C++ (Cpp) ofPixelsRef::setFromPixels示例

示例#1

文件： ofxFastFboReader.cpp 项目： galsasson/ofxFastFboReader

bool ofxFastFboReader::readToPixels(ofFbo &fbo, ofPixelsRef pix, ofImageType type)
{
	genPBOs();
	
	int channels;
	int glType;
	
	if (type == OF_IMAGE_COLOR)
	{
		channels = 3;
		glType = GL_RGB;
	}
	else if (type == OF_IMAGE_COLOR_ALPHA)
	{
		channels = 4;
		glType = GL_RGBA;
	}
	else if (type == OF_IMAGE_GRAYSCALE)
	{
		channels = 1;
		glType = GL_LUMINANCE;
	}
	else
	{
		return false;
	}
	
	const int width = fbo.getWidth();
	const int height = fbo.getHeight();
	
	if (async)
	{
		index = (index + 1) % num_buffers;
		nextIndex = (index + 1) % num_buffers;
	}
	else
	{
		index = nextIndex = 0;
	}
	
	size_t nb = width * height * channels;
	
	if (nb != num_bytes)
	{
		num_bytes = nb;
		setupPBOs(num_bytes);
	}
	
	glReadBuffer(GL_FRONT);
	
	fbo.bind();
	
	glBindBuffer(GL_PIXEL_PACK_BUFFER, pboIds[index]);
	glReadPixels(0, 0, width, height, glType, GL_UNSIGNED_BYTE, NULL);
	
	glBindBuffer(GL_PIXEL_PACK_BUFFER, pboIds[nextIndex]);
	unsigned char* mem = (unsigned char*)glMapBuffer(GL_PIXEL_PACK_BUFFER, GL_READ_ONLY);
	
	if (mem)
	{
		pix.setFromPixels(mem, width, height, channels);
		glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
	}
	
	glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
	
	fbo.unbind();
	
	return mem != NULL;
}