ebiten/internal/graphicsdriver/opengl/context.go
2020-10-04 04:30:40 +09:00

121 lines
3.1 KiB
Go

// Copyright 2016 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 opengl
import (
"fmt"
"sync"
"github.com/hajimehoshi/ebiten/v2/internal/driver"
"github.com/hajimehoshi/ebiten/v2/internal/thread"
)
func convertOperation(op driver.Operation) operation {
switch op {
case driver.Zero:
return zero
case driver.One:
return one
case driver.SrcAlpha:
return srcAlpha
case driver.DstAlpha:
return dstAlpha
case driver.OneMinusSrcAlpha:
return oneMinusSrcAlpha
case driver.OneMinusDstAlpha:
return oneMinusDstAlpha
case driver.DstColor:
return dstColor
default:
panic(fmt.Sprintf("opengl: invalid operation %d at convertOperation", op))
}
}
type context struct {
locationCache *locationCache
screenFramebuffer framebufferNative // This might not be the default frame buffer '0' (e.g. iOS).
lastFramebuffer framebufferNative
lastTexture textureNative
lastViewportWidth int
lastViewportHeight int
lastCompositeMode driver.CompositeMode
maxTextureSize int
maxTextureSizeOnce sync.Once
highp bool
highpOnce sync.Once
t *thread.Thread
contextImpl
}
func (c *context) bindTexture(t textureNative) {
if c.lastTexture.equal(t) {
return
}
c.bindTextureImpl(t)
c.lastTexture = t
}
func (c *context) bindFramebuffer(f framebufferNative) {
if c.lastFramebuffer.equal(f) {
return
}
c.bindFramebufferImpl(f)
c.lastFramebuffer = f
}
func (c *context) setViewport(f *framebuffer) {
c.bindFramebuffer(f.native)
if c.lastViewportWidth != f.width || c.lastViewportHeight != f.height {
// On some environments, viewport size must be within the framebuffer size.
// e.g. Edge (#71), Chrome on GPD Pocket (#420), macOS Mojave (#691).
// Use the same size of the framebuffer here.
c.setViewportImpl(f.width, f.height)
// glViewport must be called at least at every frame on iOS.
// As the screen framebuffer is the last render target, next SetViewport should be
// the first call at a frame.
if f.native.equal(c.screenFramebuffer) {
c.lastViewportWidth = 0
c.lastViewportHeight = 0
} else {
c.lastViewportWidth = f.width
c.lastViewportHeight = f.height
}
}
}
func (c *context) getScreenFramebuffer() framebufferNative {
return c.screenFramebuffer
}
func (c *context) getMaxTextureSize() int {
c.maxTextureSizeOnce.Do(func() {
c.maxTextureSize = c.maxTextureSizeImpl()
})
return c.maxTextureSize
}
// highpPrecision represents an enough mantissa of float values in a shader.
const highpPrecision = 23
func (c *context) hasHighPrecisionFloat() bool {
c.highpOnce.Do(func() {
c.highp = c.getShaderPrecisionFormatPrecision() >= highpPrecision
})
return c.highp
}