mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 13:22:19 +02:00
85 lines
2.3 KiB
Go
85 lines
2.3 KiB
Go
// Copyright 2014 Hajime Hoshi
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ebiten
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import (
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"github.com/hajimehoshi/ebiten/internal/graphics"
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)
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func newGraphicsContext(screenWidth, screenHeight, screenScale int) (*graphicsContext, error) {
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c := &graphicsContext{}
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if err := c.setSize(screenWidth, screenHeight, screenScale); err != nil {
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return nil, err
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}
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return c, nil
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}
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type graphicsContext struct {
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screen *Image
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defaultRenderTarget *Image
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screenScale int
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}
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func (c *graphicsContext) update(f func(*Image) error) error {
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if err := c.screen.Clear(); err != nil {
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return err
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}
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if err := f(c.screen); err != nil {
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return err
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}
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if IsRunningSlowly() {
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return nil
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}
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// TODO: In WebGL, we don't need to clear the image here.
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if err := c.defaultRenderTarget.Clear(); err != nil {
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return err
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}
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scale := float64(c.screenScale)
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options := &DrawImageOptions{}
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options.GeoM.Scale(scale, scale)
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if err := c.defaultRenderTarget.DrawImage(c.screen, options); err != nil {
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return err
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}
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return nil
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}
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func (c *graphicsContext) setSize(screenWidth, screenHeight, screenScale int) error {
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if c.defaultRenderTarget != nil {
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c.defaultRenderTarget.Dispose()
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}
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if c.screen != nil {
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c.screen.Dispose()
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}
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f, err := graphics.NewZeroFramebuffer(glContext, screenWidth*screenScale, screenHeight*screenScale)
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if err != nil {
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return err
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}
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texture, err := graphics.NewTexture(glContext, screenWidth, screenHeight, glContext.Nearest)
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if err != nil {
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return err
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}
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screenF, err := graphics.NewFramebufferFromTexture(glContext, texture)
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if err != nil {
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return err
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}
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screen := &Image{framebuffer: screenF, texture: texture}
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c.defaultRenderTarget = &Image{framebuffer: f, texture: nil}
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c.screen = screen
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c.screenScale = screenScale
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return nil
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}
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