Create separate rendering functions

src/Renderer.zig

@@ -7,6 +7,7 @@ window: sdl.Window,
 context: sdl.gl.Context,
 color_loc: u32,
 buffer: gl.Buffer,
+color: [4]f32,
 
 pub fn init() !Self {
     try sdl.init(.{ .video = true, .audio = true, .events = true });
@@ -49,18 +50,8 @@ pub fn init() !Self {
     var vertex_array = gl.VertexArray.gen();
     vertex_array.bind();
 
-    const vertex_buffer = [_]f32{
-        -1.0, -1.0, 0.0,
-        -1.0, 1.0, 0.0,
-        0.0, 1.0, 0.0,
-        1.0, 1.0, 0.0,
-        0.0, -1.0, 0.0,
-        1.0, -1.0, 0.0,
-    };
-
     const buf = gl.Buffer.gen();
     buf.bind(.array_buffer);
-    buf.data(f32, &vertex_buffer, .static_draw);
 
     gl.clearColor(0.91, 0.97, 1.00, 1.00);
 
@@ -69,25 +60,14 @@ pub fn init() !Self {
         .context = ctx,
         .color_loc = color_loc,
         .buffer = buf,
+        .color = .{0,0,0,0}
     };
 }
 
 pub fn render(self: Self) void {
-    gl.clear(.{ .color = true });
-
-    gl.enableVertexAttribArray(0);
-    self.buffer.bind(.array_buffer);
-    gl.vertexAttribPointer(0, 3, .float, false, 0, 0);
-
-    gl.uniform4f(self.color_loc, 0.45, 0.21, 0.70, 1);
-    gl.drawArrays(.triangles, 0, 3);
-
-    gl.uniform4f(self.color_loc, 0.2, 0.5, 1.0, 1);
-    gl.drawArrays(.triangles, 3, 3);
-
-    gl.disableVertexAttribArray(0);
-
     sdl.gl.swapWindow(self.window);
+
+    gl.clear(.{ .color = true });
 }
 
 pub fn deinit(self: Self) void {
@@ -95,3 +75,39 @@ pub fn deinit(self: Self) void {
     self.window.destroy();
     sdl.gl.deleteContext(self.context);
 }
+
+pub fn setColor(self: *Self, r: u8, g: u32, b: u32, a: u32) void {
+    self.*.color = .{
+        @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: u32, y: u32, w: u32, h: u32) void {
+    gl.enableVertexAttribArray(0);
+    gl.vertexAttribPointer(0, 3, .float, false, 0, 0);
+
+    const vertex_buffer = [_]f32{
+        -1.0, -1.0, 0.0,
+        -1.0, 1.0, 0.0,
+        0.0, 1.0, 0.0,
+        1.0, 1.0, 0.0,
+        0.0, -1.0, 0.0,
+        1.0, -1.0, 0.0,
+    };
+    self.buffer.data(f32, &vertex_buffer, .static_draw);
+
+    gl.uniform4fv(self.color_loc, &.{ self.color });
+    gl.drawArrays(.triangles, 0, 3);
+    gl.drawArrays(.triangles, 3, 3);
+
+    gl.disableVertexAttribArray(0);
+
+    _ = self;
+    _ = x;
+    _ = y;
+    _ = w;
+    _ = h;
+}

src/main.zig

@@ -26,6 +26,9 @@ pub fn main() !void {
             }
         }
 
+        renderer.setColor(255, 127, 0, 255);
+        renderer.drawRectangle(20, 20, 20, 20);
+
         renderer.render();
 
         //current_state = switch (current_state) {