examples: support better placment and scaling on nonsquare viewports in cube.v (#8513)

examples/sokol/cube.v

@@ -31,7 +31,7 @@ mut:
 	texture       C.sg_image
 	init_flag     bool
 	frame_count   int
-	
+
 	mouse_x       int = -1
 	mouse_y       int = -1
 }
@@ -60,7 +60,7 @@ fn create_texture(w int, h int, buf byteptr) C.sg_image{
 		ptr: buf
 		size: sz
 	}
-	
+
 	sg_img := C.sg_make_image(&img_desc)
 	return sg_img
 }
@@ -136,7 +136,7 @@ fn cube() {
 fn draw_cubes(app App) {
 	rot := [f32(1.0)*(app.frame_count % 360), 0.5*f32(app.frame_count%360)]
 	//rot := [f32(app.mouse_x), f32(app.mouse_y)]
-	
+
 	sgl.defaults()
 	sgl.load_pipeline(app.pip_3d)
 
@@ -240,7 +240,7 @@ fn cube_field(app App){
 	rot := [f32(app.mouse_x), f32(app.mouse_y)]
 	xyz_sz := f32(2.0)
 	field_size := 20
-		
+
 	sgl.defaults()
 	sgl.load_pipeline(app.pip_3d)
 
@@ -249,13 +249,13 @@ fn cube_field(app App){
 
 	sgl.matrix_mode_projection()
 	sgl.perspective(sgl.rad(45.0), 1.0, 0.1, 200.0)
-		
+
 	sgl.matrix_mode_modelview()
-		
+
 	sgl.translate(field_size, 0.0, -120.0)
 	sgl.rotate(sgl.rad(rot[0]), 0.0, 1.0, 0.0)
 	sgl.rotate(sgl.rad(rot[1]), 1.0, 0.0, 0.0)
-		
+
 	// draw field_size*field_size cubes
 	for y in 0..field_size {
 		for x in 0..field_size {
@@ -265,41 +265,43 @@ fn cube_field(app App){
 			cube_t(f32(f32(x)/field_size), f32(f32(y)/field_size),1)
 			sgl.pop_matrix()
 		}
-	}		
+	}
 	sgl.disable_texture()
 }
 
 fn frame(mut app App) {
-	dw := app.gg.width
-	dh := app.gg.height
-	ww := dh/2 /* not a bug */
-	hh := dh/2
-	x0 := dw/2 - hh
+	ws := gg.window_size()
+	ratio := f32(ws.width)/ws.height
+	dw := ws.width
+	dh := ws.height
+	ww := int(dh/3) /* not a bug */
+	hh := int(dh/3)
+	x0 := int(f32(dw) * 0.05)
 	//x1 := dw/2
 	y0 := 0
-	y1 := dh/2
-		
+	y1 := int(f32(dh) * 0.5)
+
 	app.gg.begin()
 	//sgl.defaults()
 
 	// 2d triangle
 	sgl.viewport(x0, y0, ww, hh, true)
 	draw_triangle()
-	
+
 	// colored cubes with viewport
 	sgl.viewport(x0, y1, ww, hh, true)
 	draw_cubes(app)
-	
+
 	// textured cubed with viewport
-	sgl.viewport(0, 0, dw, dh, true)
+	sgl.viewport(0, int(dh/5), dw, int(dh*ratio), true)
 	draw_texture_cubes(app)
-	
+
 	// textured field of cubes with viewport
-	sgl.viewport(0, 0, dw, dh, true)
+	sgl.viewport(0, int(dh/5), dw, int(dh*ratio), true)
 	cube_field(app)
 
 	app.frame_count++
-	
+
 	app.gg.end()
 }
 
@@ -310,7 +312,7 @@ fn frame(mut app App) {
 ******************************************************************************/
 fn my_init(mut app App) {
 	app.init_flag = true
-	
+
 	// set max vertices,
 	// for a large number of the same type of object it is better use the instances!!
 	desc := sapp.create_desc()
@@ -319,7 +321,7 @@ fn my_init(mut app App) {
 		max_vertices: 50 * 65536
 	}
 	sgl.setup(&sgl_desc)
-	
+
 	// 3d pipeline
 	mut pipdesc := C.sg_pipeline_desc{}
 	unsafe {C.memset(&pipdesc, 0, sizeof(pipdesc))}
@@ -334,7 +336,7 @@ fn my_init(mut app App) {
 		cull_mode: .back
 	}
 	app.pip_3d = sgl.make_pipeline(&pipdesc)
-	
+
 	// create chessboard texture 256*256 RGBA
 	w := 256
 	h := 256
@@ -359,7 +361,7 @@ fn my_init(mut app App) {
 				tmp_txt[i+2] =  byte(0)
 				tmp_txt[i+3] =  byte(0xFF)
 			} else {
-				col := if ((x+y) & 1) == 1 {0xFF} else {0}		
+				col := if ((x+y) & 1) == 1 {0xFF} else {0}
 				tmp_txt[i  ] =  byte(col)   // red
 				tmp_txt[i+1] =  byte(col)   // green
 				tmp_txt[i+2] =  byte(col)   // blue
@@ -386,6 +388,13 @@ fn my_event_manager(mut ev sapp.Event, mut app App) {
 		app.mouse_x = int(ev.mouse_x)
 		app.mouse_y = int(ev.mouse_y)
 	}
+	if ev.typ == .touches_began || ev.typ == .touches_moved {
+		if ev.num_touches > 0 {
+			touch_point := ev.touches[0]
+			app.mouse_x = int(touch_point.pos_x)
+			app.mouse_y = int(touch_point.pos_y)
+		}
+	}
 }
 
 /******************************************************************************