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09a7d39874
This is a preparation to specify blend factors and blend operators. Updates #2382
165 lines
5.7 KiB
Go
165 lines
5.7 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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"fmt"
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"github.com/hajimehoshi/ebiten/v2/internal/builtinshader"
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"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
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"github.com/hajimehoshi/ebiten/v2/internal/ui"
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)
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// Filter represents the type of texture 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 = Filter(builtinshader.FilterNearest)
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// FilterLinear represents linear filter
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FilterLinear Filter = Filter(builtinshader.FilterLinear)
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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 = iota
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// c_out = 0
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CompositeModeClear
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// c_out = c_src
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CompositeModeCopy
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// c_out = c_dst
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CompositeModeDestination
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// c_out = c_src × (1 - α_dst) + c_dst
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CompositeModeDestinationOver
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// c_out = c_src × α_dst
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CompositeModeSourceIn
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// c_out = c_dst × α_src
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CompositeModeDestinationIn
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// c_out = c_src × (1 - α_dst)
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CompositeModeSourceOut
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// c_out = c_dst × (1 - α_src)
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CompositeModeDestinationOut
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// c_out = c_src × α_dst + c_dst × (1 - α_src)
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CompositeModeSourceAtop
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// c_out = c_src × (1 - α_dst) + c_dst × α_src
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CompositeModeDestinationAtop
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// c_out = c_src × (1 - α_dst) + c_dst × (1 - α_src)
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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
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// The product of source and destination (a.k.a 'multiply blend mode')
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// c_out = c_src * c_dst
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CompositeModeMultiply
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)
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func (c CompositeMode) blend() graphicsdriver.Blend {
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src, dst := c.blendFactors()
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return graphicsdriver.Blend{
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BlendFactorSourceColor: src,
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BlendFactorSourceAlpha: src,
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BlendFactorDestinationColor: dst,
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BlendFactorDestinationAlpha: dst,
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BlendOperationColor: graphicsdriver.BlendOperationAdd,
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BlendOperationAlpha: graphicsdriver.BlendOperationAdd,
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}
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}
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func (c CompositeMode) blendFactors() (src graphicsdriver.BlendFactor, dst graphicsdriver.BlendFactor) {
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switch c {
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case CompositeModeSourceOver:
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return graphicsdriver.BlendFactorOne, graphicsdriver.BlendFactorOneMinusSourceAlpha
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case CompositeModeClear:
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return graphicsdriver.BlendFactorZero, graphicsdriver.BlendFactorZero
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case CompositeModeCopy:
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return graphicsdriver.BlendFactorOne, graphicsdriver.BlendFactorZero
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case CompositeModeDestination:
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return graphicsdriver.BlendFactorZero, graphicsdriver.BlendFactorOne
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case CompositeModeDestinationOver:
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return graphicsdriver.BlendFactorOneMinusDestinationAlpha, graphicsdriver.BlendFactorOne
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case CompositeModeSourceIn:
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return graphicsdriver.BlendFactorDestinationAlpha, graphicsdriver.BlendFactorZero
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case CompositeModeDestinationIn:
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return graphicsdriver.BlendFactorZero, graphicsdriver.BlendFactorSourceAlpha
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case CompositeModeSourceOut:
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return graphicsdriver.BlendFactorOneMinusDestinationAlpha, graphicsdriver.BlendFactorZero
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case CompositeModeDestinationOut:
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return graphicsdriver.BlendFactorZero, graphicsdriver.BlendFactorOneMinusSourceAlpha
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case CompositeModeSourceAtop:
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return graphicsdriver.BlendFactorDestinationAlpha, graphicsdriver.BlendFactorOneMinusSourceAlpha
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case CompositeModeDestinationAtop:
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return graphicsdriver.BlendFactorOneMinusDestinationAlpha, graphicsdriver.BlendFactorSourceAlpha
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case CompositeModeXor:
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return graphicsdriver.BlendFactorOneMinusDestinationAlpha, graphicsdriver.BlendFactorOneMinusSourceAlpha
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case CompositeModeLighter:
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return graphicsdriver.BlendFactorOne, graphicsdriver.BlendFactorOne
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case CompositeModeMultiply:
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return graphicsdriver.BlendFactorDestinationColor, graphicsdriver.BlendFactorZero
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default:
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panic(fmt.Sprintf("ebiten: invalid composite mode: %d", c))
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}
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}
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// GraphicsLibrary represets graphics libraries supported by the engine.
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type GraphicsLibrary = ui.GraphicsLibrary
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const (
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// GraphicsLibraryUnknown represents the state at which graphics library cannot be determined,
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// e.g. hasn't loaded yet or failed to initialize.
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GraphicsLibraryUnknown GraphicsLibrary = ui.GraphicsLibraryUnknown
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// GraphicsLibraryOpenGL represents the graphics library OpenGL.
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GraphicsLibraryOpenGL GraphicsLibrary = ui.GraphicsLibraryOpenGL
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// GraphicsLibraryDirectX represents the graphics library Microsoft DirectX.
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GraphicsLibraryDirectX GraphicsLibrary = ui.GraphicsLibraryDirectX
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// GraphicsLibraryMetal represents the graphics library Apple's Metal.
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GraphicsLibraryMetal GraphicsLibrary = ui.GraphicsLibraryMetal
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)
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// DebugInfo is a struct to store debug info about the graphics.
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type DebugInfo struct {
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// GraphicsLibrary represents the graphics library currently in use.
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GraphicsLibrary GraphicsLibrary
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}
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// ReadDebugInfo writes debug info (e.g. current graphics library) into a provided struct.
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func ReadDebugInfo(d *DebugInfo) {
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d.GraphicsLibrary = ui.GetGraphicsLibrary()
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}
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