Bug 41768

Summary:	Logic error in mesa/drivers/common/meta.c
Product:	Mesa	Reporter:	Ryan Sleevi <rsleevi>
Component:	Mesa core	Assignee:	mesa-dev
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	medium
Version:	git
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Ryan Sleevi 2011-10-13 15:53:32 UTC

This was reported upstream to Chromium by way of http://www.viva64.com/en/b/0113/ (Item N6)

http://cgit.freedesktop.org/mesa/mesa/tree/src/mesa/drivers/common/meta.c#n2934

Lines 2943 - 2948
      if (ctx->DrawBuffer->Visual.redBits <= 8)
         return GL_UNSIGNED_BYTE;
      else if (ctx->DrawBuffer->Visual.redBits <= 8)
         return GL_UNSIGNED_SHORT;
      else
         return GL_FLOAT;

The logic appears incorrect, in that GL_UNSIGNED_SHORT will never be returned - instead, it will return GL_FLOAT.

Cursory inspection of the Mesa sources indicates it supports 16bpp, so should this be written instead as:
      if (ctx->DrawBuffer->Visual.redBits <= 8)
         return GL_UNSIGNED_BYTE;
      else if (ctx->DrawBuffer->Visual.redBits <= 16)
         return GL_UNSIGNED_SHORT;
      else
         return GL_FLOAT;

Comment 1 Brian Paul 2011-10-13 16:13:43 UTC

Thanks.  Fixed with commit 6fc6d5a09e36c56f4debd17bbbed15f732403619

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