GLSL 片段着色器不会使用未注释的 texture2D 调用进行编译

Question

我有一个 N910f note 4，最后一个棒棒糖 5.0.1。好吧，片段着色器没有编译，但是如果我注释掉纹理采样行（texture2D 调用），着色器就会编译。我不知道编译器发生了什么，因为 Log.e(TAG, GLES20.glGetShaderInfoLog(shader)) 调用没有抛出任何信息。

这是我的片段 glsl 代码：

#define numLights 1
#pragma glsl

precision mediump float;

struct LightSourceParameters {
    vec3 ambient;
    vec3 lightColor;
    vec4 position;
    float spotExponent;
    float spotCutoff; // (range: [0.0,90.0], 180.0)
    vec3 spotDirection;
    float constantAttenuation;
    float linearAttenuation;
    float quadraticAttenuation;
};
uniform LightSourceParameters LightSource[numLights];

struct MaterialParameters {
    vec4 emission;
    vec4 ambient;
    vec4 diffuse;
    vec4 specular;
    float shininess;
    bool hasDiffuseTexture;
    bool hasSpecularTexture;
    bool hasEmissionTexture;
    bool hasAmbientTexture;
    bool hasNormalTexture;
    sampler2D diffuseTexture;
    sampler2D specularTexture;
    sampler2D emissionTexture;
    sampler2D ambientTexture;
    sampler2D normalTexture;
};
uniform MaterialParameters Material;

varying vec2 outTextCoord;
varying vec3 outNormal;
varying vec3 outViewVector;
varying vec3 outLightVector[numLights];

/* Declaramos cabecera de funcion, necesaria para que GLSL no diga que la funcion no existe, al definirse despues de main */
vec4 computeLight(in MaterialParameters material, in LightSourceParameters lightSource, in vec3 normal, in vec2 textCoord, in vec3 lightVector, in vec3 halfVector);
vec4 computeEmissionLight(in MaterialParameters material, in vec2 textCoord);

void main(){

    // Normalize the incoming vectors
    vec3 normal = normalize(outNormal);
    vec3 viewVector = normalize(outViewVector);

    // BACKFACE CULLING:
    float NdotVV = dot(normal,viewVector);
    if (NdotVV <= 0.0) discard;


    // normalize lightvector, compute half vectors and lights
    vec4 totalColorLighting = vec4(0.0);


    for (int indexComputeLights = 0; indexComputeLights <  numLights; indexComputeLights++){

        LightSourceParameters light = LightSource[indexComputeLights];

        vec3 currentLightVector = vec3(0.0);
        vec3 currentHalfVector = vec3(0.0);


        if (length(light.ambient) == 0.0 ){ /* no es ambiental, que no tienen vector ni half vector */

            currentLightVector = outLightVector[indexComputeLights]; // normalizamos posteriormente, para poder obtener la distancia a la luz del m�dulo de este vector
            currentHalfVector = normalize(outLightVector[indexComputeLights] + outViewVector);
        }
        else {
            // nothing
        }



        /* Si la luz es ambiental, halfVector y lightVector son
         * indefinidos para esa luz, pero da igual porque no son
         * utilizados en el algoritmo que calcula las luces
         */

     /*
        totalColorLighting = totalColorLighting + computeLight(Material, light, normal, outTextCoord, currentLightVector, currentHalfVector);
        totalColorLighting = clamp(totalColorLighting,vec4(0.0),vec4(1.0));
    */
    }

    totalColorLighting = totalColorLighting + computeEmissionLight(Material, outTextCoord);
    totalColorLighting = clamp(totalColorLighting,vec4(0.0),vec4(1.0));

    /* Devolvemos el color de fragmento calculado para almacenarlo en el framebuffer */
    totalColorLighting = vec4(1.0,1.0,0.34, 0.68);
    gl_FragColor = clamp(totalColorLighting,vec4(0.0),vec4(1.0));
    // gl_FragColor = vec4(1.0)*vec4(outTextCoord,1.0,1.0);

}

vec4 computeEmissionLight(in MaterialParameters material, in vec2 textCoord){
    vec4 totalEmissionColorLighting = vec4(0.0, 0.0, 0.0, 0.0);

    if ((length(vec3(material.emission)) != 0.0) || (material.hasEmissionTexture)) {
        /* El material tiene un termino emisivo, es decir, emite luz. Lo andimos al total de color calculado */
        if (!material.hasEmissionTexture) {
            totalEmissionColorLighting = material.emission;
        }
        else {
            totalEmissionColorLighting.rgba = texture2D(material.emissionTexture, textCoord).rgba;
            // texture2D(material.diffuseTexture, textCoord);
        }

    }
    return totalEmissionColorLighting;
}

代码中还有一个方法被注释掉了，computeLight。

好吧，在 computeEmissionLight 中，如果我对此发表评论，一切都会好起来的：

totalEmissionColorLighting.rgba = texture2D(material.emissionTexture, textCoord).rgba; // tried also without rgba

除了我糟糕的编码方式之外，有人发现有什么问题吗？

Answer 1

我不知道为什么您的 GLSL 编译器在编译此着色器失败时没有返回编译器信息日志，但已知使用具有不透明类型（例如 sampler2D）的 struct 会导致问题。不透明类型不能在着色器运行时分配值，因此将它们作为结构的一部分传递给函数并不总是有效（一些编译器允许，许多不允许）。

如果您的编译器遇到问题，重写着色器可能会有所帮助：

vec4 computeEmissionLight(in vec2 textCoord){
    vec4 totalEmissionColorLighting = vec4(0.0, 0.0, 0.0, 0.0);

    if ((length(vec3(Material.emission)) != 0.0) || (Material.hasEmissionTexture)) {
        /* El material tiene un termino emisivo, es decir, emite luz. Lo andimos al total de color calculado */
        if (!Material.hasEmissionTexture) {
            totalEmissionColorLighting = Material.emission;
        }
        else {
            totalEmissionColorLighting.rgba = texture2D(Material.emissionTexture, textCoord).rgba;
            // texture2D(Material.diffuseTexture, textCoord);
        }

    }
    return totalEmissionColorLighting;
}

我过去写过一个相关的答案，更详细地解释了这一点，here。