Added Shader Example & PGEX - VERY EXPERIMENTAL

Author: OneLoneCoder

examples/TEST_Shaders.cpp

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+/*
+	Example file for olcPGEX_Shaders.h
+
+	License (OLC-3)
+	~~~~~~~~~~~~~~~
+
+	Copyright 2018 - 2025 OneLoneCoder.com
+
+	Redistribution and use in source and binary forms, with or without
+	modification, are permitted provided that the following conditions
+	are met:
+
+	1. Redistributions or derivations of source code must retain the above
+	copyright notice, this list of conditions and the following disclaimer.
+
+	2. Redistributions or derivative works in binary form must reproduce
+	the above copyright notice. This list of conditions and the following
+	disclaimer must be reproduced in the documentation and/or other
+	materials provided with the distribution.
+
+	3. Neither the name of the copyright holder nor the names of its
+	contributors may be used to endorse or promote products derived
+	from this software without specific prior written permission.
+
+	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+	A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+	LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+	DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+	THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+	OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+	Links
+	~~~~~
+	YouTube:	https://www.youtube.com/javidx9
+	Discord:	https://discord.gg/WhwHUMV
+	Twitter:	https://www.twitter.com/javidx9
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+	GitHub:		https://www.github.com/onelonecoder
+	Homepage:	https://www.onelonecoder.com
+
+	Author
+	~~~~~~
+	David Barr, aka javidx9 
+	©OneLoneCoder 2019, 2020, 2021, 2022, 2022, 2023, 2024, 2025
+
+*/
+
+#define OLC_PGE_APPLICATION
+#define OLC_GFX_OPENGL33
+#include "olcPixelGameEngine.h"
+
+#define OLC_PGEX_SHADERS
+#include "extensions/olcPGEX_Shaders.h"
+
+#define OLC_PGEX_TRANSFORMEDVIEW
+#include "extensions/olcPGEX_TransformedView.h"
+
+class Example : public olc::PixelGameEngine
+{
+public:
+	Example()
+	{
+		// Name your application
+		sAppName = "Example";
+	}
+
+	/*
+	
+	PLEASE NOTE! This is all an ill-thought through idea. I do not recommend you actually use this.
+	
+	*/
+
+	// You need an instance of a shader object to apply pixel shading
+	olc::Shade shader;
+
+	// Effects are the pixel shaders. They can be custom, or selected from a built in library
+	olc::Effect fxScanlines;
+	olc::Effect fxNormal;
+	olc::Effect fxBoxblur;
+	olc::Effect fxGreyscale;
+	olc::Effect fxThreshold;
+	olc::Effect fxSobel;
+
+	// Pixel shading is all done in Decal land, so for this demo we render to several decals with
+	// different shading, and composite the result
+	olc::Renderable gfxNormalBouncers;
+	olc::Renderable gfxShadedBouncers;
+	olc::Renderable gfxTexture1;
+	olc::Renderable gfxTexture2;
+
+	olc::Renderable gfxEffect1;
+	olc::Renderable gfxEffect2;
+	olc::Renderable gfxEffect3;
+	olc::Renderable gfxEffect4;
+	olc::Renderable gfxEffect5;
+
+
+	size_t nBouncers = 50;
+	std::vector<std::pair<olc::vf2d, olc::vf2d>> vBouncers;
+
+	olc::TransformedView tv;
+
+
+public:
+	bool OnUserCreate() override
+	{
+		// Transformed view is for panning and zooming
+		tv.Initialise({ ScreenWidth(), ScreenHeight() }, { 1.0f, 1.0f });
