st/mesa: implement accelerated stencil blitting using shader stencil export
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/src/gallium/auxiliary/postprocess/pp_mlaa.c b/src/gallium/auxiliary/postprocess/pp_mlaa.c
index 80db862..951b76f 100644
--- a/src/gallium/auxiliary/postprocess/pp_mlaa.c
+++ b/src/gallium/auxiliary/postprocess/pp_mlaa.c
@@ -179,7 +179,7 @@
util_blit_pixels(p->blitctx, in, 0, 0, 0,
w, h, 0, p->framebuffer.cbufs[0],
0, 0, w, h, 0, PIPE_TEX_MIPFILTER_NEAREST,
- TGSI_WRITEMASK_XYZW);
+ TGSI_WRITEMASK_XYZW, 0);
u_sampler_view_default_template(&v_tmp, in, in->format);
arr[0] = p->pipe->create_sampler_view(p->pipe, in, &v_tmp);
diff --git a/src/gallium/auxiliary/postprocess/pp_run.c b/src/gallium/auxiliary/postprocess/pp_run.c
index 9d0bfdf..d2f7aa6 100644
--- a/src/gallium/auxiliary/postprocess/pp_run.c
+++ b/src/gallium/auxiliary/postprocess/pp_run.c
@@ -60,7 +60,7 @@
util_blit_pixels(ppq->p->blitctx, in, 0, 0, 0,
w, h, 0, ppq->tmps[0],
0, 0, w, h, 0, PIPE_TEX_MIPFILTER_NEAREST,
- TGSI_WRITEMASK_XYZW);
+ TGSI_WRITEMASK_XYZW, 0);
in = ppq->tmp[0];
}
diff --git a/src/gallium/auxiliary/util/u_blit.c b/src/gallium/auxiliary/util/u_blit.c
index 30f4a93..b52f4c0 100644
--- a/src/gallium/auxiliary/util/u_blit.c
+++ b/src/gallium/auxiliary/util/u_blit.c
@@ -57,8 +57,10 @@
struct cso_context *cso;
struct pipe_blend_state blend_write_color, blend_keep_color;
- struct pipe_depth_stencil_alpha_state depthstencil_keep;
- struct pipe_depth_stencil_alpha_state depthstencil_write;
+ struct pipe_depth_stencil_alpha_state dsa_keep_depthstencil;
+ struct pipe_depth_stencil_alpha_state dsa_write_depthstencil;
+ struct pipe_depth_stencil_alpha_state dsa_write_depth;
+ struct pipe_depth_stencil_alpha_state dsa_write_stencil;
struct pipe_rasterizer_state rasterizer;
struct pipe_sampler_state sampler;
struct pipe_viewport_state viewport;
@@ -67,12 +69,16 @@
void *vs;
void *fs[PIPE_MAX_TEXTURE_TYPES][TGSI_WRITEMASK_XYZW + 1];
+ void *fs_depthstencil[PIPE_MAX_TEXTURE_TYPES];
void *fs_depth[PIPE_MAX_TEXTURE_TYPES];
+ void *fs_stencil[PIPE_MAX_TEXTURE_TYPES];
struct pipe_resource *vbuf; /**< quad vertices */
unsigned vbuf_slot;
float vertices[4][2][4]; /**< vertex/texcoords for quad */
+
+ boolean has_stencil_export;
};
@@ -96,10 +102,19 @@
/* disabled blending/masking */
ctx->blend_write_color.rt[0].colormask = PIPE_MASK_RGBA;
- /* no-op depth/stencil/alpha */
- ctx->depthstencil_write.depth.enabled = 1;
- ctx->depthstencil_write.depth.writemask = 1;
- ctx->depthstencil_write.depth.func = PIPE_FUNC_ALWAYS;
+ /* depth stencil states */
+ ctx->dsa_write_depth.depth.enabled = 1;
+ ctx->dsa_write_depth.depth.writemask = 1;
+ ctx->dsa_write_depth.depth.func = PIPE_FUNC_ALWAYS;
