我正在为 iPhone 和 iPad 开发绘画应用程序 [参考 GLPaint 应用程序]。我正在研究画笔效果。我想为我的绘画应用程序获得画笔效果，如 Image1 所示
我的笔触类似于图 2
我正在为画笔纹理使用以下代码：
CGImageRef brushImage;
CGContextRef brushContext;
GLubyte *brushData;
size_t width, height;
if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
brushImage = [UIImage imageNamed:@"flower@2x.png"].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画笔笔触相关的代码，但我找不到任何代码。帮助我获得类似于 image1 的“所需”笔触。