1 files changed, 366 insertions, 0 deletions
diff --git a/opengl-bindings/src/shader.rs b/opengl-bindings/src/shader.rs
new file mode 100644
index 0000000..5ed66a2
--- /dev/null
+++ b/opengl-bindings/src/shader.rs
@@ -0,0 +1,366 @@
+use std::ffi::CStr;
+use std::ptr::null_mut;
+
+use safer_ffi::layout::ReprC;
+
+use crate::data_types::{Matrix, Vec3};
+use crate::CurrentContextWithFns;
+
+#[derive(Debug)]
+pub struct Shader
+{
+    shader: crate::sys::types::GLuint,
+}
+
+impl Shader
+{
+    #[must_use]
+    pub fn new(current_context: &CurrentContextWithFns<'_>, kind: Kind) -> Self
+    {
+        let shader = unsafe {
+            current_context
+                .fns()
+                .CreateShader(kind as crate::sys::types::GLenum)
+        };
+
+        Self { shader }
+    }
+
+    /// Sets the source code of this shader.
+    ///
+    /// # Errors
+    /// Returns `Err` if `source` is not ASCII.
+    pub fn set_source(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        source: &str,
+    ) -> Result<(), Error>
+    {
+        if !source.is_ascii() {
+            return Err(Error::SourceNotAscii);
+        }
+
+        let length: crate::sys::types::GLint =
+            source.len().try_into().map_err(|_| Error::SourceTooLarge {
+                length: source.len(),
+                max_length: crate::sys::types::GLint::MAX as usize,
+            })?;
+
+        unsafe {
+            current_context.fns().ShaderSource(
+                self.shader,
+                1,
+                &source.as_ptr().cast(),
+                &raw const length,
+            );
+        }
+
+        Ok(())
+    }
+
+    /// Compiles this shader.
+    ///
+    /// # Errors
+    /// Returns `Err` if compiling fails.
+    pub fn compile(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+    ) -> Result<(), Error>
+    {
+        unsafe {
+            current_context.fns().CompileShader(self.shader);
+        }
+
+        let mut compile_success = crate::sys::types::GLint::default();
+
+        unsafe {
+            current_context.fns().GetShaderiv(
+                self.shader,
+                crate::sys::COMPILE_STATUS,
+                &raw mut compile_success,
+            );
+        }
+
+        if compile_success == 0 {
+            let info_log = self.get_info_log(current_context);
+
+            return Err(Error::CompileFailed { log: info_log });
+        }
+
+        Ok(())
+    }
+
+    pub fn delete(self, current_context: &CurrentContextWithFns<'_>)
+    {
+        unsafe {
+            current_context.fns().DeleteShader(self.shader);
+        }
+    }
+
+    fn get_info_log(&self, current_context: &CurrentContextWithFns<'_>) -> String
+    {
+        const BUF_SIZE: crate::sys::types::GLsizei = 512;
+
+        let mut buf = vec![crate::sys::types::GLchar::default(); BUF_SIZE as usize];
+
+        unsafe {
+            current_context.fns().GetShaderInfoLog(
+                self.shader,
+                BUF_SIZE,
+                null_mut(),
+                buf.as_mut_ptr(),
+            );
+        }
+
+        let info_log = unsafe { CStr::from_ptr(buf.as_ptr()) };
+
+        unsafe { String::from_utf8_unchecked(info_log.to_bytes().to_vec()) }
+    }
+}
+
+/// Shader kind.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[repr(u32)]
+pub enum Kind
+{
+    Vertex = crate::sys::VERTEX_SHADER,
+    Fragment = crate::sys::FRAGMENT_SHADER,
+}
+
+/// Shader program
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub struct Program
+{
+    program: crate::sys::types::GLuint,
+}
+
+impl Program
+{
+    #[must_use]
+    pub fn new(current_context: &CurrentContextWithFns<'_>) -> Self
+    {
+        let program = unsafe { current_context.fns().CreateProgram() };
+
+        Self { program }
+    }
+
+    pub fn attach(&self, current_context: &CurrentContextWithFns<'_>, shader: &Shader)
+    {
+        unsafe {
+            current_context
+                .fns()
+                .AttachShader(self.program, shader.shader);
+        }
+    }
+
+    /// Links this program.
+    ///
+    /// # Errors
+    /// Returns `Err` if linking fails.
