zorldo

shader.go (6652B)

---

 // 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"
 	"strings"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/graphics"
 	"github.com/hajimehoshi/ebiten/v2/internal/mipmap"
 	"github.com/hajimehoshi/ebiten/v2/internal/shader"
 	"github.com/hajimehoshi/ebiten/v2/internal/shaderir"
 )
 
 var shaderSuffix string
 
 func init() {
 	shaderSuffix = `
 var __imageDstTextureSize vec2
 
 // imageSrcTextureSize returns the destination image's texture size in pixels.
 func imageDstTextureSize() vec2 {
 	return __imageDstTextureSize
 }
 `
 
 	shaderSuffix += fmt.Sprintf(`
 var __textureSizes [%[1]d]vec2
 
 // imageSrcTextureSize returns the source image's texture size in pixels.
 // As an image is a part of internal texture, the texture is usually bigger than the image.
 // The texture's size is useful when you want to calculate pixels from texels.
 func imageSrcTextureSize() vec2 {
 	return __textureSizes[0]
 }
 
 // The unit is the source texture's texel.
 var __textureDestinationRegionOrigin vec2
 
 // The unit is the source texture's texel.
 var __textureDestinationRegionSize vec2
 
 // imageDstRegionOnTexture returns the destination image's region (the origin and the size) on its texture.
 // The unit is the source texture's texel.
 //
 // As an image is a part of internal texture, the image can be located at an arbitrary position on the texture.
 func imageDstRegionOnTexture() (vec2, vec2) {
 	return __textureDestinationRegionOrigin, __textureDestinationRegionSize
 }
 
 // The unit is the source texture's texel.
 var __textureSourceOffsets [%[2]d]vec2
 
 // The unit is the source texture's texel.
 var __textureSourceRegionOrigin vec2
 
 // The unit is the source texture's texel.
 var __textureSourceRegionSize vec2
 
 // imageSrcRegionOnTexture returns the source image's region (the origin and the size) on its texture.
 // The unit is the source texture's texel.
 //
 // As an image is a part of internal texture, the image can be located at an arbitrary position on the texture.
 func imageSrcRegionOnTexture() (vec2, vec2) {
 	return __textureSourceRegionOrigin, __textureSourceRegionSize
 }
 `, 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 imageSrc%[1]dUnsafeAt(pos vec2) vec4 {
 	// pos is the position in texels of the source texture (= 0th image's texture).
 	return texture2D(__t%[1]d, %[2]s)
 }
 
 func imageSrc%[1]dAt(pos vec2) vec4 {
 	// pos is the position in texels of the source texture (= 0th image's texture).
 	return texture2D(__t%[1]d, %[2]s) *
 		step(__textureSourceRegionOrigin.x, pos.x) *
 		(1 - step(__textureSourceRegionOrigin.x + __textureSourceRegionSize.x, pos.x)) *
 		step(__textureSourceRegionOrigin.y, pos.y) *
 		(1 - step(__textureSourceRegionOrigin.y + __textureSourceRegionSize.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
 }
 `
 }
 
 // Shader represents a compiled shader program.
 //
 // For the details about the shader, see https://ebiten.org/documents/shader.html.
 type Shader struct {
 	shader       *mipmap.Shader
 	uniformNames []string
 	uniformTypes []shaderir.Type
 }
 
 // NewShader compiles a shader program in the shading language Kage, and retruns the result.
 //
 // If the compilation fails, NewShader returns an error.
 //
 // For the details about the shader, see https://ebiten.org/documents/shader.html.
 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
 	}
 
 	const (
 		vert = "__vertex"
 		frag = "Fragment"
 	)
 	s, err := shader.Compile(fs, f, vert, frag, graphics.ShaderImageNum)
 	if err != nil {
 		return nil, err
 	}
 
 	if s.VertexFunc.Block == nil {
 		return nil, fmt.Errorf("ebiten: vertex shader entry point '%s' is missing", vert)
 	}
 	if s.FragmentFunc.Block == nil {
 		return nil, fmt.Errorf("ebiten: fragment shader entry point '%s' is missing", frag)
 	}
 
 	return &Shader{
 		shader:       mipmap.NewShader(s),
 		uniformNames: s.UniformNames,
 		uniformTypes: s.Uniforms,
 	}, nil
 }
 
 // Dispose disposes the shader program.
 // After disposing, the shader is no longer available.
 func (s *Shader) Dispose() {
 	s.shader.MarkDisposed()
 	s.shader = nil
 }
 
 func (s *Shader) convertUniforms(uniforms map[string]interface{}) []interface{} {
 	type index struct {
 		resultIndex        int
 		shaderUniformIndex int
 	}
 
 	names := map[string]index{}
 	var idx int
 	for i, n := range s.uniformNames {
 		if strings.HasPrefix(n, "__") {
 			continue
 		}
 		names[n] = index{
 			resultIndex:        idx,
 			shaderUniformIndex: i,
 		}
 		idx++
 	}
 
 	us := make([]interface{}, len(names))
 	for name, idx := range names {
 		if v, ok := uniforms[name]; ok {
 			// TODO: Check the uniform variable types?
 			us[idx.resultIndex] = v
 			continue
 		}
 
 		t := s.uniformTypes[idx.shaderUniformIndex]
 		v := zeroUniformValue(t)
 		if v == nil {
 			panic(fmt.Sprintf("ebiten: unexpected uniform variable type: %s", t.String()))
 		}
 		us[idx.resultIndex] = v
 	}
 
 	// TODO: Panic if uniforms include an invalid name
 
 	return us
 }
 
 func zeroUniformValue(t shaderir.Type) interface{} {
 	switch t.Main {
 	case shaderir.Bool:
 		return false
 	case shaderir.Int:
 		return 0
 	case shaderir.Float:
 		return float32(0)
 	case shaderir.Array:
 		switch t.Sub[0].Main {
 		case shaderir.Bool:
 			return make([]bool, t.Length)
 		case shaderir.Int:
 			return make([]int, t.Length)
 		default:
 			return make([]float32, t.FloatNum())
 		}
 	default:
 		return make([]float32, t.FloatNum())
 	}
 }