GLSL++ Documentation

Overview

GLSL++ is an extended preprocessor designed to enhance code reusability, modularity, and maintainability while maintaining compatibility with standard GLSL compilers.

Features

• Module Imports: Supports import statements for modular code.
• Instance Method Transformation: Converts Struct::method() syntax into function calls.
• Syntactic Sugar for Method Calls: Rewrites object.method(args) to Struct_method(object, args).
• Automatic File Watching: Watches .glslp files and generates .glsl files on changes.

Installation

GLSL++ requires Bun for execution. Install Bun first:

curl -fsSL https://bun.sh/install | bash

Clone the repository and install dependencies:

git clone https://github.com/your-repo/glslpp.git
cd glslpp
bun install

Usage

Transpile a Single File

bun run glslpp input_shader.glslp

Watch for File Changes

bun run glslpp watch shader.glslp

Example

Input Shader (shader.glslp)

import "common.glsl"

#define SHIFT_X 10
#define SHIFT_Y 01
#define SHIFT_XY 11
#define MIDDLE_MAN_REDUCTION 0.5

struct ChromaticAbberation {
    float shift;
    vec3 lastChromaticTransformation;
    int shiftMode;
    vec2 tUv;
};

void ChromaticAbberation::new(inout ChromaticAbberation self, int shiftMode, vec2 uv) {
    self.shiftMode = shiftMode;
    self.tUv = uv;
}

vec3 ChromaticAbberation::getChromaticAbberation(inout ChromaticAbberation self, sampler2D txt) {
    vec2 uvDisplacement = vec2(0.0, 0.0);
    if (self.shiftMode == SHIFT_X) uvDisplacement.x = self.shift;
    if (self.shiftMode == SHIFT_Y) uvDisplacement.y = self.shift;
    if (self.shiftMode == SHIFT_XY) uvDisplacement = vec2(self.shift);
    vec4 textureShift0 = texture(txt, self.tUv);
    vec4 textureShift1 = texture(txt, self.tUv + uvDisplacement * MIDDLE_MAN_REDUCTION);
    vec4 textureShift2 = texture(txt, self.tUv + uvDisplacement);
    vec3 abberation = vec3(textureShift0.r, textureShift1.g, textureShift2.b);
    self.lastChromaticTransformation = abberation;
    return abberation;
}

void ChromaticAbberation::setShift(inout ChromaticAbberation self, float shift) {
    self.shift = shift;
}

void ChromaticAbberation::setUv(inout ChromaticAbberation self, vec2 uv) {
    self.tUv = uv;
}

Processed Output (shader.glsl)

// Contents of common.glsl

#define SHIFT_X 10
#define SHIFT_Y 01
#define SHIFT_XY 11
#define MIDDLE_MAN_REDUCTION 0.5

struct ChromaticAbberation {
    float shift;
    vec3 lastChromaticTransformation;
    int shiftMode;
    vec2 tUv;
};

void ChromaticAbberation_new(inout ChromaticAbberation self, int shiftMode, vec2 uv) {
    self.shiftMode = shiftMode;
    self.tUv = uv;
}

vec3 ChromaticAbberation_getChromaticAbberation(inout ChromaticAbberation self, sampler2D txt) {
    vec2 uvDisplacement = vec2(0.0, 0.0);
    if (self.shiftMode == SHIFT_X) uvDisplacement.x = self.shift;
    if (self.shiftMode == SHIFT_Y) uvDisplacement.y = self.shift;
    if (self.shiftMode == SHIFT_XY) uvDisplacement = vec2(self.shift);
    vec4 textureShift0 = texture(txt, self.tUv);
    vec4 textureShift1 = texture(txt, self.tUv + uvDisplacement * MIDDLE_MAN_REDUCTION);
    vec4 textureShift2 = texture(txt, self.tUv + uvDisplacement);
    vec3 abberation = vec3(textureShift0.r, textureShift1.g, textureShift2.b);
    self.lastChromaticTransformation = abberation;
    return abberation;
}

void ChromaticAbberation_setShift(inout ChromaticAbberation self, float shift) {
    self.shift = shift;
}

void ChromaticAbberation_setUv(inout ChromaticAbberation self, vec2 uv) {
    self.tUv = uv;
}

How It Works

import "file.glsl"

Includes the content of another GLSL file before preprocessing.

Struct::method() Syntax

Transforms instance methods into standalone functions prefixed with Struct_.

object.method(args) Syntax

Rewrites method calls to Struct_method(object, args), ensuring compatibility with GLSL.

License

GLSL++ is licensed under MIT. Contributions are welcome!