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, 5 deletions

diff --git a/src/mesa/state_tracker/st_cb_fbo.c b/src/mesa/state_tracker/st_cb_fbo.c
index e5c956d561..c02121fbd1 100644
--- a/src/mesa/state_tracker/st_cb_fbo.c
+++ b/src/mesa/state_tracker/st_cb_fbo.c
@@ -321,15 +321,13 @@ st_render_texture(GLcontext *ctx,
    struct pipe_resource *pt = st_get_texobj_resource(att->Texture);
    struct st_texture_object *stObj;
    const struct gl_texture_image *texImage;
-   GLint pt_level;
 
    /* When would this fail?  Perhaps assert? */
    if (!pt) 
       return;
 
-   /* The first gallium texture level = Mesa BaseLevel */
-   pt_level = MAX2(0, (GLint) att->TextureLevel - att->Texture->BaseLevel);
-   texImage = att->Texture->Image[att->CubeMapFace][pt_level];
+   /* get pointer to texture image we're rendeing to */
+   texImage = att->Texture->Image[att->CubeMapFace][att->TextureLevel];
 
    /* create new renderbuffer which wraps the texture image */
    rb = st_new_renderbuffer(ctx, 0);
@@ -350,7 +348,7 @@ st_render_texture(GLcontext *ctx,
 
    /* point renderbuffer at texobject */
    strb->rtt = stObj;
-   strb->rtt_level = pt_level;
+   strb->rtt_level = att->TextureLevel;
    strb->rtt_face = att->CubeMapFace;
    strb->rtt_slice = att->Zoffset;