具有透明背景的OpenGL ES 2.0 GLKit

Question

有没有办法让GLKView的背景透明？我在这里尝试了解决方案,但这对我不起作用.

*编辑:我需要帮助使它完全透明.背景主要是白色和灰色,但我只是用更鲜艳的色彩测试它,当然你可以模糊地看到背景.任何想法为什么它将部分透明但不完全使用以下代码？

这是我的视图控制器中的代码:

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.context = [[[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2] autorelease];
    CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.view.layer;
    eaglLayer.opaque = NO;

    if (!self.context) {
       NSLog(@"Failed to create ES context");
    }

    GLKView *view = (GLKView *)self.view;
    view.context = self.context;

    view.backgroundColor = [UIColor clearColor];

    view.drawableDepthFormat = GLKViewDrawableDepthFormat24;

    [self setupGL];
}

- (void)setupGL
{
    [EAGLContext setCurrentContext:self.context];

    self.effect = [[[GLKBaseEffect alloc] init] autorelease];
    self.effect.light0.enabled = GL_FALSE;
    self.effect.light0.diffuseColor = GLKVector4Make(1.0f, 0.4f, 0.4f, 0.0f);
    self.effect.light0.ambientColor = GLKVector4Make(1.0f, 0.4f, 0.4f, 0.0f);

    glDisable(GL_DEPTH_TEST);

    glGenVertexArraysOES(1, &_vertexArray);
    glBindVertexArrayOES(_vertexArray);

    glGenBuffers(1, &_vertexBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertexData), vertexData, GL_DYNAMIC_DRAW);

    glEnableVertexAttribArray(GLKVertexAttribPosition);
    glVertexAttribPointer(GLKVertexAttribPosition, VERTEX_POS_DATA_SIZE, GL_FLOAT, GL_FALSE, VERTEX_DATA_SIZE * sizeof(GLfloat), BUFFER_OFFSET(0));

    glEnableVertexAttribArray(GLKVertexAttribColor);
    glVertexAttribPointer(GLKVertexAttribColor, VERTEX_COLOR_DATA_SIZE, GL_FLOAT, GL_FLOAT, VERTEX_DATA_SIZE * sizeof(GLfloat), BUFFER_OFFSET(VERTEX_POS_DATA_SIZE * sizeof(GLfloat)));    

    glLineWidth(10.0);
}

- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
    if (!needsRedraw) return;
    needsRedraw = NO;

    glClearColor(0.65f, 0.65f, 0.65f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    [self.effect prepareToDraw];

    glDrawArrays(GL_LINE_STRIP, 0, vertexCount);    
}

我已经尝试将backgroundColor设置为[UIColor clearColor]并将eaglLayer设置为不透明.哎呀,我甚至尝试将eaglLayer的backgroundColor设置为具有0不透明度的CGColorRef.

Answer 1

嗯,我不认为这很重要,因为alpha已经是0.0f,但是当我改变时

glClearColor(0.65f, 0.65f, 0.65f, 0.0f);

至

glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

它使背景完全透明.

感谢大家的建议和帮助!

Answer 2

对我来说,它有助于使视图不透明:

view.opaque = NO

除了glClearColor调用当然还有透明度.

0.5f的透明度将背景与另一个具有半透明度的UIImageview完美地融合在一起.