i965: Implement support for ARB_clip_control.

Switch between the two clip space definitions already available
in hardware. Update winding order dependent state according
to the clip control state.
This change did not introduce new piglit quick.test regressions on
an Ivybridge Mobile and a GM45 Express chipset.
Also it enables and passes the clip-control and clip-control-depth-precision
tests on these two chipsets.

Reviewed-by: Kenneth Graunke <[email protected]>
Signed-off-by: Mathias Froehlich <[email protected]>

11 files changed, 21 insertions, 16 deletions

diff --git a/docs/GL3.txt b/docs/GL3.txt
index 94166e284e8..456d76bb956 100644
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -188,7 +188,7 @@ GL 4.4, GLSL 4.40:
 GL 4.5, GLSL 4.50:
 
   GL_ARB_ES3_1_compatibility                           not started
-  GL_ARB_clip_control                                  DONE (nv50, nvc0, r600, radeonsi, llvmpipe, softpipe)
+  GL_ARB_clip_control                                  DONE (i965, nv50, nvc0, r600, radeonsi, llvmpipe, softpipe)
   GL_ARB_conditional_render_inverted                   DONE (i965, nv50, nvc0, llvmpipe, softpipe)
   GL_ARB_cull_distance                                 not started
   GL_ARB_derivative_control                            DONE (i965, nv50, nvc0, r600)
diff --git a/docs/relnotes/10.6.0.html b/docs/relnotes/10.6.0.html
index 22201e174e1..2378e3d5240 100644
--- a/docs/relnotes/10.6.0.html
+++ b/docs/relnotes/10.6.0.html
@@ -51,6 +51,7 @@ Note: some of the new features are only available with certain drivers.
 <li>GL_ARB_instanced_arrays on freedreno</li>
 <li>GL_ARB_pipeline_statistics_query on i965, nv50, nvc0, r600, radeonsi, softpipe</li>
 <li>GL_EXT_draw_buffers2 on freedreno</li>
+<li>GL_ARB_clip_control on i965</li>
 </ul>
 
 <h2>Bug fixes</h2>
diff --git a/src/mesa/drivers/dri/i965/brw_clip.c b/src/mesa/drivers/dri/i965/brw_clip.c
index 3fef38ccab9..de78f46de99 100644
--- a/src/mesa/drivers/dri/i965/brw_clip.c
+++ b/src/mesa/drivers/dri/i965/brw_clip.c
@@ -224,8 +224,7 @@ brw_upload_clip_prog(struct brw_context *brw)
 	       key.offset_factor = ctx->Polygon.OffsetFactor * ctx->DrawBuffer->_MRD;
 	    }
 
-	    switch (ctx->Polygon.FrontFace) {
-	    case GL_CCW:
+	    if (!ctx->Polygon._FrontBit) {
 	       key.fill_ccw = fill_front;
 	       key.fill_cw = fill_back;
 	       key.offset_ccw = offset_front;
@@ -233,8 +232,7 @@ brw_upload_clip_prog(struct brw_context *brw)
 	       if (ctx->Light.Model.TwoSide &&
 		   key.fill_cw != CLIP_CULL)
 		  key.copy_bfc_cw = 1;
-	       break;
-	    case GL_CW:
+	    } else {
 	       key.fill_cw = fill_front;
 	       key.fill_ccw = fill_back;
 	       key.offset_cw = offset_front;
@@ -242,7 +240,6 @@ brw_upload_clip_prog(struct brw_context *brw)
 	       if (ctx->Light.Model.TwoSide &&
 		   key.fill_ccw != CLIP_CULL)
 		  key.copy_bfc_ccw = 1;
-	       break;
 	    }
 	 }
       }
diff --git a/src/mesa/drivers/dri/i965/brw_clip_state.c b/src/mesa/drivers/dri/i965/brw_clip_state.c
index 4f241ac29b7..32238341aae 100644
--- a/src/mesa/drivers/dri/i965/brw_clip_state.c
+++ b/src/mesa/drivers/dri/i965/brw_clip_state.c
@@ -147,7 +147,10 @@ brw_upload_clip_unit(struct brw_context *brw)
       clip->clip5.viewport_z_clip_enable = 1;
    clip->clip5.viewport_xy_clip_enable = 1;
    clip->clip5.vertex_position_space = BRW_CLIP_NDCSPACE;
-   clip->clip5.api_mode = BRW_CLIP_API_OGL;
+   if (ctx->Transform.ClipDepthMode == GL_ZERO_TO_ONE)
+      clip->clip5.api_mode = BRW_CLIP_API_DX;
+   else
+      clip->clip5.api_mode = BRW_CLIP_API_OGL;
    clip->clip5.clip_mode = brw->clip.prog_data->clip_mode;
 
    if (brw->is_g4x)
diff --git a/src/mesa/drivers/dri/i965/brw_sf.c b/src/mesa/drivers/dri/i965/brw_sf.c
index a41a4ad4a43..d5395de021b 100644
--- a/src/mesa/drivers/dri/i965/brw_sf.c
+++ b/src/mesa/drivers/dri/i965/brw_sf.c
@@ -204,7 +204,7 @@ brw_upload_sf_prog(struct brw_context *brw)
        * face orientation, just as we invert the viewport in
        * sf_unit_create_from_key().
        */
-      key.frontface_ccw = (ctx->Polygon.FrontFace == GL_CCW) != render_to_fbo;
+      key.frontface_ccw = ctx->Polygon._FrontBit == render_to_fbo;
    }
 
    if (!brw_search_cache(&brw->cache, BRW_CACHE_SF_PROG,
diff --git a/src/mesa/drivers/dri/i965/brw_sf_state.c b/src/mesa/drivers/dri/i965/brw_sf_state.c
index 2ed418bd4cb..014b43448ad 100644
--- a/src/mesa/drivers/dri/i965/brw_sf_state.c
+++ b/src/mesa/drivers/dri/i965/brw_sf_state.c
@@ -183,10 +183,10 @@ static void upload_sf_unit( struct brw_context *brw )
       sf->sf6.scissor = 1;
 
