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/*
* Copyright © 2009 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.
*
* Authors:
* Eric Anholt <eric@anholt.net>
*
*/
#include "brw_context.h"
#include "brw_state.h"
#include "brw_defines.h"
#include "brw_util.h"
#include "intel_batchbuffer.h"
#include "main/fbobject.h"
static void
upload_clip_state(struct brw_context *brw)
{
struct gl_context *ctx = &brw->ctx;
/* BRW_NEW_META_IN_PROGRESS */
uint32_t dw1 = brw->meta_in_progress ? 0 : GEN6_CLIP_STATISTICS_ENABLE;
uint32_t dw2 = 0;
/* _NEW_BUFFERS */
struct gl_framebuffer *fb = ctx->DrawBuffer;
/* CACHE_NEW_WM_PROG */
if (brw->wm.prog_data->barycentric_interp_modes &
BRW_WM_NONPERSPECTIVE_BARYCENTRIC_BITS) {
dw2 |= GEN6_CLIP_NON_PERSPECTIVE_BARYCENTRIC_ENABLE;
}
if (brw->gen >= 7)
dw1 |= GEN7_CLIP_EARLY_CULL;
if (brw->gen == 7) {
/* _NEW_POLYGON */
if ((ctx->Polygon.FrontFace == GL_CCW) ^ _mesa_is_user_fbo(fb))
dw1 |= GEN7_CLIP_WINDING_CCW;
if (ctx->Polygon.CullFlag) {
switch (ctx->Polygon.CullFaceMode) {
case GL_FRONT:
dw1 |= GEN7_CLIP_CULLMODE_FRONT;
break;
case GL_BACK:
dw1 |= GEN7_CLIP_CULLMODE_BACK;
break;
case GL_FRONT_AND_BACK:
dw1 |= GEN7_CLIP_CULLMODE_BOTH;
break;
default:
unreachable("Should not get here: invalid CullFlag");
}
} else {
dw1 |= GEN7_CLIP_CULLMODE_NONE;
}
}
if (brw->gen < 8 && !ctx->Transform.DepthClamp)
dw2 |= GEN6_CLIP_Z_TEST;
/* _NEW_LIGHT */
if (ctx->Light.ProvokingVertex == GL_FIRST_VERTEX_CONVENTION) {
dw2 |=
(0 << GEN6_CLIP_TRI_PROVOKE_SHIFT) |
(1 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT) |
(0 << GEN6_CLIP_LINE_PROVOKE_SHIFT);
} else {
dw2 |=
(2 << GEN6_CLIP_TRI_PROVOKE_SHIFT) |
(2 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT) |
(1 << GEN6_CLIP_LINE_PROVOKE_SHIFT);
}
/* _NEW_TRANSFORM */
dw2 |= (ctx->Transform.ClipPlanesEnabled <<
GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT);
dw2 |= GEN6_CLIP_GB_TEST;
/* We need to disable guardband clipping if the guardband (which we always
* program to the maximum screen-space bounding box of 8K x 8K) will be
* smaller than the viewport.
*
* Closely examining the clip determination formulas in the documentation
* reveals that objects will be discarded entirely if they're outside the
* (small) guardband, even if they're within the (large) viewport:
*
* TR = TR_GB || TR_VPXY || TR_VPZ || TR_UC || TR_NEGW
* TA = !TR && TA_GB && TA_VPZ && TA_NEGW
* MC = !(TA || TR)
*
* (TA is "Trivial Accept", TR is "Trivial Reject", MC is "Must Clip".)
*
* Disabling guardband clipping removes the TR_GB condition, which means
* they'll be considered MC ("Must Clip") unless they're rejected for
* some other reason.
*
* Note that there is no TA_VPXY condition. If there were, objects entirely
* inside a 16384x16384 viewport would be trivially accepted, breaking the
* "objects must have a screenspace bounding box not exceeding 8K in the X
* or Y direction" restriction. Instead, they're clipped.
*/
for (unsigned i = 0; i < ctx->Const.MaxViewports; i++) {
if (ctx->ViewportArray[i].Width > 8192 ||
ctx->ViewportArray[i].Height > 8192) {
dw2 &= ~GEN6_CLIP_GB_TEST;
break;
}
}
/* If the viewport dimensions are smaller than the drawable dimensions,
* we have to disable guardband clipping prior to Gen8. We always program
* the guardband to a fixed size, which is almost always larger than the
* viewport. Any geometry which intersects the viewport but lies within
* the guardband would bypass the 3D clipping stage, so it wouldn't be
* clipped to the viewport. Rendering would happen beyond the viewport,
* but still inside the drawable.
*
* Gen8+ introduces a viewport extents test which restricts rendering to
* the viewport, so we can ignore this restriction.
*/
if (brw->gen < 8) {
for (unsigned i = 0; i < ctx->Const.MaxViewports; i++) {
if (ctx->ViewportArray[i].X != 0 ||
ctx->ViewportArray[i].Y != 0 ||
ctx->ViewportArray[i].Width != (float) fb->Width ||
ctx->ViewportArray[i].Height != (float) fb->Height) {
dw2 &= ~GEN6_CLIP_GB_TEST;
break;
}
}
}
/* BRW_NEW_RASTERIZER_DISCARD */
if (ctx->RasterDiscard) {
dw2 |= GEN6_CLIP_MODE_REJECT_ALL;
perf_debug("Rasterizer discard is currently implemented via the clipper; "
"%s be faster.\n", brw->gen >= 7 ? "using the SOL unit may" :
"having the GS not write primitives would likely");
}
uint32_t enable;
if (brw->primitive == _3DPRIM_RECTLIST)
enable = 0;
else
enable = GEN6_CLIP_ENABLE;
BEGIN_BATCH(4);
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);
OUT_BATCH(U_FIXED(0.125, 3) << GEN6_CLIP_MIN_POINT_WIDTH_SHIFT |
U_FIXED(255.875, 3) << GEN6_CLIP_MAX_POINT_WIDTH_SHIFT |
(fb->MaxNumLayers > 0 ? 0 : GEN6_CLIP_FORCE_ZERO_RTAINDEX) |
((ctx->Const.MaxViewports - 1) & GEN6_CLIP_MAX_VP_INDEX_MASK));
ADVANCE_BATCH();
}
const struct brw_tracked_state gen6_clip_state = {
.dirty = {
.mesa = _NEW_TRANSFORM | _NEW_LIGHT | _NEW_BUFFERS,
.brw = BRW_NEW_CONTEXT |
BRW_NEW_META_IN_PROGRESS |
BRW_NEW_RASTERIZER_DISCARD,
.cache = CACHE_NEW_WM_PROG
},
.emit = upload_clip_state,
};
const struct brw_tracked_state gen7_clip_state = {
.dirty = {
.mesa = _NEW_BUFFERS | _NEW_LIGHT | _NEW_POLYGON | _NEW_TRANSFORM,
.brw = BRW_NEW_CONTEXT |
BRW_NEW_META_IN_PROGRESS |
BRW_NEW_RASTERIZER_DISCARD,
.cache = CACHE_NEW_WM_PROG
},
.emit = upload_clip_state,
};
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