问题描述:

I am trying to draw some lines in my GLView, but it just doesn't do anything.

I'm using Xcode 4.5 for iOS 6.0 application.

This is my code:

//Draw Axes

{

const GLfloat lineX[] = {

-100.0f, 0.0f, 0.0f, //point A

100.0f, 0.0f, 0.0f //point B

};

const GLfloat lineY[] = {

0.0f, -100.0f, 0.0f, //point A

0.0f, 100.0f, 0.0f //point B

};

const GLfloat lineZ[] = {

0.0f, 0.0f, -100.0f, //point A

0.0f, 0.0f, 100.0f //point B

};

glEnableClientState(GL_VERTEX_ARRAY);

glColor4f(1.0f, 0.0f, 0.0f, 1.0f); // opaque red

glVertexPointer(3, GL_FLOAT, 0, lineX);

glDrawArrays(GL_LINES, 0, 2);

glColor4f(0.0f, 1.0f, 0.0f, 1.0f); // opaque green

glVertexPointer(3, GL_FLOAT, 0, lineY);

glDrawArrays(GL_LINES, 0, 2);

glColor4f(0.0f, 0.0f, 1.0f, 1.0f); // opaque blue

glVertexPointer(3, GL_FLOAT, 0, lineZ);

glDrawArrays(GL_LINES, 0, 2);

glDisableClientState(GL_VERTEX_ARRAY);

}

I'm new to openGL and I'm just trying to do some basic stuff.

I can use glClear:

glClearColor(1, 0, 1, 1);

glClear(GL_COLOR_BUFFER_BIT);

so it seems that the context is right but I can't draw the lines.

any help...

Thank you.

网友答案:

Why don't you try having a look at the GLPaint sample code.

It draws lines (based on touch input) using OpenGL ES 1.0

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