+
+/**
+ * Helper function for mipmap generation.
+ * Make sure the specified destination mipmap level is the right size/format
+ * for mipmap generation. If not, (re) allocate it.
+ * \return GL_TRUE if successful, GL_FALSE if mipmap generation should stop
+ */
+static GLboolean
+prepare_mipmap_level(struct gl_context *ctx,
+ struct gl_texture_object *texObj, GLuint level,
+ GLsizei width, GLsizei height, GLsizei depth,
+ GLsizei border, GLenum intFormat, mesa_format format)
+{
+ const GLuint numFaces = _mesa_num_tex_faces(texObj->Target);
+ GLuint face;
+
+ if (texObj->Immutable) {
+ /* The texture was created with glTexStorage() so the number/size of
+ * mipmap levels is fixed and the storage for all images is already
+ * allocated.
+ */
+ if (!texObj->Image[0][level]) {
+ /* No more levels to create - we're done */
+ return GL_FALSE;
+ }
+ else {
+ /* Nothing to do - the texture memory must have already been
+ * allocated to the right size so we're all set.
+ */
+ return GL_TRUE;
+ }
+ }
+
+ for (face = 0; face < numFaces; face++) {
+ struct gl_texture_image *dstImage;
+ const GLenum target = _mesa_cube_face_target(texObj->Target, face);
+
+ dstImage = _mesa_get_tex_image(ctx, texObj, target, level);
+ if (!dstImage) {
+ /* out of memory */
+ return GL_FALSE;
+ }
+
+ if (dstImage->Width != width ||
+ dstImage->Height != height ||
+ dstImage->Depth != depth ||
+ dstImage->Border != border ||
+ dstImage->InternalFormat != intFormat ||
+ dstImage->TexFormat != format) {
+ /* need to (re)allocate image */
+ ctx->Driver.FreeTextureImageBuffer(ctx, dstImage);
+
+ _mesa_init_teximage_fields(ctx, dstImage,
+ width, height, depth,
+ border, intFormat, format);
+
+ ctx->Driver.AllocTextureImageBuffer(ctx, dstImage);
+
+ /* in case the mipmap level is part of an FBO: */
+ _mesa_update_fbo_texture(ctx, texObj, face, level);
+
+ ctx->NewState |= _NEW_TEXTURE;
+ }
+ }
+
+ return GL_TRUE;
+}
+
+
+/**
+ * Prepare all mipmap levels beyond 'baseLevel' for mipmap generation.
+ * When finished, all the gl_texture_image structures for the smaller
+ * mipmap levels will be consistent with the base level (in terms of
+ * dimensions, format, etc).
+ */
+void
+_mesa_prepare_mipmap_levels(struct gl_context *ctx,
+ struct gl_texture_object *texObj,
+ unsigned baseLevel, unsigned maxLevel)
+{
+ const struct gl_texture_image *baseImage =
+ _mesa_select_tex_image(texObj, texObj->Target, baseLevel);
+ const GLint border = 0;
+ GLint width = baseImage->Width;
+ GLint height = baseImage->Height;
+ GLint depth = baseImage->Depth;
+ const GLenum intFormat = baseImage->InternalFormat;
+ const mesa_format texFormat = baseImage->TexFormat;
+ GLint newWidth, newHeight, newDepth;
+
+ /* Prepare baseLevel + 1, baseLevel + 2, ... */
+ for (unsigned level = baseLevel + 1; level <= maxLevel; level++) {
+ if (!_mesa_next_mipmap_level_size(texObj->Target, border,
+ width, height, depth,
+ &newWidth, &newHeight, &newDepth)) {
+ /* all done */
+ break;
+ }
+
+ if (!prepare_mipmap_level(ctx, texObj, level,
+ newWidth, newHeight, newDepth,
+ border, intFormat, texFormat)) {
+ break;
+ }
+
+ width = newWidth;
+ height = newHeight;
+ depth = newDepth;
+ }
+}
+
+