c ++ / OpenGL / GLSL，具有“随机”工件 [英] c++/OpenGL/GLSL, textures with "random" artifacts

问题描述

想知道某人是否经历过这种情况，知道原因。我使用纹理数组后得到这些奇怪的工件。

Would like to know if someone has experienced this and knows the reason. I'm getting these strange artifacts after using "texture arrays"

http://i.imgur.com/ZfLYmQB.png

（我的gpu是AMD R9 270）

(My gpu is AMD R9 270)

• 忍者编辑删除了其余部分的可读性，因为它只是显示出可能出现问题的代码，因为项目已打开source现在我只显示问题的来源（片段着色器）

• ninja edit deleted the rest of the post for readability since it was just showing code where the problem could have been, since the project is open source now I only show the source of the problem(fragment shader)

Frag：

#version 330 core

layout (location = 0) out vec4 color;

uniform vec4 colour;
uniform vec2 light;

in DATA{
    vec4 position;
    vec2 uv;
    float tid;
    vec4 color;
}fs_in;

uniform sampler2D textures[32];

void main()
{
    float intensity = 1.0 / length(fs_in.position.xy - light);
    vec4 texColor = fs_in.color;
    if(fs_in.tid > 0.0){    
        int tid = int(fs_in.tid - 0.5);
        texColor = texture(textures[tid], fs_in.uv);
    }
    color = texColor; // * intensity;
}

编辑：github repos（对不起，如果它缺少一些libs，他们到github） https://github.com/PedDavid/NubDevEngineCpp

github repos (sorry if It is missing some libs, having trouble linking them to github) https://github.com/PedDavid/NubDevEngineCpp

修改： derhass 指出我在做某事与未定义的结果（访问数组没有常量（[tid]））。我有它现在使用

Credits to derhass for pointing out I was doing something with undefined results (accessing the array without a constant ([tid])). I have it now working with

switch(tid){
    case 0: textureColor = texture(textures[0], fs_in.uv); break;
    ...
    case 31: textureColor = texture(textures[31], fs_in.uv); break;
}

不是最漂亮，但现在很好！

Not the prettiest, but fine for now!

推荐答案

我使用纹理数组后得到这些奇怪的工件

I'm getting these strange artifacts after using "texture arrays"

您没有使用纹理数组。您使用纹理采样器数组。从您的片段着色器：

You are not using "texture arrays". You use arrays of texture samplers. From your fragment shader:

#version 330 core
// ...
in DATA{
    // ...
    float tid;
}fs_in;

//...

    if(fs_in.tid > 0.0){    
        int tid = int(fs_in.tid - 0.5);
        texColor = texture(textures[tid], fs_in.uv);
    }

根据 GLSL 3.30规范允许， p>

What you try to do here is not allowed as per the GLSL 3.30 specification which states

在着色器中聚集到数组中的采样器（使用方括号
[]）只能用整数常量表达式索引$ b section 4.3.3常量表达式）。

Samplers aggregated into arrays within a shader (using square brackets [ ]) can only be indexed with integral constant expressions (see section 4.3.3 "Constant Expressions").

您的 tid 不是一个常数，所以这不会工作。

Your tid is not a constant, so this will not work.

在GL 4中，这个约束有点放松了（quote是从 GLSL 4.50 spec ）：

In GL 4, this constraint has been somewhat relaxed to (quote is from GLSL 4.50 spec):

当在着色器中聚合为数组时，采样器只能使用动态统一的整数表达式来索引
，否则
的结果未定义。

When aggregated into arrays within a shader, samplers can only be indexed with a dynamically uniform integral expression, otherwise results are undefined.

您现在的输入也不是动态统一，因此您也会得到未定义的结果。

Your now your input also isn't dynamically uniform either, so you will get undefined results too.

我不知道你想要实现什么，但也许你可以通过使用阵列贴图，它将一组完整的图像表示为单个GL纹理对象，并且不会在访问它们时施加这样的约束。

I don't know what you are trying to achieve, but maybe you can get it dobe by using array textures, which will represent a complete set of images as a single GL texture object and will not impose such constraints at accessing them.

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