From 0e02f904424fbd7a8283083e57faf291e311790f Mon Sep 17 00:00:00 2001
From: Ian Chamberlain <ian.h.chamberlain@gmail.com>
Date: Sat, 25 Nov 2023 00:13:35 -0500
Subject: [PATCH] Initial texenv implementation

---
 citro3d-sys/bindgen.sh       |  5 --
 citro3d/examples/triangle.rs | 25 +++------
 citro3d/src/lib.rs           |  1 +
 citro3d/src/texenv.rs        | 99 ++++++++++++++++++++++++++++++++++++
 4 files changed, 106 insertions(+), 24 deletions(-)
 delete mode 100755 citro3d-sys/bindgen.sh
 create mode 100644 citro3d/src/texenv.rs

diff --git a/citro3d-sys/bindgen.sh b/citro3d-sys/bindgen.sh
deleted file mode 100755
index ebb4ff9..0000000
--- a/citro3d-sys/bindgen.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/usr/bin/env bash
-
-set -euxo pipefail
-
-cargo run --package bindgen-citro3d > src/bindings.rs
diff --git a/citro3d/examples/triangle.rs b/citro3d/examples/triangle.rs
index a6a5152..ca1358a 100644
--- a/citro3d/examples/triangle.rs
+++ b/citro3d/examples/triangle.rs
@@ -6,6 +6,7 @@
 use citro3d::macros::include_shader;
 use citro3d::math::{AspectRatio, ClipPlanes, Matrix4, Projection, StereoDisplacement};
 use citro3d::render::ClearFlags;
+use citro3d::texenv::{self, CombineFunc, TexEnv};
 use citro3d::{attrib, buffer, render, shader};
 use ctru::prelude::*;
 use ctru::services::gfx::{RawFrameBuffer, Screen, TopScreen3D};
@@ -88,7 +89,11 @@ fn main() {
     let mut buf_info = buffer::Info::new();
     let (attr_info, vbo_idx) = prepare_vbos(&mut buf_info, &vbo_data);
 
-    scene_init();
+    // Configure the first fragment shading substage to just pass through the vertex color
+    // See https://www.opengl.org/sdk/docs/man2/xhtml/glTexEnv.xml for more insight
+    TexEnv::get(&mut instance, texenv::Id(0))
+        .src(texenv::Mode::BOTH, texenv::Source::PrimaryColor, None, None)
+        .func(texenv::Mode::BOTH, CombineFunc::Replace);
 
     let projection_uniform_idx = program.get_uniform("projection").unwrap();
 
@@ -191,21 +196,3 @@ fn calculate_projections() -> Projections {
         center,
     }
 }
-
-fn scene_init() {
-    // Load the vertex shader, create a shader program and bind it
-    unsafe {
-        // Configure the first fragment shading substage to just pass through the vertex color
-        // See https://www.opengl.org/sdk/docs/man2/xhtml/glTexEnv.xml for more insight
-        let env = citro3d_sys::C3D_GetTexEnv(0);
-        citro3d_sys::C3D_TexEnvInit(env);
-        citro3d_sys::C3D_TexEnvSrc(
-            env,
-            citro3d_sys::C3D_Both,
-            ctru_sys::GPU_PRIMARY_COLOR,
-            0,
-            0,
-        );
-        citro3d_sys::C3D_TexEnvFunc(env, citro3d_sys::C3D_Both, ctru_sys::GPU_REPLACE);
-    }
-}
diff --git a/citro3d/src/lib.rs b/citro3d/src/lib.rs
index 9368b5c..3cdd983 100644
--- a/citro3d/src/lib.rs
+++ b/citro3d/src/lib.rs
@@ -15,6 +15,7 @@ pub mod error;
 pub mod math;
 pub mod render;
 pub mod shader;
+pub mod texenv;
 pub mod uniform;
 
