iPhoneアプリ開発と留学

- (void)loadView
{
	picker = [[UIPickerView alloc] initWithFrame:CGRectZero];
	picker.delegate = self;
	picker.dataSource = self;
	picker.showsSelectionIndicator = YES;

	CGAffineTransform t0 = CGAffineTransformMakeTranslation(picker.bounds.size.width/2, picker.bounds.size.height/2);
	CGAffineTransform s0 = CGAffineTransformMakeScale(0.5, 0.5);
	CGAffineTransform t1 = CGAffineTransformMakeTranslation(-picker.bounds.size.width/2, -picker.bounds.size.height/2);
	picker.transform = CGAffineTransformConcat(t0, CGAffineTransformConcat(s0, t1));

	self.view = [[UIView alloc] initWithFrame:CGRectZero];
	[self.view addSubview:picker];
}

		int i;
		
		SInt8 *data_ptr = (SInt8 *)(ioData->mBuffers[0].mData);
		for (i=0; i<inNumberFrames; i++)
		{
			if ((i+drawBufferIdx) >= drawBufferLen)
			{
				cycleOscilloscopeLines();
				drawBufferIdx = -i;
			}
			drawBuffers[0][i + drawBufferIdx] = data_ptr[2];
			data_ptr += 4;
		}
		drawBufferIdx += inNumberFrames;

// This determines how slowly the oscilloscope lines fade away from the display.
// Larger numbers = slower fade (and more strain on the graphics processing)
SInt8 *drawBuffers[kNumDrawBuffers];

#define kNumDrawBuffers 12

int drawBufferLen = kDefaultDrawSamples;

#define kDefaultDrawSamples 1024

	int drawBuffer_i;
	// Draw a line for each stored line in our buffer (the lines are stored and fade over time)
	for (drawBuffer_i=0; drawBuffer_i<kNumDrawBuffers; drawBuffer_i++)
	{
		if (!drawBuffers[drawBuffer_i]) continue;
		
		oscilLine_ptr = oscilLine;
		drawBuffer_ptr = drawBuffers[drawBuffer_i];
		
		GLfloat i;
		// Fill our vertex array with points
		for (i=0.; i<max; i=i+1.)
		{
			*oscilLine_ptr++ = i/max;
			*oscilLine_ptr++ = (Float32)(*drawBuffer_ptr++) / 128.;
		}
		
		// If we're drawing the newest line, draw it in solid green. Otherwise, draw it in a faded green.
		if (drawBuffer_i == 0)
			glColor4f(0., 1., 0., 1.);
		else
			glColor4f(0., 1., 0., (.24 * (1. - ((GLfloat)drawBuffer_i / (GLfloat)kNumDrawBuffers))));
		
		// Set up vertex pointer,
		glVertexPointer(2, GL_FLOAT, 0, oscilLine);
		
		// and draw the line.
		glDrawArrays(GL_LINE_STRIP, 0, drawBufferLen);
		
	}