every pipeline builder call clears the buffer, so only the last viewport is shown

2 files changed, 60 insertions, 17 deletions

diff --git a/src/constants.rs b/src/constants.rs
new file mode 100644
index 0000000..4f87ae4
--- /dev/null
+++ b/src/constants.rs
@@ -0,0 +1,2 @@
+pub const WIDTH: u32 = 640;
+pub const HEIGHT: u32 = 480;
diff --git a/src/main.rs b/src/main.rs
index bf607eb..07d3857 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
+pub mod constants;
 use luminance::context::GraphicsContext;
-use luminance::pipeline::PipelineState;
+use luminance::pipeline::{PipelineState, Viewport};
 use luminance::render_state::RenderState;
 use luminance::shader::program::Program;
 use luminance::tess::{Mode, TessBuilder, TessSliceIndex};
@@ -50,10 +51,47 @@ fn alter_vertices(vertices: &mut Vec<Vertex>) {
     }
 }
 
+fn gen_viewports() -> Vec<Viewport> {
+    let mut viewports = Vec::new();
+
+    viewports.push(Viewport::Specific {
+        x: 0,
+        y: 0,
+        width: constants::WIDTH / 2,
+        height: constants::HEIGHT / 2,
+    });
+
+    viewports.push(Viewport::Specific {
+        x: 0,
+        y: constants::WIDTH / 2,
+        width: constants::WIDTH / 2,
+        height: constants::HEIGHT / 2,
+    });
+
+    viewports.push(Viewport::Specific {
+        x: constants::WIDTH / 2,
+        y: 0,
+        width: constants::WIDTH / 2,
+        height: constants::HEIGHT / 2,
+    });
+
+    viewports.push(Viewport::Specific {
+        x: constants::WIDTH / 2,
+        y: constants::HEIGHT / 2,
+        width: constants::WIDTH / 2,
+        height: constants::HEIGHT / 2,
+    });
+
+    viewports
+}
+
 fn main() {
-    let mut surface =
-        GlfwSurface::new(WindowDim::Windowed(500, 500), "art", WindowOpt::default()).unwrap();
-    //GlfwSurface::new(WindowDim::Fullscreen, "art", WindowOpt::default()).unwrap();
+    let mut surface = GlfwSurface::new(
+        WindowDim::Windowed(constants::WIDTH, constants::HEIGHT),
+        "art",
+        WindowOpt::default(),
+    )
+    .unwrap();
 
     let program: Program<VertexSemantics, (), ()> =
         Program::from_strings(None, include_str!("vs.glsl"), None, include_str!("fs.glsl"))
@@ -61,18 +99,16 @@ fn main() {
             .ignore_warnings();
 
     let mut vertices = gen_vertices();
+    let viewports = gen_viewports();
 
     let mut run = true;
-
     while run {
         for event in surface.poll_events() {
             if let WindowEvent::Close = event {
                 run = false;
             }
         }
-
         let back_buffer = surface.back_buffer().unwrap();
-
         alter_vertices(&mut vertices);
 
         let triangle = TessBuilder::new(&mut surface)
@@ -81,17 +117,22 @@ fn main() {
             .build()
             .unwrap();
 
-        surface.pipeline_builder().pipeline(
-            &back_buffer,
-            &PipelineState::default(),
-            |_pipeline, mut shd_gate| {
-                shd_gate.shade(&program, |_, mut rdr_gate| {
-                    rdr_gate.render(&RenderState::default(), |mut tess_gate| {
-                        tess_gate.render(triangle.slice(..));
+        let mut pipeline_state = PipelineState::default();
+        for viewport in viewports.iter() {
+            pipeline_state = pipeline_state.set_viewport(*viewport);
+
+            surface.pipeline_builder().pipeline(
+                &back_buffer,
+                &pipeline_state,
+                |_pipeline, mut shd_gate| {
+                    shd_gate.shade(&program, |_, mut rdr_gate| {
+                        rdr_gate.render(&RenderState::default(), |mut tess_gate| {
+                            tess_gate.render(triangle.slice(..));
+                        });
                     });
-                });
-            },
-        );
+                },
+            );
+        }
 
         surface.swap_buffers();
     }