SkRasterPipeline.h revision b0b17d1e5375a65b8956a8990d63e0d02357fdaf
1/* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#ifndef SkRasterPipeline_DEFINED 9#define SkRasterPipeline_DEFINED 10 11#include "SkNx.h" 12#include "SkTArray.h" 13#include "SkTypes.h" 14#include <functional> 15#include <vector> 16 17/** 18 * SkRasterPipeline provides a cheap way to chain together a pixel processing pipeline. 19 * 20 * It's particularly designed for situations where the potential pipeline is extremely 21 * combinatoric: {N dst formats} x {M source formats} x {K mask formats} x {C transfer modes} ... 22 * No one wants to write specialized routines for all those combinations, and if we did, we'd 23 * end up bloating our code size dramatically. SkRasterPipeline stages can be chained together 24 * at runtime, so we can scale this problem linearly rather than combinatorically. 25 * 26 * Each stage is represented by a function conforming to a common interface, SkRasterPipeline::Fn, 27 * and by an arbitrary context pointer. Fn's arguments, and sometimes custom calling convention, 28 * are designed to maximize the amount of data we can pass along the pipeline cheaply. 29 * On many machines all arguments stay in registers the entire time. 30 * 31 * The meaning of the arguments to Fn are sometimes fixed: 32 * - The Stage* always represents the current stage, mainly providing access to ctx(). 33 * - The first size_t is always the destination x coordinate. 34 * (If you need y, put it in your context.) 35 * - The second size_t is always tail: 0 when working on a full 4-pixel slab, 36 * or 1..3 when using only the bottom 1..3 lanes of each register. 37 * - By the time the shader's done, the first four vectors should hold source red, 38 * green, blue, and alpha, up to 4 pixels' worth each. 39 * 40 * Sometimes arguments are flexible: 41 * - In the shader, the first four vectors can be used for anything, e.g. sample coordinates. 42 * - The last four vectors are scratch registers that can be used to communicate between 43 * stages; transfer modes use these to hold the original destination pixel components. 44 * 45 * On some platforms the last four vectors are slower to work with than the other arguments. 46 * 47 * When done mutating its arguments and/or context, a stage can either: 48 * 1) call st->next() with its mutated arguments, chaining to the next stage of the pipeline; or 49 * 2) return, indicating the pipeline is complete for these pixels. 50 * 51 * Some stages that typically return are those that write a color to a destination pointer, 52 * but any stage can short-circuit the rest of the pipeline by returning instead of calling next(). 53 */ 54 55// TODO: There may be a better place to stuff tail, e.g. in the bottom alignment bits of 56// the Stage*. This mostly matters on 64-bit Windows where every register is precious. 57 58#define SK_RASTER_PIPELINE_STAGES(M) \ 59 M(trace) M(registers) \ 60 M(move_src_dst) M(move_dst_src) M(swap_rb) M(swap_rb_d) \ 61 M(clamp_0) M(clamp_a) M(clamp_1) \ 62 M(unpremul) M(premul) \ 63 M(set_rgb) \ 64 M(from_srgb) M(from_srgb_d) M(to_srgb) \ 65 M(to_2dot2) \ 66 M(constant_color) M(store_f32) \ 67 M(load_565) M(load_565_d) M(store_565) \ 68 M(load_f16) M(load_f16_d) M(store_f16) \ 69 M(load_8888) M(load_8888_d) M(store_8888) \ 70 M(load_tables) M(store_tables) \ 71 M(scale_u8) M(scale_1_float) \ 72 M(lerp_u8) M(lerp_565) M(lerp_1_float) \ 73 M(dstatop) M(dstin) M(dstout) M(dstover) \ 74 M(srcatop) M(srcin) M(srcout) M(srcover) \ 75 M(clear) M(modulate) M(multiply) M(plus_) M(screen) M(xor_) \ 76 M(colorburn) M(colordodge) M(darken) M(difference) \ 77 M(exclusion) M(hardlight) M(lighten) M(overlay) M(softlight) \ 78 M(luminance_to_alpha) \ 79 M(matrix_2x3) M(matrix_3x4) M(matrix_4x5) \ 80 M(matrix_perspective) \ 81 M(parametric_r) M(parametric_g) M(parametric_b) \ 82 M(parametric_a) \ 83 M(table_r) M(table_g) M(table_b) M(table_a) \ 84 M(color_lookup_table) M(lab_to_xyz) \ 85 M(clamp_x) M(mirror_x) M(repeat_x) \ 86 M(clamp_y) M(mirror_y) M(repeat_y) \ 87 M(gather_a8) M(gather_g8) M(gather_i8) \ 88 M(gather_565) M(gather_4444) M(gather_8888) M(gather_f16) \ 89 M(bilinear_nx) M(bilinear_px) M(bilinear_ny) M(bilinear_py) \ 90 M(bicubic_n3x) M(bicubic_n1x) M(bicubic_p1x) M(bicubic_p3x) \ 91 M(bicubic_n3y) M(bicubic_n1y) M(bicubic_p1y) M(bicubic_p3y) \ 92 M(save_xy) M(accumulate) 93 94class SkRasterPipeline { 95public: 96 SkRasterPipeline(); 97 98 enum StockStage { 99 #define M(stage) stage, 100 SK_RASTER_PIPELINE_STAGES(M) 101 #undef M 102 }; 103 void append(StockStage, void* = nullptr); 104 void append(StockStage stage, const void* ctx) { this->append(stage, const_cast<void*>(ctx)); } 105 106 // Append all stages to this pipeline. 107 void extend(const SkRasterPipeline&); 108 109 // Runs the pipeline walking x through [x,x+n), holding y constant. 110 void run(size_t x, size_t y, size_t n) const; 111 112 // If you're going to run() the pipeline more than once, it's best to compile it. 113 std::function<void(size_t x, size_t y, size_t n)> compile() const; 114 115 void dump() const; 116 117 struct Stage { 118 StockStage stage; 119 void* ctx; 120 }; 121 122private: 123 std::vector<Stage> fStages; 124}; 125 126#endif//SkRasterPipeline_DEFINED 127