Re: [RFC] winex11.drv: Prepare ChoosePixelFormat() for code rewrite.

[Vitaliy Margolen]

Tomas Carnecky wrote:
> This partial rewrite aims at cleaning up the pixelformat code. Windows
> sometimes advertises one or more almost identical and completely
> compatible pixelformats. These pixelformats differ in attributes like
> color-bits, but I suspect the driver developers do that only to work
> around buggy applications that don't follow the spec.
> This rewrite will also simplify the pixelformat code by removing
> redundant blocks and moving the core functionality to a few main functions.
>
> This is the first patch that simplifies ChoosePixelFormat() by
> converting the PFD structure to a list of WGL attributes and then using
> a function to choose the pixelformat. This function doesn't do anything
> as we support only one pixelformat, but this function will be shared
> with wglChoosePixelFormat() once the infrastructure for that is in place.
>
> I also have a second patch that converts DescribePixelFormat() to use
> the same approach, eg. querying the pixelformat attributes using a WGL
> attribute list and then copying the values back the the PFD structure.
>
> ---
> Few notes:
> You constructed the array of some attributes which you never use. You don't 
> check if those attributes match anything - the part you removed. When app 
> will ask for something that can't be supported your code will return it to 
> the app - which is plain wrong.

And being picky - you using tabs for indentation, please use 4 spaces 
instead, and no tabs.

Vitaliy

[RFC] winex11.drv: Prepare ChoosePixelFormat() for code rewrite.

[Tomas Carnecky]

Vitaliy Margolen wrote:
> Few notes:
> You constructed the array of some attributes which you never use. You
> don't check if those attributes match anything - the part you removed.
> When app will ask for something that can't be supported your code will
> return it to the app - which is plain wrong.

We simply have nothing to choose from, wine supports only a single
pixelformat. And as described in the comment, once the infrastructure is
in place the helper function will do the real job.

MSDN: If the function succeeds, the return value is a pixel format index
(one-based) that is the closest match to the given pixel format descriptor.
You must ensure that the pixel format matched by the ChoosePixelFormat
function satisfies your requirements. For example, if you request a
pixel format with a 24-bit RGB color buffer but the device context
offers only 8-bit RGB color buffers, the function returns a pixel format
with an 8-bit RGB color buffer.

There's also a _lot_ code that goes like this:

GLXFBConfig *pCfgs = glXGetFBConfigs(...);
ConvertPixelFormatWGLtoGLX(.., &index, ..);
glXGetFBConfigAttrib(.., *pCfgs[index], ..);
XFree(pCfgs);

This malloc()/free() can be removed by keeping a copy of the GLXFBConfig
the the pixelformat registry (instead of the index to the GLXFBConfig list).

tom