mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-11-10 04:57:26 +01:00
126 lines
2.3 KiB
Go
126 lines
2.3 KiB
Go
// Copyright 2019 The Ebiten Authors
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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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"sync"
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"github.com/hajimehoshi/ebiten/internal/graphics"
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)
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var (
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theVerticesBackend = &verticesBackend{}
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)
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type verticesBackend struct {
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backend []float32
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head int
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m sync.Mutex
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}
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func (v *verticesBackend) slice(n int) []float32 {
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v.m.Lock()
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need := n * graphics.VertexFloatNum
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if v.head+need > len(v.backend) {
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v.backend = nil
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v.head = 0
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}
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if v.backend == nil {
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l := 1024
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if n > l {
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l = n
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}
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v.backend = make([]float32, graphics.VertexFloatNum*l)
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}
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s := v.backend[v.head : v.head+need]
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v.head += need
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v.m.Unlock()
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return s
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}
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func vertexSlice(n int) []float32 {
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return theVerticesBackend.slice(n)
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}
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func quadVertices(sx0, sy0, sx1, sy1 int, a, b, c, d, tx, ty float32, cr, cg, cb, ca float32) []float32 {
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x := float32(sx1 - sx0)
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y := float32(sy1 - sy0)
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ax, by, cx, dy := a*x, b*y, c*x, d*y
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u0, v0, u1, v1 := float32(sx0), float32(sy0), float32(sx1), float32(sy1)
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// This function is very performance-sensitive and implement in a very dumb way.
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vs := vertexSlice(4)
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_ = vs[:48]
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// For each values, see the comment at shareable.(*Image).DrawTriangles.
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vs[0] = tx
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vs[1] = ty
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vs[2] = u0
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vs[3] = v0
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vs[4] = u0
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vs[5] = v0
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vs[6] = u1
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vs[7] = v1
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vs[8] = cr
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vs[9] = cg
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vs[10] = cb
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vs[11] = ca
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vs[12] = ax + tx
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vs[13] = cx + ty
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vs[14] = u1
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vs[15] = v0
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vs[16] = u0
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vs[17] = v0
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vs[18] = u1
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vs[19] = v1
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vs[20] = cr
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vs[21] = cg
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vs[22] = cb
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vs[23] = ca
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vs[24] = by + tx
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vs[25] = dy + ty
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vs[26] = u0
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vs[27] = v1
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vs[28] = u0
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vs[29] = v0
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vs[30] = u1
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vs[31] = v1
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vs[32] = cr
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vs[33] = cg
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vs[34] = cb
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vs[35] = ca
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vs[36] = ax + by + tx
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vs[37] = cx + dy + ty
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vs[38] = u1
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vs[39] = v1
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vs[40] = u0
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vs[41] = v0
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vs[42] = u1
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vs[43] = v1
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vs[44] = cr
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vs[45] = cg
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vs[46] = cb
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vs[47] = ca
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return vs
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}
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