[Mesa-dev] [PATCH] i965: handle gl_PointCoord for Gen4 and Gen5 platforms
Yuanhan Liu
yuanhan.liu at linux.intel.com
Tue Feb 28 17:48:28 PST 2012
Ping......
Comments?
Thanks,
Yuanhan Liu
On Mon, Feb 27, 2012 at 03:46:32PM +0800, Yuanhan Liu wrote:
> This patch add the support of gl_PointCoord gl builtin variable for
> platform gen4 and gen5(ILK).
>
> Unlike gen6+, we don't have a hardware support of gl_PointCoord, means
> hardware will not calculate the interpolation coefficient for you.
> Instead, you should handle it yourself in sf shader stage.
>
> But badly, gl_PointCoord is a FS instead of VS builtin variable, thus
> it's not included in c.vue_map generated in VS stage. Thus the current
> code doesn't aware of this attribute. And to handle it correctly, we
> need add it to c.vue_map manually to let SF shader generate the needed
> interpolation coefficient for FS shader. SF stage has it's own copy of
> vue_map, thus I think it's safe to do it manually.
>
> Since handling gl_PointCoord for gen4 and gen5 platforms is somehow a
> little special, I added a lot of comments and hope I didn't overdo it ;)
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45975
> Piglit: glsl-fs-pointcoord and fbo-gl_pointcoord
>
> NOTE: This is a candidate for stable release branches.
>
> Signed-off-by: Yuanhan Liu <yuanhan.liu at linux.intel.com>
> ---
> src/mesa/drivers/dri/i965/brw_context.h | 6 ++++++
> src/mesa/drivers/dri/i965/brw_fs.cpp | 9 +++++++++
> src/mesa/drivers/dri/i965/brw_sf.c | 26 ++++++++++++++++++++++----
> src/mesa/drivers/dri/i965/brw_sf.h | 1 +
> src/mesa/drivers/dri/i965/brw_sf_emit.c | 4 ++++
> 5 files changed, 42 insertions(+), 4 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
> index 09d8373..7c794ad 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.h
> +++ b/src/mesa/drivers/dri/i965/brw_context.h
> @@ -296,6 +296,12 @@ typedef enum
> BRW_VERT_RESULT_NDC = VERT_RESULT_MAX,
> BRW_VERT_RESULT_HPOS_DUPLICATE,
> BRW_VERT_RESULT_PAD,
> + /*
> + * It's actually not a vert_result but just a _mark_ to let sf aware that
> + * he need do something special to handle gl_PointCoord builtin variable
> + * correctly. see compile_sf_prog() for more info.
> + */
> + BRW_VERT_RESULT_PNTC,
> BRW_VERT_RESULT_MAX
> } brw_vert_result;
>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> index bf59da3..5f3d79d 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> @@ -710,6 +710,15 @@ fs_visitor::calculate_urb_setup()
> urb_setup[fp_index] = urb_next++;
> }
> }
> +
> + /*
> + * It's a FS only attribute, and we did interpolation for this attribute
> + * in SF thread. So, count it here, too.
> + *
> + * See compile_sf_prog() for more info.
> + */
> + if (brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(FRAG_ATTRIB_PNTC))
> + urb_setup[FRAG_ATTRIB_PNTC] = urb_next++;
> }
>
> /* Each attribute is 4 setup channels, each of which is half a reg. */
> diff --git a/src/mesa/drivers/dri/i965/brw_sf.c b/src/mesa/drivers/dri/i965/brw_sf.c
> index 6e63583..7950c47 100644
> --- a/src/mesa/drivers/dri/i965/brw_sf.c
> +++ b/src/mesa/drivers/dri/i965/brw_sf.c
> @@ -64,6 +64,16 @@ static void compile_sf_prog( struct brw_context *brw,
>
> c.key = *key;
> c.vue_map = brw->vs.prog_data->vue_map;
> + if (c.key.do_point_coord) {
> + /*
> + * gl_PointCoord is a FS instead of VS builtin variable, thus it's
> + * not included in c.vue_map generated in VS stage. Here we add
> + * it manually to let SF shader generate the needed interpolation
> + * coefficient for FS shader.
