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我想使用 openGL 为我的 3D 游戏实现雷达。我一直在尝试以多种方式完成它，但没有一个被批准是正确的。这是我的代码片段如下：

int xi, yi;
GLfloat x,z;
glPushMatrix();
{
    glTranslatef(-0.8f, 0.2f, -3.0f);

    glColor3f(0.0f, 0.0f, 1.0f);
    x = playerTank->givePosX();
    z = playerTank->givePosZ();
    xi = (int)((x + 1000) / 20) + 5;
    yi = (int)(((z + 1000) / 20) + screenHeight - 105);
    glPushMatrix();
    {
        glScalef(xi,yi,1.0f);
        glBegin(GL_QUADS);
        glVertex2i(xi-5, yi-5);
        glVertex2i(xi+5, yi-5);
        glVertex2i(xi+5, yi+5);
        glVertex2i(xi-5, yi+5);
        glEnd();
    }
    glPopMatrix();

    glColor3f(1.0f, 0.0f, 0.0f);
    glPushMatrix();
    {
        glScalef(xi,yi,1.0f);
        for (int i = 0; i < tanks.size(); i++)
        {
            x = tanks[i]->givePosX();
            z = tanks[i]->givePosZ();
            xi = (int)((x + 1000) / 20) + 5;
            yi = (int)(((z + 1000) / 20) + screenHeight - 105);
            if (xi > 0 && xi < 110 && yi > (screenHeight - 110) && yi < screenHeight)
            {
                if (tanks[i] != playerTank)
                {
                    glBegin(GL_TRIANGLES);
                    glVertex2i(xi, yi-5);
                    glVertex2i(xi+5, yi+5);
                    glVertex2i(xi-5, yi+5);
                    glEnd();
                }
            }
        }
    }
    glPopMatrix();

    glColor3f(0.0f, 1.0f, 0.0f);
    glPushMatrix();
    {
        glScalef(xi,yi,1.0f);
        for (int i = 0; i < obstacles.size(); i++)
        {
            x = obstacles[i]->givePosX();
            z = obstacles[i]->givePosZ();
            xi = (int)((x + 1000) / 20) + 5;
            yi = (int)(((z + 1000) / 20) + screenHeight - 105);

            glBegin(GL_LINE_LOOP);
            glVertex2i(xi-3, yi-3);
            glVertex2i(xi+3, yi-3);
            glVertex2i(xi+3, yi+3);
            glVertex2i(xi-3, yi+3);
            glEnd();
        }
    }
    glPopMatrix();
}
glPopMatrix();

为什么屏幕上什么都没有出现？

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1 回答 1

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一些事情要尝试：

  1. 确保您已正确设置渲染器 - 您为设置场景所做的调用是什么？看看关于 nehe的一些课程以获得一些提示。
  2. 制作一个屏幕大小的简单正方形。您正在按照顶部的这些线（蓝色四边形对吗？）做一些事情，但要确保它居中 - 看起来您可能会将它向上和向右推 1000 个单位。
  3. Check you're winding the correct way. Looks like you are from my somewhat rusty OGL memories.
  4. Try translating in different directions. Looks to me like you might be translating the wrong way with your first translatef.
于 2012-06-19T20:30:33.460 回答