diff options
| -rw-r--r-- | src/gallium/docs/source/cso/rasterizer.rst | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/src/gallium/docs/source/cso/rasterizer.rst b/src/gallium/docs/source/cso/rasterizer.rst index ad1612f93e3..ee3419ccfca 100644 --- a/src/gallium/docs/source/cso/rasterizer.rst +++ b/src/gallium/docs/source/cso/rasterizer.rst @@ -126,11 +126,15 @@ sprite_coord_enable Specifies if a texture unit has its texture coordinates replaced or not. This is a packed bitfield containing the enable for all texcoords -- if all bits -are zero, point sprites are effectively disabled. If any bit is set, then -point_smooth and point_quad_rasterization are ignored; point smoothing is -disabled and points are always rasterized as quads. If enabled, the four -vertices of the resulting quad will be assigned texture coordinates, -according to sprite_coord_mode. +are zero, point sprites are effectively disabled. + +If any bit is set, then point_smooth MUST be disabled (there are no +round sprites) and point_quad_rasterization MUST be true (sprites are +always rasterized as quads). Any mismatch between these states should +be considered a bug in the state-tracker. + +If enabled, the four vertices of the resulting quad will be assigned +texture coordinates, according to sprite_coord_mode. sprite_coord_mode ^^^^^^^^^^^^^^^^^ @@ -141,20 +145,23 @@ have coordinates (0,0,0,1). For PIPE_SPRITE_COORD_UPPER_LEFT, the upper-left vertex will have coordinates (0,0,0,1). This state is used by :ref:`Draw` to generate texcoords. -.. note:: - - When geometry shaders are available, a special geometry shader could be - used instead of this functionality, to convert incoming points into quads - with the proper texture coordinates. - point_quad_rasterization ^^^^^^^^^^^^^^^^^^^^^^^^ -Determines if points should be rasterized as quads or points. Certain APIs, -like Direct3D, always use quad rasterization for points, regardless of -whether point sprites are enabled or not. If this state is enabled, point -smoothing and antialiasing are disabled. If it is disabled, point sprite -coordinates are not generated. +Determines if points should be rasterized according to quad or point +rasterization rules. + +OpenGL actually has quite different rasterization rules for points and +point sprites - hence this indicates if points should be rasterized as +points or according to point sprite (which decomposes them into quads, +basically) rules. + +Additionally Direct3D will always use quad rasterization rules for +points, regardless of whether point sprites are enabled or not. + +If this state is enabled, point smoothing and antialiasing are +disabled. If it is disabled, point sprite coordinates are not +generated. .. note:: |