ebiten/internal/graphics/program.go

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// 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.
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package graphics
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import (
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"github.com/hajimehoshi/ebiten/internal/graphics/opengl"
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"math"
)
var (
indexBufferLines opengl.Buffer
indexBufferQuads opengl.Buffer
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)
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var (
programTexture opengl.Program
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)
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const indicesNum = math.MaxUint16 + 1
const quadsMaxNum = indicesNum / 6
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// unsafe.SizeOf can't be used because unsafe doesn't work with GopherJS.
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const int16Size = 2
const float32Size = 4
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func initialize(c *opengl.Context) error {
shaderVertexModelviewNative, err := c.NewShader(c.VertexShader, shader(c, shaderVertexModelview))
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if err != nil {
return err
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}
defer c.DeleteShader(shaderVertexModelviewNative)
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shaderFragmentTextureNative, err := c.NewShader(c.FragmentShader, shader(c, shaderFragmentTexture))
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if err != nil {
return err
}
defer c.DeleteShader(shaderFragmentTextureNative)
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programTexture, err = c.NewProgram([]opengl.Shader{
shaderVertexModelviewNative,
shaderFragmentTextureNative,
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})
if err != nil {
return err
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}
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// 16 [bytse] is an arbitrary number which seems enough to draw anything. Fix this if necessary.
const stride = 16
c.NewBuffer(c.ArrayBuffer, 4*stride*quadsMaxNum, c.DynamicDraw)
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indices := make([]uint16, 6*quadsMaxNum)
for i := uint16(0); i < quadsMaxNum; i++ {
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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
}
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indexBufferQuads = c.NewBuffer(c.ElementArrayBuffer, indices, c.StaticDraw)
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indices = make([]uint16, indicesNum)
for i := 0; i < len(indices); i++ {
indices[i] = uint16(i)
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}
indexBufferLines = c.NewBuffer(c.ElementArrayBuffer, indices, c.StaticDraw)
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return nil
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}
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
}
var (
lastProgram opengl.Program
lastProjectionMatrix []float32
lastModelviewMatrix []float32
lastColorMatrix []float32
)
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type programContext struct {
program opengl.Program
context *opengl.Context
projectionMatrix []float32
texture opengl.Texture
geoM Matrix
colorM Matrix
}
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func (p *programContext) begin() {
c := p.context
if !lastProgram.Equals(p.program) {
c.UseProgram(p.program)
lastProgram = programTexture
lastProjectionMatrix = nil
lastModelviewMatrix = nil
lastColorMatrix = nil
}
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c.BindElementArrayBuffer(indexBufferQuads)
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if !areSameFloat32Array(lastProjectionMatrix, p.projectionMatrix) {
c.UniformFloats(p.program, "projection_matrix", p.projectionMatrix)
if lastProjectionMatrix == nil {
lastProjectionMatrix = make([]float32, 16)
}
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copy(lastProjectionMatrix, p.projectionMatrix)
}
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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{
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ma, mc, 0, 0,
mb, md, 0, 0,
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0, 0, 1, 0,
tx, ty, 0, 1,
}
if !areSameFloat32Array(lastModelviewMatrix, modelviewMatrix) {
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c.UniformFloats(p.program, "modelview_matrix", modelviewMatrix)
if lastModelviewMatrix == nil {
lastModelviewMatrix = make([]float32, 16)
}
copy(lastModelviewMatrix, modelviewMatrix)
}
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c.UniformInt(p.program, "texture", 0)
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e := [4][5]float32{}
for i := 0; i < 4; i++ {
for j := 0; j < 5; j++ {
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e[i][j] = float32(p.colorM.Element(i, j))
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}
}
colorMatrix := []float32{
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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(lastColorMatrix, colorMatrix) {
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c.UniformFloats(p.program, "color_matrix", colorMatrix)
if lastColorMatrix == nil {
lastColorMatrix = make([]float32, 16)
}
copy(lastColorMatrix, colorMatrix)
}
colorMatrixTranslation := []float32{
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e[0][4], e[1][4], e[2][4], e[3][4],
}
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c.UniformFloats(p.program, "color_matrix_translation", colorMatrixTranslation)
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// 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
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c.BindTexture(p.texture)
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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)
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}
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func (p *programContext) end() {
c := p.context
c.DisableVertexAttribArray(p.program, "tex_coord")
c.DisableVertexAttribArray(p.program, "vertex")
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}