[Mesa-dev] [PATCH 7/7] mesa: optimize out the realloc from glCopyTexImagexD()

[Miklós Máté]

On 02/05/2016 10:26 PM, Ilia Mirkin wrote:
> On Fri, Feb 5, 2016 at 4:11 PM, Miklós Máté <mtmkls at gmail.com> wrote:
>> 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;
> Also need to compare the texFormat no?
I don't know. I now added it to make sure everything is ok.

MM

>
>> +}
>> +
>>   /**
>>    * 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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