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|
use std::ffi::CStr;
use std::fmt;
use crate::gl;
use crate::gl::types::*;
/// A wrapper for a shader program id, with automatic lifetime management.
#[derive(Debug)]
pub struct ShaderProgram(GLuint);
#[derive(Copy, Clone, Debug)]
pub enum ShaderVersion {
/// OpenGL 3.3 core shaders.
Glsl3,
/// OpenGL ES 2.0 shaders.
Gles2,
}
impl ShaderVersion {
// Header to which we concatenate the entire shader. The newlines are required.
fn shader_header(&self) -> &'static str {
match self {
Self::Glsl3 => "#version 330 core\n",
Self::Gles2 => "#version 100\n#define GLES2_RENDERER\n",
}
}
}
impl ShaderProgram {
pub fn new(
shader_version: ShaderVersion,
shader_header: Option<&str>,
vertex_shader: &'static str,
fragment_shader: &'static str,
) -> Result<Self, ShaderError> {
let vertex_shader =
Shader::new(shader_version, shader_header, gl::VERTEX_SHADER, vertex_shader)?;
let fragment_shader =
Shader::new(shader_version, shader_header, gl::FRAGMENT_SHADER, fragment_shader)?;
let program = unsafe { Self(gl::CreateProgram()) };
let mut success: GLint = 0;
unsafe {
gl::AttachShader(program.id(), vertex_shader.id());
gl::AttachShader(program.id(), fragment_shader.id());
gl::LinkProgram(program.id());
gl::GetProgramiv(program.id(), gl::LINK_STATUS, &mut success);
}
if success != i32::from(gl::TRUE) {
return Err(ShaderError::Link(get_program_info_log(program.id())));
}
Ok(program)
}
/// Get uniform location by name. Panic if failed.
pub fn get_uniform_location(&self, name: &'static CStr) -> Result<GLint, ShaderError> {
// This call doesn't require `UseProgram`.
let ret = unsafe { gl::GetUniformLocation(self.id(), name.as_ptr()) };
if ret == -1 {
return Err(ShaderError::Uniform(name));
}
Ok(ret)
}
/// Get the shader program id.
pub fn id(&self) -> GLuint {
self.0
}
}
impl Drop for ShaderProgram {
fn drop(&mut self) {
unsafe { gl::DeleteProgram(self.0) }
}
}
/// A wrapper for a shader id, with automatic lifetime management.
#[derive(Debug)]
struct Shader(GLuint);
impl Shader {
fn new(
shader_version: ShaderVersion,
shader_header: Option<&str>,
kind: GLenum,
source: &'static str,
) -> Result<Self, ShaderError> {
let version_header = shader_version.shader_header();
let mut sources = Vec::<*const GLchar>::with_capacity(3);
let mut lengths = Vec::<GLint>::with_capacity(3);
sources.push(version_header.as_ptr().cast());
lengths.push(version_header.len() as GLint);
if let Some(shader_header) = shader_header {
sources.push(shader_header.as_ptr().cast());
lengths.push(shader_header.len() as GLint);
}
sources.push(source.as_ptr().cast());
lengths.push(source.len() as GLint);
let shader = unsafe { Self(gl::CreateShader(kind)) };
let mut success: GLint = 0;
unsafe {
gl::ShaderSource(
shader.id(),
lengths.len() as GLint,
sources.as_ptr().cast(),
lengths.as_ptr(),
);
gl::CompileShader(shader.id());
gl::GetShaderiv(shader.id(), gl::COMPILE_STATUS, &mut success);
}
if success == GLint::from(gl::TRUE) {
Ok(shader)
} else {
Err(ShaderError::Compile(get_shader_info_log(shader.id())))
}
}
fn id(&self) -> GLuint {
self.0
}
}
impl Drop for Shader {
fn drop(&mut self) {
unsafe { gl::DeleteShader(self.0) }
}
}
fn get_program_info_log(program: GLuint) -> String {
// Get expected log length.
let mut max_length: GLint = 0;
unsafe {
gl::GetProgramiv(program, gl::INFO_LOG_LENGTH, &mut max_length);
}
// Read the info log.
let mut actual_length: GLint = 0;
let mut buf: Vec<u8> = Vec::with_capacity(max_length as usize);
unsafe {
gl::GetProgramInfoLog(program, max_length, &mut actual_length, buf.as_mut_ptr() as *mut _);
}
// Build a string.
unsafe {
buf.set_len(actual_length as usize);
}
String::from_utf8_lossy(&buf).to_string()
}
fn get_shader_info_log(shader: GLuint) -> String {
// Get expected log length.
let mut max_length: GLint = 0;
unsafe {
gl::GetShaderiv(shader, gl::INFO_LOG_LENGTH, &mut max_length);
}
// Read the info log.
let mut actual_length: GLint = 0;
let mut buf: Vec<u8> = Vec::with_capacity(max_length as usize);
unsafe {
gl::GetShaderInfoLog(shader, max_length, &mut actual_length, buf.as_mut_ptr() as *mut _);
}
// Build a string.
unsafe {
buf.set_len(actual_length as usize);
}
String::from_utf8_lossy(&buf).to_string()
}
#[derive(Debug)]
pub enum ShaderError {
/// Error compiling shader.
Compile(String),
/// Error linking shader.
Link(String),
/// Error getting uniform location.
Uniform(&'static CStr),
}
impl std::error::Error for ShaderError {}
impl fmt::Display for ShaderError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Compile(reason) => write!(f, "Failed compiling shader: {}", reason),
Self::Link(reason) => write!(f, "Failed linking shader: {}", reason),
Self::Uniform(name) => write!(f, "Failed to get uniform location of {:?}", name),
}
}
}
|
