iPhone OpenGL ES Paint App刷机效果

我正在开发用于iPhone和iPad的绘画应用程序[参考来自GLPaint应用程序]。我正在研究画笔效果。我想为我的油漆刷的应用效果如图image1的iPhone OpenGL ES Paint App刷机效果

enter image description here

我有类似的图像2

enter image description here

我使用毛刷质地下面的代码笔触：

CGImageRef  brushImage; 
CGContextRef brushContext; 
GLubyte   *brushData; 
size_t   width, height; 
    if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) 
    { 
     brushImage = [UIImage imageNamed:@"[email protected]"].CGImage; 
    } 
    else { 
     brushImage = [UIImage imageNamed:@"flower.png"].CGImage; 
    } 
    width = CGImageGetWidth(brushImage) ; 
    height = CGImageGetHeight(brushImage) ; 
    if(brushImage) { 

     brushData = (GLubyte *) calloc(width * height * 4, sizeof(GLubyte)); 
       brushContext = CGBitmapContextCreate(brushData, width, height, 8, width * 4, CGImageGetColorSpace(brushImage),kCGImageAlphaPremultipliedLast); 
     CGContextDrawImage(brushContext, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height), brushImage); 
     CGContextRelease(brushContext); 
     glGenTextures(1, &brushTexture); 
     glBindTexture(GL_TEXTURE_2D, brushTexture); 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); 
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, brushData); 
     free(brushData); 
    } 
     CGFloat scale; 
     scale = self.contentScaleFactor; 

    glMatrixMode(GL_PROJECTION); 
    CGRect frame = self.bounds; 
    glLoadIdentity(); 
    glOrthof(0, (frame.size.width) * scale, 0, (frame.size.height) * scale, -1, 1); 
    glViewport(0, 0, (frame.size.width) * scale, (frame.size.height) * scale); 
    glMatrixMode(GL_MODELVIEW); 
    glDisable(GL_DITHER); 
    glEnable(GL_BLEND); 
    glEnable(GL_TEXTURE_2D); 
    glEnableClientState(GL_VERTEX_ARRAY); 
    glEnable(GL_BLEND); 
    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); 
    glEnable(GL_POINT_SPRITE_OES); 
    glTexEnvf(GL_POINT_SPRITE_OES, GL_COORD_REPLACE_OES, GL_TRUE); 
    glPointSize(width/kBrushScale); 
    // Define a starting color 
    HSL2RGB((CGFloat) 0.0/(CGFloat)kPaletteSize, kSaturation, kLuminosity, &components[0], &components[1], &components[2]); 
    glColor4f(components[0] * kBrushOpacity, components[1] * kBrushOpacity, components[2] * kBrushOpacity, kBrushOpacity);

我一直在寻找与不同油漆刷笔画相关的代码，但是我找不到任何代码。帮助我获得类似于image1的“所需”画笔描边。

来源

2012-04-11 user392406

请勿使用GL_POINT_SPRITE_OES模式。通过标准三角形绘制精灵。然后它需要将精灵纹理坐标绑定到目标输出坐标并使精灵纹理可重复。假设精灵纹理尺寸是32x32。默认的纹理坐标是rect {{0,0},{1.0,1.0}}。对于在{x,y}位置绘制精灵，需要使用基于rect {{(x%32)/32.0, (y%32)/32.0},{1.0, 1.0}}的精灵纹理坐标。这样可以防止精灵内容模糊。

来源

2012-06-27 18:49:43 onegray

iPhone OpenGL ES Paint App刷机效果

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