v2: comment about the purpose of the code
---
src/mesa/main/teximage.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
index 50141be..cac05d5 100644
--- a/src/mesa/main/teximage.c
+++ b/src/mesa/main/teximage.c
@@ -3486,6 +3486,21 @@ formats_differ_in_component_sizes(mesa_format f1,
mesa_format f2)
return GL_FALSE;
}
+static GLboolean
+canAvoidRealloc(struct gl_texture_image *texImage, GLenum internalFormat,
+ GLint x, GLint y, GLsizei width, GLsizei height, GLint border)
+{
+ if (texImage->InternalFormat != internalFormat)
+ return false;
+ if (texImage->Border != border)
+ return false;
+ if (texImage->Width2 != width)
+ return false;
+ if (texImage->Height2 != height)
+ return false;
+ return true;
+}
+
/**
* Implement the glCopyTexImage1/2D() functions.
*/
@@ -3526,6 +3541,23 @@ copyteximage(struct gl_context *ctx, GLuint dims,
texObj = _mesa_get_current_tex_object(ctx, target);
assert(texObj);
+ /* First check if reallocating the texture buffer can be avoided.
+ * Without the realloc the copy can be 20x faster.
+ */
+ _mesa_lock_texture(ctx, texObj);
+ {
+ texImage = _mesa_select_tex_image(texObj, target, level);
+ if (texImage && canAvoidRealloc(texImage, internalFormat,
+ x, y, width, height, border)) {
+ _mesa_unlock_texture(ctx, texObj);
+ /*_mesa_debug(ctx, "using shortcut\n");*/
+ return _mesa_copy_texture_sub_image(ctx, dims, texObj, target, level,
+ 0, 0, 0, x, y, width, height, "CopyTexImage");
+ }
+ /*_mesa_debug(ctx, "can't shortcut\n");*/
+ }
+ _mesa_unlock_texture(ctx, texObj);
+
texFormat = _mesa_choose_texture_format(ctx, texObj, target, level,
internalFormat, GL_NONE, GL_NONE);
--
2.7.0
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