+    pub fn link(&self, current_context: &CurrentContextWithFns<'_>) -> Result<(), Error>
+    {
+        unsafe {
+            current_context.fns().LinkProgram(self.program);
+        }
+
+        let mut link_success = crate::sys::types::GLint::default();
+
+        unsafe {
+            current_context.fns().GetProgramiv(
+                self.program,
+                crate::sys::LINK_STATUS,
+                &raw mut link_success,
+            );
+        }
+
+        if link_success == 0 {
+            let info_log = self.get_info_log(current_context);
+
+            return Err(Error::LinkFailed { log: info_log });
+        }
+
+        Ok(())
+    }
+
+    pub fn activate(&self, current_context: &CurrentContextWithFns<'_>)
+    {
+        unsafe {
+            current_context.fns().UseProgram(self.program);
+        }
+    }
+
+    pub fn set_uniform(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        name: &CStr,
+        var: &impl UniformVariable,
+    )
+    {
+        let location = UniformLocation(unsafe {
+            current_context
+                .fns()
+                .GetUniformLocation(self.program, name.as_ptr().cast())
+        });
+
+        var.set(current_context, self, location);
+    }
+
+    pub fn delete(self, current_context: &CurrentContextWithFns<'_>)
+    {
+        unsafe {
+            current_context.fns().DeleteProgram(self.program);
+        }
+    }
+
+    fn get_info_log(&self, current_context: &CurrentContextWithFns<'_>) -> String
+    {
+        const BUF_SIZE: crate::sys::types::GLsizei = 512;
+
+        let mut buf = vec![crate::sys::types::GLchar::default(); BUF_SIZE as usize];
+
+        unsafe {
+            current_context.fns().GetProgramInfoLog(
+                self.program,
+                BUF_SIZE,
+                null_mut(),
+                buf.as_mut_ptr(),
+            );
+        }
+
+        let info_log = unsafe { CStr::from_ptr(buf.as_ptr()) };
+
+        unsafe { String::from_utf8_unchecked(info_log.to_bytes().to_vec()) }
+    }
+}
+
+pub trait UniformVariable: ReprC + sealed::Sealed
+{
+    fn set(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        program: &Program,
+        uniform_location: UniformLocation,
+    );
+}
+
+impl UniformVariable for f32
+{
+    fn set(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        program: &Program,
+        uniform_location: UniformLocation,
+    )
+    {
+        unsafe {
+            current_context.fns().ProgramUniform1f(
+                program.program,
+                uniform_location.0,
+                *self,
+            );
+        }
+    }
+}
+
+impl sealed::Sealed for f32 {}
+
+impl UniformVariable for i32
+{
+    fn set(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        program: &Program,
+        uniform_location: UniformLocation,
+    )
+    {
+        unsafe {
+            current_context.fns().ProgramUniform1i(
+                program.program,
+                uniform_location.0,
+                *self,
+            );
+        }
+    }
+}
+
+impl sealed::Sealed for i32 {}
+
+impl UniformVariable for Vec3<f32>
+{
+    fn set(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        program: &Program,
+        uniform_location: UniformLocation,
+    )
+    {
+        unsafe {
+            current_context.fns().ProgramUniform3f(
+                program.program,
+                uniform_location.0,
+                self.x,
+                self.y,
+                self.z,
+            );
+        }
+    }
+}
+
+impl sealed::Sealed for Vec3<f32> {}
+
+impl UniformVariable for Matrix<f32, 4, 4>
+{
+    fn set(
+        &self,
+        current_context: &CurrentContextWithFns<'_>,
+        program: &Program,
+        uniform_location: UniformLocation,
+    )
+    {
+        unsafe {
+            current_context.fns().ProgramUniformMatrix4fv(
+                program.program,
+                uniform_location.0,
+                1,
+                crate::sys::FALSE,
+                self.items.as_ptr().cast::<f32>(),
+            );
+        }
+    }
+}
+
+impl sealed::Sealed for Matrix<f32, 4, 4> {}
+
+#[derive(Debug)]
+pub struct UniformLocation(crate::sys::types::GLint);
+
+/// Shader error.
+#[derive(Debug, thiserror::Error)]
+pub enum Error
+{
+    #[error("All characters in source are not within the ASCII range")]
+    SourceNotAscii,
+
+    #[error("Source is too large. Length ({length}) must be < {max_length}")]
+    SourceTooLarge
+    {
+        length: usize, max_length: usize
+    },
+
+    #[error("Failed to compile shader")]
+    CompileFailed
+    {
+        log: String
+    },
+
+    #[error("Failed to link shader program")]
+    LinkFailed
+    {
+        log: String
+    },
+}
+
+mod sealed
+{
+    pub trait Sealed {}
+}