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我正在为 Android/iOS 开发游戏，需要优化渲染。游戏使用户能够变形地形，所以我使用地形的灰度图像（地形中的值 1 表示实心地面，0 表示无地面）并在其上应用片段着色器（还有背景图像）。这适用于 60 fps 常数，但问题是我还需要在地形边缘渲染边框。因此，我在变形时模糊了边缘，在片段着色器中，我根据地形密度/透明度（边界是 1x64 纹理）绘制边界。

问题是，在渲染边框时，我需要进行动态纹理读取，将帧速率降至 20。有什么办法可以优化吗？如果我用统一的浮点数组替换边框纹理会有所帮助还是与从二维纹理读取相同？

着色器代码：

 varying mediump vec2 frag_background_texcoord;
 varying mediump vec2 frag_density_texcoord;
 varying mediump vec2 frag_terrain_texcoord;

 uniform sampler2D density_texture;
 uniform sampler2D terrain_texture;
 uniform sampler2D mix_texture;
 uniform sampler2D background_texture;

 void main()
 {
    lowp vec4 background_color = texture2D(background_texture, frag_background_texcoord);
    lowp vec4 terrain_color = texture2D(terrain_texture, frag_terrain_texcoord);

    highp float density = texture2D(density_texture, frag_density_texcoord).a;

    if(density > 0.5)
    {
         lowp vec4 mix_color = texture2D(mix_texture, vec2(density, 1.0)); <- dynamic texture read (FPS drops to 20), would replacing this with a uniform float array help (would also need to calculate the index in the array)?
         gl_FragColor = mix(terrain_color, mix_color, mix_color.a);
    } else
    {
         gl_FragColor =  background_color;
    }
 }
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1 回答 1

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弄清楚了。我修复它的方法是删除所有分支。现在运行〜60fps。优化后的代码：

varying mediump vec2 frag_background_texcoord;
varying mediump vec2 frag_density_texcoord;
varying mediump vec2 frag_terrain_texcoord;

uniform sampler2D density_texture;   
uniform sampler2D terrain_texture;
uniform sampler2D mix_texture;
uniform sampler2D background_texture;

void main()
{
   lowp vec4 background_color = texture2D(background_texture, frag_background_texcoord);
   lowp vec4 terrain_color = texture2D(terrain_texture, frag_terrain_texcoord);

   lowp vec4 mix_color = texture2D(mix_texture, vec2(density, 0.0));
   lowp float density = texture2D(density_texture, frag_density_texcoord).a;

   gl_FragColor = mix(mix(bg_color, terrain_color, mix_color.r), mix_color, mix_color.a);       
}
于 2013-10-19T11:45:05.047 回答