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Diffstat (limited to 'src/gallium/docs/source/cso/rasterizer.rst')
| -rw-r--r-- | src/gallium/docs/source/cso/rasterizer.rst | 76 |
1 files changed, 44 insertions, 32 deletions
diff --git a/src/gallium/docs/source/cso/rasterizer.rst b/src/gallium/docs/source/cso/rasterizer.rst index ccd9136a2eb..e8dc82964fa 100644 --- a/src/gallium/docs/source/cso/rasterizer.rst +++ b/src/gallium/docs/source/cso/rasterizer.rst @@ -7,7 +7,7 @@ The rasterizer state controls the rendering of points, lines and triangles. Attributes include polygon culling state, line width, line stipple, multisample state, scissoring and flat/smooth shading. -Members +Shading ------- flatshade @@ -46,6 +46,49 @@ There are several important exceptions to the specification of this rule. second vertex, not the first. This permits each segment of the fan to have a different color. +Points +------ + +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. + +sprite_coord_mode +^^^^^^^^^^^^^^^^^ + +Specifies how the value for each shader output should be computed when drawing +point sprites. For PIPE_SPRITE_COORD_LOWER_LEFT, the lower-left vertex will +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, and sprite coordinates are not +generated. + +.. note:: + + Some renderers always internally translate points into quads; this state + still affects those renderers by overriding other rasterization state. + Other Members ^^^^^^^^^^^^^ @@ -107,37 +150,6 @@ point_size_per_vertex Whether vertices have a point size element. point_size The size of points, if not specified per-vertex. -sprite_coord_enable - Specifies if a coord has its texture coordinates replaced or not. This - is a packed bitfield containing the enable for all coords - if all are 0 - point sprites are effectively disabled, though points may still be - rendered slightly different according to point_quad_rasterization. - If any coord is non-zero, point_smooth should be disabled, and - point_quad_rasterization enabled. - If enabled, the four vertices of the resulting quad will be assigned - texture coordinates, according to sprite_coord_mode. -sprite_coord_mode - Specifies how the value for each shader output should be computed when - drawing sprites, for each coord which has sprite_coord_enable set. - For PIPE_SPRITE_COORD_LOWER_LEFT, the lower left vertex will have - coordinate (0,0,0,1). - For PIPE_SPRITE_COORD_UPPER_LEFT, the upper-left vertex will have - coordinate (0,0,0,1). - This state is needed by :ref:`Draw` because that's where each - point vertex is converted into four quad vertices. There's no other - place to emit the new vertex texture coordinates which are required for - sprite rendering. - Note that when geometry shaders are available, this state could be - removed. A special geometry shader defined by the state tracker could - convert the incoming points into quads with the proper texture coords. -point_quad_rasterization - This determines if points should be rasterized as quads or points. - d3d always uses quad rasterization for points, regardless if point sprites - are enabled or not, but OGL has different rules. If point_quad_rasterization - is set, point_smooth should be disabled, and points will be rendered as - squares even if multisample is enabled. - sprite_coord_enable should be zero if point_quad_rasterization is not - enabled. scissor Whether the scissor test is enabled. |