1 files changed, 100 insertions, 0 deletions
diff --git a/src/framebuffer.rs b/src/framebuffer.rs
new file mode 100644
index 0000000..c0ac72b
--- /dev/null
+++ b/src/framebuffer.rs
@@ -0,0 +1,100 @@
+use glow::HasContext;
+
+use crate::context;
+
+pub struct Framebuffer {
+    pub tex: Option<glow::Texture>,
+    pub fbo: Option<glow::Framebuffer>,
+    pub dims: glam::Vec2,
+    pub offsets: glam::Vec2,
+}
+
+impl Framebuffer {
+    pub fn screen(ctx: &context::Context) -> Self {
+        let (windoww, windowh): (f32, f32) = ctx.window.inner_size().into();
+        let ratio = context::compute_upscale(windoww as _, windowh as _) as f32;
+        let upscalew = context::RENDER_WIDTH * ratio;
+        let upscaleh = context::RENDER_HEIGHT * ratio;
+        let offsetx = (windoww - upscalew) / 2.0;
+        let offsety = (windowh - upscaleh) / 2.0;
+        log::info!("{} {} {} {} {} {}", windoww, windowh, upscalew, upscaleh, offsetx, offsety);
+        Self {
+            tex: None,
+            fbo: None,
+            dims: glam::Vec2::new(upscalew, upscaleh),
+            offsets: glam::Vec2::new(offsetx, offsety),
+        }
+    }
+
+    pub fn new(ctx: &context::Context, dims: &glam::Vec2, offsets: &glam::Vec2) -> Self {
+        unsafe {
+            let fbo = ctx.gl.create_framebuffer()
+                .expect("failed to create framebuffer");
+            ctx.gl.bind_framebuffer(glow::FRAMEBUFFER, Some(fbo));
+
+            let depth_buffer = ctx.gl.create_renderbuffer()
+                .expect("failed to create depth buffer");
+            ctx.gl.bind_renderbuffer(glow::RENDERBUFFER, Some(depth_buffer));
+            ctx.gl.renderbuffer_storage(glow::RENDERBUFFER, glow::DEPTH_COMPONENT32F, dims.x as _, dims.y as _);
+            ctx.gl.framebuffer_renderbuffer(glow::FRAMEBUFFER, glow::DEPTH_ATTACHMENT, glow::RENDERBUFFER, Some(depth_buffer));
+
+            let stencil_buffer = ctx.gl.create_renderbuffer()
+                .expect("failed to create stencil buffer");
+            ctx.gl.bind_renderbuffer(glow::RENDERBUFFER, Some(stencil_buffer));
+            ctx.gl.renderbuffer_storage(glow::RENDERBUFFER, glow::DEPTH_STENCIL, dims.x as _, dims.y as _);
+            ctx.gl.framebuffer_renderbuffer(glow::FRAMEBUFFER, glow::DEPTH_STENCIL_ATTACHMENT, glow::RENDERBUFFER, Some(stencil_buffer));
+
+            let tex = ctx.gl.create_texture()
+                .expect("failed to create framebuffer texture");
+            ctx.gl.bind_texture(glow::TEXTURE_2D, Some(tex));
+            ctx.gl.tex_image_2d(
+                glow::TEXTURE_2D,
+                0,
+                glow::RGBA as _,
+                dims.x as _,
+                dims.y as _,
+                0,
+                glow::RGBA,
+                glow::UNSIGNED_BYTE,
+                None,
+            );
+            ctx.gl.tex_parameter_i32(glow::TEXTURE_2D, glow::TEXTURE_WRAP_S, glow::CLAMP_TO_EDGE as _);
+            ctx.gl.tex_parameter_i32(glow::TEXTURE_2D, glow::TEXTURE_WRAP_T, glow::CLAMP_TO_EDGE as _);
+            ctx.gl.tex_parameter_i32(glow::TEXTURE_2D, glow::TEXTURE_MIN_FILTER, glow::NEAREST as _);
+            ctx.gl.tex_parameter_i32(glow::TEXTURE_2D, glow::TEXTURE_MAG_FILTER, glow::NEAREST as _);
+            ctx.gl.framebuffer_texture_2d(glow::FRAMEBUFFER, glow::COLOR_ATTACHMENT0, glow::TEXTURE_2D, Some(tex), 0);
+            ctx.gl.draw_buffer(glow::COLOR_ATTACHMENT0);
+
+            let status = ctx.gl.check_framebuffer_status(glow::FRAMEBUFFER);
+            if status != glow::FRAMEBUFFER_COMPLETE {
+                panic!("error initializing framebuffer:\n{}", status);
+            }
+
+            Self {
+                tex: Some(tex),
+                fbo: Some(fbo),
+                dims: dims.clone(),
+                offsets: offsets.clone(),
+            }
+        }
+    }
+
+    pub fn bind_texture(&self, ctx: &context::Context) {
+        unsafe {
+            ctx.gl.active_texture(glow::TEXTURE0);
+            ctx.gl.bind_texture(glow::TEXTURE_2D, self.tex);
+        }
+    }
+
+    pub fn bind(&self, ctx: &context::Context) {
+        unsafe {
+            ctx.gl.bind_framebuffer(glow::FRAMEBUFFER, self.fbo);
+            ctx.gl.viewport(
+                self.offsets.x as _,
+                self.offsets.y as _,
+                self.dims.x as _,
+                self.dims.y as _,
+            );
+        }
+    }
+}