如何在开放的gl中画一个圆 [英] How to draw a circle in open gl

问题描述

有人可以帮我如何在图像中绘制与圆相似的圆，以便使用android的open gl v1.5来使M大于N.

[IMG] http://i49.tinypic.com/254y5bs.png [/IMG]

Can anyone help me how to draw a circle similar to one in the image, such that M is greater than N using open gl v1.5 for android

[IMG]http://i49.tinypic.com/254y5bs.png[/IMG]

推荐答案

很多建议易于查找 [ ^ ].

请尝试一下...

Please try this...

int RADIUS = 2;
float DEGREE_TO_RAD = 3.14 / 180;
glBegin( GL_LINE_LOOP );
glVertex2f( 0,0 );
int M_IN_DEGREE = 370;
int N_IN_DEGREE = 100;
for( int nR =N_IN_DEGREE; nR < M_IN_DEGREE; nR++ )
{
    float fX = sin((float)nR * DEGREE_TO_RAD ) ;
    float fY = cos((float)nR * DEGREE_TO_RAD );
    glVertex2f( fX, fY );
}
glEnd();

使用glDrawArrays

With glDrawArrays

int M_IN_DEGREE = 370;
int N_IN_DEGREE = 100;
int nCount = 1;
float stVertexArray[2*360];

stVertexArray[0] = 0.0;
stVertexArray[1] = 0.0;

for( int nR =N_IN_DEGREE; nR < M_IN_DEGREE; nR++ )
{
    float fX = sin((float)nR * DEGREE_TO_RAD ) ;
    float fY = cos((float)nR * DEGREE_TO_RAD );
    stVertexArray[nCount*2] = fX;
    stVertexArray[nCount*2 + 1] = fY;
    nCount++;
}

glEnableClientState( GL_VERTEX_ARRAY );
glVertexPointer( 2, GL_FLOAT, 0, stVertexArray );
glDrawArrays( GL_LINE_LOOP, 0, nCount );

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