void DrawGLText(string text, float loc_x, float loc_y) { glColor4f(1.0, 1.0, 1.0, 0.5); glRasterPos3f(loc_x, loc_y, 1); glutBitmapString(GLUT_BITMAP_HELVETICA_18), text.c_str()); }
这是用于在特定位置绘制文本的My代码。我想调整它以绘制居中(loc_x，loc_y)而不是左对齐的文本。
epggiuax1#
使用glutBitmapWidth()或glutBitmapLength()(来自FreeGLUT)计算字符串的宽度，并沿X轴平移-textWidth / 2.0f：
glutBitmapWidth()
glutBitmapLength()
-textWidth / 2.0f
// call glRasterPos*() before this // x/y offsets are in pixels void bitmapString( void* aFont, const unsigned char* aString, float aXoffset, float aYoffset ) { GLboolean valid = GL_FALSE; glGetBooleanv( GL_CURRENT_RASTER_POSITION_VALID, &valid ); if( !valid ) { return; } GLfloat pos[4] = { 0.0f }; glGetFloatv( GL_CURRENT_RASTER_POSITION, pos ); glWindowPos2f( pos[0] + aXoffset, pos[1] + aYoffset ); glutBitmapString( aFont, aString ); } // usage std::string text = "Lorem ipsum"; glRasterPos2f( 50.0f, 100.0f ); const auto* str = reinterpret_cast<const unsigned char*>(text.c_str()); const int width = glutBitmapLength( font, str ); bitmapString( font, str, -width / 2.0f, 0.0f );
1条答案
按热度按时间epggiuax1#
使用
glutBitmapWidth()或glutBitmapLength()(来自FreeGLUT)计算字符串的宽度，并沿X轴平移-textWidth / 2.0f：