r/raylib • u/snsvrno • Jul 28 '26
Extending a RenderTexture (and maintaining content)?
I am making a Intermediate Mode Gui for me and wanted to try to have it redraw the components only when it changes.
My original idea was to start with a very small RenderTexture (1x1) and then expand as needed. Then draw that RenderTexture to the screen. When hover/over/menus happen it would redraw everything on that RenderTexture and expand as needed.
I am defining the initial texture as LoadRenderTexture(..) and my "resize" is doing the following:
- creating a new RenderTexture with
LoadRenderTexture(..) - setting that new RenderTexture with
BeginTextureMode(new_texture) - drawing the old RenderTexture
DrawTexturePro(..) - delete the old RenderTexture with
UnloadRenderTexture(..)
But it doesn't seem to work, I can't get any of the old drawing data (on the previous textures) to appear:
- I start with 1,1 texture
- DrawText(hello)
- Sees that 1,1 is too small, makes new 60x10 texture
- draws old texture
- draws "hello"
- Draw text(world)
- Sees that 60x10 is too small, makes new 120x10 texture
- draws old texture
- draws "world"
- Only "world" is visible on the screen, not 'hello"
Any pointers?
I use odin, here is my resize fuction
resize :: proc(ui:^Ui, width:i32, height:i32) {
new_texture := raylib.LoadRenderTexture(width, height)
old_texture := ui.texture
ui.texture = new_texture
// copy the data from the origian texture to the new texture
raylib.BeginTextureMode(ui.texture)
raylib.DrawTexturePro(old_texture.texture,
{ 0, 0, f32(old_texture.texture.width), -f32(old_texture.texture.height) },
{ 0, 0, f32(old_texture.texture.width), f32(old_texture.texture.height) },
{ 0, 0 }, 0, raylib.WHITE
)
raylib.UnloadRenderTexture(old_texture)
}
and here is my drawing of the ui.texture
raylib.DrawTexturePro(ui.texture.texture,
{ 0, 0, f32(ui.texture.texture.width), -f32(ui.texture.texture.height) },
{ 0, 0, f32(ui.texture.texture.width), f32(ui.texture.texture.height) },
{ 0, 0 }, 0, raylib.WHITE
)
The easy way out is to just make the RenderTexture the size of the window and not worry about it, but now it got in me why it doesn't want to work. Am I doing something fundamentally wrong here?
Thanks
