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// Copyright 2017 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef COBALT_RENDERER_RASTERIZER_EGL_DRAW_RECT_SHADOW_BLUR_H_
#define COBALT_RENDERER_RASTERIZER_EGL_DRAW_RECT_SHADOW_BLUR_H_
#include <vector>
#include "cobalt/math/rect_f.h"
#include "cobalt/render_tree/color_rgba.h"
#include "cobalt/renderer/rasterizer/egl/draw_object.h"
#include "egl/generated_shader_impl.h"
namespace cobalt {
namespace renderer {
namespace rasterizer {
namespace egl {
// Example CSS box shadow (outset):
// +-------------------------------------+
// | Box shadow "blur" region |
// | +-----------------------------+ |
// | | Box shadow "spread" region | |
// | | +---------------------+ | |
// | | | Box shadow rect | | |
// | | | (exclude geometry) | | |
// | | +---------------------+ | |
// | | | |
// | +-----------------------------+ |
// | (include scissor) |
// +-------------------------------------+
// NOTE: Despite the CSS naming, the actual blur effect starts inside the
// "spread" region.
// Handles drawing a box shadow with blur. This uses a gaussian kernel to fade
// the "blur" region.
class DrawRectShadowBlur : public DrawObject {
public:
// Draw a blurred box shadow.
// The box shadow exists in the area between |base_rect| and |spread_rect|
// extended (inset or outset accordingly) to cover the blur kernel.
DrawRectShadowBlur(GraphicsState* graphics_state, const BaseState& base_state,
const math::RectF& base_rect,
const OptionalRoundedCorners& base_corners,
const math::RectF& spread_rect,
const OptionalRoundedCorners& spread_corners,
const render_tree::ColorRGBA& color, float blur_sigma,
bool inset);
void ExecuteUpdateVertexBuffer(
GraphicsState* graphics_state,
ShaderProgramManager* program_manager) override;
void ExecuteRasterize(GraphicsState* graphics_state,
ShaderProgramManager* program_manager) override;
base::TypeId GetTypeId() const override;
private:
struct VertexAttributesSquare {
VertexAttributesSquare(float x, float y, float offset_scale);
float position[2];
float offset[2];
};
struct VertexAttributesRound {
VertexAttributesRound(float x, float y, float offset_scale,
const RCorner& rcorner);
float position[2];
float offset[2];
RCorner rcorner_scissor;
};
void SetupVertexShader(GraphicsState* graphics_state,
const ShaderVertexOffset& shader);
void SetupVertexShader(GraphicsState* graphics_state,
const ShaderVertexOffsetRcorner& shader);
void SetFragmentUniforms(GLint color_uniform, GLint scale_add_uniform);
void SetGeometry(GraphicsState* graphics_state, const math::RectF& base_rect,
const OptionalRoundedCorners& base_corners);
void SetGeometry(GraphicsState* graphics_state, const math::RectF& inner_rect,
const math::RectF& outer_rect);
void SetGeometry(GraphicsState* graphics_state,
const RRectAttributes (&rrect)[8]);
void SetGeometry(GraphicsState* graphics_state,
const RRectAttributes (&rrect_outer)[4],
const RRectAttributes (&rrect_inner)[8]);
void AddQuad(const math::RectF& rect, float scale, const RCorner& rcorner);
math::RectF spread_rect_;
OptionalRoundedCorners spread_corners_;
render_tree::ColorRGBA color_;
float blur_sigma_;
bool is_inset_;
std::vector<VertexAttributesSquare> attributes_square_;
std::vector<VertexAttributesRound> attributes_round_;
std::vector<uint16_t> indices_;
uint8_t* vertex_buffer_;
uint16_t* index_buffer_;
};
} // namespace egl
} // namespace rasterizer
} // namespace renderer
} // namespace cobalt
#endif // COBALT_RENDERER_RASTERIZER_EGL_DRAW_RECT_SHADOW_BLUR_H_