/* * 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 * */ #include "brw_context.h" #include "brw_state.h" #include "brw_defines.h" #include "brw_util.h" #include "compiler/nir/nir.h" #include "main/macros.h" #include "main/fbobject.h" #include "main/framebuffer.h" #include "intel_batchbuffer.h" /** * Determine the appropriate attribute override value to store into the * 3DSTATE_SF structure for a given fragment shader attribute. The attribute * override value contains two pieces of information: the location of the * attribute in the VUE (relative to urb_entry_read_offset, see below), and a * flag indicating whether to "swizzle" the attribute based on the direction * the triangle is facing. * * If an attribute is "swizzled", then the given VUE location is used for * front-facing triangles, and the VUE location that immediately follows is * used for back-facing triangles. We use this to implement the mapping from * gl_FrontColor/gl_BackColor to gl_Color. * * urb_entry_read_offset is the offset into the VUE at which the SF unit is * being instructed to begin reading attribute data. It can be set to a * nonzero value to prevent the SF unit from wasting time reading elements of * the VUE that are not needed by the fragment shader. It is measured in * 256-bit increments. */ static uint32_t get_attr_override(const struct brw_vue_map *vue_map, int urb_entry_read_offset, int fs_attr, bool two_side_color, uint32_t *max_source_attr) { /* Find the VUE slot for this attribute. */ int slot = vue_map->varying_to_slot[fs_attr]; /* Viewport and Layer are stored in the VUE header. We need to override * them to zero if earlier stages didn't write them, as GL requires that * they read back as zero when not explicitly set. */ if (fs_attr == VARYING_SLOT_VIEWPORT || fs_attr == VARYING_SLOT_LAYER) { unsigned override = ATTRIBUTE_0_OVERRIDE_X | ATTRIBUTE_0_OVERRIDE_W | ATTRIBUTE_CONST_0000 << ATTRIBUTE_0_CONST_SOURCE_SHIFT; if (!(vue_map->slots_valid & VARYING_BIT_LAYER)) override |= ATTRIBUTE_0_OVERRIDE_Y; if (!(vue_map->slots_valid & VARYING_BIT_VIEWPORT)) override |= ATTRIBUTE_0_OVERRIDE_Z; return override; } /* If there was only a back color written but not front, use back * as the color instead of undefined */ if (slot == -1 && fs_attr == VARYING_SLOT_COL0) slot = vue_map->varying_to_slot[VARYING_SLOT_BFC0]; if (slot == -1 && fs_attr == VARYING_SLOT_COL1) slot = vue_map->varying_to_slot[VARYING_SLOT_BFC1]; if (slot == -1) { /* This attribute does not exist in the VUE--that means that the vertex * shader did not write to it. This means that either: * * (a) This attribute is a texture coordinate, and it is going to be * replaced with point coordinates (as a consequence of a call to * glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE)), so the * hardware will ignore whatever attribute override we supply. * * (b) This attribute is read by the fragment shader but not written by * the vertex shader, so its value is undefined. Therefore the * attribute override we supply doesn't matter. * * (c) This attribute is gl_PrimitiveID, and it wasn't written by the * previous shader stage. * * Note that we don't have to worry about the cases where the attribute * is gl_PointCoord or is undergoing point sprite coordinate * replacement, because in those cases, this function isn't called. * * In case (c), we need to program the attribute overrides so that the * primitive ID will be stored in this slot. In every other case, the * attribute override we supply doesn't matter. So just go ahead and * program primitive ID in every case. */ return (ATTRIBUTE_0_OVERRIDE_W | ATTRIBUTE_0_OVERRIDE_Z | ATTRIBUTE_0_OVERRIDE_Y | ATTRIBUTE_0_OVERRIDE_X | (ATTRIBUTE_CONST_PRIM_ID << ATTRIBUTE_0_CONST_SOURCE_SHIFT)); } /* Compute the location of the attribute relative to urb_entry_read_offset. * Each increment of urb_entry_read_offset represents a 256-bit value, so * it counts for two 128-bit VUE slots. */ int source_attr = slot - 2 * urb_entry_read_offset; assert(source_attr >= 0 && source_attr < 32); /* If we are doing two-sided color, and the VUE slot following this one * represents a back-facing color, then we need to instruct the SF unit to * do back-facing swizzling. */ bool swizzling = two_side_color && ((vue_map->slot_to_varying[slot] == VARYING_SLOT_COL0 && vue_map->slot_to_varying[slot+1] == VARYING_SLOT_BFC0) || (vue_map->slot_to_varying[slot] == VARYING_SLOT_COL1 && vue_map->slot_to_varying[slot+1] == VARYING_SLOT_BFC1)); /* Update max_source_attr. If swizzling, the SF will read this slot + 1. */ if (*max_source_attr < source_attr + swizzling) *max_source_attr = source_attr + swizzling; if (swizzling) { return source_attr | (ATTRIBUTE_SWIZZLE_INPUTATTR_FACING << ATTRIBUTE_SWIZZLE_SHIFT); } return source_attr; } /** * Create the mapping from the FS inputs we produce to the previous pipeline * stage (GS or VS) outputs they source from. */ void calculate_attr_overrides(const struct brw_context *brw, uint16_t *attr_overrides, uint32_t *point_sprite_enables, uint32_t *urb_entry_read_length, uint32_t *urb_entry_read_offset) { /* BRW_NEW_FS_PROG_DATA */ const struct brw_wm_prog_data *wm_prog_data = brw_wm_prog_data(brw->wm.base.prog_data); uint32_t max_source_attr = 0; *point_sprite_enables = 0; *urb_entry_read_offset = BRW_SF_URB_ENTRY_READ_OFFSET; /* BRW_NEW_FRAGMENT_PROGRAM * * If the fragment shader reads VARYING_SLOT_LAYER, then we need to pass in * the full vertex header. Otherwise, we can program the SF to start * reading at an offset of 1 (2 varying slots) to skip unnecessary data: * - VARYING_SLOT_PSIZ and BRW_VARYING_SLOT_NDC on gen4-5 * - VARYING_SLOT_{PSIZ,LAYER} and VARYING_SLOT_POS on gen6+ */ bool fs_needs_vue_header = brw->fragment_program->info.inputs_read & (VARYING_BIT_LAYER | VARYING_BIT_VIEWPORT); *urb_entry_read_offset = fs_needs_vue_header ? 0 : 1; /* From the Ivybridge PRM, Vol 2 Part 1, 3DSTATE_SBE, * description of dw10 Point Sprite Texture Coordinate Enable: * * "This field must be programmed to zero when non-point primitives * are rendered." * * The SandyBridge PRM doesn't explicitly say that point sprite enables * must be programmed to zero when rendering non-point primitives, but * the IvyBridge PRM does, and if we don't, we get garbage. * * This is not required on Haswell, as the hardware ignores this state * when drawing non-points -- although we do still need to be careful to * correctly set the attr overrides. * * _NEW_POLYGON * BRW_NEW_PRIMITIVE | BRW_NEW_GS_PROG_DATA | BRW_NEW_TES_PROG_DATA */ bool drawing_points = brw_is_drawing_points(brw); /* Initialize all the attr_overrides to 0. In the loop below we'll modify * just the ones that correspond to inputs used by the fs. */ memset(attr_overrides, 0, 16*sizeof(*attr_overrides)); for (int attr = 0; attr < VARYING_SLOT_MAX; attr++) { int input_index = wm_prog_data->urb_setup[attr]; if (input_index < 0) continue; /* _NEW_POINT */ bool point_sprite = false; if (drawing_points) { if (brw->ctx.Point.PointSprite && (attr >= VARYING_SLOT_TEX0 && attr <= VARYING_SLOT_TEX7) && (brw->ctx.Point.CoordReplace & (1u << (attr - VARYING_SLOT_TEX0)))) { point_sprite = true; } if (attr == VARYING_SLOT_PNTC) point_sprite = true; if (point_sprite) *point_sprite_enables |= (1 << input_index); } /* BRW_NEW_VUE_MAP_GEOM_OUT | _NEW_LIGHT | _NEW_PROGRAM */ uint16_t attr_override = point_sprite ? 0 : get_attr_override(&brw->vue_map_geom_out, *urb_entry_read_offset, attr, brw->ctx.VertexProgram._TwoSideEnabled, &max_source_attr); /* The hardware can only do the overrides on 16 overrides at a * time, and the other up to 16 have to be lined up so that the * input index = the output index. We'll need to do some * tweaking to make sure that's the case. */ if (input_index < 16) attr_overrides[input_index] = attr_override; else assert(attr_override == input_index); } /* From the Sandy Bridge PRM, Volume 2, Part 1, documentation for * 3DSTATE_SF DWord 1 bits 15:11, "Vertex URB Entry Read Length": * * "This field should be set to the minimum length required to read the * maximum source attribute. The maximum source attribute is indicated * by the maximum value of the enabled Attribute # Source Attribute if * Attribute Swizzle Enable is set, Number of Output Attributes-1 if * enable is not set. * read_length = ceiling((max_source_attr + 1) / 2) * * [errata] Corruption/Hang possible if length programmed larger than * recommended" * * Similar text exists for Ivy Bridge. */ *urb_entry_read_length = ALIGN(max_source_attr + 1, 2) / 2; }