mirror of
https://github.com/hajimehoshi/ebiten.git
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91 lines
2.9 KiB
Go
91 lines
2.9 KiB
Go
// Copyright 2014 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ebiten
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import (
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"github.com/hajimehoshi/ebiten/internal/opengl"
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)
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// Filter represents the type of filter to be used when an image is maginified or minified.
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type Filter int
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const (
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// FilterNearest represents nearest (crisp-edged) filter
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FilterNearest Filter = iota
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// FilterLinear represents linear filter
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FilterLinear
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)
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func glFilter(filter Filter) opengl.Filter {
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switch filter {
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case FilterNearest:
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return opengl.Nearest
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case FilterLinear:
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return opengl.Linear
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}
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panic("not reach")
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}
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// CompositeMode represents Porter-Duff composition mode.
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type CompositeMode int
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// This name convention follows CSS compositing: https://drafts.fxtf.org/compositing-2/.
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//
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// In the comments,
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// c_src, c_dst and c_out represent alpha-premultiplied RGB values of source, destination and output respectively. α_src and α_dst represent alpha values of source and destination respectively.
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const (
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// Regular alpha blending
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// c_out = c_src + c_dst × (1 - α_src)
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CompositeModeSourceOver CompositeMode = CompositeMode(opengl.CompositeModeSourceOver)
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// c_out = 0
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CompositeModeClear = CompositeMode(opengl.CompositeModeClear)
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// c_out = c_src
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CompositeModeCopy = CompositeMode(opengl.CompositeModeCopy)
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// c_out = c_dst
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CompositeModeDestination = CompositeMode(opengl.CompositeModeDestination)
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// c_out = c_src × (1 - α_dst) + c_dst
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CompositeModeDestinationOver = CompositeMode(opengl.CompositeModeDestinationOver)
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// c_out = c_src × α_dst
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CompositeModeSourceIn = CompositeMode(opengl.CompositeModeSourceIn)
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// c_out = c_dst × α_src
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CompositeModeDestinationIn = CompositeMode(opengl.CompositeModeDestinationIn)
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// c_out = c_src × (1 - α_dst)
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CompositeModeSourceOut = CompositeMode(opengl.CompositeModeSourceOut)
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// c_out = c_dst × (1 - α_src)
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CompositeModeDestinationOut = CompositeMode(opengl.CompositeModeDestinationOut)
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// c_out = c_src × α_dst + c_dst × (1 - α_src)
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CompositeModeSourceAtop = CompositeMode(opengl.CompositeModeSourceAtop)
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// c_out = c_src × (1 - α_dst) + c_dst × α_src
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CompositeModeDestinationAtop = CompositeMode(opengl.CompositeModeDestinationAtop)
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// c_out = c_src × (1 - α_dst) + c_dst × (1 - α_src)
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CompositeModeXor = CompositeMode(opengl.CompositeModeXor)
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// Sum of source and destination (a.k.a. 'plus' or 'additive')
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// c_out = c_src + c_dst
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CompositeModeLighter = CompositeMode(opengl.CompositeModeLighter)
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)
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