ebiten/opengl/context.go
2014-12-09 22:19:30 +09:00

102 lines
2.3 KiB
Go

package opengl
import (
"github.com/go-gl/gl"
"github.com/hajimehoshi/ebiten"
)
func Initialize(screenWidth, screenHeight, screenScale int) (*GraphicsContext, error) {
gl.Init()
gl.Enable(gl.TEXTURE_2D)
gl.Enable(gl.BLEND)
c := &GraphicsContext{
screenWidth: screenWidth,
screenHeight: screenHeight,
screenScale: screenScale,
}
// The defualt framebuffer should be 0.
c.defaultId = idsInstance.addRenderTarget(&renderTarget{
width: screenWidth * screenScale,
height: screenHeight * screenScale,
flipY: true,
})
var err error
c.screenId, err = idsInstance.createRenderTarget(screenWidth, screenHeight, ebiten.FilterNearest)
if err != nil {
return nil, err
}
c.ResetOffscreen()
c.Clear()
return c, nil
}
type GraphicsContext struct {
screenId ebiten.RenderTargetID
defaultId ebiten.RenderTargetID
currentId ebiten.RenderTargetID
screenWidth int
screenHeight int
screenScale int
}
var _ ebiten.GraphicsContext = new(GraphicsContext)
func (c *GraphicsContext) dispose() {
// NOTE: Now this method is not used anywhere.
idsInstance.deleteRenderTarget(c.screenId)
}
func (c *GraphicsContext) Clear() {
c.Fill(0, 0, 0)
}
func (c *GraphicsContext) Fill(r, g, b uint8) {
idsInstance.fillRenderTarget(c.currentId, r, g, b)
}
func (c *GraphicsContext) Texture(id ebiten.TextureID) ebiten.Drawer {
return &textureWithContext{id, c}
}
func (c *GraphicsContext) RenderTarget(id ebiten.RenderTargetID) ebiten.Drawer {
return &textureWithContext{idsInstance.toTexture(id), c}
}
func (c *GraphicsContext) ResetOffscreen() {
c.currentId = c.screenId
}
func (c *GraphicsContext) SetOffscreen(renderTargetId ebiten.RenderTargetID) {
c.currentId = renderTargetId
}
func (c *GraphicsContext) PreUpdate() {
c.ResetOffscreen()
c.Clear()
}
func (c *GraphicsContext) PostUpdate() {
c.SetOffscreen(c.defaultId)
c.Clear()
scale := float64(c.screenScale)
geo := ebiten.GeometryMatrixI()
geo.Scale(scale, scale)
ebiten.DrawWhole(c.RenderTarget(c.screenId), c.screenWidth, c.screenHeight, geo, ebiten.ColorMatrixI())
gl.Flush()
}
type textureWithContext struct {
id ebiten.TextureID
context *GraphicsContext
}
func (t *textureWithContext) Draw(parts []ebiten.TexturePart, geo ebiten.GeometryMatrix, color ebiten.ColorMatrix) {
idsInstance.drawTexture(t.context.currentId, t.id, parts, geo, color)
}