Method OnUserUpdate

examples/TEST_Shaders.cpp:153–258

	}

	bool OnUserUpdate(float fElapsedTime) override
	{
		// Handle Pan & Zoom
		if (GetMouse(2).bPressed) tv.StartPan(GetMousePos());
		if (GetMouse(2).bHeld) tv.UpdatePan(GetMousePos());
		if (GetMouse(2).bReleased) tv.EndPan(GetMousePos());
		if (GetMouseWheel() > 0) tv.ZoomAtScreenPos(2.0f, GetMousePos());
		if (GetMouseWheel() < 0) tv.ZoomAtScreenPos(0.5f, GetMousePos());


		// Stage 1) Just draw the bouncers normally into the NormalBouncers decal
		// This uses the "pass-thru" effect, i.e. nothing

		// Set the target decal
		shader.SetTargetDecal(gfxNormalBouncers.Decal(), 0);
		// Tell the shading system to use a shader
		shader.Start(&fxNormal);
		// Several PGE-like drawing commands are available. Here we clear the decal
		shader.Clear();

		// Update Locations & Render "Stock" Bouncers
		for (auto& bouncer : vBouncers)
		{
			bouncer.first += bouncer.second * fElapsedTime * 100.0f;

			if (bouncer.first.x < 0.0f)
			{
				bouncer.first.x = 0.0f; bouncer.second.x *= -1.0f;
			}
			if (bouncer.first.x + gfxTexture2.Sprite()->width > ScreenWidth())
			{
				bouncer.first.x = float(ScreenWidth() - gfxTexture2.Sprite()->width); bouncer.second.x *= -1.0f;
			}

			if (bouncer.first.y < 0.0f)
			{
				bouncer.first.y = 0.0f; bouncer.second.y *= -1.0f;
			}
			if (bouncer.first.y + gfxTexture2.Sprite()->height > ScreenHeight())
			{
				bouncer.first.y = float(ScreenHeight() - gfxTexture2.Sprite()->height); bouncer.second.y *= -1.0f;
			}

			// Using the transformed view, draw the bouncer using the pass-thru shader
			tv.DrawDecal(shader, bouncer.first, gfxTexture2.Decal(), { 1.0f, 1.0f }, olc::WHITE);
		}

		// Stop shading
		shader.End();

		// Stage 2) A selection of different effects are demonstrated. For each one, we "cut" out of normal bouncers
		// a small region, then draw it into its own decal just for that effect. The cut is done with DrawPartialDecal()

		shader.SetTargetDecal(gfxEffect1.Decal(), 0);
		shader.Start(&fxBoxblur);
		shader.Clear(olc::WHITE);
		shader.DrawPartialDecal({ 0.0f, 0.0f }, gfxNormalBouncers.Decal(), { 50.0f, 50.0f }, { 200.0f, 200.0f });
		shader.End();