+ ctx->dsa_write_stencil.stencil[0].enabled = 1;
+ ctx->dsa_write_stencil.stencil[0].func = PIPE_FUNC_ALWAYS;
+ ctx->dsa_write_stencil.stencil[0].fail_op = PIPE_STENCIL_OP_REPLACE;
+ ctx->dsa_write_stencil.stencil[0].zpass_op = PIPE_STENCIL_OP_REPLACE;
+ ctx->dsa_write_stencil.stencil[0].zfail_op = PIPE_STENCIL_OP_REPLACE;
+ ctx->dsa_write_stencil.stencil[0].valuemask = 0xff;
+ ctx->dsa_write_stencil.stencil[0].writemask = 0xff;
+ ctx->dsa_write_depthstencil.depth = ctx->dsa_write_depth.depth;
+ ctx->dsa_write_depthstencil.stencil[0] = ctx->dsa_write_stencil.stencil[0];
/* rasterizer */
ctx->rasterizer.cull_face = PIPE_FACE_NONE;
@@ -136,6 +151,9 @@
else
ctx->internal_target = PIPE_TEXTURE_RECT;
+ ctx->has_stencil_export =
+ pipe->screen->get_param(pipe->screen, PIPE_CAP_SHADER_STENCIL_EXPORT);
+
return ctx;
}
@@ -159,10 +177,16 @@
}
}
- for (i = 0; i < Elements(ctx->fs_depth); i++) {
+ for (i = 0; i < PIPE_MAX_TEXTURE_TYPES; i++) {
+ if (ctx->fs_depthstencil[i]) {
+ pipe->delete_fs_state(pipe, ctx->fs_depthstencil[i]);
+ }
if (ctx->fs_depth[i]) {
pipe->delete_fs_state(pipe, ctx->fs_depth[i]);
}
+ if (ctx->fs_stencil[i]) {
+ pipe->delete_fs_state(pipe, ctx->fs_stencil[i]);
+ }
}
pipe_resource_reference(&ctx->vbuf, NULL);
@@ -192,7 +216,26 @@
/**
- * Helper function to set the depthwrite shader.
+ * Helper function to set the shader which writes depth and stencil.
+ */
+static INLINE void
+set_depthstencil_fragment_shader(struct blit_state *ctx,
+ enum pipe_texture_target pipe_tex)
+{
+ if (!ctx->fs_depthstencil[pipe_tex]) {
+ unsigned tgsi_tex = util_pipe_tex_to_tgsi_tex(pipe_tex);
+
+ ctx->fs_depthstencil[pipe_tex] =
+ util_make_fragment_tex_shader_writedepthstencil(ctx->pipe, tgsi_tex,
+ TGSI_INTERPOLATE_LINEAR);
+ }
+
+ cso_set_fragment_shader_handle(ctx->cso, ctx->fs_depthstencil[pipe_tex]);
+}
+
+
+/**
+ * Helper function to set the shader which writes depth.
*/
static INLINE void
set_depth_fragment_shader(struct blit_state *ctx,
@@ -211,6 +254,25 @@
/**
+ * Helper function to set the shader which writes stencil.
+ */
+static INLINE void
+set_stencil_fragment_shader(struct blit_state *ctx,
+ enum pipe_texture_target pipe_tex)
+{
+ if (!ctx->fs_stencil[pipe_tex]) {
+ unsigned tgsi_tex = util_pipe_tex_to_tgsi_tex(pipe_tex);
+
+ ctx->fs_stencil[pipe_tex] =
+ util_make_fragment_tex_shader_writestencil(ctx->pipe, tgsi_tex,
+ TGSI_INTERPOLATE_LINEAR);
+ }
+
+ cso_set_fragment_shader_handle(ctx->cso, ctx->fs_stencil[pipe_tex]);
+}
+
+
+/**
* Helper function to set the vertex shader.
*/
static INLINE void
@@ -358,7 +420,6 @@
* \param writemask controls which channels in the dest surface are sourced
* from the src surface. Disabled channels are sourced
* from (0,0,0,1).
- * XXX need some control over blitting stencil.
