Use a Vec2 uniform for new atlas size instead of pulling from a sampler2D so that we don't have to bind the new atlas texture while rendering to it

Author: Cleptomania

arcade/context.py

@@ -186,9 +186,8 @@ def __init__(
             fragment_shader=":system:shaders/atlas/resize_simple_fs.glsl",
         )
         self.atlas_resize_program["atlas_old"] = 0  # Configure texture channels
-        self.atlas_resize_program["atlas_new"] = 1
-        self.atlas_resize_program["texcoords_old"] = 2
-        self.atlas_resize_program["texcoords_new"] = 3
+        self.atlas_resize_program["texcoords_old"] = 1
+        self.atlas_resize_program["texcoords_new"] = 2
 
         if gl_api != "webgl":
             # SpriteList collision resources

arcade/resources/system/shaders/atlas/resize_simple_vs.glsl

@@ -8,20 +8,19 @@
 
 // Old and new texture coordinates
 uniform sampler2D atlas_old;
-uniform sampler2D atlas_new;
 
 uniform sampler2D texcoords_old;
 uniform sampler2D texcoords_new;
 
 uniform mat4 projection;
 uniform float border;
+uniform vec2 size_new;
 
 out vec2 uv;
 
 void main() {
     // Get the texture sizes
     ivec2 size_old = textureSize(atlas_old, 0).xy;
-    ivec2 size_new = textureSize(atlas_new, 0).xy;
 
     // Read texture coordinates from UV texture here
     int texture_id = gl_VertexID / 6;

arcade/texture_atlas/atlas_default.py

@@ -712,10 +712,10 @@ def resize(self, size: tuple[int, int], force=False) -> None:
 
         # Bind textures for atlas copy shader
         atlas_texture_old.use(0)
-        self._texture.use(1)
-        image_uvs_old.texture.use(2)
-        self._image_uvs.texture.use(3)
+        image_uvs_old.texture.use(1)
+        self._image_uvs.texture.use(2)
         self._ctx.atlas_resize_program["border"] = float(self._border)
+        self._ctx.atlas_resize_program["size_new"] = size
         self._ctx.atlas_resize_program["projection"] = Mat4.orthogonal_projection(
             0,
             self.width,