+
+		// These are decals, but created manually rather than from a file
+		gfxNormalBouncers.Create(ScreenWidth(), ScreenHeight());
+		gfxShadedBouncers.Create(ScreenWidth(), ScreenHeight());
+		gfxEffect1.Create(200, 200);
+		gfxEffect2.Create(200, 200);
+		gfxEffect3.Create(200, 200);
+		gfxEffect4.Create(200, 200);
+		gfxEffect5.Create(200, 200);
+
+		// This decal uses a graphic - you'll need your own
+		gfxTexture2.Load("E:\\work\\repos\\OneLoneCoder\\olcProjects2\\DEMO_Quad3D\\assets\\Baby.png");
+		
+		// All of these effects "pixel shaders" are built-in. You can easily define your own EffectConfig
+		fxScanlines = shader.MakeEffect(olc::fx::FX_SCANLINE);
+		fxNormal = shader.MakeEffect(olc::fx::FX_NORMAL);
+		fxBoxblur = shader.MakeEffect(olc::fx::FX_BOXBLUR);
+		fxGreyscale = shader.MakeEffect(olc::fx::FX_GREYSCALE);
+		fxThreshold = shader.MakeEffect(olc::fx::FX_THRESHOLD);
+		fxSobel = shader.MakeEffect(olc::fx::FX_SOBEL);
+
+		
+
+
+
+		vBouncers.resize(nBouncers);
+		for (size_t i = 0; i < nBouncers; i++)
+		{
+			float a = (float(rand()) / float(RAND_MAX)) * 2.0f * 3.14159f;
+
+			vBouncers[i] =
+				std::make_pair<olc::vf2d, olc::vf2d>(
+					{ float(rand() % (ScreenWidth() - gfxTexture2.Sprite()->width)) + 100, float(rand() % (ScreenHeight() - gfxTexture2.Sprite()->height)) + 100 },
+					{ cos(a), sin(a) });
+		}
+
+		return true;
+	}
+
+	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();
+
+		shader.SetTargetDecal(gfxEffect2.Decal(), 0);
+		shader.Start(&fxScanlines);
+		shader.Clear(olc::WHITE);
+		shader.DrawPartialDecal({ 0.0f, 0.0f }, gfxNormalBouncers.Decal(), { 300.0f, 50.0f }, { 200.0f, 200.0f });
+		shader.End();
+
+		shader.SetTargetDecal(gfxEffect3.Decal(), 0);
+		shader.Start(&fxGreyscale);
+		shader.Clear(olc::WHITE);
+		shader.DrawPartialDecal({ 0.0f, 0.0f }, gfxNormalBouncers.Decal(), { 550.0f, 50.0f }, { 200.0f, 200.0f });
+		shader.End();
+
+		shader.SetTargetDecal(gfxEffect4.Decal(), 0);
+		shader.Start(&fxThreshold);
+		shader.Clear(olc::WHITE);
+		shader.DrawPartialDecal({ 0.0f, 0.0f }, gfxNormalBouncers.Decal(), { 800.0f, 50.0f }, { 200.0f, 200.0f });
+		shader.End();
+
+		shader.SetTargetDecal(gfxEffect5.Decal(), 0);
+		shader.Start(&fxSobel);
+		shader.Clear(olc::WHITE);
+		shader.DrawPartialDecal({ 0.0f, 0.0f }, gfxNormalBouncers.Decal(), { 1050.0f, 50.0f }, { 200.0f, 200.0f });
+		shader.End();
+
+		// Stage 3) Composite final display - NOT USING SHADERS NOW
+
+		Clear(olc::WHITE);
+		DrawDecal({ 0,0 }, gfxNormalBouncers.Decal());
+
+		FillRectDecal({ 48.0f, 48.0f }, { 204.0f, 204.0f }, olc::BLUE);
+		DrawDecal({ 50.0f, 50.0f }, gfxEffect1.Decal());
+
+		FillRectDecal({ 298.0f, 48.0f }, { 204.0f, 204.0f }, olc::BLUE);
+		DrawDecal({ 300.0f, 50.0f }, gfxEffect2.Decal());
+
+		FillRectDecal({ 548.0f, 48.0f }, { 204.0f, 204.0f }, olc::BLUE);
+		DrawDecal({ 550.0f, 50.0f }, gfxEffect3.Decal());
+
+		FillRectDecal({ 798.0f, 48.0f }, { 204.0f, 204.0f }, olc::BLUE);
+		DrawDecal({ 800.0f, 50.0f }, gfxEffect4.Decal());
+
+		FillRectDecal({ 1048.0f, 48.0f }, { 204.0f, 204.0f }, olc::BLUE);
+		DrawDecal({ 1050.0f, 50.0f }, gfxEffect5.Decal());
+
+
+		return true;
+	}
+};
+
+int main()
+{
+	Example demo;
+	if (demo.Construct(1280, 720, 1, 1, false, false))
+		demo.Start();
+	return 0;
+}