*/
void
util_blit_pixels(struct blit_state *ctx,
@@ -371,7 +432,7 @@
int dstX0, int dstY0,
int dstX1, int dstY1,
float z, uint filter,
- uint writemask)
+ uint writemask, uint zs_writemask)
{
struct pipe_context *pipe = ctx->pipe;
struct pipe_screen *screen = pipe->screen;
@@ -383,9 +444,12 @@
const int srcW = abs(srcX1 - srcX0);
const int srcH = abs(srcY1 - srcY0);
unsigned offset;
- boolean overlap, dst_is_depth;
+ boolean overlap;
float s0, t0, s1, t1;
boolean normalized;
+ boolean is_stencil, is_depth, blit_depth, blit_stencil;
+ const struct util_format_description *src_desc =
+ util_format_description(src_tex->format);
assert(filter == PIPE_TEX_MIPFILTER_NEAREST ||
filter == PIPE_TEX_MIPFILTER_LINEAR);
@@ -402,12 +466,24 @@
src_format = util_format_linear(src_tex->format);
dst_format = util_format_linear(dst->format);
+ /* See whether we will blit depth or stencil. */
+ is_depth = util_format_has_depth(src_desc);
+ is_stencil = util_format_has_stencil(src_desc);
+
+ blit_depth = is_depth && (zs_writemask & BLIT_WRITEMASK_Z);
+ blit_stencil = is_stencil && (zs_writemask & BLIT_WRITEMASK_STENCIL);
+
+ assert((writemask && !zs_writemask && !is_depth && !is_stencil) ||
+ (!writemask && (blit_depth || blit_stencil)));
+
/*
* Check for simple case: no format conversion, no flipping, no stretching,
* no overlapping.
* Filter mode should not matter since there's no stretching.
*/
if (formats_compatible(src_format, dst_format) &&
+ is_stencil == blit_stencil &&
+ is_depth == blit_depth &&
srcX0 < srcX1 &&
dstX0 < dstX1 &&
srcY0 < srcY1 &&
@@ -430,6 +506,17 @@
return;
}
+ /* It's a mistake to call this function with a stencil format and
+ * without shader stencil export. We don't do software fallbacks here.
+ * Ignore stencil and only copy depth.
+ */
+ if (blit_stencil && !ctx->has_stencil_export) {
+ blit_stencil = FALSE;
+
+ if (!blit_depth)
+ return;
+ }
+
if (dst_format == dst->format) {
dst_surface = dst;
} else {
@@ -508,6 +595,11 @@
}
u_sampler_view_default_template(&sv_templ, tex, tex->format);
+ if (!blit_depth && blit_stencil) {
+ /* set a stencil-only format, e.g. Z24S8 --> X24S8 */
+ sv_templ.format = util_format_stencil_only(tex->format);
+ assert(sv_templ.format != PIPE_FORMAT_NONE);
+ }
sampler_view = pipe->create_sampler_view(pipe, tex, &sv_templ);
if (!sampler_view) {
@@ -519,6 +611,11 @@
else {
/* Directly sample from the source resource/texture */
u_sampler_view_default_template(&sv_templ, src_tex, src_format);
+ if (!blit_depth && blit_stencil) {
+ /* set a stencil-only format, e.g. Z24S8 --> X24S8 */
+ sv_templ.format = util_format_stencil_only(src_format);
+ assert(sv_templ.format != PIPE_FORMAT_NONE);
+ }
sampler_view = pipe->create_sampler_view(pipe, src_tex, &sv_templ);
if (!sampler_view) {
@@ -539,15 +636,14 @@
}
}
- dst_is_depth = util_format_is_depth_or_stencil(dst_format);
-
- assert(screen->is_format_supported(screen, sampler_view->format, ctx->internal_target,
- sampler_view->texture->nr_samples,
- PIPE_BIND_SAMPLER_VIEW));
+ assert(screen->is_format_supported(screen, sampler_view->format,
+ ctx->internal_target, sampler_view->texture->nr_samples,
+ PIPE_BIND_SAMPLER_VIEW));
assert(screen->is_format_supported(screen, dst_format, ctx->internal_target,
- dst_surface->texture->nr_samples,
- dst_is_depth ? PIPE_BIND_DEPTH_STENCIL :
- PIPE_BIND_RENDER_TARGET));
+ dst_surface->texture->nr_samples,
+ is_depth || is_stencil ? PIPE_BIND_DEPTH_STENCIL :
+ PIPE_BIND_RENDER_TARGET));
+
/* save state (restored below) */
cso_save_blend(ctx->cso);
cso_save_depth_stencil_alpha(ctx->cso);
@@ -569,22 +665,71 @@
else
cso_set_blend(ctx->cso, &ctx->blend_keep_color);
- cso_set_depth_stencil_alpha(ctx->cso,
- dst_is_depth ? &ctx->depthstencil_write :
- &ctx->depthstencil_keep);
cso_set_rasterizer(ctx->cso, &ctx->rasterizer);
cso_set_vertex_elements(ctx->cso, 2, ctx->velem);
cso_set_stream_outputs(ctx->cso, 0, NULL, 0);
- /* sampler */
+ /* default sampler state */
ctx->sampler.normalized_coords = normalized;
ctx->sampler.min_img_filter = filter;
ctx->sampler.mag_img_filter = filter;
ctx->sampler.min_lod = src_level;
ctx->sampler.max_lod = src_level;
- cso_single_sampler(ctx->cso, 0, &ctx->sampler);
+
+ /* Depth stencil state, fragment shader and sampler setup depending on what
+ * we blit.
