chromium/third_party/skia/src/gpu/graphite/DrawList.h

/*
 * Copyright 2021 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef skgpu_graphite_DrawList_DEFINED
#define skgpu_graphite_DrawList_DEFINED

#include "include/core/SkPaint.h"
#include "src/base/SkTBlockList.h"

#include "src/gpu/graphite/DrawOrder.h"
#include "src/gpu/graphite/DrawParams.h"
#include "src/gpu/graphite/PaintParams.h"
#include "src/gpu/graphite/geom/Geometry.h"
#include "src/gpu/graphite/geom/Rect.h"
#include "src/gpu/graphite/geom/Transform_graphite.h"

#include <limits>
#include <optional>

namespace skgpu::graphite {

class Renderer;

/**
 * A DrawList represents a collection of drawing commands (and related clip/shading state) in
 * a form that closely mirrors what can be rendered efficiently and directly by the GPU backend
 * (while balancing how much pre-processing to do for draws that might get eliminated later due to
 * occlusion culling).
 *
 * A draw command combines:
 *   - a shape
 *   - a transform
 *   - a primitive clip (not affected by the transform)
 *   - optional shading description (shader, color filter, blend mode, etc)
 *   - a draw ordering (compressed painters index, stencil set, and write/test depth)
 *
 * Commands are accumulated in an arbitrary order and then sorted by increasing sort z when the list
 * is prepared into an actual command buffer. The result of a draw command is the rasterization of
 * the transformed shape, restricted by its primitive clip (e.g. a scissor rect) and a depth test
 * of "GREATER" vs. its write/test z. (A test of GREATER, as opposed to GEQUAL, avoids double hits
 * for draws that may have overlapping geometry, e.g. stroking.) If the command has a shading
 * description, the color buffer will be modified; if not, it will be a depth-only draw.
 *
 * In addition to sorting the collected commands, the command list can be optimized during
 * preparation. Commands that are fully occluded by later operations can be skipped entirely without
 * affecting the final results. Adjacent commands (post sort) that would use equivalent GPU
 * pipelines are merged to produce fewer (but larger) operations on the GPU.
 *
 * Other than flush-time optimizations (sort, cull, and merge), the command list does what you tell
 * it to. Draw-specific simplification, style application, and advanced clipping should be handled
 * at a higher layer.
 */
class DrawList { … };

} // namespace skgpu::graphite

#endif // skgpu_graphite_DrawList_DEFINED