ebiten/graphics/opengl/context.go
2014-12-07 05:21:20 +09:00

115 lines
2.5 KiB
Go

package opengl
import (
"github.com/go-gl/gl"
"github.com/hajimehoshi/ebiten/graphics"
"github.com/hajimehoshi/ebiten/graphics/matrix"
"github.com/hajimehoshi/ebiten/ui"
"sync"
)
func flush() {
gl.Flush()
}
var onceInit sync.Once
type Context struct {
screenId graphics.RenderTargetID
defaultId graphics.RenderTargetID
currentId graphics.RenderTargetID
screenWidth int
screenHeight int
screenScale int
}
func NewContext(screenWidth, screenHeight, screenScale int) *Context {
onceInit.Do(func() {
gl.Init()
gl.Enable(gl.TEXTURE_2D)
gl.Enable(gl.BLEND)
})
context := &Context{
screenWidth: screenWidth,
screenHeight: screenHeight,
screenScale: screenScale,
}
defaultRenderTarget := &RenderTarget{
width: screenWidth * screenScale,
height: screenHeight * screenScale,
flipY: true,
}
context.defaultId = idsInstance.addRenderTarget(defaultRenderTarget)
var err error
context.screenId, err = idsInstance.createRenderTarget(screenWidth, screenHeight, graphics.FilterNearest)
if err != nil {
panic("initializing the offscreen failed: " + err.Error())
}
context.ResetOffscreen()
context.Clear()
return context
}
func (c *Context) Dispose() {
// TODO: remove the default framebuffer?
idsInstance.deleteRenderTarget(c.screenId)
}
// TODO: This interface is confusing: Can we change this?
func (c *Context) Update(drawer ui.Drawer) error {
c.ResetOffscreen()
c.Clear()
if err := drawer.Draw(c); err != nil {
return err
}
c.SetOffscreen(c.defaultId)
c.Clear()
scale := float64(c.screenScale)
geo := matrix.GeometryI()
geo.Scale(scale, scale)
graphics.DrawWhole(c.RenderTarget(c.screenId), c.screenWidth, c.screenHeight, geo, matrix.ColorI())
flush()
return nil
}
func (c *Context) Clear() {
c.Fill(0, 0, 0)
}
func (c *Context) Fill(r, g, b uint8) {
idsInstance.fillRenderTarget(c.currentId, r, g, b)
}
func (c *Context) Texture(id graphics.TextureID) graphics.Drawer {
return &textureWithContext{id, c}
}
func (c *Context) RenderTarget(id graphics.RenderTargetID) graphics.Drawer {
return &textureWithContext{idsInstance.toTexture(id), c}
}
func (c *Context) ResetOffscreen() {
c.currentId = c.screenId
}
func (c *Context) SetOffscreen(renderTargetId graphics.RenderTargetID) {
c.currentId = renderTargetId
}
type textureWithContext struct {
id graphics.TextureID
context *Context
}
func (t *textureWithContext) Draw(parts []graphics.TexturePart, geo matrix.Geometry, color matrix.Color) {
idsInstance.drawTexture(t.context.currentId, t.id, parts, geo, color)
}