opengl贴图的问题，为什么中间会有一条线？？？

IT_magnate 2010-11-08 05:17:45

我先把图片分割，然后再贴到相邻的两个长方形内，为什么中间这个地方会有一条线呢，请高手给点提示。。。
谢谢了！

纹理设置代码如下：



	int i, width, height;

	BOOL sizeToFit = NO;

	GLubyte * data = NULL;

	CGContextRef ct = NULL;	

	width = CGImageGetWidth(image);

	height = CGImageGetHeight(image);



	if((width != 1) && (width & (width - 1))) 

	{

		i = 1;

		while((sizeToFit ? 2 * i : i) < width)

			i *= 2;

		width = i;

	}

	if((height != 1) && (height & (height - 1))) 

	{

		i = 1;

		while((sizeToFit ? 2 * i : i) < height)

			i *= 2;

		height = i;

	}

	while((width > kMaxTextureSize) || (height > kMaxTextureSize)) 

	{

		width /= 2;

		height /= 2;

	}

	

	data = (GLubyte *)malloc(height * width * 4);

	ct = CGBitmapContextCreate(data,

							   width,

							   height,

							   8,

							   width * 4,

							   CGImageGetColorSpace(image),

							   kCGImageAlphaPremultipliedLast);



	CGContextClearRect(ct, CGRectMake(0, 0, width, height));

	CGContextTranslateCTM(ct, 0.0, height);

	CGContextScaleCTM(ct, 1.0, -1.0);

	CGContextDrawImage(ct, CGRectMake(0, 0, width, height), image);

//	CGImageRef saveImageRef = CGBitmapContextCreateImage(ct);

//	UIImage * saveImage = [UIImage imageWithCGImage:saveImageRef];

//	NSString * savePath = [NSString stringWithFormat:@"%@/Documents/%d.jpg", NSHomeDirectory(), location];

//	[UIImageJPEGRepresentation(saveImage, 1.0) writeToFile:savePath atomically:YES];

//	CGImageRelease(saveImageRef);

//	CGContextRelease(ct);

	

	glBindTexture(GL_TEXTURE_2D, location);

	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);

	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

//    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);     

//    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

//	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

	

	free(data);

绘图代码如下：



	// Our new object definition code goes here

	[EAGLContext setCurrentContext:context];

	glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);

	glViewport(0, 0, backingWidth, backingHeight);

	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);



//	glEnable(GL_CULL_FACE);

//	glFrontFace(GL_CCW);



	

	glMatrixMode(GL_MODELVIEW);

	glLoadIdentity();

	glScalef(scaleX, scaleY, scaleZ);	

	_angle = 30;

//	_angle += 5;

	glRotatef(_angle, 0, 1, 0);

	glRotatef(10.0, 0, 1, 0);

	

	glVertexPointer(3, GL_FLOAT, 0, vertices);

	glTexCoordPointer(2, GL_SHORT, 0, texCoords);	

	glEnableClientState(GL_VERTEX_ARRAY);	

	glEnableClientState(GL_TEXTURE_COORD_ARRAY);

	

	for (int i = 0; i < POLYGON; i++) 

	{

		glBindTexture(GL_TEXTURE_2D, _textures[i]);

		glDrawArrays(GL_TRIANGLE_FAN, i * 4, 4);

	}

	

	// Our new drawing code goes here

	glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);

	[context presentRenderbuffer:GL_RENDERBUFFER_OES];

我把data里面的内容保存的时候，并没有发现有这条缝隙



	CGImageRef saveImageRef = CGBitmapContextCreateImage(ct);

	UIImage * saveImage = [UIImage imageWithCGImage:saveImageRef];

	NSString * savePath = [NSString stringWithFormat:@"%@/Documents/%d.jpg", NSHomeDirectory(), location];

	[UIImageJPEGRepresentation(saveImage, 1.0) writeToFile:savePath atomically:YES];

	CGImageRelease(saveImageRef);

	CGContextRelease(ct);

...全文