问题描述
我正在尝试为iPad编写模糊着色器。我有它的工作,但我对结果不是很满意。帧速率非常不稳定,当模糊量很高时,模糊看起来像废话。
I am trying to write a blur shader for the iPad. I have it working but I am not very happy with the results. I get very choppy frame rates and the blur looks like crap when blur amount is high.
关于如何改善事情的任何想法?
Any ideas on how to improve things?
一些样本输出:
uniform sampler2D texture;
varying mediump vec2 fragTexCoord;
varying mediump vec3 eyespaceNormal;
varying highp float blurAmount;
void main(void)
{
highp vec2 gaussFilter[7];
gaussFilter[0] = vec2(-3.0, 0.015625);
gaussFilter[1] = vec2(-2.0, 0.09375);
gaussFilter[2] = vec2(-1.0, 0.234375);
gaussFilter[3] = vec2(0.0, 0.3125);
gaussFilter[4] = vec2(1.0, 0.234375);
gaussFilter[5] = vec2(2.0, 0.09375);
gaussFilter[6] = vec2(3.0, 0.015625);
highp float blurSize = blurAmount * 1.0;
/////////////////////////////////////////////////
// 7x1 gaussian blur fragment shader
/////////////////////////////////////////////////
highp vec4 color = vec4(0,0,0,1);
for( int i = 0; i < 7; i++ )
{
color += texture2D( texture, vec2( fragTexCoord.x+gaussFilter[i].x*blurSize, fragTexCoord.y+gaussFilter[i].x*blurSize ) )*gaussFilter[i].y;
}
gl_FragColor = color;
}
编辑:
盒子模糊可能是要走的路。
以下是着色器的框模糊版本:
A box blur may be the way to go.Here is a box blur version of the shader:
highp vec4 color = vec4(0,0,0,1);
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y - 4.0*blurAmount)) * 0.05;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y - 3.0*blurAmount)) * 0.09;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y - 2.0*blurAmount)) * 0.12;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y - blurAmount)) * 0.15;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y)) * 0.16;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y + blurAmount)) * 0.15;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y + 2.0*blurAmount)) * 0.12;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y + 3.0*blurAmount)) * 0.09;
color += texture2D(texture, vec2(fragTexCoord.x, fragTexCoord.y + 4.0*blurAmount)) * 0.05;
gl_FragColor = color;
这是盒子模糊输出(注意它只是一个水平模糊,但它可能就足够了我想):
Here is the box blur output(note it's only a horizontal blur, but it might be enough for what i want) :
推荐答案
该着色器需要运行两次才能工作,你所谓的 blurSize
应该是 vec2
,其值应为 vec2(0,1.0 / height)
表示垂直模糊, vec2(1.0 /宽, 0)
用于水平模糊。
That shader needs to run twice for it to work, what you call blurSize
should be a vec2
and the value of that should be vec2(0, 1.0/height)
for vertical blur and vec2(1.0/width, 0)
for horizontal blur.
参见
做两次模糊的想法是它会大大减少纹理查找次数,并希望提高速度。内核大小为7x7的双通模糊将需要14次纹理查找,但如果它在嵌套循环中完成,则需要进行49次纹理查找。
The idea behind doing a two pass blur is that it will dramatically reduce the number of texture lookups and hopefully increase the speed. A two pass blur with kernel size of 7x7 will require 14 texture lookups but if it done in a nested loop you'll need to do 49 texture lookups.
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