 pub use error::{Error, Result};
diff --git a/citro3d/src/texenv.rs b/citro3d/src/texenv.rs
new file mode 100644
index 0000000..fc5798a
--- /dev/null
+++ b/citro3d/src/texenv.rs
@@ -0,0 +1,99 @@
+//! Texture environment support. See `<c3d/texenv.h>` for more information.
+
+use bitflags::bitflags;
+
+use crate::Instance;
+
+#[doc(alias = "C3D_TexEnv")]
+pub struct TexEnv<'a> {
+    raw: *mut citro3d_sys::C3D_TexEnv,
+    _instance: &'a mut Instance,
+}
+
+impl<'a> TexEnv<'a> {
+    #[doc(alias = "C3D_TexEnvInit")]
+    pub fn set(&self, _instance: &mut Instance, id: Id) {
+        unsafe {
+            // SAFETY: pointee is only copied from, not modified
+            citro3d_sys::C3D_SetTexEnv(id.0, self.raw);
+        }
+    }
+
+    pub fn get(instance: &'a mut Instance, id: Id) -> Self {
+        unsafe {
+            Self {
+                raw: citro3d_sys::C3D_GetTexEnv(id.0),
+                _instance: instance,
+            }
+        }
+    }
+
+    pub fn src(
+        &mut self,
+        mode: Mode,
+        s1: Source,
+        s2: Option<Source>,
+        s3: Option<Source>,
+    ) -> &mut Self {
+        unsafe {
+            citro3d_sys::C3D_TexEnvSrc(
+                self.raw,
+                mode.bits(),
+                s1 as _,
+                s2.unwrap_or(Source::PrimaryColor) as _,
+                s3.unwrap_or(Source::PrimaryColor) as _,
+            )
+        }
+        self
+    }
+
+    pub fn func(&mut self, mode: Mode, func: CombineFunc) -> &mut Self {
+        unsafe {
+            citro3d_sys::C3D_TexEnvFunc(self.raw, mode.bits(), func as _);
+        }
+
+        self
+    }
+}
+
+bitflags! {
+    #[doc(alias = "C3D_TexEnvMode")]
+    pub struct Mode: citro3d_sys::C3D_TexEnvMode {
+        const RGB = citro3d_sys::C3D_RGB;
+        const ALPHA = citro3d_sys::C3D_Alpha;
+        const BOTH = citro3d_sys::C3D_Both;
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u32)]
+#[doc(alias = "GPU_TEVSRC")]
+pub enum Source {
+    PrimaryColor = ctru_sys::GPU_PRIMARY_COLOR,
+    FragmentPrimaryColor = ctru_sys::GPU_FRAGMENT_PRIMARY_COLOR,
+    FragmentSecondaryColor = ctru_sys::GPU_FRAGMENT_SECONDARY_COLOR,
+    Texture0 = ctru_sys::GPU_TEXTURE0,
+    Texture1 = ctru_sys::GPU_TEXTURE1,
+    Texture2 = ctru_sys::GPU_TEXTURE2,
+    Texture3 = ctru_sys::GPU_TEXTURE3,
+    PreviousBuffer = ctru_sys::GPU_PREVIOUS_BUFFER,
+    Constant = ctru_sys::GPU_CONSTANT,
+    Previous = ctru_sys::GPU_PREVIOUS,
+}
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u32)]
+#[doc(alias = "GPU_COMBINEFUNC")]
+pub enum CombineFunc {
+    Replace = ctru_sys::GPU_REPLACE,
+    Modulate = ctru_sys::GPU_MODULATE,
+    Add = ctru_sys::GPU_ADD,
+    AddSigned = ctru_sys::GPU_ADD_SIGNED,
+    Interpolate = ctru_sys::GPU_INTERPOLATE,
+    Subtract = ctru_sys::GPU_SUBTRACT,
+    Dot3Rgb = ctru_sys::GPU_DOT3_RGB,
+    Dot3Rgba = ctru_sys::GPU_DOT3_RGBA,
+}
+
+#[derive(Copy, Clone, Debug)]
+pub struct Id(/* TODO maybe non pub? idk */ pub libc::c_int);