ebiten/internal/graphics/program.go

211 lines
5.8 KiB
Go

// Copyright 2014 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 graphics
import (
"fmt"
"github.com/hajimehoshi/ebiten/internal/graphics/opengl"
)
type openGLState struct {
initialized bool
indexBufferLines opengl.Buffer
indexBufferQuads opengl.Buffer
programTexture opengl.Program
lastProgram opengl.Program
lastProjectionMatrix []float32
lastModelviewMatrix []float32
lastColorMatrix []float32
}
var theOpenGLState openGLState
const (
indicesNum = 1 << 16
MaxQuads = indicesNum / 6
)
// unsafe.SizeOf can't be used because unsafe doesn't work with GopherJS.
const (
int16Size = 2
float32Size = 4
)
func InitializeIfNeeded(c *opengl.Context) error {
return theOpenGLState.initializeIfNeeded(c)
}
func (s *openGLState) initializeIfNeeded(c *opengl.Context) error {
if s.initialized {
return nil
}
var zeroProgram opengl.Program
s.lastProgram = zeroProgram
s.lastProjectionMatrix = nil
s.lastModelviewMatrix = nil
s.lastColorMatrix = nil
shaderVertexModelviewNative, err := c.NewShader(c.VertexShader, shader(c, shaderVertexModelview))
if err != nil {
panic(fmt.Sprintf("graphics: shader compiling error:\n%s", err))
}
defer c.DeleteShader(shaderVertexModelviewNative)
shaderFragmentTextureNative, err := c.NewShader(c.FragmentShader, shader(c, shaderFragmentTexture))
if err != nil {
panic(fmt.Sprintf("graphics: shader compiling error:\n%s", err))
}
defer c.DeleteShader(shaderFragmentTextureNative)
s.programTexture, err = c.NewProgram([]opengl.Shader{
shaderVertexModelviewNative,
shaderFragmentTextureNative,
})
if err != nil {
return err
}
// 16 [bytes] is an arbitrary number which seems enough to draw anything. Fix this if necessary.
const stride = 16
c.NewBuffer(c.ArrayBuffer, 4*stride*MaxQuads, c.DynamicDraw)
indices := make([]uint16, 6*MaxQuads)
for i := uint16(0); i < MaxQuads; i++ {
indices[6*i+0] = 4*i + 0
indices[6*i+1] = 4*i + 1
indices[6*i+2] = 4*i + 2
indices[6*i+3] = 4*i + 1
indices[6*i+4] = 4*i + 2
indices[6*i+5] = 4*i + 3
}
s.indexBufferQuads = c.NewBuffer(c.ElementArrayBuffer, indices, c.StaticDraw)
indices = make([]uint16, indicesNum)
for i := 0; i < len(indices); i++ {
indices[i] = uint16(i)
}
s.indexBufferLines = c.NewBuffer(c.ElementArrayBuffer, indices, c.StaticDraw)
s.initialized = true
return nil
}
func areSameFloat32Array(a, b []float32) bool {
if len(a) != len(b) {
return false
}
for i := 0; i < len(a); i++ {
if a[i] != b[i] {
return false
}
}
return true
}
type programContext struct {
state *openGLState
program opengl.Program
context *opengl.Context
projectionMatrix []float32
texture opengl.Texture
geoM Matrix
colorM Matrix
}
func (p *programContext) begin() {
c := p.context
if p.state.lastProgram != p.program {
c.UseProgram(p.program)
p.state.lastProgram = p.state.programTexture
p.state.lastProjectionMatrix = nil
p.state.lastModelviewMatrix = nil
p.state.lastColorMatrix = nil
}
c.BindElementArrayBuffer(p.state.indexBufferQuads)
if !areSameFloat32Array(p.state.lastProjectionMatrix, p.projectionMatrix) {
c.UniformFloats(p.program, "projection_matrix", p.projectionMatrix)
if p.state.lastProjectionMatrix == nil {
p.state.lastProjectionMatrix = make([]float32, 16)
}
copy(p.state.lastProjectionMatrix, p.projectionMatrix)
}
ma := float32(p.geoM.Element(0, 0))
mb := float32(p.geoM.Element(0, 1))
mc := float32(p.geoM.Element(1, 0))
md := float32(p.geoM.Element(1, 1))
tx := float32(p.geoM.Element(0, 2))
ty := float32(p.geoM.Element(1, 2))
modelviewMatrix := []float32{
ma, mc, 0, 0,
mb, md, 0, 0,
0, 0, 1, 0,
tx, ty, 0, 1,
}
if !areSameFloat32Array(p.state.lastModelviewMatrix, modelviewMatrix) {
c.UniformFloats(p.program, "modelview_matrix", modelviewMatrix)
if p.state.lastModelviewMatrix == nil {
p.state.lastModelviewMatrix = make([]float32, 16)
}
copy(p.state.lastModelviewMatrix, modelviewMatrix)
}
c.UniformInt(p.program, "texture", 0)
e := [4][5]float32{}
for i := 0; i < 4; i++ {
for j := 0; j < 5; j++ {
e[i][j] = float32(p.colorM.Element(i, j))
}
}
colorMatrix := []float32{
e[0][0], e[1][0], e[2][0], e[3][0],
e[0][1], e[1][1], e[2][1], e[3][1],
e[0][2], e[1][2], e[2][2], e[3][2],
e[0][3], e[1][3], e[2][3], e[3][3],
}
if !areSameFloat32Array(p.state.lastColorMatrix, colorMatrix) {
c.UniformFloats(p.program, "color_matrix", colorMatrix)
if p.state.lastColorMatrix == nil {
p.state.lastColorMatrix = make([]float32, 16)
}
copy(p.state.lastColorMatrix, colorMatrix)
}
colorMatrixTranslation := []float32{
e[0][4], e[1][4], e[2][4], e[3][4],
}
c.UniformFloats(p.program, "color_matrix_translation", colorMatrixTranslation)
// We don't have to call gl.ActiveTexture here: GL_TEXTURE0 is the default active texture
// See also: https://www.opengl.org/sdk/docs/man2/xhtml/glActiveTexture.xml
c.BindTexture(p.texture)
c.EnableVertexAttribArray(p.program, "vertex")
c.EnableVertexAttribArray(p.program, "tex_coord")
c.VertexAttribPointer(p.program, "vertex", false, int16Size*4, 2, int16Size*0)
c.VertexAttribPointer(p.program, "tex_coord", true, int16Size*4, 2, int16Size*2)
}
func (p *programContext) end() {
c := p.context
c.DisableVertexAttribArray(p.program, "tex_coord")
c.DisableVertexAttribArray(p.program, "vertex")
}