2 * Copyright © 2009 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Eric Anholt <eric@anholt.net>
28 #include "brw_context.h"
29 #include "brw_state.h"
30 #include "brw_defines.h"
32 #include "intel_batchbuffer.h"
33 #include "main/fbobject.h"
36 upload_clip_state(struct brw_context
*brw
)
38 struct gl_context
*ctx
= &brw
->ctx
;
39 /* BRW_NEW_META_IN_PROGRESS */
40 uint32_t dw1
= brw
->meta_in_progress
? 0 : GEN6_CLIP_STATISTICS_ENABLE
;
44 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
46 /* BRW_NEW_FS_PROG_DATA */
47 if (brw
->wm
.prog_data
->barycentric_interp_modes
&
48 BRW_WM_NONPERSPECTIVE_BARYCENTRIC_BITS
) {
49 dw2
|= GEN6_CLIP_NON_PERSPECTIVE_BARYCENTRIC_ENABLE
;
53 dw1
|= GEN7_CLIP_EARLY_CULL
;
57 if ((ctx
->Polygon
.FrontFace
== GL_CCW
) ^ _mesa_is_user_fbo(fb
))
58 dw1
|= GEN7_CLIP_WINDING_CCW
;
60 if (ctx
->Polygon
.CullFlag
) {
61 switch (ctx
->Polygon
.CullFaceMode
) {
63 dw1
|= GEN7_CLIP_CULLMODE_FRONT
;
66 dw1
|= GEN7_CLIP_CULLMODE_BACK
;
68 case GL_FRONT_AND_BACK
:
69 dw1
|= GEN7_CLIP_CULLMODE_BOTH
;
72 unreachable("Should not get here: invalid CullFlag");
75 dw1
|= GEN7_CLIP_CULLMODE_NONE
;
79 if (brw
->gen
< 8 && !ctx
->Transform
.DepthClamp
)
80 dw2
|= GEN6_CLIP_Z_TEST
;
83 if (ctx
->Light
.ProvokingVertex
== GL_FIRST_VERTEX_CONVENTION
) {
85 (0 << GEN6_CLIP_TRI_PROVOKE_SHIFT
) |
86 (1 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT
) |
87 (0 << GEN6_CLIP_LINE_PROVOKE_SHIFT
);
90 (2 << GEN6_CLIP_TRI_PROVOKE_SHIFT
) |
91 (2 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT
) |
92 (1 << GEN6_CLIP_LINE_PROVOKE_SHIFT
);
96 dw2
|= (ctx
->Transform
.ClipPlanesEnabled
<<
97 GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT
);
99 dw2
|= GEN6_CLIP_GB_TEST
;
101 /* We need to disable guardband clipping if the guardband (which we always
102 * program to the maximum screen-space bounding box of 8K x 8K) will be
103 * smaller than the viewport.
105 * Closely examining the clip determination formulas in the documentation
106 * reveals that objects will be discarded entirely if they're outside the
107 * (small) guardband, even if they're within the (large) viewport:
109 * TR = TR_GB || TR_VPXY || TR_VPZ || TR_UC || TR_NEGW
110 * TA = !TR && TA_GB && TA_VPZ && TA_NEGW
113 * (TA is "Trivial Accept", TR is "Trivial Reject", MC is "Must Clip".)
115 * Disabling guardband clipping removes the TR_GB condition, which means
116 * they'll be considered MC ("Must Clip") unless they're rejected for
119 * Note that there is no TA_VPXY condition. If there were, objects entirely
120 * inside a 16384x16384 viewport would be trivially accepted, breaking the
121 * "objects must have a screenspace bounding box not exceeding 8K in the X
122 * or Y direction" restriction. Instead, they're clipped.
124 for (unsigned i
= 0; i
< ctx
->Const
.MaxViewports
; i
++) {
125 if (ctx
->ViewportArray
[i
].Width
> 8192 ||
126 ctx
->ViewportArray
[i
].Height
> 8192) {
127 dw2
&= ~GEN6_CLIP_GB_TEST
;
132 /* If the viewport dimensions are smaller than the drawable dimensions,
133 * we have to disable guardband clipping prior to Gen8. We always program
134 * the guardband to a fixed size, which is almost always larger than the
135 * viewport. Any geometry which intersects the viewport but lies within
136 * the guardband would bypass the 3D clipping stage, so it wouldn't be
137 * clipped to the viewport. Rendering would happen beyond the viewport,
138 * but still inside the drawable.
140 * Gen8+ introduces a viewport extents test which restricts rendering to
141 * the viewport, so we can ignore this restriction.
144 for (unsigned i
= 0; i
< ctx
->Const
.MaxViewports
; i
++) {
145 if (ctx
->ViewportArray
[i
].X
!= 0 ||
146 ctx
->ViewportArray
[i
].Y
!= 0 ||
147 ctx
->ViewportArray
[i
].Width
!= (float) fb
->Width
||
148 ctx
->ViewportArray
[i
].Height
!= (float) fb
->Height
) {
149 dw2
&= ~GEN6_CLIP_GB_TEST
;
155 /* BRW_NEW_RASTERIZER_DISCARD */
156 if (ctx
->RasterDiscard
) {
157 dw2
|= GEN6_CLIP_MODE_REJECT_ALL
;
158 perf_debug("Rasterizer discard is currently implemented via the clipper; "
159 "%s be faster.\n", brw
->gen
>= 7 ? "using the SOL unit may" :
160 "having the GS not write primitives would likely");
164 if (brw
->primitive
== _3DPRIM_RECTLIST
)
167 enable
= GEN6_CLIP_ENABLE
;
170 OUT_BATCH(_3DSTATE_CLIP
<< 16 | (4 - 2));
174 GEN6_CLIP_MODE_NORMAL
|
177 OUT_BATCH(U_FIXED(0.125, 3) << GEN6_CLIP_MIN_POINT_WIDTH_SHIFT
|
178 U_FIXED(255.875, 3) << GEN6_CLIP_MAX_POINT_WIDTH_SHIFT
|
179 (fb
->MaxNumLayers
> 0 ? 0 : GEN6_CLIP_FORCE_ZERO_RTAINDEX
) |
180 ((ctx
->Const
.MaxViewports
- 1) & GEN6_CLIP_MAX_VP_INDEX_MASK
));
184 const struct brw_tracked_state gen6_clip_state
= {
186 .mesa
= _NEW_BUFFERS
|
189 .brw
= BRW_NEW_CONTEXT
|
190 BRW_NEW_FS_PROG_DATA
|
191 BRW_NEW_META_IN_PROGRESS
|
192 BRW_NEW_RASTERIZER_DISCARD
,
194 .emit
= upload_clip_state
,
197 const struct brw_tracked_state gen7_clip_state
= {
199 .mesa
= _NEW_BUFFERS
|
203 .brw
= BRW_NEW_CONTEXT
|
204 BRW_NEW_FS_PROG_DATA
|
205 BRW_NEW_META_IN_PROGRESS
|
206 BRW_NEW_RASTERIZER_DISCARD
,
208 .emit
= upload_clip_state
,