Question

事实上,Im drawing drawing ,I m 检查ube子的轮换问题,但为此,我需要从屏幕的0,0,-1开放gl协调中抽出一个点,I m 采用视角预测、MyGLSurfaceView和1x1.5 开放gl 。

我如何能够在0,0,-1开放式屏幕上抽取黑白点?

Answer 1

如果你希望能够直接利用窗户空间,那么最容易的事情是把模型勘察和预测与身份表相连接,并提取一个<代码>GL_POINT,与你需要的地点相连接。因此,情况如下:

glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();

glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();

// draw the point here; specifics depending on whether you
// favour VBOs, VBAs, etc

// e.g. (assuming you don t have any client state enabled
// on entry and don t care about leaving the vertex array
// enabled on exit)
GLfloat vertexLocation[] = {0.0f, 0.0f, -1.0f};

glColor4f(0.0f, 0.0f, 0.0f, 1.0f);
glEnableClientState(GL_VERTEX_ARRAY);
glVertexPointer(3, GL_FLOAT, 0, vertexLocation);

glDrawArrays(GL_POINTS, 0, 1);

// end of example to plot a GL_POINT

glPopMatrix();

glMatrixMode(GL_MODELVIEW);
glPopMatrix();

// and possibly restore yourself to some other matrix mode
// if, atypically, the rest of your code doesn t assume modelview

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