Iphone像素失真，同时缩放Paint应用的OpenGL ES内容

我有一个openGL ES的一个奇怪的问题。 我正在为iPhone的绘画应用程序[从GLPaint应用程序引用]。在我的代码中，我正在使用包含大纲图像，我把[CAEAGLLayer] paintView填充颜色的imageView。 根据用户触摸的位置，通过屏幕上的绘图线填充轮廓图像中的颜色。 我使用“renderLineFromPoint”函数来绘制两点之间的一条线，使用“touchesMoved”获取起点和终点。

- (void) renderLineFromPoint:(CGPoint)start toPoint:(CGPoint)end{ 

//根据用户触摸的位置在屏幕上绘制一条线

 static GLfloat* vertexBuffer = NULL; static NSUInteger vertexMax = 64; NSUInteger vertexCount = 0, count, i; [EAGLContext setCurrentContext:context]; glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer); // Convert locations from Points to Pixels //CGFloat scale = self.contentScaleFactor; CGFloat scale; if ([self respondsToSelector: @selector(contentScaleFactor)]) { scale=self.contentScaleFactor; } else{ //scale = 1.000000; if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)] == YES && [[UIScreen mainScreen] scale] == 2.00) { // RETINA DISPLAY scale = 2.000000; } else { scale = 1.000000; } } start.x *= scale; start.y *= scale; end.x *= scale; end.y *= scale; float dx = end.x - start.x; float dy = end.y - start.y; float dist = (sqrtf(dx * dx + dy * dy)/ kBrushPixelStep); // Allocate vertex array buffer if(vertexBuffer == NULL) vertexBuffer = malloc(vertexMax * 2 * sizeof(GLfloat)); // Add points to the buffer so there are drawing points every X pixels count = MAX(ceilf(dist), 1); //NSLog(@"count %d",count); for(i = 0; i < count; ++i) { if(vertexCount == vertexMax) { vertexMax = 2 * vertexMax; vertexBuffer = realloc(vertexBuffer, vertexMax * 2 * sizeof(GLfloat)); // NSLog(@"if loop"); } vertexBuffer[2 * vertexCount + 0] = start.x + (dx) * ((GLfloat)i / (GLfloat)count); vertexBuffer[2 * vertexCount + 1] = start.y + (dy) * ((GLfloat)i / (GLfloat)count); vertexCount += 1; } // Render the vertex array glVertexPointer(2, GL_FLOAT, 0, vertexBuffer); glDrawArrays(GL_POINTS, 0, vertexCount); // Display the buffer glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer); [context presentRenderbuffer:GL_RENDERBUFFER_OES]; } 

现在我正在使用捏手势缩放涂料视图：

  UIPinchGestureRecognizer *twoFingerPinch = [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(twoFingerPinch:)] autorelease]; [self addGestureRecognizer:twoFingerPinch]; - (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer { if([recognizer state] == UIGestureRecognizerStateBegan) { // Reset the last scale, necessary if there are multiple objects with different scales lastScale = [recognizer scale]; } if ([recognizer state] == UIGestureRecognizerStateBegan || [recognizer state] == UIGestureRecognizerStateChanged) { CGFloat currentScale = [[[recognizer view].layer valueForKeyPath:@"transform.scale"] floatValue]; // Constants to adjust the max/min values of zoom const CGFloat kMaxScale = 2.0; const CGFloat kMinScale = 1.0; CGFloat newScale = 1 - (lastScale - [recognizer scale]); newScale = MIN(newScale, kMaxScale / currentScale); newScale = MAX(newScale, kMinScale / currentScale); CGAffineTransform transform = CGAffineTransformScale([self transform], newScale, newScale); self.transform = transform; lastScale = [recognizer scale]; // Store the prev textureScale = lastScale; [self setContentScaleFactor:2.0f]; CGRect frame = self.bounds; NSLog(@"Scale %f Last scale %f width %f Height %f", newScale , lastScale, frame.size.width * newScale, frame.size.height * newScale); } } 

上面的代码正在工作，但在缩放后的paintView线已扭曲像素[不视网膜显示]。

有没有什么办法重新绘制基于缩放比例的opengl的内容。

提前感谢你，

Answer 1

这并不奇怪。 当您绘制到OpenGL时，您正在绘制一个固定的分辨率，该分辨率是您的OpenGL上下文的大小。 你很可能创build一个上下文，这是你的屏幕分辨率。

如果您希望能够在不插入图像的情况下进行放大，则必须创build大于屏幕的GL上下文。 例如，如果您希望能够放大到200％，则必须创build一个具有屏幕像素数两倍的上下文。