i965: Update SF_CLIP_VIEWPORT for Broadwell.

It has additional fields to support clipping to the viewport even if
guardband clipping is enabled.

v2: Update for viewport array changes.
v3: No, seriously, update for viewport array changes.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net> [v1]

src/mesa/drivers/dri/i965/Makefile.sources

@@ -153,6 +153,7 @@ i965_FILES = \
 	gen8_sol_state.c \
 	gen8_surface_state.c \
 	gen8_vec4_generator.cpp \
+	gen8_viewport_state.c \
 	gen8_vs_state.c \
 	gen8_wm_depth_stencil.c \
 	gen8_ps_state.c \

src/mesa/drivers/dri/i965/brw_state.h

@@ -143,6 +143,7 @@ extern const struct brw_tracked_state gen8_sbe_state;
 extern const struct brw_tracked_state gen8_sf_state;
 extern const struct brw_tracked_state gen8_state_base_address;
 extern const struct brw_tracked_state gen8_sol_state;
+extern const struct brw_tracked_state gen8_sf_clip_viewport;
 extern const struct brw_tracked_state gen8_vertices;
 extern const struct brw_tracked_state gen8_vf_topology;
 extern const struct brw_tracked_state gen8_vs_state;

src/mesa/drivers/dri/i965/brw_state_upload.c

@@ -262,7 +262,7 @@ static const struct brw_tracked_state *gen8_atoms[] =
 
    &brw_cc_vp,
    &gen7_cc_viewport_state_pointer, /* must do after brw_cc_vp */
-   &gen7_sf_clip_viewport,
+   &gen8_sf_clip_viewport,
 
    &gen7_push_constant_space,
    &gen7_urb,

src/mesa/drivers/dri/i965/gen8_viewport_state.c

@@ -0,0 +1,118 @@
+/*
+ * Copyright © 2011 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "brw_context.h"
+#include "brw_state.h"
+#include "brw_defines.h"
+#include "intel_batchbuffer.h"
+#include "main/fbobject.h"
+
+static void
+gen8_upload_sf_clip_viewport(struct brw_context *brw)
+{
+   struct gl_context *ctx = &brw->ctx;
+   const GLfloat depth_scale = 1.0F / ctx->DrawBuffer->_DepthMaxF;
+   float y_scale, y_bias;
+   const bool render_to_fbo = _mesa_is_user_fbo(ctx->DrawBuffer);
+
+   float *vp = brw_state_batch(brw, AUB_TRACE_SF_VP_STATE,
+                               16 * 4 * ctx->Const.MaxViewports,
+                               64, &brw->sf.vp_offset);
+   /* Also assign to clip.vp_offset in case something uses it. */
+   brw->clip.vp_offset = brw->sf.vp_offset;
+
+   /* _NEW_BUFFERS */
+   if (render_to_fbo) {
+      y_scale = 1.0;
+      y_bias = 0;
+   } else {
+      y_scale = -1.0;
+      y_bias = ctx->DrawBuffer->Height;
+   }
+
+   for (unsigned i = 0; i < ctx->Const.MaxViewports; i++) {
+      const GLfloat *const v = ctx->ViewportArray[i]._WindowMap.m;
+
+      /* _NEW_VIEWPORT: Viewport Matrix Elements */
+      vp[0] = v[MAT_SX];                    /* m00 */
+      vp[1] = v[MAT_SY] * y_scale;          /* m11 */
+      vp[2] = v[MAT_SZ] * depth_scale;      /* m22 */
+      vp[3] = v[MAT_TX];                    /* m30 */
+      vp[4] = v[MAT_TY] * y_scale + y_bias; /* m31 */
+      vp[5] = v[MAT_TZ] * depth_scale;      /* m32 */
+
+      /* Reserved */
+      vp[6] = 0;
+      vp[7] = 0;
+
+      /* According to the "Vertex X,Y Clamping and Quantization" section of the
+       * Strips and Fans documentation, objects must not have a screen-space
+       * extents of over 8192 pixels, or they may be mis-rasterized.  The
+       * maximum screen space coordinates of a small object may larger, but we
+       * have no way to enforce the object size other than through clipping.
+       *
+       * If you're surprised that we set clip to -gbx to +gbx and it seems like
+       * we'll end up with 16384 wide, note that for a 8192-wide render target,
+       * we'll end up with a normal (-1, 1) clip volume that just covers the
+       * drawable.
+       */
+      const float maximum_guardband_extent = 8192;
+      float gbx = maximum_guardband_extent / ctx->ViewportArray[i].Width;
+      float gby = maximum_guardband_extent / ctx->ViewportArray[i].Height;
+
+      /* _NEW_VIEWPORT: Guardband Clipping */
+      vp[8]  = -gbx; /* x-min */
+      vp[9]  =  gbx; /* x-max */
+      vp[10] = -gby; /* y-min */
+      vp[11] =  gby; /* y-max */
+
+      /* Screen Space Viewport */
+      if (render_to_fbo) {
+         vp[12] = ctx->DrawBuffer->_Xmin;
+         vp[13] = ctx->DrawBuffer->_Xmax - 1;
+         vp[14] = ctx->DrawBuffer->_Ymin;
+         vp[15] = ctx->DrawBuffer->_Ymax - 1;
+      } else {
+         vp[12] = ctx->DrawBuffer->_Xmin;
+         vp[13] = ctx->DrawBuffer->_Xmax - 1;
+         vp[14] = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymax;
+         vp[15] = ctx->DrawBuffer->Height - ctx->DrawBuffer->_Ymin - 1;
+      }
+
+      vp += 16;
+   }
+
+   BEGIN_BATCH(2);
+   OUT_BATCH(_3DSTATE_VIEWPORT_STATE_POINTERS_SF_CL << 16 | (2 - 2));
+   OUT_BATCH(brw->sf.vp_offset);
+   ADVANCE_BATCH();
+}
+
+const struct brw_tracked_state gen8_sf_clip_viewport = {
+   .dirty = {
+      .mesa = _NEW_VIEWPORT | _NEW_BUFFERS,
+      .brw = BRW_NEW_BATCH,
+      .cache = 0,
+   },
+   .emit = gen8_upload_sf_clip_viewport,
+};