Renderer general cleanup

src/Renderer.zig

@@ -15,7 +15,6 @@ color: [4]f32,
 pub fn init() !Self {
     try sdl.init(.{ .video = true, .audio = true, .events = true });
 
-    // Set OpenGL version
     try sdl.gl.setAttribute(.{ .context_major_version = 3 });
     try sdl.gl.setAttribute(.{ .context_minor_version = 3 });
     try sdl.gl.setAttribute(.{ .multisamplebuffers = true });
@@ -27,43 +26,52 @@ pub fn init() !Self {
         .{ .centered = {} },
         1280,
         720,
-        .{ .context = .opengl, .vis = .shown }
+        .{ .context = .opengl, .vis = .shown },
     );
 
     const ctx = try sdl.gl.createContext(window);
-    sdl.gl.setSwapInterval( .immediate ) catch {
+    sdl.gl.setSwapInterval(.immediate) catch {
         std.debug.print("WARNING: Unable to configure the swap interval.\n", .{});
     };
 
+    // Shader stuff
     var mvp_loc: u32 = undefined;
     var color_loc: u32 = undefined;
     const program = gl.Program.create();
     {
         const vs = gl.Shader.create(.vertex);
         defer vs.delete();
-        vs.source(1, &.{@embedFile("shaders/vector.vs")});
-        vs.compile();
         const fs = gl.Shader.create(.fragment);
         defer fs.delete();
+
+        vs.source(1, &.{@embedFile("shaders/vector.vs")});
         fs.source(1, &.{@embedFile("shaders/fragment.fs")});
+
+        vs.compile();
         fs.compile();
+
         program.attach(vs);
         defer program.detach(vs);
         program.attach(fs);
         defer program.detach(fs);
+
         program.link();
+
         mvp_loc = program.uniformLocation("mvp").?;
         color_loc = program.uniformLocation("color").?;
     }
     program.use();
 
-    var wsize = window.getSize();
-    var xunit = @intToFloat(f32, wsize.width);
-    var yunit = @intToFloat(f32, wsize.height);
+    // Get the matrix that converts coordinates to 1:1 on the screen from the OpenGL default
+    {
+        const wsize = window.getSize();
+        const xunit = @intToFloat(f32, wsize.width);
+        const yunit = @intToFloat(f32, wsize.height);
 
-    const ortho = m.Mat4.createOrthogonal(0.0, xunit, yunit, 0.0, 0.0, 100.0);
+        const ortho = m.Mat4.createOrthogonal(0.0, xunit, yunit, 0.0, 0.0, 100.0);
 
-    gl.uniformMatrix4fv(mvp_loc, false, &.{ ortho.fields });
+        gl.uniformMatrix4fv(mvp_loc, false, &.{ortho.fields});
+    }
 
     var vertex_array = gl.VertexArray.gen();
     vertex_array.bind();
@@ -73,21 +81,15 @@ pub fn init() !Self {
 
     gl.clearColor(0.91, 0.97, 1.00, 1.00);
 
+    // TODO: See if there's a more optimal solution to this, maybe activating only when necessary
     gl.enable(.blend);
     gl.blendFunc(.src_alpha, .one_minus_src_alpha);
 
-    return Self{
-        .window = window,
-        .context = ctx,
-        .color_loc = color_loc,
-        .buffer = buf,
-        .color = .{0,0,0,0}
-    };
+    return Self{ .window = window, .context = ctx, .color_loc = color_loc, .buffer = buf, .color = .{ 0, 0, 0, 0 } };
 }
 
 pub fn render(self: Self) void {
     sdl.gl.swapWindow(self.window);
-
     gl.clear(.{ .color = true });
 }
 
@@ -99,65 +101,44 @@ pub fn deinit(self: Self) void {
 
 pub fn setColor(self: *Self, r: u8, g: i32, b: i32, a: i32) void {
     self.*.color = .{
-        @intToFloat(f32, r)/255.0,
-        @intToFloat(f32, g)/255.0,
-        @intToFloat(f32, b)/255.0,
-        @intToFloat(f32, a)/255.0,
+        @intToFloat(f32, r) / 255.0,
+        @intToFloat(f32, g) / 255.0,
+        @intToFloat(f32, b) / 255.0,
+        @intToFloat(f32, a) / 255.0,
     };
 }
 
-pub fn drawRectangle(self: *Self, x: i32, y: i32, w: i32, h: i32) void {
+pub fn drawRectangle(self: Self, x: i32, y: i32, w: i32, h: i32) void {
+    const indices = [_]u8{ 0, 1, 1, 2, 2, 3, 3, 0 };
+    self.renderRectangle(x, y, w, h, .lines, &indices);
+}
+
+pub fn fillRectangle(self: Self, x: i32, y: i32, w: i32, h: i32) void {
+    const indices = [_]u8{ 1, 3, 0, 1, 3, 2 };
+    self.renderRectangle(x, y, w, h, .triangles, &indices);
+}
+
+fn renderRectangle(self: Self, x: i32, y: i32, w: i32, h: i32, primitive: gl.PrimitiveType, indices: []const u8) void {
+    gl.uniform4fv(self.color_loc, &.{self.color});
+
     var xf = @intToFloat(f32, x);
     var yf = @intToFloat(f32, y);
     var wf = @intToFloat(f32, w);
     var hf = @intToFloat(f32, h);
 
-    gl.enableVertexAttribArray(0);
     gl.vertexAttribPointer(0, 2, .float, false, 0, 0);
 
     const vertex_buffer = [_]f32{
-        xf,      yf     ,
-        xf + wf, yf     ,
-        xf + wf, yf + hf,
-        xf,      yf + hf,
+        xf     , yf     , // up-left
+        xf + wf, yf     , // up-right
+        xf + wf, yf + hf, // down-right
+        xf     , yf + hf, // down-left
     };
 
-    const indices = [_]u8{0, 1, 1, 2, 2, 3, 3, 0};
-
     self.buffer.data(f32, &vertex_buffer, .static_draw);
 
-    gl.uniform4fv(self.color_loc, &.{ self.color });
-    _ = indices;
-
-    gl.drawElements(.lines, 8, .u8, @ptrToInt(&indices));
-
-    gl.disableVertexAttribArray(0);
-}
-
-pub fn fillRectangle(self: *Self, x: i32, y: i32, w: i32, h: i32) void {
-    var xf = @intToFloat(f32, x);
-    var yf = @intToFloat(f32, y);
-    var wf = @intToFloat(f32, w);
-    var hf = @intToFloat(f32, h);
-
     gl.enableVertexAttribArray(0);
-    gl.vertexAttribPointer(0, 2, .float, false, 0, 0);
-
-    const vertex_buffer = [_]f32{
-        xf + wf, yf     ,
-        xf,      yf + hf,
-        xf,      yf     ,
-        xf + wf, yf + hf,
-    };
-
-    const indices = [_]u8{0, 1, 2, 0, 1, 3};
-
-    self.buffer.data(f32, &vertex_buffer, .static_draw);
-
-    gl.uniform4fv(self.color_loc, &.{ self.color });
-
-    gl.drawElements(.triangles, 6, .u8, @ptrToInt(&indices));
-
+    gl.drawElements(primitive, indices.len, .u8, @ptrToInt(indices.ptr));
     gl.disableVertexAttribArray(0);
 }