使用Obj C中的Brad Larson GPUImage为照片创建草图效果 [英] Create Sketch effect to photos using Brad Larson GPUImage in Obj C
问题描述
您好我想在 iOS
中使用Brad Larson的 GPUImage
sdk对照片进行素描效果。我正在尝试创建这样的草图效果
Hi I would like to try sketch effect on photos using Brad Larson's GPUImage
sdk in iOS
. I am trying to create sketch effect like this
但我得到的草图效果是这样的
But the sketch effect i get is like this
我正在使用GPUImageSketchFilter创建此效果,以下是我提供的参数来实现这个效果:
I am using GPUImageSketchFilter to create this effect, Following are the parameters I provide to achieve this effect:
setTexelHeight:(1.12 / 480.0)
setTexelWidth:(0.5 / 320.0)
请建议我如何达到这个效果..
Please suggest me how to achieve this effect..
Brad根据你的建议,我有这个......
Brad going by your suggestions, i have got this...
我的目标:我需要使正确的图像看起来像左图像。 。
请建议我.. !!
My Objective: I need to make the right image look like the left one.. Pls suggest me..!!
推荐答案
我看到了更好的素描效果ect代码,但我不擅长过滤器,我不能为GPUImage写一个自定义过滤器来应用这个:
I have seen a better sketch effect code,but I am not good at filter ,I can not write a custom filter for GPUImage to apply this:
float res = iResolution.x;
float n0 = 97.0 / res;
float n1 = 15.0 / res;
float n2 = 97.0 / res;
float n3 = 9.7 / res;
float total = n2 + ( 4.0 * n0 ) + ( 4.0 * n1 );
const vec3 div3 = vec3(1.0 / 3.0);
void main(void) {
float offset, temp1, temp2;
vec4 m, p0, p1, p2, p3, p4, p5, p6, p7, p8;
offset = n3;
p0=texture2D(iCamera,iScreen);
p1=texture2D(iCamera,iScreen+vec2(-offset,-offset));
p2=texture2D(iCamera,iScreen+vec2( offset,-offset));
p3=texture2D(iCamera,iScreen+vec2( offset, offset));
p4=texture2D(iCamera,iScreen+vec2(-offset, offset));
offset=n3*2.0;
p5=texture2D(iCamera,iScreen+vec2(-offset,-offset));
p6=texture2D(iCamera,iScreen+vec2( offset,-offset));
p7=texture2D(iCamera,iScreen+vec2( offset, offset));
p8=texture2D(iCamera,iScreen+vec2(-offset, offset));
m = (p0 * n2 + (p1 + p2 + p3 + p4) * n0 + (p5 + p6 + p7 + p8) * n1) / total;
//convert to b/w
temp1 = dot(p0.rgb, div3);
temp2 = dot(m.rgb, div3);
//color dodge blend mode
if (temp2 <= 0.0005) {
gl_FragColor = vec4( 1.0, 1.0, 1.0, p0.a);
} else {
gl_FragColor = vec4( vec3(min(temp1 / temp2, 1.0)), p0.a);
}
}
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