mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-27 04:08:53 +01:00
353 lines
9.9 KiB
Go
353 lines
9.9 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 opengl
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import (
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"fmt"
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"github.com/hajimehoshi/ebiten/internal/affine"
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"github.com/hajimehoshi/ebiten/internal/graphics"
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"github.com/hajimehoshi/ebiten/internal/web"
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)
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// arrayBufferLayoutPart is a part of an array buffer layout.
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type arrayBufferLayoutPart struct {
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// TODO: This struct should belong to a program and know it.
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name string
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num int
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}
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// arrayBufferLayout is an array buffer layout.
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//
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// An array buffer in OpenGL is a buffer representing vertices and
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// is passed to a vertex shader.
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type arrayBufferLayout struct {
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parts []arrayBufferLayoutPart
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total int
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}
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// totalBytes returns the size in bytes for one element of the array buffer.
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func (a *arrayBufferLayout) totalBytes() int {
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if a.total != 0 {
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return a.total
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}
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t := 0
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for _, p := range a.parts {
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t += float.SizeInBytes() * p.num
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}
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a.total = t
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return a.total
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}
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// newArrayBuffer creates OpenGL's buffer object for the array buffer.
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func (a *arrayBufferLayout) newArrayBuffer(context *context) buffer {
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return context.newArrayBuffer(a.totalBytes() * graphics.IndicesNum)
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}
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// enable binds the array buffer the given program to use the array buffer.
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func (a *arrayBufferLayout) enable(context *context, program program) {
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for _, p := range a.parts {
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context.enableVertexAttribArray(program, p.name)
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}
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total := a.totalBytes()
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offset := 0
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for _, p := range a.parts {
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context.vertexAttribPointer(program, p.name, p.num, float, total, offset)
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offset += float.SizeInBytes() * p.num
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}
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}
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// disable stops using the array buffer.
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func (a *arrayBufferLayout) disable(context *context, program program) {
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// TODO: Disabling should be done in reversed order?
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for _, p := range a.parts {
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context.disableVertexAttribArray(program, p.name)
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}
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}
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// theArrayBufferLayout is the array buffer layout for Ebiten.
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var theArrayBufferLayout arrayBufferLayout
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func initializeArrayBuferLayout() {
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theArrayBufferLayout = arrayBufferLayout{
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// Note that GL_MAX_VERTEX_ATTRIBS is at least 16.
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parts: []arrayBufferLayoutPart{
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{
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name: "vertex",
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num: 2,
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},
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{
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name: "tex_coord",
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num: 4,
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},
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{
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name: "color_scale",
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num: 4,
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},
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},
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}
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}
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func init() {
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vertexFloatNum := theArrayBufferLayout.totalBytes() / float.SizeInBytes()
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if graphics.VertexFloatNum != vertexFloatNum {
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panic(fmt.Sprintf("vertex float num must be %d but %d", graphics.VertexFloatNum, vertexFloatNum))
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}
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}
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// openGLState is a state for
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type openGLState struct {
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// arrayBuffer is OpenGL's array buffer (vertices data).
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arrayBuffer buffer
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// elementArrayBuffer is OpenGL's element array buffer (indices data).
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elementArrayBuffer buffer
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// programNearest is OpenGL's program for rendering a texture with nearest filter.
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programNearest program
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// programLinear is OpenGL's program for rendering a texture with linear filter.
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programLinear program
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programScreen program
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lastProgram program
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lastViewportWidth int
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lastViewportHeight int
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lastColorMatrix []float32
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lastColorMatrixTranslation []float32
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lastSourceWidth int
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lastSourceHeight int
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source *Image
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destination *Image
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}
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var (
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zeroBuffer buffer
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zeroProgram program
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)
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const (
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maxTriangles = graphics.IndicesNum / 3
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maxQuads = maxTriangles / 2
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)
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// reset resets or initializes the OpenGL state.
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func (s *openGLState) reset(context *context) error {
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if err := context.reset(); err != nil {
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return err
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}
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s.lastProgram = zeroProgram
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s.lastViewportWidth = 0
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s.lastViewportHeight = 0
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s.lastColorMatrix = nil
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s.lastColorMatrixTranslation = nil
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s.lastSourceWidth = 0
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s.lastSourceHeight = 0
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// When context lost happens, deleting programs or buffers is not necessary.
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// However, it is not assumed that reset is called only when context lost happens.
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// Let's delete them explicitly.
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if s.programNearest != zeroProgram {
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context.deleteProgram(s.programNearest)
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}
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if s.programLinear != zeroProgram {
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context.deleteProgram(s.programLinear)
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}
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if s.programScreen != zeroProgram {
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context.deleteProgram(s.programScreen)
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}
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// On browsers (at least Chrome), buffers are already detached from the context
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// and must not be deleted by DeleteBuffer.
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if !web.IsBrowser() {
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if s.arrayBuffer != zeroBuffer {
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context.deleteBuffer(s.arrayBuffer)
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}
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if s.elementArrayBuffer != zeroBuffer {
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context.deleteBuffer(s.elementArrayBuffer)
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}
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}
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shaderVertexModelviewNative, err := context.newShader(vertexShader, shaderStr(shaderVertexModelview))
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if err != nil {
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panic(fmt.Sprintf("graphics: shader compiling error:\n%s", err))
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}
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defer context.deleteShader(shaderVertexModelviewNative)
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shaderFragmentNearestNative, err := context.newShader(fragmentShader, shaderStr(shaderFragmentNearest))
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if err != nil {
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panic(fmt.Sprintf("graphics: shader compiling error:\n%s", err))
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}
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defer context.deleteShader(shaderFragmentNearestNative)
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shaderFragmentLinearNative, err := context.newShader(fragmentShader, shaderStr(shaderFragmentLinear))
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if err != nil {
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panic(fmt.Sprintf("graphics: shader compiling error:\n%s", err))
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}
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defer context.deleteShader(shaderFragmentLinearNative)
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shaderFragmentScreenNative, err := context.newShader(fragmentShader, shaderStr(shaderFragmentScreen))
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if err != nil {
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panic(fmt.Sprintf("graphics: shader compiling error:\n%s", err))
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}
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defer context.deleteShader(shaderFragmentScreenNative)
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s.programNearest, err = context.newProgram([]shader{
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shaderVertexModelviewNative,
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shaderFragmentNearestNative,
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})
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if err != nil {
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return err
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}
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s.programLinear, err = context.newProgram([]shader{
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shaderVertexModelviewNative,
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shaderFragmentLinearNative,
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})
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if err != nil {
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return err
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}
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s.programScreen, err = context.newProgram([]shader{
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shaderVertexModelviewNative,
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shaderFragmentScreenNative,
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})
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if err != nil {
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return err
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}
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s.arrayBuffer = theArrayBufferLayout.newArrayBuffer(context)
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// Note that the indices passed to NewElementArrayBuffer is not under GC management
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// in opengl package due to unsafe-way.
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// See NewElementArrayBuffer in context_mobile.go.
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s.elementArrayBuffer = context.newElementArrayBuffer(graphics.IndicesNum * 2)
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return nil
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}
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// areSameFloat32Array returns a boolean indicating if a and b are deeply equal.
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func areSameFloat32Array(a, b []float32) bool {
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if len(a) != len(b) {
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return false
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}
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for i := 0; i < len(a); i++ {
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if a[i] != b[i] {
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return false
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}
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}
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return true
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}
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// useProgram uses the program (programTexture).
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func (d *Driver) useProgram(mode graphics.CompositeMode, colorM *affine.ColorM, filter graphics.Filter) error {
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destination := d.state.destination
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if destination == nil {
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panic("destination image is not set")
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}
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source := d.state.source
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if source == nil {
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panic("source image is not set")
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}
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if err := destination.setViewport(); err != nil {
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return err
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}
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dstW := destination.width
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srcW, srcH := source.width, source.height
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d.context.blendFunc(mode)
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var program program
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switch filter {
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case graphics.FilterNearest:
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program = d.state.programNearest
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case graphics.FilterLinear:
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program = d.state.programLinear
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case graphics.FilterScreen:
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program = d.state.programScreen
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default:
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panic("not reached")
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}
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if d.state.lastProgram != program {
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d.context.useProgram(program)
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if d.state.lastProgram != zeroProgram {
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theArrayBufferLayout.disable(&d.context, d.state.lastProgram)
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}
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theArrayBufferLayout.enable(&d.context, program)
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if d.state.lastProgram == zeroProgram {
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d.context.bindBuffer(arrayBuffer, d.state.arrayBuffer)
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d.context.bindBuffer(elementArrayBuffer, d.state.elementArrayBuffer)
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d.context.uniformInt(program, "texture", 0)
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}
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d.state.lastProgram = program
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d.state.lastViewportWidth = 0
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d.state.lastViewportHeight = 0
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d.state.lastColorMatrix = nil
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d.state.lastColorMatrixTranslation = nil
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d.state.lastSourceWidth = 0
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d.state.lastSourceHeight = 0
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}
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vw := destination.framebuffer.width
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vh := destination.framebuffer.height
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if d.state.lastViewportWidth != vw || d.state.lastSourceHeight != vh {
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d.context.uniformFloats(program, "viewport_size", []float32{float32(vw), float32(vh)})
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d.state.lastViewportWidth = vw
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d.state.lastViewportHeight = vh
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}
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esBody, esTranslate := colorM.UnsafeElements()
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if !areSameFloat32Array(d.state.lastColorMatrix, esBody) {
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d.context.uniformFloats(program, "color_matrix_body", esBody)
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// ColorM's elements are immutable. It's OK to hold the reference without copying.
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d.state.lastColorMatrix = esBody
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}
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if !areSameFloat32Array(d.state.lastColorMatrixTranslation, esTranslate) {
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d.context.uniformFloats(program, "color_matrix_translation", esTranslate)
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// ColorM's elements are immutable. It's OK to hold the reference without copying.
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d.state.lastColorMatrixTranslation = esTranslate
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}
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sw := graphics.NextPowerOf2Int(srcW)
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sh := graphics.NextPowerOf2Int(srcH)
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if d.state.lastSourceWidth != sw || d.state.lastSourceHeight != sh {
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d.context.uniformFloats(program, "source_size", []float32{float32(sw), float32(sh)})
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d.state.lastSourceWidth = sw
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d.state.lastSourceHeight = sh
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}
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if program == d.state.programScreen {
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scale := float32(dstW) / float32(srcW)
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d.context.uniformFloat(program, "scale", scale)
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}
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// We don't have to call gl.ActiveTexture here: GL_TEXTURE0 is the default active texture
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// See also: https://www.opengl.org/sdk/docs/man2/xhtml/glActiveTexture.xml
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d.context.bindTexture(source.textureNative)
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d.state.source = nil
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d.state.destination = nil
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return nil
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}
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