115 lines
2.8 KiB
Plaintext
115 lines
2.8 KiB
Plaintext
Name
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MESA_window_pos
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Name Strings
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GL_MESA_window_pos
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Contact
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Brian Paul, brianp 'at' mesa3d.org
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Status
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Shipping (since Mesa version 1.2.8)
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Version
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$Id: MESA_window_pos.spec,v 1.1 1999/07/20 00:30:41 brianp Exp $
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Number
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XXX non assigned
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Dependencies
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OpenGL 1.0 is required.
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The extension is written against the OpenGL 1.2 Specification
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Overview
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In order to set the current raster position to a specific window
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coordinate with the RasterPos command, the modelview matrix, projection
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matrix and viewport must be set very carefully. Furthermore, if the
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desired window coordinate is outside of the window's bounds one must
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rely a subtle side-effect of the Bitmap command in order to circumvent
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frustum clipping.
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This extension provides a set of functions to directly set the
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current raster position, bypassing the modelview matrix, the
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projection matrix and the viewport to window mapping. Furthermore,
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clip testing is not performed.
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This greatly simplifies the process of setting the current raster
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position to a specific window coordinate prior to calling DrawPixels,
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CopyPixels or Bitmap.
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New Procedures and Functions
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void WindowPos2dMESA(double x, double y)
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void WindowPos2fMESA(float x, float y)
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void WindowPos2iMESA(int x, int y)
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void WindowPos2sMESA(short x, short y)
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New Tokens
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none
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Additions to Chapter 2 of the OpenGL 1.2 Specification (OpenGL Operation)
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- (2.12, p. 41) Insert after third paragraph:
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Alternately, the current raster position may be set by one of the
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WindowPosMESA commands:
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void WindowPos{234}{sidf}MESA( T coords );
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void Window Pos{234}{sidf}vMESA( T coords );
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WindosPos4MESA takes four values indicating x, y, z, and w.
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WindowPos3MESA (or WindowPos2MESA) is analaguos, but sets only
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x, y, and z with w implicitly set to 1 (or only x and y with z
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implicititly set to 0 and w implicitly set to 1).
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WindowPosMESA operates like RasterPos except that the current modelview
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matrix, projection matrix and viewport parameters are ignored and the
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clip test operation always passes. The current raster position values
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are directly set to the parameters passed to WindowPosMESA. The current
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color, color index and texture coordinate update the current raster
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position's associated data.
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The current raster distance ??? XXX ???
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Additions to the AGL/GLX/WGL Specifications
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None
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GLX Protocol
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Not specified at this time. However, a protocol message very similar
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to that of RasterPos is expected.
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Errors
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INVALID_OPERATION is generated if WindowPosMESA is called betweeen
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Begin and End.
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New State
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None.
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New Implementation Dependent State
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None.
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Revision History
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* Revision 1.0 - Initial specification
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