+ */
+ if (blit_depth && blit_stencil) {
+ cso_single_sampler(ctx->cso, 0, &ctx->sampler);
+ /* don't filter stencil */
+ ctx->sampler.min_img_filter = PIPE_TEX_FILTER_NEAREST;
+ ctx->sampler.mag_img_filter = PIPE_TEX_FILTER_NEAREST;
+ cso_single_sampler(ctx->cso, 1, &ctx->sampler);
+
+ cso_set_depth_stencil_alpha(ctx->cso, &ctx->dsa_write_depthstencil);
+ set_depthstencil_fragment_shader(ctx, sampler_view->texture->target);
+ }
+ else if (blit_depth) {
+ cso_single_sampler(ctx->cso, 0, &ctx->sampler);
+ cso_set_depth_stencil_alpha(ctx->cso, &ctx->dsa_write_depth);
+ set_depth_fragment_shader(ctx, sampler_view->texture->target);
+ }
+ else if (blit_stencil) {
+ /* don't filter stencil */
+ ctx->sampler.min_img_filter = PIPE_TEX_FILTER_NEAREST;
+ ctx->sampler.mag_img_filter = PIPE_TEX_FILTER_NEAREST;
+ cso_single_sampler(ctx->cso, 0, &ctx->sampler);
+
+ cso_set_depth_stencil_alpha(ctx->cso, &ctx->dsa_write_stencil);
+ set_stencil_fragment_shader(ctx, sampler_view->texture->target);
+ }
+ else { /* color */
+ cso_single_sampler(ctx->cso, 0, &ctx->sampler);
+ cso_set_depth_stencil_alpha(ctx->cso, &ctx->dsa_keep_depthstencil);
+ set_fragment_shader(ctx, writemask, sampler_view->texture->target);
+ }
cso_single_sampler_done(ctx->cso);
+ /* textures */
+ if (blit_depth && blit_stencil) {
+ /* Setup two samplers, one for depth and the other one for stencil. */
+ struct pipe_sampler_view templ;
+ struct pipe_sampler_view *views[2];
+
+ templ = *sampler_view;
+ templ.format = util_format_stencil_only(templ.format);
+ assert(templ.format != PIPE_FORMAT_NONE);
+
+ views[0] = sampler_view;
+ views[1] = pipe->create_sampler_view(pipe, views[0]->texture, &templ);
+ cso_set_fragment_sampler_views(ctx->cso, 2, views);
+
+ pipe_sampler_view_reference(&views[1], NULL);
+ }
+ else {
+ cso_set_fragment_sampler_views(ctx->cso, 1, &sampler_view);
+ }
+
/* viewport */
ctx->viewport.scale[0] = 0.5f * dst_surface->width;
ctx->viewport.scale[1] = 0.5f * dst_surface->height;
@@ -596,15 +741,6 @@
ctx->viewport.translate[3] = 0.0f;
cso_set_viewport(ctx->cso, &ctx->viewport);
- /* texture */
- cso_set_fragment_sampler_views(ctx->cso, 1, &sampler_view);
-
- /* shaders */
- if (dst_is_depth) {
- set_depth_fragment_shader(ctx, sampler_view->texture->target);
- } else {
- set_fragment_shader(ctx, writemask, sampler_view->texture->target);
- }
set_vertex_shader(ctx);
cso_set_geometry_shader_handle(ctx->cso, NULL);
@@ -612,7 +748,7 @@
memset(&fb, 0, sizeof(fb));
fb.width = dst_surface->width;
fb.height = dst_surface->height;
- if (dst_is_depth) {
+ if (blit_depth || blit_stencil) {
fb.zsbuf = dst_surface;
} else {
fb.nr_cbufs = 1;
@@ -726,7 +862,7 @@
/* set misc state we care about */
cso_set_blend(ctx->cso, &ctx->blend_write_color);
- cso_set_depth_stencil_alpha(ctx->cso, &ctx->depthstencil_keep);
