Question

我正在尝试在一个着色器中使用sampler2D和samplerCube。我曾经用struct来做几个sampler2D。但是现在我决定停止将它们放在struct中，并注意到一些功能。如果将sampler2D放入struct中，则将samplerCube绑定1次就足够了。但是，如果将sampler2D放在结构外部，则每次绘制每个模型时都必须绑定samplerCube。下面，我给出了伪代码的示例。

sampler2D 进入 struct：

uniform samplerCube shadowMaps;
uniform struct Mapping {
    sampler2D ambientMapping;
    sampler2D diffuseMapping;
    sampler2D specularMapping;
    sampler2D normalMapping;
} mapping;

C ++伪代码：

// somewhere in init
// samplerCube
glUniform1i(shadow, 4);
glActiveTexture(GL_TEXTURE4);
glBindTexture(GL_TEXTURE_CUBE_MAP, shadowMapId);

// ...

// drawing models
for (size_t i = 0; i < MODELS_COUNT; i++) {
    glUniform1i(model[i].ambientMapping, 0);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, model[i].texturesIds[0]);

    glUniform1i(model[i].diffuseMapping, 1);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, model[i].texturesIds[1]);
    // analogically for specular and normal

    // model
}

sampler2D 外部 struct：

uniform samplerCube shadowMaps;
uniform sampler2D ambientMapping;
uniform sampler2D diffuseMapping;
uniform sampler2D specularMapping;
uniform sampler2D normalMapping;

C ++伪代码：

// drawing models
for (size_t i = 0; i < MODELS_COUNT; i++) {
    glUniform1i(model[i].ambientMapping, 0);
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, model[i].texturesIds[0]);

    glUniform1i(model[i].diffuseMapping, 1);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, model[i].texturesIds[1]);
    // analogically for specular and normal

    // samplerCube
    glUniform1i(shadow, 4);
    glActiveTexture(GL_TEXTURE4);
    glBindTexture(GL_TEXTURE_CUBE_MAP, shadowMapId);

    // model
}

在第二种情况下，为什么我每次都应该做glBindTexture(GL_TEXTURE_CUBE_MAP, shadowMapId)？最好的方法是什么？什么会更有生产力？

一个着色器中的sampler2D和samplerCube

0 个答案: