91 lines
2.9 KiB
Go
91 lines
2.9 KiB
Go
package tins2020
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import (
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"log"
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"github.com/veandco/go-sdl2/sdl"
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)
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type projection struct {
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center PointF
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zoom float32
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zoomInv float32
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windowRect sdl.Rect
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tileScreenDelta PointF
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tileScreenDeltaInv PointF
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tileScreenOffset Point
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tileScreenSize Point
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tileFitScreenSize Point
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windowCenter Point
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}
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func newProjection() projection {
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return projection{zoom: 1, tileScreenDelta: PtF(65, 32), tileScreenDeltaInv: PtF(1./65, 1./32)}
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}
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func (p *projection) mapToScreen(x, y int32) Point {
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return p.mapToScreenF(float32(x), float32(y))
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}
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func (p *projection) mapToScreenF(x, y float32) Point {
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translated := PtF(x-p.center.X, y-p.center.Y)
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return Pt(p.windowCenter.X+int32((translated.X-translated.Y)*65*p.zoomInv), p.windowCenter.Y+int32((translated.X+translated.Y)*32*p.zoomInv))
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}
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func (p *projection) screenToMap(x, y int32) PointF {
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pos := p.screenToMapRel(x-p.windowCenter.X, y-p.windowCenter.Y)
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return p.center.Add(pos)
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}
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func (p *projection) screenToMapRel(x, y int32) PointF {
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normX := p.zoom * float32(x)
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normY := p.zoom * float32(y)
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return PtF(.5*(p.tileScreenDeltaInv.X*normX+p.tileScreenDeltaInv.Y*normY), .5*(-p.tileScreenDeltaInv.X*normX+p.tileScreenDeltaInv.Y*normY))
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}
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func (p *projection) screenToTileFitRect(pos Point) *sdl.Rect {
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return &sdl.Rect{X: pos.X - p.tileFitScreenSize.X, Y: pos.Y - p.tileFitScreenSize.Y, W: 2 * p.tileFitScreenSize.X, H: 2 * p.tileFitScreenSize.Y}
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}
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func (p *projection) screenToTileRect(pos Point) *sdl.Rect {
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return &sdl.Rect{X: pos.X - p.tileScreenOffset.X, Y: pos.Y - p.tileScreenOffset.Y, W: p.tileScreenSize.X, H: p.tileScreenSize.Y}
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}
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func (p *projection) update(renderer *sdl.Renderer) {
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p.zoomInv = 1 / p.zoom
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p.tileScreenOffset = Pt(int32(p.zoomInv*256), int32(p.zoomInv*300))
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p.tileScreenSize = Pt(int32(p.zoomInv*512), int32(p.zoomInv*512))
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p.tileFitScreenSize = Pt(int32(p.zoomInv*65), int32(p.zoomInv*32))
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windowW, windowH, err := renderer.GetOutputSize()
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if err != nil {
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log.Fatal(err)
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}
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p.windowCenter = Pt(windowW/2, windowH/2)
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p.windowRect = sdl.Rect{X: 0, Y: 0, W: windowW - 0, H: windowH - 0}
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}
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func (p *projection) visibleTiles(action func(int32, int32, Point)) {
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topLeft := p.screenToMap(p.windowRect.X, p.windowRect.Y)
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topRight := p.screenToMap(p.windowRect.X+p.windowRect.W, p.windowRect.Y)
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bottomLeft := p.screenToMap(p.windowRect.X, p.windowRect.Y+p.windowRect.H)
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bottomRight := p.screenToMap(p.windowRect.X+p.windowRect.W, p.windowRect.Y+p.windowRect.H)
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minY, maxY := int32(Floor32(topRight.Y)), int32(Ceil32(bottomLeft.Y))
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minX, maxX := int32(Floor32(topLeft.X)), int32(Ceil32(bottomRight.X))
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for y := minY; y <= maxY; y++ {
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for x := minX; x <= maxX; x++ {
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pos := p.mapToScreen(x, y)
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rectFit := p.screenToTileFitRect(pos)
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if rectFit.X+rectFit.W < p.windowRect.X || rectFit.Y+rectFit.H < p.windowRect.Y {
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continue
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}
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if rectFit.X > p.windowRect.X+p.windowRect.W || rectFit.Y > p.windowRect.Y+p.windowRect.H {
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break
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}
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action(x, y, pos)
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}
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}
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}
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