在iO中使用Open GL 1.0模板缓冲区进行掩膜的问题 [英] Issue with masking using Open GL 1.0 stencil buffer in iOs

问题描述

我一直在努力寻找在iO上使用OPEN GL 1.0中的模板缓冲区进行简单遮罩的解决方案.

I have been struggling to find a solution for a simple masking using Stencil Buffer in OPEN GL 1.0 on the iOs.

我先绘制背景，然后使用glPushMatrix在其上绘制一个框架，该框架是使用drawFrame绘制的.

I draw the background and then I draw on top of it using glPushMatrix a frame which is drawn using drawFrame.

我的框架由VideoFrameTexture组成，我尝试使用模板缓冲区使用maskTexture进行遮罩.我的目标是仅将videoFrameTexture的一部分(由我的蒙版的白色区域定义，并且对应于圆形)绘制到背景上.

My frame is made of a VideoFrameTexture which I try to mask using maskTexture using the stencil buffer. My objective is to draw only part of the videoFrameTexture (which is defined by the white area of my mask and which corresponds to a circle shape) onto the background.

我使用以下代码，但未考虑遮罩图像.这是黑色的白色png.

I use the following code but the mask image is not taken into account. It's a Black an white png.

-(void) drawFrame{

GLfloat vertexes[] =
{
    -1.0f,  -1.0f, 0.0f,
    1.0f,  -1.0f, 0.0f,
    1.0f,  1.0f, 0.0f,
    -1.0f, 1.0f, 0.0f
};
GLshort texes[] = {
    1, 1,
    0, 1,
    0, 0,
    1, 0,
};

glColor4f(1.0, 1.0, 1.0, 1.0);
glVertexPointer(3, GL_FLOAT, 0, vertexes);
glEnableClientState(GL_VERTEX_ARRAY);
glTexCoordPointer(2, GL_SHORT, 0, texes);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);


glDisable(GL_DEPTH_TEST);
glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);

glEnable(GL_STENCIL_TEST);
glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
glStencilFunc(GL_ALWAYS, 1, 0xffffffff);  


/// Mask Drawing
glBindTexture(GL_TEXTURE_2D, maskTexture);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
glEnable(GL_DEPTH_TEST);
glStencilFunc(GL_EQUAL, 1, 0xffffffff); /* draw if ==1 */
glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);


///Frame Drawing
glBindTexture(GL_TEXTURE_2D, videoFrameTexture);
glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

glDisable(GL_STENCIL_TEST);


glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);


glDeleteTextures(1, &videoFrameTexture);

}

我使用以下代码绘制视图:

I draw my view using the following code:

- (void) drawView
{
[EAGLContext setCurrentContext:context];
//glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT| GL_STENCIL_BUFFER_BIT);

   glOrthof(-1.0f, 1.0f, -1.5f, 1.5f, -10.0f, 10.0f);
   glViewport(0, 0, backingWidth, backingHeight);

   glMatrixMode(GL_MODELVIEW);

glPushMatrix();
glScalef(1, 0.75, 1);
glTranslatef(0, -1, 0);
glRotatef(90, 0.0f, 0.0f, 1.0f);
[self drawBackground];
glPopMatrix();

 glPushMatrix();

glScalef(1, 1, 1);
glTranslatef(0, 1, 0);
glRotatef(90, 0.0f, 0.0f, 1.0f);
[self drawFrame];
glPopMatrix();

//present frame buffer
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

推荐答案

模板缓冲区不适用于1.0.只有2.0

Stencil buffer is not available for 1.0. Only 2.0

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