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Diffstat (limited to 'src/gallium/docs/source/cso/rasterizer.rst')
| -rw-r--r-- | src/gallium/docs/source/cso/rasterizer.rst | 101 |
1 files changed, 51 insertions, 50 deletions
diff --git a/src/gallium/docs/source/cso/rasterizer.rst b/src/gallium/docs/source/cso/rasterizer.rst index 4d8e1708e7..bfa4a1170a 100644 --- a/src/gallium/docs/source/cso/rasterizer.rst +++ b/src/gallium/docs/source/cso/rasterizer.rst @@ -7,32 +7,69 @@ 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 ------- +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:: + + Implementations may still clip away vertices that are not in the viewport + when this is set. + flatshade - If set, the provoking vertex of each polygon is used to determine the - 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 +^^^^^^^^^ + +If set, the provoking vertex of each polygon is used to determine the color +of the entire polygon. If not set, fragment colors will be interpolated +between the vertex colors. + +The actual interpolated shading algorithm is obviously +implementation-dependent, but will usually be Gourard for most hardware. + +.. note:: + + This is separate from the fragment shader input attributes + CONSTANT, LINEAR and PERSPECTIVE. The flatshade state is needed 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. + + :ref:`Draw` 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. +^^^^^^^^^^^^^^^ + +Whether the first vertex should be the provoking vertex, for most primitives. +If not set, the last vertex is the provoking vertex. + +There are several important exceptions to the specification of this rule. + +* ``PIPE_PRIMITIVE_POLYGON``: The provoking vertex is always the first + vertex. If the caller wishes to change the provoking vertex, they merely + need to rotate the vertices themselves. +* ``PIPE_PRIMITIVE_QUAD``, ``PIPE_PRIMITIVE_QUAD_STRIP``: This option has no + effect; the provoking vertex is always the last vertex. +* ``PIPE_PRIMITIVE_TRIANGLE_FAN``: When set, the provoking vertex is the + second vertex, not the first. This permits each segment of the fan to have + a different color. + +Other Members +^^^^^^^^^^^^^ light_twoside - If set, there are per-vertex back-facing colors. The draw module + If set, there are per-vertex back-facing colors. :ref:`Draw` 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), @@ -68,7 +105,7 @@ line_stipple_enable 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 + When drawing a 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 @@ -96,7 +133,7 @@ sprite_coord_mode 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 + 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. @@ -108,45 +145,9 @@ scissor Whether the scissor test is enabled. multisample - Whether :ref:`MSAA` is enabled. - -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. + Whether :term:`MSAA` is enabled. 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. - -Notes ------ - -flatshade -^^^^^^^^^ - -The actual interpolated shading algorithm is obviously -implementation-dependent, but will usually be Gourard for most hardware. - -bypass_vs_clip_and_viewport -^^^^^^^^^^^^^^^^^^^^^^^^^^^ - -When set, 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 visible. - -flatshade_first -^^^^^^^^^^^^^^^ - -There are several important exceptions to the specification of this rule. - -* ``PIPE_PRIMITIVE_POLYGON``: The provoking vertex is always the first - vertex. If the caller wishes to change the provoking vertex, they merely - need to rotate the vertices themselves. -* ``PIPE_PRIMITIVE_QUAD``, ``PIPE_PRIMITIVE_QUAD_STRIP``: This option has no - effect; the provoking vertex is always the last vertex. -* ``PIPE_PRIMITIVE_TRIANGLE_FAN``: When set, the provoking vertex is the - second vertex, not the first. This permits each segment of the fan to have - a different color. |