如何让 texelFetchOffset 环绕？

Question

我像这样创建纹理：

this->width = width;
this->height = height;
glGenFramebuffers(1, &framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);

glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

switch (components) {
    case 1: glTexImage2D(GL_TEXTURE_2D, 0, GL_R16F, width, height, 0, GL_RED, GL_HALF_FLOAT, 0); break;
    case 2: glTexImage2D(GL_TEXTURE_2D, 0, GL_RG16F, width, height, 0, GL_RG, GL_HALF_FLOAT, 0); break;
    case 3: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB16F, width, height, 0, GL_RGB, GL_HALF_FLOAT, 0); break;
    case 4: glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, width, height, 0, GL_RGBA, GL_HALF_FLOAT, 0); break;
    default: Log::Write("Unknown format");
}


if(GL_NO_ERROR != glGetError()) Log::Write("Could not create texture");

GLuint colorbuffer;
glGenRenderbuffers(1, &colorbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, colorbuffer);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);

if(GL_NO_ERROR != glGetError()) Log::Write("Could not attach framebuffer");

if(GL_FRAMEBUFFER_COMPLETE != glCheckFramebufferStatus(GL_FRAMEBUFFER)) Log::Write("Could not create framebuffer");

glClearColor(0, 0, 0, 0);
glClear(GL_COLOR_BUFFER_BIT);
glBindFramebuffer(GL_FRAMEBUFFER, 0);

但在我的着色器中 texelFetchOffset 似乎没有环绕纹理的边缘。我究竟做错了什么？

Answer 1

纹理坐标环绕是采样器状态，该texelFetch函数系列完全绕过采样并直接访问纹理的数据存储。它永远不会为你做坐标包装。