examples: add examples/gg/rotating_textured_quad.v

examples/gg/rotating_textured_quad.v

@@ -0,0 +1,49 @@
+import gg
+import gx
+import os
+import sokol.sgl
+
+pub struct Window {
+pub mut:
+	ctx &gg.Context = unsafe { nil }
+	img gg.Image
+}
+
+pub fn (mut window Window) init() {
+	window.img = window.ctx.create_image(os.resource_abs_path('../assets/logo.png'))
+}
+
+pub fn (mut window Window) draw() {
+	angle := f32(window.ctx.frame) / 64 // since window.ctx.frame is increased by 1 on every frame -> the angle will be increasing too
+	window.ctx.begin()
+	sgl.load_pipeline(window.ctx.timage_pip)
+
+	sgl.translate(400, 400, 0) // center of the screen
+	sgl.rotate(angle, 0.0, 0.0, 1.0) // rotate around the Z axis pointing towards the camera
+
+	sgl.enable_texture()
+	sgl.texture(window.img.simg)
+	sgl.begin_quads()
+	sgl.c4b(255, 255, 255, 255)
+	sgl.v3f_t2f(200, 200, 0, 1.0, 1.0)
+	sgl.v3f_t2f(200, -200, 0, 1.0, 0.0)
+	sgl.v3f_t2f(-200, -200, 0, 0.0, 0.0)
+	sgl.v3f_t2f(-200, 200, 0, 0.0, 1.0)
+	sgl.end()
+	sgl.disable_texture()
+	window.ctx.end()
+}
+
+fn main() {
+	mut window := &Window{}
+	window.ctx = gg.new_context(
+		window_title: 'Rotating V logo'
+		bg_color: gx.light_green
+		width: 800
+		height: 800
+		user_data: window
+		init_fn: window.init
+		frame_fn: window.draw
+	)
+	window.ctx.run()
+}