mesa: Move compute_num_levels from st_gen_mipmap.c to mipmap.c.

I want to use compute_num_levels inside i965.  Rather than duplicating
it, move it from mesa/st to core Mesa, and make it non-static.

Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/mesa/main/mipmap.c b/src/mesa/main/mipmap.c
index fc36d408f91..1ed82c52ab6 100644
--- a/src/mesa/main/mipmap.c
+++ b/src/mesa/main/mipmap.c
@@ -42,6 +42,30 @@
 #include "util/format_r11g11b10f.h"
 
 
+/**
+ * Compute the expected number of mipmap levels in the texture given
+ * the width/height/depth of the base image and the GL_TEXTURE_BASE_LEVEL/
+ * GL_TEXTURE_MAX_LEVEL settings.  This will tell us how many mipmap
+ * levels should be generated.
+ */
+unsigned
+_mesa_compute_num_levels(struct gl_context *ctx,
+                         struct gl_texture_object *texObj,
+                         GLenum target)
+{
+   const struct gl_texture_image *baseImage;
+   GLuint numLevels;
+
+   baseImage = _mesa_get_tex_image(ctx, texObj, target, texObj->BaseLevel);
+
+   numLevels = texObj->BaseLevel + baseImage->MaxNumLevels;
+   numLevels = MIN2(numLevels, (GLuint) texObj->MaxLevel + 1);
+   if (texObj->Immutable)
+      numLevels = MIN2(numLevels, texObj->NumLevels);
+   assert(numLevels >= 1);
+
+   return numLevels;
+}
 
 static GLint
 bytes_per_pixel(GLenum datatype, GLuint comps)