mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-25 03:08:54 +01:00
134 lines
3.9 KiB
Go
134 lines
3.9 KiB
Go
// Copyright 2020 The Ebiten Authors
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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 ebiten
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import (
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"bytes"
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"fmt"
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"go/parser"
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"go/token"
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"github.com/hajimehoshi/ebiten/internal/graphics"
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"github.com/hajimehoshi/ebiten/internal/mipmap"
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"github.com/hajimehoshi/ebiten/internal/shader"
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)
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var shaderSuffix string
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func init() {
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shaderSuffix = `
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var __imageDstTextureSize vec2
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// imageSrcTextureSize returns the destination image's texture size in pixels.
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func imageDstTextureSize() vec2 {
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return __imageDstTextureSize
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}
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`
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shaderSuffix += fmt.Sprintf(`
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var __textureSizes [%[1]d]vec2
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// imageSrcTextureSize returns the source image's texture size in pixels.
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// As an image is a part of internal texture, the texture is usually bigger than the image.
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// The texture's size is useful when you want to calculate pixels from texels.
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func imageSrcTextureSize() vec2 {
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return __textureSizes[0]
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}
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// The unit is the source texture's texel.
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var __textureSourceOffsets [%[2]d]vec2
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// The unit is the source texture's texel.
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var __textureSourceRegionOrigin vec2
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// The unit is the source texture's texel.
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var __textureSourceRegionSize vec2
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// imageSrcTextureSourceRegion returns the source image's region (the origin and the size) on its texture.
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// The unit is the source texture's texel.
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//
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// As an image is a part of internal texture, the image can be located at an arbitrary position on the texture.
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func imageSrcTextureSourceRegion() (vec2, vec2) {
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return __textureSourceRegionOrigin, __textureSourceRegionSize
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}
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`, graphics.ShaderImageNum, graphics.ShaderImageNum-1)
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for i := 0; i < graphics.ShaderImageNum; i++ {
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pos := "pos"
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if i >= 1 {
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// Convert the position in texture0's texels to the target texture texels.
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pos = fmt.Sprintf("(pos + __textureSourceOffsets[%d]) * __textureSizes[0] / __textureSizes[%d]", i-1, i)
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}
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// __t%d is a special variable for a texture variable.
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shaderSuffix += fmt.Sprintf(`
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func image%[1]dTextureAt(pos vec2) vec4 {
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// pos is the position in texels of the source texture (= 0th image's texture).
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return texture2D(__t%[1]d, %[2]s)
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}
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func image%[1]dTextureBoundsAt(pos vec2) vec4 {
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// pos is the position in texels of the source texture (= 0th image's texture).
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return texture2D(__t%[1]d, %[2]s) *
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step(__textureSourceRegionOrigin.x, pos.x) *
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(1 - step(__textureSourceRegionOrigin.x + __textureSourceRegionSize.x, pos.x)) *
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step(__textureSourceRegionOrigin.y, pos.y) *
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(1 - step(__textureSourceRegionOrigin.y + __textureSourceRegionSize.y, pos.y))
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}
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`, i, pos)
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}
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shaderSuffix += `
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func __vertex(position vec2, texCoord vec2, color vec4) (vec4, vec2, vec4) {
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return mat4(
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2/imageDstTextureSize().x, 0, 0, 0,
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0, 2/imageDstTextureSize().y, 0, 0,
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0, 0, 1, 0,
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-1, -1, 0, 1,
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) * vec4(position, 0, 1), texCoord, color
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}
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`
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}
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type Shader struct {
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shader *mipmap.Shader
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}
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func NewShader(src []byte) (*Shader, error) {
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var buf bytes.Buffer
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buf.Write(src)
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buf.WriteString(shaderSuffix)
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fs := token.NewFileSet()
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f, err := parser.ParseFile(fs, "", buf.Bytes(), parser.AllErrors)
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if err != nil {
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return nil, err
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}
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// TODO: Create a pseudo vertex entrypoint to treat the attribute values correctly.
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s, err := shader.Compile(fs, f, "__vertex", "Fragment", graphics.ShaderImageNum)
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if err != nil {
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return nil, err
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}
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return &Shader{
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shader: mipmap.NewShader(s),
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}, nil
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}
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func (s *Shader) Dispose() {
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s.shader.MarkDisposed()
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s.shader = nil
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}
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