+ cso_set_depth_stencil_alpha(ctx->cso, &ctx->dsa_keep_depthstencil);
cso_set_rasterizer(ctx->cso, &ctx->rasterizer);
cso_set_vertex_elements(ctx->cso, 2, ctx->velem);
cso_set_stream_outputs(ctx->cso, 0, NULL, 0);
diff --git a/src/gallium/auxiliary/util/u_blit.h b/src/gallium/auxiliary/util/u_blit.h
index f26d429..56ab030 100644
--- a/src/gallium/auxiliary/util/u_blit.h
+++ b/src/gallium/auxiliary/util/u_blit.h
@@ -46,6 +46,8 @@
struct pipe_sampler_view;
struct pipe_surface;
+#define BLIT_WRITEMASK_Z 1
+#define BLIT_WRITEMASK_STENCIL 2
extern struct blit_state *
util_create_blit(struct pipe_context *pipe, struct cso_context *cso);
@@ -64,7 +66,7 @@
int dstX0, int dstY0,
int dstX1, int dstY1,
float z, uint filter,
- uint writemask);
+ uint writemask, uint zs_writemask);
extern void
util_blit_pixels_tex(struct blit_state *ctx,
diff --git a/src/mesa/state_tracker/st_cb_blit.c b/src/mesa/state_tracker/st_cb_blit.c
index a50b79a..1486779 100644
--- a/src/mesa/state_tracker/st_cb_blit.c
+++ b/src/mesa/state_tracker/st_cb_blit.c
@@ -242,7 +242,7 @@
srcX0, srcY0, srcX1, srcY1,
srcAtt->Zoffset + srcAtt->CubeMapFace,
dstSurf, dstX0, dstY0, dstX1, dstY1,
- 0.0, pFilter, TGSI_WRITEMASK_XYZW);
+ 0.0, pFilter, TGSI_WRITEMASK_XYZW, 0);
}
else {
struct st_renderbuffer *srcRb =
@@ -257,7 +257,7 @@
srcX0, srcY0, srcX1, srcY1,
srcSurf->u.tex.first_layer,
dstSurf, dstX0, dstY0, dstX1, dstY1,
- 0.0, pFilter, TGSI_WRITEMASK_XYZW);
+ 0.0, pFilter, TGSI_WRITEMASK_XYZW, 0);
}
}
@@ -281,6 +281,13 @@
struct pipe_surface *dstDepthSurf =
dstDepthRb ? dstDepthRb->surface : NULL;
+ struct st_renderbuffer *srcStencilRb =
+ st_renderbuffer(readFB->Attachment[BUFFER_STENCIL].Renderbuffer);
+ struct st_renderbuffer *dstStencilRb =
+ st_renderbuffer(drawFB->Attachment[BUFFER_STENCIL].Renderbuffer);
+ struct pipe_surface *dstStencilSurf =
+ dstStencilRb ? dstStencilRb->surface : NULL;
+
if ((mask & depthStencil) == depthStencil &&
st_is_depth_stencil_combined(srcDepth, srcStencil) &&
st_is_depth_stencil_combined(dstDepth, dstStencil)) {
@@ -294,7 +301,15 @@
srcX0, srcY0, srcX1, srcY1,
srcDepthRb->surface->u.tex.first_layer,
dstDepthSurf, dstX0, dstY0, dstX1, dstY1,
- 0.0, pFilter, 0);
+ 0.0, pFilter, 0,
+ BLIT_WRITEMASK_Z |
+ (st->has_stencil_export ? BLIT_WRITEMASK_STENCIL
+ : 0));
+
+ if (!st->has_stencil_export) {
+ _mesa_problem(ctx, "st_BlitFramebuffer(STENCIL) "
+ "software fallback not implemented");
+ }
}
else {
/* blitting depth and stencil separately */
@@ -305,12 +320,22 @@
srcX0, srcY0, srcX1, srcY1,
srcDepthRb->surface->u.tex.first_layer,
dstDepthSurf, dstX0, dstY0, dstX1, dstY1,
- 0.0, pFilter, 0);
+ 0.0, pFilter, 0, BLIT_WRITEMASK_Z);
}
if (mask & GL_STENCIL_BUFFER_BIT) {
- /* blit stencil only */
- _mesa_problem(ctx, "st_BlitFramebuffer(STENCIL) not completed");
