ebiten/graphicscontext.go
2016-02-28 00:11:27 +09:00

82 lines
2.2 KiB
Go

// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ebiten
import (
"github.com/hajimehoshi/ebiten/internal/graphics"
)
func newGraphicsContext(screenWidth, screenHeight, screenScale int) (*graphicsContext, error) {
c := &graphicsContext{}
if err := c.setSize(screenWidth, screenHeight, screenScale); err != nil {
return nil, err
}
return c, nil
}
type graphicsContext struct {
screen *Image
defaultRenderTarget *Image
screenScale int
}
func (c *graphicsContext) update(f func(*Image) error) error {
if err := c.screen.Clear(); err != nil {
return err
}
if err := f(c.screen); err != nil {
return err
}
// TODO: In WebGL, we don't need to clear the image here.
if err := c.defaultRenderTarget.Clear(); err != nil {
return err
}
scale := float64(c.screenScale)
options := &DrawImageOptions{}
options.GeoM.Scale(scale, scale)
if err := c.defaultRenderTarget.DrawImage(c.screen, options); err != nil {
return err
}
return nil
}
func (c *graphicsContext) setSize(screenWidth, screenHeight, screenScale int) error {
if c.defaultRenderTarget != nil {
c.defaultRenderTarget.Dispose()
}
if c.screen != nil {
c.screen.Dispose()
}
f, err := graphics.NewZeroFramebuffer(glContext, screenWidth*screenScale, screenHeight*screenScale)
if err != nil {
return err
}
texture, err := graphics.NewTexture(glContext, screenWidth, screenHeight, glContext.Nearest)
if err != nil {
return err
}
screenF, err := graphics.NewFramebufferFromTexture(glContext, texture)
if err != nil {
return err
}
screen := &Image{framebuffer: screenF, texture: texture}
c.defaultRenderTarget = &Image{framebuffer: f, texture: nil}
c.screen = screen
c.screenScale = screenScale
return nil
}