145 lines
3.5 KiB
Go
145 lines
3.5 KiB
Go
package system
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import (
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_ "image/png"
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"time"
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"golang.org/x/image/colornames"
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"code.rocketnine.space/tslocum/monovania/world"
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"code.rocketnine.space/tslocum/gohan"
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"code.rocketnine.space/tslocum/monovania/component"
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"github.com/hajimehoshi/ebiten/v2"
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)
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const TileWidth = 16
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var CamX, CamY float64
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type RenderSystem struct {
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ScreenW int
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ScreenH int
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op *ebiten.DrawImageOptions
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camScale float64
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renderer gohan.Entity
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debugImg *ebiten.Image
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}
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func NewRenderSystem() *RenderSystem {
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s := &RenderSystem{
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renderer: gohan.NewEntity(),
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op: &ebiten.DrawImageOptions{},
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camScale: 4,
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}
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return s
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}
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func (s *RenderSystem) Matches(entity gohan.Entity) bool {
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position := component.Position(entity)
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sprite := component.Sprite(entity)
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return position != nil && sprite != nil
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}
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func (s *RenderSystem) Update(_ gohan.Entity) error {
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return gohan.ErrSystemWithoutUpdate
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}
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func (s *RenderSystem) levelCoordinatesToScreen(x, y float64) (float64, float64) {
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px, py := CamX, CamY
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py *= -1
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return ((x - px) * s.camScale) + float64(s.ScreenW/2.0), ((y + py) * s.camScale) + float64(s.ScreenH/2.0)
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}
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// renderSprite renders a sprite on the screen.
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func (s *RenderSystem) renderSprite(x float64, y float64, offsetx float64, offsety float64, angle float64, geoScale float64, colorScale float64, alpha float64, hFlip bool, vFlip bool, sprite *ebiten.Image, target *ebiten.Image) int {
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if alpha < .01 || colorScale < .01 {
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return 0
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}
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// Skip drawing off-screen tiles.
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drawX, drawY := s.levelCoordinatesToScreen(x, y)
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padding := float64(TileWidth) * 2
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w, h := sprite.Size()
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width, height := float64(w), float64(h)
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left := drawX
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right := drawX + width
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top := drawY
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bottom := drawY + height
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if (left < -padding || left > float64(s.ScreenW)+padding) && (top < -padding || top > float64(s.ScreenH)+padding) &&
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(right < -padding || right > float64(s.ScreenW)+padding) && (bottom < -padding || bottom > float64(s.ScreenH)+padding) {
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return 0
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}
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s.op.GeoM.Reset()
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if hFlip {
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s.op.GeoM.Scale(-1, 1)
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s.op.GeoM.Translate(16, 0)
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}
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if vFlip {
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s.op.GeoM.Scale(1, -1)
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s.op.GeoM.Translate(0, 16)
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}
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s.op.GeoM.Scale(geoScale, geoScale)
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// Rotate
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s.op.GeoM.Translate(offsetx, offsety)
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s.op.GeoM.Rotate(angle)
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// Move to current isometric position.
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s.op.GeoM.Translate(x, y)
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// Translate camera position.
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s.op.GeoM.Translate(-CamX, -CamY)
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// Zoom.
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s.op.GeoM.Scale(s.camScale, s.camScale)
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// Center.
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s.op.GeoM.Translate(float64(s.ScreenW/2.0), float64(s.ScreenH/2.0))
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s.op.ColorM.Scale(colorScale, colorScale, colorScale, alpha)
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// Apply monochrome filter.
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//s.op.ColorM.ChangeHSV(1, 0, 1)
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target.DrawImage(sprite, s.op)
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s.op.ColorM.Reset()
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return 1
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}
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func (s *RenderSystem) Draw(entity gohan.Entity, screen *ebiten.Image) error {
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if world.World.GameOver {
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if entity == world.World.Player {
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screen.Fill(colornames.Darkred)
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}
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return nil
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}
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position := component.Position(entity)
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sprite := component.Sprite(entity)
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if sprite.NumFrames > 0 && time.Since(sprite.LastFrame) > sprite.FrameTime {
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sprite.Frame++
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if sprite.Frame >= sprite.NumFrames {
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sprite.Frame = 0
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}
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sprite.Image = sprite.Frames[sprite.Frame]
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sprite.LastFrame = time.Now()
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}
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colorScale := 1.0
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if sprite.OverrideColorScale {
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colorScale = sprite.ColorScale
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}
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// TODO
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var drawn int
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drawn += s.renderSprite(position.X+world.World.OffsetX, position.Y+world.World.OffsetY, 0, 0, 0, 1.0, colorScale, 1.0, sprite.HorizontalFlip, sprite.VerticalFlip, sprite.Image, screen)
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return nil
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}
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