D);
    // since this is double buffered, swap the buffers to display what just got drawn.
    //  glutSwapBuffers();
}

void drawtri() {
    glBegin(GL_TRIANGLES);                  
        glColor3f(0.0f,0.0f,1.0f);          
        glVertex3f( 0.0f, 1.0f, 0.0f);      
        glColor3f(0.0f,1.0f,0.0f);          
        glVertex3f(-1.0f,-1.0f, 0.0f);      
        glColor3f(1.0f,0.0f,0.0f);          
        glVertex3f( 1.0f,-1.0f, 0.0f);      
    glEnd();
}
void zdisplay() 
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);          // Clear Screen and Depth Buffer

    glLoadIdentity();
    glTranslatef(0.0f,0.0f,-3.0f);          


    //drawtri();
    DrawGLScene();

    glutSwapBuffers();
}

Answer 1

红色滤镜是由应用的颜色引起的：

glColor3f(0.0f,0.0f,1.0f);

在绘制四边形之前将颜色重置为白色：

glColor3f(1.0f,1.0f,1.0f);

概要是由以下规范引起的：

glPolygonMode(GL_FRONT, GL_LINE);

指定填充模式：

glPolygonMode(GL_FRONT, GL_FILL);

Answer 2

调用这两个函数时，您是否按照代码显示的顺序调用方法？因为我怀疑订单是逆转的。如果我是对的，我认为你必须在绘制三角形时重置glPolygonMode。尝试在调用glBegin（GL_TRIANGLES）之前添加glPolygonMode（GL_FRONT_AND_BACK，GL_FILL）。

openGL：纹理和三角形不渲染

2 个答案: