mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-09-20 13:22:19 +02:00
310 lines
8.8 KiB
Go
310 lines
8.8 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 graphics
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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/opengl"
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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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dataType opengl.DataType
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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 += p.dataType.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() opengl.Buffer {
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return opengl.GetContext().NewArrayBuffer(a.totalBytes() * 4 * maxQuads)
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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(program opengl.Program) {
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for _, p := range a.parts {
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opengl.GetContext().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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opengl.GetContext().VertexAttribPointer(program, p.name, p.num, p.dataType, total, offset)
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offset += p.dataType.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(program opengl.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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opengl.GetContext().DisableVertexAttribArray(program, p.name)
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}
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}
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var (
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// theArrayBufferLayout is the array buffer layout for Ebiten.
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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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dataType: opengl.Float,
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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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dataType: opengl.Float,
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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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// openGLState is a state for OpenGL.
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type openGLState struct {
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// arrayBuffer is OpenGL's array buffer (vertices data).
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arrayBuffer opengl.Buffer
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// elementArrayBuffer is OpenGL's element array buffer (indices data).
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elementArrayBuffer opengl.Buffer
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// programNearest is OpenGL's program for rendering a texture with nearest filter.
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programNearest opengl.Program
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// programLinear is OpenGL's program for rendering a texture with linear filter.
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programLinear opengl.Program
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lastProgram opengl.Program
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lastProjectionMatrix []float32
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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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}
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var (
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// theOpenGLState is the OpenGL state in the current process.
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theOpenGLState openGLState
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zeroBuffer opengl.Buffer
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zeroProgram opengl.Program
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)
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const (
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indicesNum = 1 << 16
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maxQuads = indicesNum / 6
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)
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// ResetGLState resets or initializes the current OpenGL state.
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func ResetGLState() error {
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return theOpenGLState.reset()
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}
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// reset resets or initializes the OpenGL state.
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func (s *openGLState) reset() error {
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if err := opengl.GetContext().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.lastProjectionMatrix = nil
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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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opengl.GetContext().DeleteProgram(s.programNearest)
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}
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if s.programLinear != zeroProgram {
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opengl.GetContext().DeleteProgram(s.programLinear)
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}
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if s.arrayBuffer != zeroBuffer {
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opengl.GetContext().DeleteBuffer(s.arrayBuffer)
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}
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if s.elementArrayBuffer != zeroBuffer {
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opengl.GetContext().DeleteBuffer(s.elementArrayBuffer)
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}
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shaderVertexModelviewNative, err := opengl.GetContext().NewShader(opengl.VertexShader, shader(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 opengl.GetContext().DeleteShader(shaderVertexModelviewNative)
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shaderFragmentNearestNative, err := opengl.GetContext().NewShader(opengl.FragmentShader, shader(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 opengl.GetContext().DeleteShader(shaderFragmentNearestNative)
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shaderFragmentLinearNative, err := opengl.GetContext().NewShader(opengl.FragmentShader, shader(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 opengl.GetContext().DeleteShader(shaderFragmentLinearNative)
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s.programNearest, err = opengl.GetContext().NewProgram([]opengl.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 = opengl.GetContext().NewProgram([]opengl.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.arrayBuffer = theArrayBufferLayout.newArrayBuffer()
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indices := make([]uint16, 6*maxQuads)
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for i := uint16(0); i < maxQuads; i++ {
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indices[6*i+0] = 4*i + 0
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indices[6*i+1] = 4*i + 1
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indices[6*i+2] = 4*i + 2
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indices[6*i+3] = 4*i + 1
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indices[6*i+4] = 4*i + 2
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indices[6*i+5] = 4*i + 3
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}
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s.elementArrayBuffer = opengl.GetContext().NewElementArrayBuffer(indices)
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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 (s *openGLState) useProgram(proj []float32, texture opengl.Texture, sourceWidth, sourceHeight int, colorM affine.ColorM, filter Filter) {
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c := opengl.GetContext()
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var program opengl.Program
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switch filter {
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case FilterNearest:
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program = s.programNearest
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case FilterLinear:
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program = s.programLinear
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default:
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panic("not reached")
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}
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if s.lastProgram != program {
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c.UseProgram(program)
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if s.lastProgram != zeroProgram {
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theArrayBufferLayout.disable(s.lastProgram)
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}
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theArrayBufferLayout.enable(program)
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s.lastProgram = program
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s.lastProjectionMatrix = nil
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s.lastColorMatrix = nil
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s.lastColorMatrixTranslation = nil
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c.BindElementArrayBuffer(s.elementArrayBuffer)
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c.UniformInt(program, "texture", 0)
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}
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if !areSameFloat32Array(s.lastProjectionMatrix, proj) {
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c.UniformFloats(program, "projection_matrix", proj)
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if s.lastProjectionMatrix == nil {
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s.lastProjectionMatrix = make([]float32, 16)
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}
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copy(s.lastProjectionMatrix, proj)
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}
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esBody, esTranslate := colorM.UnsafeElements()
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// transpose
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colorMatrix := make([]float32, (affine.ColorMDim-1)*(affine.ColorMDim-1))
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for i := 0; i < affine.ColorMDim-1; i++ {
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for j := 0; j < affine.ColorMDim-1; j++ {
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colorMatrix[i+j*(affine.ColorMDim-1)] = float32(esBody[i*(affine.ColorMDim-1)+j])
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}
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}
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if !areSameFloat32Array(s.lastColorMatrix, colorMatrix) {
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c.UniformFloats(program, "color_matrix", colorMatrix)
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if s.lastColorMatrix == nil {
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s.lastColorMatrix = make([]float32, 16)
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}
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copy(s.lastColorMatrix, colorMatrix)
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}
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colorMatrixTranslation := []float32{
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float32(esTranslate[0]),
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float32(esTranslate[1]),
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float32(esTranslate[2]),
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float32(esTranslate[3]),
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}
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if !areSameFloat32Array(s.lastColorMatrixTranslation, colorMatrixTranslation) {
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c.UniformFloats(program, "color_matrix_translation", colorMatrixTranslation)
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if s.lastColorMatrixTranslation == nil {
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s.lastColorMatrixTranslation = make([]float32, 4)
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}
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copy(s.lastColorMatrixTranslation, colorMatrixTranslation)
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}
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if program == s.programLinear {
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if s.lastSourceWidth != sourceWidth || s.lastSourceHeight != sourceHeight {
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c.UniformFloats(program, "source_size",
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[]float32{float32(sourceWidth), float32(sourceHeight)})
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s.lastSourceWidth = sourceWidth
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s.lastSourceHeight = sourceHeight
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}
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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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c.BindTexture(texture)
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}
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