fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2026-05-08 19:58:09 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

mesa: Add a gl_vert_result for gl_ClipVertex.

Browse source 
Before this patch, clip planes didn't work properly in Mesa when using
vertex shaders, because Mesa assigned both gl_ClipVertex and
gl_Position to the same gl_vert_result (VERT_RESULT_HPOS).  As a
result, backends couldn't distinguish between the two variables, so
any shader that wrote different values to them would fail to work
properly.

This patch paves the way for proper support of gl_ClipVertex by
creating a new enumerated value in gl_vert_result for it
(VERT_RESULT_CLIP_VERTEX).  After this patch, a back-end may add
support for gl_ClipVertex using the following algorithm:

- If using a user-supplied GLSL vertex shader:
  - If the bit corresponding to VERT_RESULT_CLIP_VERTEX is set in
    gl_program::OutputsWritten:
    - Clip using the vertex shader output VERT_RESULT_CLIP_VERTEX and
      the clip planes defined in gl_context::Transform.EyeUserPlane.
  - Else:
    - Clip using the vertex shader output VERT_RESULT_HPOS and the
      clip planes defined in gl_context::Transform.EyeUserPlane.
- Else (either using fixed function or an ARB vertex program):
  - Clip using the vertex shader output VERT_RESULT_HPOS and the clip
    planes defined in gl_context::Transform._ClipUserPlane (*)

where (*) represents the normal Mesa behavior before this patch.

An example of implementing the above algorithm can be found in the
patch that follows this one, which implements gl_ClipVertex in i965
Gen6.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Paul Berry 2011-09-26 13:15:57 -07:00
parent e2072a1046
commit 7d68c639dd
2 changed files with 23 additions and 22 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

38
src/glsl/builtin_variables.h
View file

@ -56,25 +56,25 @@ static const builtin_variable builtin_110_deprecated_fs_variables[] = {
};
static const builtin_variable builtin_110_deprecated_vs_variables[] = {
{ ir_var_in, VERT_ATTRIB_POS, "vec4", "gl_Vertex" },
{ ir_var_in, VERT_ATTRIB_NORMAL, "vec3", "gl_Normal" },
{ ir_var_in, VERT_ATTRIB_COLOR0, "vec4", "gl_Color" },
{ ir_var_in, VERT_ATTRIB_COLOR1, "vec4", "gl_SecondaryColor" },
{ ir_var_in, VERT_ATTRIB_TEX0, "vec4", "gl_MultiTexCoord0" },
{ ir_var_in, VERT_ATTRIB_TEX1, "vec4", "gl_MultiTexCoord1" },
{ ir_var_in, VERT_ATTRIB_TEX2, "vec4", "gl_MultiTexCoord2" },
{ ir_var_in, VERT_ATTRIB_TEX3, "vec4", "gl_MultiTexCoord3" },
{ ir_var_in, VERT_ATTRIB_TEX4, "vec4", "gl_MultiTexCoord4" },
{ ir_var_in, VERT_ATTRIB_TEX5, "vec4", "gl_MultiTexCoord5" },
{ ir_var_in, VERT_ATTRIB_TEX6, "vec4", "gl_MultiTexCoord6" },
{ ir_var_in, VERT_ATTRIB_TEX7, "vec4", "gl_MultiTexCoord7" },
{ ir_var_in, VERT_ATTRIB_FOG, "float", "gl_FogCoord" },
{ ir_var_out, VERT_RESULT_HPOS, "vec4", "gl_ClipVertex" },
{ ir_var_out, VERT_RESULT_COL0, "vec4", "gl_FrontColor" },
{ ir_var_out, VERT_RESULT_BFC0, "vec4", "gl_BackColor" },
{ ir_var_out, VERT_RESULT_COL1, "vec4", "gl_FrontSecondaryColor" },
{ ir_var_out, VERT_RESULT_BFC1, "vec4", "gl_BackSecondaryColor" },
{ ir_var_out, VERT_RESULT_FOGC, "float", "gl_FogFragCoord" },
{ ir_var_in, VERT_ATTRIB_POS, "vec4", "gl_Vertex" },
{ ir_var_in, VERT_ATTRIB_NORMAL, "vec3", "gl_Normal" },
{ ir_var_in, VERT_ATTRIB_COLOR0, "vec4", "gl_Color" },
{ ir_var_in, VERT_ATTRIB_COLOR1, "vec4", "gl_SecondaryColor" },
{ ir_var_in, VERT_ATTRIB_TEX0, "vec4", "gl_MultiTexCoord0" },
{ ir_var_in, VERT_ATTRIB_TEX1, "vec4", "gl_MultiTexCoord1" },
{ ir_var_in, VERT_ATTRIB_TEX2, "vec4", "gl_MultiTexCoord2" },
{ ir_var_in, VERT_ATTRIB_TEX3, "vec4", "gl_MultiTexCoord3" },
{ ir_var_in, VERT_ATTRIB_TEX4, "vec4", "gl_MultiTexCoord4" },
{ ir_var_in, VERT_ATTRIB_TEX5, "vec4", "gl_MultiTexCoord5" },
{ ir_var_in, VERT_ATTRIB_TEX6, "vec4", "gl_MultiTexCoord6" },
{ ir_var_in, VERT_ATTRIB_TEX7, "vec4", "gl_MultiTexCoord7" },
{ ir_var_in, VERT_ATTRIB_FOG, "float", "gl_FogCoord" },
{ ir_var_out, VERT_RESULT_CLIP_VERTEX, "vec4", "gl_ClipVertex" },
{ ir_var_out, VERT_RESULT_COL0, "vec4", "gl_FrontColor" },
{ ir_var_out, VERT_RESULT_BFC0, "vec4", "gl_BackColor" },
{ ir_var_out, VERT_RESULT_COL1, "vec4", "gl_FrontSecondaryColor" },
{ ir_var_out, VERT_RESULT_BFC1, "vec4", "gl_BackSecondaryColor" },
{ ir_var_out, VERT_RESULT_FOGC, "float", "gl_FogFragCoord" },
};
static const builtin_variable builtin_120_fs_variables[] = {

7
src/mesa/main/mtypes.h
View file

@ -214,9 +214,10 @@ typedef enum
VERT_RESULT_BFC0 = 13,
VERT_RESULT_BFC1 = 14,
VERT_RESULT_EDGE = 15,
VERT_RESULT_CLIP_DIST0 = 16,
VERT_RESULT_CLIP_DIST1 = 17,
VERT_RESULT_VAR0 = 18, /**< shader varying */
VERT_RESULT_CLIP_VERTEX = 16,
VERT_RESULT_CLIP_DIST0 = 17,
VERT_RESULT_CLIP_DIST1 = 18,
VERT_RESULT_VAR0 = 19, /**< shader varying */
VERT_RESULT_MAX = (VERT_RESULT_VAR0 + MAX_VARYING)
} gl_vert_result;