Loading textures take an unreasonable amount of VRAM

[Liran]

Hi

I am working with Windows 10, Visual Studio 2019, SFML 2.5.1 32bit and using GPU-Z to analyze the VRAM usage.

I am loading some sprites and spritesheets using sf::Texture::loadFromFile and while some of the smaller files <1MB  don't raise the VRAM usage too much, I tried loading 3 textures which produced a very high VRAM increase.

All are in PNG format.
1. 5MB texture raised the VRAM usage by 100+MB.
2. 3.3MB texture raised the VRAM usage by 450+MB.
2. 11.8MB texture raised the VRAM usage by about 600MB.

I would not be surprised by a bit of overhead but I am really confused by this.

Thank you

[Laurent]

PNG has RLE compression (which is noticable if your image has long ranges of pixels with same color), that can explain a difference. There's also the bit depth: SFML uses 32-bits pixels, PNG can probably use lower, like 8-bit.

Can you give us the specs of your PNG files (width, height, bits per pixel)? Or better, upload one so that we can play with it directly.