ebiten/internal/testing/shader.go

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// 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 testing
import (
"github.com/hajimehoshi/ebiten/internal/shaderir"
)
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var (
projectionMatrix = shaderir.Expr{
Type: shaderir.Call,
Exprs: []shaderir.Expr{
{
Type: shaderir.BuiltinFuncExpr,
BuiltinFunc: shaderir.Mat4F,
},
{
Type: shaderir.Binary,
Op: shaderir.Div,
Exprs: []shaderir.Expr{
{
Type: shaderir.FloatExpr,
Float: 2,
},
{
Type: shaderir.FieldSelector,
Exprs: []shaderir.Expr{
{
Type: shaderir.UniformVariable,
Index: 0,
},
{
Type: shaderir.SwizzlingExpr,
Swizzling: "x",
},
},
},
},
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.Binary,
Op: shaderir.Div,
Exprs: []shaderir.Expr{
{
Type: shaderir.FloatExpr,
Float: 2,
},
{
Type: shaderir.FieldSelector,
Exprs: []shaderir.Expr{
{
Type: shaderir.UniformVariable,
Index: 0,
},
{
Type: shaderir.SwizzlingExpr,
Swizzling: "y",
},
},
},
},
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 1,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: -1,
},
{
Type: shaderir.FloatExpr,
Float: -1,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 1,
},
},
}
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vertexPosition = shaderir.Expr{
Type: shaderir.Call,
Exprs: []shaderir.Expr{
{
Type: shaderir.BuiltinFuncExpr,
BuiltinFunc: shaderir.Vec4F,
},
{
Type: shaderir.LocalVariable,
Index: 0,
},
{
Type: shaderir.FloatExpr,
Float: 0,
},
{
Type: shaderir.FloatExpr,
Float: 1,
},
},
}
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defaultVertexFunc = shaderir.VertexFunc{
Block: shaderir.Block{
Stmts: []shaderir.Stmt{
{
Type: shaderir.Assign,
Exprs: []shaderir.Expr{
{
Type: shaderir.LocalVariable,
Index: 4, // the varying variable
},
{
Type: shaderir.LocalVariable,
Index: 1, // the 2nd attribute variable
},
},
},
{
Type: shaderir.Assign,
Exprs: []shaderir.Expr{
{
Type: shaderir.LocalVariable,
Index: 5, // gl_Position in GLSL
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},
{
Type: shaderir.Binary,
Op: shaderir.Mul,
Exprs: []shaderir.Expr{
projectionMatrix,
vertexPosition,
},
},
},
},
},
},
}
)
func defaultProgram() shaderir.Program {
return shaderir.Program{
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Uniforms: []shaderir.Type{
{Main: shaderir.Vec2},
},
Attributes: []shaderir.Type{
{Main: shaderir.Vec2}, // Local var (0) in the vertex shader
{Main: shaderir.Vec2}, // Local var (1) in the vertex shader
{Main: shaderir.Vec4}, // Local var (2) in the vertex shader
{Main: shaderir.Vec4}, // Local var (3) in the vertex shader
},
Varyings: []shaderir.Type{
{Main: shaderir.Vec2}, // Local var (4) in the vertex shader, (0) in the fragment shader
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},
VertexFunc: defaultVertexFunc,
}
}
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// ShaderProgramFill returns a shader intermediate representation to fill the frambuffer.
//
// Uniform variable's index and its value are:
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//
// 0: the framebuffer size (Vec2)
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func ShaderProgramFill(r, g, b, a byte) shaderir.Program {
clr := shaderir.Expr{
Type: shaderir.Call,
Exprs: []shaderir.Expr{
{
Type: shaderir.BuiltinFuncExpr,
BuiltinFunc: shaderir.Vec4F,
},
{
Type: shaderir.FloatExpr,
Float: float32(r) / 0xff,
},
{
Type: shaderir.FloatExpr,
Float: float32(g) / 0xff,
},
{
Type: shaderir.FloatExpr,
Float: float32(b) / 0xff,
},
{
Type: shaderir.FloatExpr,
Float: float32(a) / 0xff,
},
},
}
p := defaultProgram()
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p.FragmentFunc = shaderir.FragmentFunc{
Block: shaderir.Block{
Stmts: []shaderir.Stmt{
{
Type: shaderir.Assign,
Exprs: []shaderir.Expr{
{
Type: shaderir.LocalVariable,
Index: 2,
},
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clr,
},
},
},
},
}
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return p
}
// ShaderProgramImages returns a shader intermediate representation to render the frambuffer with the given images.
//
// Uniform variables's indices and their values are:
//
// 0: the framebuffer size (Vec2)
// 1: the first images (Texture2D)
// 2n: the n-th image (Texture2D)
// 2n+1: the n-th image's region (Vec4)
//
// The first image's size and region are represented in attribute variables.
//
// The size and region values are actually not used in this shader so far.
func ShaderProgramImages(imageNum int) shaderir.Program {
if imageNum <= 0 {
panic("testing: imageNum must be >= 1")
}
p := defaultProgram()
for i := 0; i < imageNum; i++ {
p.Uniforms = append(p.Uniforms, shaderir.Type{Main: shaderir.Texture2D})
if i > 0 {
p.Uniforms = append(p.Uniforms, shaderir.Type{Main: shaderir.Vec4})
}
}
// In the fragment shader, local variables are:
//
// 0: Varying variables (vec2)
// 1: gl_FragCoord
// 2: gl_FragColor
// 3: Actual local variables in the main function
local := shaderir.Expr{
Type: shaderir.LocalVariable,
Index: 3,
}
fragColor := shaderir.Expr{
Type: shaderir.LocalVariable,
Index: 2,
}
texPos := shaderir.Expr{
Type: shaderir.LocalVariable,
Index: 0,
}
var stmts []shaderir.Stmt
for i := 0; i < imageNum; i++ {
var rhs shaderir.Expr
if i == 0 {
rhs = shaderir.Expr{
Type: shaderir.Call,
Exprs: []shaderir.Expr{
{
Type: shaderir.BuiltinFuncExpr,
BuiltinFunc: shaderir.Texture2DF,
},
{
Type: shaderir.UniformVariable,
Index: 1,
},
texPos,
},
}
} else {
rhs = shaderir.Expr{
Type: shaderir.Binary,
Op: shaderir.Add,
Exprs: []shaderir.Expr{
local,
{
Type: shaderir.Call,
Exprs: []shaderir.Expr{
{
Type: shaderir.BuiltinFuncExpr,
BuiltinFunc: shaderir.Texture2DF,
},
{
Type: shaderir.UniformVariable,
Index: 2 * i,
},
texPos,
},
},
},
}
}
stmts = append(stmts, shaderir.Stmt{
Type: shaderir.Assign,
Exprs: []shaderir.Expr{
local,
rhs,
},
})
}
stmts = append(stmts, shaderir.Stmt{
Type: shaderir.Assign,
Exprs: []shaderir.Expr{
fragColor,
local,
},
})
p.FragmentFunc = shaderir.FragmentFunc{
Block: shaderir.Block{
LocalVars: []shaderir.Type{
{Main: shaderir.Vec4},
},
Stmts: stmts,
},
}
return p
}