mirror of
https://github.com/hajimehoshi/ebiten.git
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110 lines
2.5 KiB
Go
110 lines
2.5 KiB
Go
// Copyright 2016 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 opengl
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import (
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"math"
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)
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var (
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zeroPlus = math.Nextafter32(0, 1)
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oneMinus = math.Nextafter32(1, 0)
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)
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// adjustForClearColor adjust the value x for glClearColor function.
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//
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// On some machines like MacBook Pro, exact 0 and exact 1 might cause problems
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// at glClearColor() (#452).
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func adjustForClearColor(x float32) float32 {
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if x <= 0 {
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return zeroPlus
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}
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if x >= 1 {
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return oneMinus
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}
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return x
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}
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var (
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VertexShader ShaderType
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FragmentShader ShaderType
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ArrayBuffer BufferType
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ElementArrayBuffer BufferType
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DynamicDraw BufferUsage
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StaticDraw BufferUsage
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Triangles Mode
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Lines Mode
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Short DataType
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Float DataType
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zero operation
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one operation
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srcAlpha operation
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dstAlpha operation
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oneMinusSrcAlpha operation
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oneMinusDstAlpha operation
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)
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type Context struct {
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locationCache *locationCache
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screenFramebuffer Framebuffer // This might not be the default frame buffer '0' (e.g. iOS).
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lastFramebuffer Framebuffer
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lastTexture Texture
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lastViewportWidth int
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lastViewportHeight int
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lastCompositeMode CompositeMode
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context
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}
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var theContext *Context
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func GetContext() *Context {
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return theContext
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}
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func (c *Context) BindTexture(t Texture) {
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if c.lastTexture.equals(t) {
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return
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}
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c.bindTextureImpl(t)
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c.lastTexture = t
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}
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func (c *Context) bindFramebuffer(f Framebuffer) {
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if c.lastFramebuffer.equals(f) {
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return
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}
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c.bindFramebufferImpl(f)
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c.lastFramebuffer = f
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}
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func (c *Context) SetViewport(f Framebuffer, width, height int) {
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c.bindFramebuffer(f)
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if c.lastViewportWidth != width || c.lastViewportHeight != height {
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c.setViewportImpl(width, height)
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c.lastViewportWidth = width
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c.lastViewportHeight = height
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}
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}
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func (c *Context) ScreenFramebuffer() Framebuffer {
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return c.screenFramebuffer
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}
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func (c *Context) ResetViewportSize() {
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c.lastViewportWidth = 0
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c.lastViewportHeight = 0
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}
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