GLUT Tutorials 14：笔画字体

博客转自：http://www.lighthouse3d.com/tutorials/glut-tutorial/stroke-fonts/

笔画是一种利用直线绘制的字体，对比位图字体，笔画字体更像3维物体。例如字体可以旋转、缩放和平移。这个小节内，我们将呈现GLUT 将笔画字体显示在屏幕上的函数。基本上只需要一个函数 glutStrokeCharacter。

void glutStrokeCharacter(void *font, int character)

Parameters:

font – the name of the font to use (see bellow for a list of what’s available
character – what to render, a letter, symbol, number, etc…

The font options available are:

• GLUT_STROKE_ROMAN
• GLUT_STROKE_MONO_ROMAN (fixed width font: 104.76 units wide).

The following line of text exemplifies a call to the glutStrokeCharacter function to output a single character at the current local coordinates:

glutStrokeCharacter(GLUT_STROKE_ROMAN,'3');

As opposed to bitmap fonts, the render location for stroke fonts is specified in the same way as for any graphical primitive, i.e. using translations, rotations and scales.The following function renders a string starting at the specified position in local world coordinates:

void renderStrokeFontString(
        float x,
        float y,
        float z,
        void *font,
        char *string) {

    char *c;
    glPushMatrix();
    glTranslatef(x, y,z);

    for (c=string; *c != ''; c++) {
        glutStrokeCharacter(font, *c);
    }

    glPopMatrix();
}

Note: GLUT uses lines to draw stroke fonts, therefore we can specify the width of the line with the function glLineWidth. This function takes a float specifying the width as the only parameter.

As for bitmap fonts, GLUT provides a function that returns the width of a character. The function is glutStrokeWidth and the syntax is as follows:

int glutStrokeWidth(void *font, int character);

Parameters:

font – one of the pre defined fonts in GLUT, see above.
character – the character which we want to know the width

显示效果如下