/* * © Copyright 2018 Alyssa Rosenzweig * * 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 #include "pan_blending.h" #include "pan_context.h" #include "gallium/auxiliary/util/u_blend.h" /* * Implements fixed-function blending on Midgard. * * Midgard splits blending into a fixed-function fast path and a programmable * slow path. The fixed function blending architecture is based on "dominant" * blend factors. Blending is encoded separately (but identically) between RGB * and alpha functions. * * Essentially, for a given blending operation, there is a single dominant * factor. The following dominant factors are possible: * * - zero * - source color * - destination color * - source alpha * - destination alpha * - constant float * * Further, a dominant factor's arithmetic compliment could be used. For * instance, to encode GL_ONE_MINUS_SOURCE_ALPHA, the dominant factor would be * MALI_DOMINANT_SRC_ALPHA with the complement_dominant bit set. * * A single constant float can be passed to the fixed-function hardware, * allowing CONSTANT_ALPHA support. Further, if all components of the constant * glBlendColor are identical, CONSTANT_COLOR can be implemented with the * constant float mode. If the components differ, programmable blending is * required. * * The nondominant factor can be either: * * - the same as the dominant factor (MALI_BLEND_NON_MIRROR) * - zero (MALI_BLEND_NON_ZERO) * * Exactly one of the blend operation's source or destination can be used as * the dominant factor; this is selected by the * MALI_BLEND_DOM_SOURCE/DESTINATION flag. * * By default, all blending follows the standard OpenGL addition equation: * * out = source_value * source_factor + destination_value * destination_factor * * By setting the negate_source or negate_dest bits, other blend functions can * be created. For instance, for SUBTRACT mode, set the "negate destination" * flag, and similarly for REVERSE_SUBTRACT with "negate source". * * Finally, there is a "clip modifier" controlling the final blending * behaviour, allowing for the following modes: * * - normal * - force source factor to one (MALI_BLEND_MODE_SOURCE_ONE) * - force destination factor to one (MALI_BLEND_MODE_DEST_ONE) * * The clipping flags can be used to encode blend modes where the nondominant * factor is ONE. * * As an example putting it all together, to encode the following blend state: * * glBlendEquation(GL_FUNC_REVERSE_SUBTRACT); * glBlendFunc(GL_ONE_MINUS_SRC_ALPHA, GL_ONE); * * We need the following configuration: * * - negate source (for REVERSE_SUBTRACT) * - dominant factor "source alpha" * - complement dominant * - source dominant * - force destination to ONE * * The following routines implement this fixed function blending encoding */ /* Helper to find the uncomplemented Gallium blend factor corresponding to a * complemented Gallium blend factor */ static int complement_factor(int factor) { switch (factor) { case PIPE_BLENDFACTOR_INV_SRC_COLOR: return PIPE_BLENDFACTOR_SRC_COLOR; case PIPE_BLENDFACTOR_INV_SRC_ALPHA: return PIPE_BLENDFACTOR_SRC_ALPHA; case PIPE_BLENDFACTOR_INV_DST_ALPHA: return PIPE_BLENDFACTOR_DST_ALPHA; case PIPE_BLENDFACTOR_INV_DST_COLOR: return PIPE_BLENDFACTOR_DST_COLOR; case PIPE_BLENDFACTOR_INV_CONST_COLOR: return PIPE_BLENDFACTOR_CONST_COLOR; case PIPE_BLENDFACTOR_INV_CONST_ALPHA: return PIPE_BLENDFACTOR_CONST_ALPHA; default: return -1; } } /* Helper to strip the complement from any Gallium blend factor */ static int uncomplement_factor(int factor) { int complement = complement_factor(factor); return (complement == -1) ? factor : complement; } /* Attempt to find the dominant factor given a particular factor, complementing * as necessary */ static bool panfrost_make_dominant_factor(unsigned src_factor, enum mali_dominant_factor *factor) { switch (src_factor) { case PIPE_BLENDFACTOR_SRC_COLOR: case PIPE_BLENDFACTOR_INV_SRC_COLOR: *factor = MALI_DOMINANT_SRC_COLOR; break; case PIPE_BLENDFACTOR_SRC_ALPHA: case PIPE_BLENDFACTOR_INV_SRC_ALPHA: *factor = MALI_DOMINANT_SRC_ALPHA; break; case PIPE_BLENDFACTOR_DST_COLOR: case PIPE_BLENDFACTOR_INV_DST_COLOR: *factor = MALI_DOMINANT_DST_COLOR; break; case PIPE_BLENDFACTOR_DST_ALPHA: case PIPE_BLENDFACTOR_INV_DST_ALPHA: *factor = MALI_DOMINANT_DST_ALPHA; break; case PIPE_BLENDFACTOR_ONE: case PIPE_BLENDFACTOR_ZERO: *factor = MALI_DOMINANT_ZERO; break; case PIPE_BLENDFACTOR_CONST_ALPHA: case PIPE_BLENDFACTOR_INV_CONST_ALPHA: case PIPE_BLENDFACTOR_CONST_COLOR: case PIPE_BLENDFACTOR_INV_CONST_COLOR: *factor = MALI_DOMINANT_CONSTANT; break; default: /* Fancy blend modes not supported */ return false; } return true; } /* Check if this is a special edge case blend factor, which may require the use * of clip modifiers */ static bool is_edge_blendfactor(unsigned factor) { return factor == PIPE_BLENDFACTOR_ONE || factor == PIPE_BLENDFACTOR_ZERO; } /* Perform the actual fixed function encoding. Encode the function with negate * bits. Check for various cases to work out the dominant/nondominant split and * accompanying flags. */ static bool panfrost_make_fixed_blend_part(unsigned func, unsigned src_factor, unsigned dst_factor, unsigned *out) { struct mali_blend_mode part = { 0 }; /* Make sure that the blend function is representible */ switch (func) { case PIPE_BLEND_ADD: break; /* TODO: Reenable subtraction modes when those fixed */ case PIPE_BLEND_SUBTRACT: case PIPE_BLEND_REVERSE_SUBTRACT: default: return false; } part.clip_modifier = MALI_BLEND_MOD_NORMAL; /* Decide which is dominant, source or destination. If one is an edge * case, use the other as a factor. If they're the same, it doesn't * matter; we just mirror. If they're different non-edge-cases, you * need a blend shader (don't do that). */ if (is_edge_blendfactor(dst_factor)) { part.dominant = MALI_BLEND_DOM_SOURCE; part.nondominant_mode = MALI_BLEND_NON_ZERO; if (dst_factor == PIPE_BLENDFACTOR_ONE) part.clip_modifier = MALI_BLEND_MOD_DEST_ONE; } else if (is_edge_blendfactor(src_factor)) { part.dominant = MALI_BLEND_DOM_DESTINATION; part.nondominant_mode = MALI_BLEND_NON_ZERO; if (src_factor == PIPE_BLENDFACTOR_ONE) part.clip_modifier = MALI_BLEND_MOD_SOURCE_ONE; } else if (src_factor == dst_factor) { /* XXX: Why? */ part.dominant = func == PIPE_BLEND_ADD ? MALI_BLEND_DOM_DESTINATION : MALI_BLEND_DOM_SOURCE; part.nondominant_mode = MALI_BLEND_NON_MIRROR; } else if (src_factor == complement_factor(dst_factor)) { /* TODO: How does this work exactly? */ part.dominant = MALI_BLEND_DOM_SOURCE; part.nondominant_mode = MALI_BLEND_NON_MIRROR; part.clip_modifier = MALI_BLEND_MOD_DEST_ONE; /* The complement is handled by the clip modifier, don't set a * complement flag */ dst_factor = src_factor; } else if (dst_factor == complement_factor(src_factor)) { part.dominant = MALI_BLEND_DOM_SOURCE; part.nondominant_mode = MALI_BLEND_NON_MIRROR; part.clip_modifier = MALI_BLEND_MOD_SOURCE_ONE; src_factor = dst_factor; } else { return false; } unsigned in_dominant_factor = part.dominant == MALI_BLEND_DOM_SOURCE ? src_factor : dst_factor; if (part.clip_modifier == MALI_BLEND_MOD_NORMAL && in_dominant_factor == PIPE_BLENDFACTOR_ONE) { part.clip_modifier = part.dominant == MALI_BLEND_DOM_SOURCE ? MALI_BLEND_MOD_SOURCE_ONE : MALI_BLEND_MOD_DEST_ONE; in_dominant_factor = PIPE_BLENDFACTOR_ZERO; } enum mali_dominant_factor dominant_factor; if (!panfrost_make_dominant_factor(in_dominant_factor, &dominant_factor)) return false; part.dominant_factor = dominant_factor; part.complement_dominant = util_blend_factor_is_inverted(in_dominant_factor); /* It's not clear what this does, but fixes some ADD blending tests. * More research is needed XXX */ if ((part.clip_modifier == MALI_BLEND_MOD_SOURCE_ONE) && (part.dominant == MALI_BLEND_DOM_SOURCE)) part.negate_dest = true; /* Write out mode */ memcpy(out, &part, sizeof(part)); return true; } /* We can upload a single constant for all of the factors. So, scan the factors * for constants used, and scan the constants for the constants used. If there * is a single unique constant, output that. If there are multiple, * fixed-function operation breaks down. */ static bool panfrost_make_constant(unsigned *factors, unsigned num_factors, const struct pipe_blend_color *blend_color, void *out) { /* Color components used */ bool cc[4] = { false }; for (unsigned i = 0; i < num_factors; ++i) { unsigned factor = uncomplement_factor(factors[i]); if (factor == PIPE_BLENDFACTOR_CONST_COLOR) cc[0] = cc[1] = cc[2] = true; else if (factor == PIPE_BLENDFACTOR_CONST_ALPHA) cc[3] = true; } /* Find the actual constant associated with the components used*/ float constant = 0.0; bool has_constant = false; for (unsigned i = 0; i < 4; ++i) { /* If the component is unused, nothing to do */ if (!cc[i]) continue; float value = blend_color->color[i]; /* Either there's a second constant, in which case we fail, or * there's no constant / a first constant, in which case we use * that constant */ if (has_constant && constant != value) { return false; } else { has_constant = true; constant = value; } } /* We have the constant -- success! */ memcpy(out, &constant, sizeof(float)); return true; } /* Create the descriptor for a fixed blend mode given the corresponding Gallium * state, if possible. Return true and write out the blend descriptor into * blend_equation. If it is not possible with the fixed function * representating, return false to handle degenerate cases with a blend shader */ bool panfrost_make_fixed_blend_mode(const struct pipe_rt_blend_state *blend, struct panfrost_blend_state *so, unsigned colormask, const struct pipe_blend_color *blend_color) { struct mali_blend_equation *out = &so->equation; /* Gallium and Mali represent colour masks identically. XXX: Static assert for future proof */ out->color_mask = colormask; /* If no blending is enabled, default back on `replace` mode */ if (!blend->blend_enable) { out->rgb_mode = 0x122; out->alpha_mode = 0x122; return true; } /* We have room only for a single float32 constant between the four * components. If we need more, spill to the programmable pipeline. */ unsigned factors[] = { blend->rgb_src_factor, blend->rgb_dst_factor, blend->alpha_src_factor, blend->alpha_dst_factor, }; if (!panfrost_make_constant(factors, ARRAY_SIZE(factors), blend_color, &so->constant)) return false; unsigned rgb_mode = 0; unsigned alpha_mode = 0; if (!panfrost_make_fixed_blend_part( blend->rgb_func, blend->rgb_src_factor, blend->rgb_dst_factor, &rgb_mode)) return false; if (!panfrost_make_fixed_blend_part( blend->alpha_func, blend->alpha_src_factor, blend->alpha_dst_factor, &alpha_mode)) return false; out->rgb_mode = rgb_mode; out->alpha_mode = alpha_mode; return true; }