+ if (st->has_stencil_export) {
+ util_blit_pixels(st->blit, srcStencilRb->texture,
+ srcStencilRb->surface->u.tex.level,
+ srcX0, srcY0, srcX1, srcY1,
+ srcStencilRb->surface->u.tex.first_layer,
+ dstStencilSurf, dstX0, dstY0, dstX1, dstY1,
+ 0.0, pFilter, 0, BLIT_WRITEMASK_STENCIL);
+ }
+ else {
+ _mesa_problem(ctx, "st_BlitFramebuffer(STENCIL) "
+ "software fallback not implemented");
+ }
}
}
}
diff --git a/src/mesa/state_tracker/st_cb_texture.c b/src/mesa/state_tracker/st_cb_texture.c
index a1d6951..a7f57b9 100644
--- a/src/mesa/state_tracker/st_cb_texture.c
+++ b/src/mesa/state_tracker/st_cb_texture.c
@@ -944,7 +944,7 @@
struct pipe_screen *screen = pipe->screen;
enum pipe_format dest_format, src_format;
GLboolean matching_base_formats;
- GLuint format_writemask, sample_count;
+ GLuint color_writemask, zs_writemask, sample_count;
struct pipe_surface *dest_surface = NULL;
GLboolean do_flip = (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP);
struct pipe_surface surf_tmpl;
@@ -1025,15 +1025,17 @@
}
if (texBaseFormat == GL_DEPTH_COMPONENT) {
- format_writemask = TGSI_WRITEMASK_XYZW;
+ color_writemask = 0;
+ zs_writemask = BLIT_WRITEMASK_Z;
dst_usage = PIPE_BIND_DEPTH_STENCIL;
}
else {
- format_writemask = compatible_src_dst_formats(ctx, &strb->Base, texImage);
+ color_writemask = compatible_src_dst_formats(ctx, &strb->Base, texImage);
+ zs_writemask = 0;
dst_usage = PIPE_BIND_RENDER_TARGET;
}
- if (!format_writemask ||
+ if ((!color_writemask && !zs_writemask) ||
!screen->is_format_supported(screen, src_format,
PIPE_TEXTURE_2D, sample_count,
PIPE_BIND_SAMPLER_VIEW) ||
@@ -1076,7 +1078,7 @@
destX, destY,
destX + width, destY + height,
0.0, PIPE_TEX_MIPFILTER_NEAREST,
- format_writemask);
+ color_writemask, zs_writemask);
pipe_surface_reference(&dest_surface, NULL);
/* Restore conditional rendering state. */
diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
index 132dcc0..117ea90 100644
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -187,6 +187,8 @@
st->pixel_xfer.cache = _mesa_new_program_cache();
st->force_msaa = st_get_msaa();
+ st->has_stencil_export =
+ screen->get_param(screen, PIPE_CAP_SHADER_STENCIL_EXPORT);
/* GL limits and extensions */
st_init_limits(st);
diff --git a/src/mesa/state_tracker/st_context.h b/src/mesa/state_tracker/st_context.h
index 734b4d9..a3f44b3 100644
--- a/src/mesa/state_tracker/st_context.h
+++ b/src/mesa/state_tracker/st_context.h
@@ -81,7 +81,7 @@
struct draw_stage *rastpos_stage; /**< For glRasterPos */
GLboolean clamp_frag_color_in_shader;
GLboolean clamp_vert_color_in_shader;
-
+ boolean has_stencil_export; /**< can do shader stencil export? */
/* On old libGL's for linux we need to invalidate the drawables
* on glViewpport calls, this is set via a option.