st/mesa: ignore gl_texture_object::BaseLevel when allocating gallium textures

Previously, when we created a gallium texture for a corresponding Mesa
texture we'd only allocate space for mipmap levels >= BaseLevel.

This patch undoes that mechanism.  This fixes a render-to-texture bug
when rendering to level 0 when BaseLevel=1.

Also, it makes sense to allocate the whole texture object memory when
BaseLevel > 0 since a common use of GL_TEXTURE_BASE_LEVEL is to
progressively load/render mipmaps.  Eventually, the app almost always
fills in the level=0 mipmap image.

Finally, the texture image code is bit easier to understand now.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/mesa/state_tracker/st_gen_mipmap.c b/src/mesa/state_tracker/st_gen_mipmap.c
index b8b75c7de6..a015c4bb58 100644
--- a/src/mesa/state_tracker/st_gen_mipmap.c
+++ b/src/mesa/state_tracker/st_gen_mipmap.c
@@ -342,10 +342,10 @@ st_generate_mipmap(GLcontext *ctx, GLenum target,
 
    assert(lastLevel <= pt->last_level);
 
-   /* Recall that the Mesa BaseLevel image is stored in the gallium
-    * texture's level[0] position.  So pass baseLevel=0 here.
+   /* Try to generate the mipmap by rendering/texturing.  If that fails,
+    * use the software fallback.
     */
-   if (!st_render_mipmap(st, target, stObj, 0, lastLevel)) {
+   if (!st_render_mipmap(st, target, stObj, baseLevel, lastLevel)) {
       fallback_generate_mipmap(ctx, target, texObj);
    }