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"
34 #include "main/framebuffer.h"
37 upload_clip_state(struct brw_context
*brw
)
39 struct gl_context
*ctx
= &brw
->ctx
;
40 /* BRW_NEW_META_IN_PROGRESS */
41 uint32_t dw1
= brw
->meta_in_progress
? 0 : GEN6_CLIP_STATISTICS_ENABLE
;
45 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
47 /* BRW_NEW_FS_PROG_DATA */
48 if (brw
->wm
.prog_data
->barycentric_interp_modes
&
49 BRW_WM_NONPERSPECTIVE_BARYCENTRIC_BITS
) {
50 dw2
|= GEN6_CLIP_NON_PERSPECTIVE_BARYCENTRIC_ENABLE
;
54 dw1
|= GEN7_CLIP_EARLY_CULL
;
58 if (ctx
->Polygon
._FrontBit
== _mesa_is_user_fbo(fb
))
59 dw1
|= GEN7_CLIP_WINDING_CCW
;
61 if (ctx
->Polygon
.CullFlag
) {
62 switch (ctx
->Polygon
.CullFaceMode
) {
64 dw1
|= GEN7_CLIP_CULLMODE_FRONT
;
67 dw1
|= GEN7_CLIP_CULLMODE_BACK
;
69 case GL_FRONT_AND_BACK
:
70 dw1
|= GEN7_CLIP_CULLMODE_BOTH
;
73 unreachable("Should not get here: invalid CullFlag");
76 dw1
|= GEN7_CLIP_CULLMODE_NONE
;
80 if (brw
->gen
< 8 && !ctx
->Transform
.DepthClamp
)
81 dw2
|= GEN6_CLIP_Z_TEST
;
84 if (ctx
->Light
.ProvokingVertex
== GL_FIRST_VERTEX_CONVENTION
) {
86 (0 << GEN6_CLIP_TRI_PROVOKE_SHIFT
) |
87 (1 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT
) |
88 (0 << GEN6_CLIP_LINE_PROVOKE_SHIFT
);
91 (2 << GEN6_CLIP_TRI_PROVOKE_SHIFT
) |
92 (2 << GEN6_CLIP_TRIFAN_PROVOKE_SHIFT
) |
93 (1 << GEN6_CLIP_LINE_PROVOKE_SHIFT
);
97 dw2
|= (ctx
->Transform
.ClipPlanesEnabled
<<
98 GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT
);
99 if (ctx
->Transform
.ClipDepthMode
== GL_ZERO_TO_ONE
)
100 dw2
|= GEN6_CLIP_API_D3D
;
102 dw2
|= GEN6_CLIP_API_OGL
;
104 dw2
|= GEN6_CLIP_GB_TEST
;
106 /* We need to disable guardband clipping if the guardband (which we always
107 * program to the maximum screen-space bounding box of 8K x 8K) will be
108 * smaller than the viewport.
110 * Closely examining the clip determination formulas in the documentation
111 * reveals that objects will be discarded entirely if they're outside the
112 * (small) guardband, even if they're within the (large) viewport:
114 * TR = TR_GB || TR_VPXY || TR_VPZ || TR_UC || TR_NEGW
115 * TA = !TR && TA_GB && TA_VPZ && TA_NEGW
118 * (TA is "Trivial Accept", TR is "Trivial Reject", MC is "Must Clip".)
120 * Disabling guardband clipping removes the TR_GB condition, which means
121 * they'll be considered MC ("Must Clip") unless they're rejected for
124 * Note that there is no TA_VPXY condition. If there were, objects entirely
125 * inside a 16384x16384 viewport would be trivially accepted, breaking the
126 * "objects must have a screenspace bounding box not exceeding 8K in the X
127 * or Y direction" restriction. Instead, they're clipped.
129 for (unsigned i
= 0; i
< ctx
->Const
.MaxViewports
; i
++) {
130 if (ctx
->ViewportArray
[i
].Width
> 8192 ||
131 ctx
->ViewportArray
[i
].Height
> 8192) {
132 dw2
&= ~GEN6_CLIP_GB_TEST
;
137 /* If the viewport dimensions are smaller than the drawable dimensions,
138 * we have to disable guardband clipping prior to Gen8. We always program
139 * the guardband to a fixed size, which is almost always larger than the
140 * viewport. Any geometry which intersects the viewport but lies within
141 * the guardband would bypass the 3D clipping stage, so it wouldn't be
142 * clipped to the viewport. Rendering would happen beyond the viewport,
143 * but still inside the drawable.
145 * Gen8+ introduces a viewport extents test which restricts rendering to
146 * the viewport, so we can ignore this restriction.
149 const float fb_width
= (float)_mesa_geometric_width(fb
);
150 const float fb_height
= (float)_mesa_geometric_height(fb
);
152 for (unsigned i
= 0; i
< ctx
->Const
.MaxViewports
; i
++) {
153 if (ctx
->ViewportArray
[i
].X
!= 0 ||
154 ctx
->ViewportArray
[i
].Y
!= 0 ||
155 ctx
->ViewportArray
[i
].Width
!= fb_width
||
156 ctx
->ViewportArray
[i
].Height
!= fb_height
) {
157 dw2
&= ~GEN6_CLIP_GB_TEST
;
163 /* BRW_NEW_RASTERIZER_DISCARD */
164 if (ctx
->RasterDiscard
) {
165 dw2
|= GEN6_CLIP_MODE_REJECT_ALL
;
166 perf_debug("Rasterizer discard is currently implemented via the clipper; "
167 "%s be faster.\n", brw
->gen
>= 7 ? "using the SOL unit may" :
168 "having the GS not write primitives would likely");
172 if (brw
->primitive
== _3DPRIM_RECTLIST
)
175 enable
= GEN6_CLIP_ENABLE
;
178 OUT_BATCH(_3DSTATE_CLIP
<< 16 | (4 - 2));
181 GEN6_CLIP_MODE_NORMAL
|
184 OUT_BATCH(U_FIXED(0.125, 3) << GEN6_CLIP_MIN_POINT_WIDTH_SHIFT
|
185 U_FIXED(255.875, 3) << GEN6_CLIP_MAX_POINT_WIDTH_SHIFT
|
186 (_mesa_geometric_layers(fb
) > 0 ? 0 : GEN6_CLIP_FORCE_ZERO_RTAINDEX
) |
187 ((ctx
->Const
.MaxViewports
- 1) & GEN6_CLIP_MAX_VP_INDEX_MASK
));
191 const struct brw_tracked_state gen6_clip_state
= {
193 .mesa
= _NEW_BUFFERS
|
196 .brw
= BRW_NEW_CONTEXT
|
197 BRW_NEW_FS_PROG_DATA
|
198 BRW_NEW_META_IN_PROGRESS
|
199 BRW_NEW_RASTERIZER_DISCARD
,
201 .emit
= upload_clip_state
,
204 const struct brw_tracked_state gen7_clip_state
= {
206 .mesa
= _NEW_BUFFERS
|
210 .brw
= BRW_NEW_CONTEXT
|
211 BRW_NEW_FS_PROG_DATA
|
212 BRW_NEW_META_IN_PROGRESS
|
213 BRW_NEW_RASTERIZER_DISCARD
,
215 .emit
= upload_clip_state
,