> + */
> + c.vue_map.vert_result_to_slot[BRW_VERT_RESULT_PNTC] = c.vue_map.num_slots;
> + c.vue_map.slot_to_vert_result[c.vue_map.num_slots++] = BRW_VERT_RESULT_PNTC;
> + }
> c.urb_entry_read_offset = brw_sf_compute_urb_entry_read_offset(intel);
> c.nr_attr_regs = (c.vue_map.num_slots + 1)/2 - c.urb_entry_read_offset;
> c.nr_setup_regs = c.nr_attr_regs;
> @@ -125,6 +135,7 @@ brw_upload_sf_prog(struct brw_context *brw)
> {
> struct gl_context *ctx = &brw->intel.ctx;
> struct brw_sf_prog_key key;
> + bool render_to_fbo = ctx->DrawBuffer->Name != 0;
>
> memset(&key, 0, sizeof(key));
>
> @@ -167,7 +178,15 @@ brw_upload_sf_prog(struct brw_context *brw)
> key.point_sprite_coord_replace |= (1 << i);
> }
> }
> - key.sprite_origin_lower_left = (ctx->Point.SpriteOrigin == GL_LOWER_LEFT);
> + if (brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(FRAG_ATTRIB_PNTC))
> + key.do_point_coord = 1;
> + /*
> + * Window coordinates in a FBO are inverted, which means point
> + * sprite origin must be inverted, too.
> + */
> + if ((ctx->Point.SpriteOrigin == GL_LOWER_LEFT) != render_to_fbo)
> + key.sprite_origin_lower_left = true;
> +
> /* _NEW_LIGHT */
> key.do_flat_shading = (ctx->Light.ShadeModel == GL_FLAT);
> key.do_twoside_color = (ctx->Light.Enabled && ctx->Light.Model.TwoSide);
> @@ -176,10 +195,9 @@ brw_upload_sf_prog(struct brw_context *brw)
> if (key.do_twoside_color) {
> /* If we're rendering to a FBO, we have to invert the polygon
> * face orientation, just as we invert the viewport in
> - * sf_unit_create_from_key(). ctx->DrawBuffer->Name will be
> - * nonzero if we're rendering to such an FBO.
> + * sf_unit_create_from_key().
> */
> - key.frontface_ccw = (ctx->Polygon.FrontFace == GL_CCW) ^ (ctx->DrawBuffer->Name != 0);
> + key.frontface_ccw = (ctx->Polygon.FrontFace == GL_CCW) != render_to_fbo;
> }
>
> if (!brw_search_cache(&brw->cache, BRW_SF_PROG,
> diff --git a/src/mesa/drivers/dri/i965/brw_sf.h b/src/mesa/drivers/dri/i965/brw_sf.h
> index 4ef0240..f908fc0 100644
> --- a/src/mesa/drivers/dri/i965/brw_sf.h
> +++ b/src/mesa/drivers/dri/i965/brw_sf.h
> @@ -52,6 +52,7 @@ struct brw_sf_prog_key {
> GLuint do_flat_shading:1;
> GLuint frontface_ccw:1;
> GLuint do_point_sprite:1;
> + GLuint do_point_coord:1;
> GLuint sprite_origin_lower_left:1;
> GLuint userclip_active:1;
> };
> diff --git a/src/mesa/drivers/dri/i965/brw_sf_emit.c b/src/mesa/drivers/dri/i965/brw_sf_emit.c
> index 1ee0098..ff6383b 100644
> --- a/src/mesa/drivers/dri/i965/brw_sf_emit.c
> +++ b/src/mesa/drivers/dri/i965/brw_sf_emit.c
> @@ -386,6 +386,8 @@ calculate_point_sprite_mask(struct brw_sf_compile *c, GLuint reg)
> if (c->key.point_sprite_coord_replace & (1 << (vert_result1 - VERT_RESULT_TEX0)))
> pc |= 0x0f;
> }
> + if (vert_result1 == BRW_VERT_RESULT_PNTC)
> + pc |= 0x0f;
>
> vert_result2 = vert_reg_to_vert_result(c, reg, 1);
> if (vert_result2 >= VERT_RESULT_TEX0 && vert_result2 <= VERT_RESULT_TEX7) {
> @@ -393,6 +395,8 @@ calculate_point_sprite_mask(struct brw_sf_compile *c, GLuint reg)
> VERT_RESULT_TEX0)))
> pc |= 0xf0;
> }
> + if (vert_result2 == BRW_VERT_RESULT_PNTC)
> + pc |= 0xf0;
>
> return pc;
> }
> --
> 1.7.4.4
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