ebiten/shader.go
Hajime Hoshi 70acb9c1f6 shader: Rename shader bultin functions
Renamed image0TextureSize to imageSrcTextureSize, and removed the
other texture-size functions.

As texture-coordinates are always in image0's texture texels,
calculations with texels are always done with image0's texture texels.
Then, other texture-size functions are useless. To avoid confusion,
let's remove the functions and leave the necessary funciton.
2020-08-11 05:02:22 +09:00

122 lines
3.0 KiB
Go

// Copyright 2020 The Ebiten Authors
//
// 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 ebiten
import (
"bytes"
"fmt"
"go/parser"
"go/token"
"github.com/hajimehoshi/ebiten/internal/graphics"
"github.com/hajimehoshi/ebiten/internal/mipmap"
"github.com/hajimehoshi/ebiten/internal/shader"
)
var shaderSuffix string
func init() {
shaderSuffix = `
var __imageDstTextureSize vec2
func imageDstTextureSize() vec2 {
return __imageDstTextureSize
}
`
shaderSuffix += fmt.Sprintf(`
var __textureSizes [%[1]d]vec2
func imageSrcTextureSize() vec2 {
return __textureSizes[0]
}
// The unit is texture0's texels.
var __textureSourceOffsets [%[2]d]vec2
// The unit is texture0's texels.
var __textureSourceOrigin vec2
// The unit is texture0's texels.
var __textureSourceSize vec2
`, graphics.ShaderImageNum, graphics.ShaderImageNum-1)
for i := 0; i < graphics.ShaderImageNum; i++ {
pos := "pos"
if i >= 1 {
// Convert the position in texture0's texels to the target texture texels.
pos = fmt.Sprintf("(pos + __textureSourceOffsets[%d]) * __textureSizes[0] / __textureSizes[%d]", i-1, i)
}
// __t%d is a special variable for a texture variable.
shaderSuffix += fmt.Sprintf(`
func image%[1]dTextureAt(pos vec2) vec4 {
// pos is the position in texture0's texels.
return texture2D(__t%[1]d, %[2]s)
}
func image%[1]dTextureBoundsAt(pos vec2) vec4 {
// pos is the position in texture0's texels.
return texture2D(__t%[1]d, %[2]s) *
step(__textureSourceOrigin.x, pos.x) *
(1 - step(__textureSourceOrigin.x + __textureSourceSize.x, pos.x)) *
step(__textureSourceOrigin.y, pos.y) *
(1 - step(__textureSourceOrigin.y + __textureSourceSize.y, pos.y))
}
`, i, pos)
}
shaderSuffix += `
func __vertex(position vec2, texCoord vec2, color vec4) (vec4, vec2, vec4) {
return mat4(
2/imageDstTextureSize().x, 0, 0, 0,
0, 2/imageDstTextureSize().y, 0, 0,
0, 0, 1, 0,
-1, -1, 0, 1,
) * vec4(position, 0, 1), texCoord, color
}
`
}
type Shader struct {
shader *mipmap.Shader
}
func NewShader(src []byte) (*Shader, error) {
var buf bytes.Buffer
buf.Write(src)
buf.WriteString(shaderSuffix)
fs := token.NewFileSet()
f, err := parser.ParseFile(fs, "", buf.Bytes(), parser.AllErrors)
if err != nil {
return nil, err
}
// TODO: Create a pseudo vertex entrypoint to treat the attribute values correctly.
s, err := shader.Compile(fs, f, "__vertex", "Fragment", graphics.ShaderImageNum)
if err != nil {
return nil, err
}
return &Shader{
shader: mipmap.NewShader(s),
}, nil
}
func (s *Shader) Dispose() {
s.shader.MarkDisposed()
s.shader = nil
}