Mesa (master): gallium/docs: finish up description of pipe_rasterizer_state fields
Brian Paul
brianp at kemper.freedesktop.org
Wed Jan 6 16:43:12 UTC 2010
Module: Mesa
Branch: master
Commit: 439b34c9dde080ba9b69791b47f93bdcdaf3ab67
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=439b34c9dde080ba9b69791b47f93bdcdaf3ab67
Author: Brian Paul <brianp at vmware.com>
Date: Wed Jan 6 09:42:53 2010 -0700
gallium/docs: finish up description of pipe_rasterizer_state fields
---
src/gallium/docs/source/cso/rasterizer.rst | 123 +++++++++++++++++++++-------
1 files changed, 94 insertions(+), 29 deletions(-)
diff --git a/src/gallium/docs/source/cso/rasterizer.rst b/src/gallium/docs/source/cso/rasterizer.rst
index afb58ea..4d8e170 100644
--- a/src/gallium/docs/source/cso/rasterizer.rst
+++ b/src/gallium/docs/source/cso/rasterizer.rst
@@ -3,58 +3,123 @@
Rasterizer
==========
-The rasterizer is the main chunk of state controlling how vertices are
-interpolated into fragments.
+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
-------
-XXX undocumented light_twoside, front_winding, cull_mode, fill_cw, fill_ccw, offset_cw, offset_ccw
-XXX moar undocumented poly_smooth, line_stipple_factor, line_last_pixel, offset_units, offset_scale
-XXX sprite_coord_mode
-
flatshade
If set, the provoking vertex of each polygon is used to determine the
- color of the entire polygon. If not set, the color fragments will be
- interpolated from each vertex's color.
-scissor
- Whether the scissor test is enabled.
+ color of the entire polygon. If not set, fragment colors will be
+ interpolated between the vertex colors.
+ Note that this is separate from the fragment shader input attributes
+ CONSTANT, LINEAR and PERSPECTIVE. We need the flatshade state at
+ clipping time to determine how to set the color of new vertices.
+ Also note that the draw module can implement flat shading by copying
+ the provoking vertex color to all the other vertices in the primitive.
+
+flatshade_first
+ Whether the first vertex should be the provoking vertex, for most
+ primitives. If not set, the last vertex is the provoking vertex.
+
+light_twoside
+ If set, there are per-vertex back-facing colors. The draw module
+ uses this state along with the front/back information to set the
+ final vertex colors prior to rasterization.
+
+front_winding
+ Indicates the window order of front-facing polygons, either
+ PIPE_WINDING_CW or PIPE_WINDING_CCW
+cull_mode
+ Indicates which polygons to cull, either PIPE_WINDING_NONE (cull no
+ polygons), PIPE_WINDING_CW (cull clockwise-winding polygons),
+ PIPE_WINDING_CCW (cull counter clockwise-winding polygons), or
+ PIPE_WINDING_BOTH (cull all polygons).
+
+fill_cw
+ Indicates how to fill clockwise polygons, either PIPE_POLYGON_MODE_FILL,
+ PIPE_POLYGON_MODE_LINE or PIPE_POLYGON_MODE_POINT.
+fill_ccw
+ Indicates how to fill counter clockwise polygons, either
+ PIPE_POLYGON_MODE_FILL, PIPE_POLYGON_MODE_LINE or PIPE_POLYGON_MODE_POINT.
+
poly_stipple_enable
Whether polygon stippling is enabled.
+poly_smooth
+ Controls OpenGL-style polygon smoothing/antialiasing
+offset_cw
+ If set, clockwise polygons will have polygon offset factors applied
+offset_ccw
+ If set, counter clockwise polygons will have polygon offset factors applied
+offset_units
+ Specifies the polygon offset bias
+offset_scale
+ Specifies the polygon offset scale
+
+line_width
+ The width of lines.
+line_smooth
+ Whether lines should be smoothed. Line smoothing is simply anti-aliasing.
+line_stipple_enable
+ Whether line stippling is enabled.
+line_stipple_pattern
+ 16-bit bitfield of on/off flags, used to pattern the line stipple.
+line_stipple_factor
+ When drawinga stippled line, each bit in the stipple pattern is
+ repeated N times, where N = line_stipple_factor + 1.
+line_last_pixel
+ Controls whether the last pixel in a line is drawn or not. OpenGL
+ omits the last pixel to avoid double-drawing pixels at the ends of lines
+ when drawing connected lines.
+
point_smooth
Whether points should be smoothed. Point smoothing turns rectangular
points into circles or ovals.
-point_sprite
- Whether point sprites are enabled.
point_size_per_vertex
Whether vertices have a point size element.
+point_size
+ The size of points, if not specified per-vertex.
+point_size_min
+ The minimum size of points.
+point_size_max
+ The maximum size of points.
+point_sprite
+ Whether points are drawn as sprites (textured quads)
+sprite_coord_mode
+ Specifies how the value for each shader output should be computed when
+ drawing sprites. If PIPE_SPRITE_COORD_NONE, don't change the vertex
+ shader output. Otherwise, the four vertices of the resulting quad will
+ be assigned texture coordinates. 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 the 'draw' module 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
+ converts the incoming points into quads with the proper texture coords.
+
+scissor
+ Whether the scissor test is enabled.
+
multisample
Whether :ref:`MSAA` is enabled.
-line_smooth
- Whether lines should be smoothed. Line smoothing is simply anti-aliasing.
-line_stipple_enable
- Whether line stippling is enabled.
-line_stipple_pattern
- 16-bit bitfield of on/off flags, used to pattern the line stipple.
+
bypass_vs_clip_and_viewport
Whether the entire TCL pipeline should be bypassed. This implies that
vertices are pre-transformed for the viewport, and will not be run
through the vertex shader. Note that implementations may still clip away
vertices that are not in the viewport.
-flatshade_first
- Whether the first vertex should be the provoking vertex, for most
- primitives. If not set, the last vertex is the provoking vertex.
+
gl_rasterization_rules
Whether the rasterizer should use (0.5, 0.5) pixel centers. When not set,
the rasterizer will use (0, 0) for pixel centers.
-line_width
- The width of lines.
-point_size
- The size of points, if not specified per-vertex.
-point_size_min
- The minimum size of points.
-point_size_max
- The maximum size of points.
+
Notes
-----
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