    /* _NEW_POLYGON */
-   if (ctx->Polygon.FrontFace == GL_CCW)
-      sf->sf5.front_winding = BRW_FRONTWINDING_CCW;
-   else
+   if (ctx->Polygon._FrontBit)
       sf->sf5.front_winding = BRW_FRONTWINDING_CW;
+   else
+      sf->sf5.front_winding = BRW_FRONTWINDING_CCW;
 
    /* _NEW_BUFFERS
     * The viewport is inverted for rendering to a FBO, and that inverts
diff --git a/src/mesa/drivers/dri/i965/gen6_clip_state.c b/src/mesa/drivers/dri/i965/gen6_clip_state.c
index e8c16ca62c9..aaf90df2b9c 100644
--- a/src/mesa/drivers/dri/i965/gen6_clip_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_clip_state.c
@@ -54,7 +54,7 @@ upload_clip_state(struct brw_context *brw)
 
    if (brw->gen == 7) {
       /* _NEW_POLYGON */
-      if ((ctx->Polygon.FrontFace == GL_CCW) ^ _mesa_is_user_fbo(fb))
+      if (ctx->Polygon._FrontBit == _mesa_is_user_fbo(fb))
          dw1 |= GEN7_CLIP_WINDING_CCW;
 
       if (ctx->Polygon.CullFlag) {
@@ -95,6 +95,10 @@ upload_clip_state(struct brw_context *brw)
    /* _NEW_TRANSFORM */
    dw2 |= (ctx->Transform.ClipPlanesEnabled <<
            GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT);
+   if (ctx->Transform.ClipDepthMode == GL_ZERO_TO_ONE)
+      dw2 |= GEN6_CLIP_API_D3D;
+   else
+      dw2 |= GEN6_CLIP_API_OGL;
 
    dw2 |= GEN6_CLIP_GB_TEST;
 
@@ -170,7 +174,6 @@ upload_clip_state(struct brw_context *brw)
    OUT_BATCH(_3DSTATE_CLIP << 16 | (4 - 2));
    OUT_BATCH(dw1);
    OUT_BATCH(enable |
-	     GEN6_CLIP_API_OGL |
 	     GEN6_CLIP_MODE_NORMAL |
 	     GEN6_CLIP_XY_TEST |
 	     dw2);
diff --git a/src/mesa/drivers/dri/i965/gen6_sf_state.c b/src/mesa/drivers/dri/i965/gen6_sf_state.c
index f9d8d27fe73..ea5c47a895f 100644
--- a/src/mesa/drivers/dri/i965/gen6_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_sf_state.c
@@ -290,7 +290,7 @@ upload_sf_state(struct brw_context *brw)
    dw4 = 0;
 
    /* _NEW_POLYGON */
-   if ((ctx->Polygon.FrontFace == GL_CCW) ^ render_to_fbo)
+   if (ctx->Polygon._FrontBit == render_to_fbo)
       dw2 |= GEN6_SF_WINDING_CCW;
 
    if (ctx->Polygon.OffsetFill)
diff --git a/src/mesa/drivers/dri/i965/gen7_sf_state.c b/src/mesa/drivers/dri/i965/gen7_sf_state.c
index c9815b03bb4..69853e67b33 100644
--- a/src/mesa/drivers/dri/i965/gen7_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_sf_state.c
@@ -120,7 +120,7 @@ upload_sf_state(struct brw_context *brw)
    dw1 |= (brw_depthbuffer_format(brw) << GEN7_SF_DEPTH_BUFFER_SURFACE_FORMAT_SHIFT);
 
    /* _NEW_POLYGON */
-   if ((ctx->Polygon.FrontFace == GL_CCW) ^ render_to_fbo)
+   if (ctx->Polygon._FrontBit == render_to_fbo)
       dw1 |= GEN6_SF_WINDING_CCW;
 
    if (ctx->Polygon.OffsetFill)
diff --git a/src/mesa/drivers/dri/i965/gen8_sf_state.c b/src/mesa/drivers/dri/i965/gen8_sf_state.c
index 27116f7e4c8..52a21b6a8e8 100644
--- a/src/mesa/drivers/dri/i965/gen8_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen8_sf_state.c
@@ -229,7 +229,7 @@ upload_raster(struct brw_context *brw)
    bool render_to_fbo = _mesa_is_user_fbo(brw->ctx.DrawBuffer);
 
    /* _NEW_POLYGON */
-   if ((ctx->Polygon.FrontFace == GL_CCW) ^ render_to_fbo)
+   if (ctx->Polygon._FrontBit == render_to_fbo)
       dw1 |= GEN8_RASTER_FRONT_WINDING_CCW;
 
    if (ctx->Polygon.CullFlag) {
diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
index 608bfac9995..48064e1eea4 100644
--- a/src/mesa/drivers/dri/i965/intel_extensions.c
+++ b/src/mesa/drivers/dri/i965/intel_extensions.c
@@ -178,6 +178,7 @@ intelInitExtensions(struct gl_context *ctx)
 
    ctx->Extensions.ARB_buffer_storage = true;
    ctx->Extensions.ARB_clear_texture = true;
+   ctx->Extensions.ARB_clip_control = true;
    ctx->Extensions.ARB_copy_image = true;
    ctx->Extensions.ARB_depth_buffer_float = true;
    ctx->Extensions.ARB_depth_clamp = true;