Gday,
I'm encountering an issue with the ARB_sparse_texture extension where my application's memory usage is jumping 120mb when committing any tile from the mipmap tail.
The minimum code I've got to reproduce this is:
GLuint page_texture;
glGenTextures(1, &page_texture);
glBindTexture(GL_TEXTURE_2D, page_texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SPARSE_ARB, GL_TRUE);
glTexStorage2D(GL_TEXTURE_2D, 15, GL_RGBA32F, 16384, 16384);
// Commit a level 0 page.
glTexPageCommitmentARB(GL_TEXTURE_2D, 0, 0, 0, 0, 64, 64, 0, GL_TRUE);
// 4kb increase here.
// Commit level 10 (first tail level).
glTexPageCommitmentARB(GL_TEXTURE_2D, 10, 0, 0, 0, 16, 16, 0, GL_TRUE);
// 120mb increase here.
It may be important to note that the 120mb increase is constant across sparse texture sizes. Creating a 256x256 sparse texture and committing the first tail level still results in a 120mb memory increase. For convenience, that code is also:
GLuint page_texture;
glGenTextures(1, &page_texture);
glBindTexture(GL_TEXTURE_2D, page_texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SPARSE_ARB, GL_TRUE);
glTexStorage2D(GL_TEXTURE_2D, 9, GL_RGBA32F, 256, 256);
glTexPageCommitmentARB(GL_TEXTURE_2D, 0, 0, 0, 0, 64, 64, 0, GL_TRUE);
glTexPageCommitmentARB(GL_TEXTURE_2D, 4, 0, 0, 0, 16, 16, 0, GL_TRUE);
// 120mb increase here.
My system is running the 18.5.2 drivers with the RX480. Has anyone else seen this problem?
Thanks,
-Lucas
