Merge pull request #307 from alexpanter/master

Add pbr bloom example code

CMakeLists.txt

@@ -183,6 +183,7 @@ set(GUEST_ARTICLES
 	#8.guest/2021/3.tessellation/terrain_cpu_src
 	8.guest/2021/4.dsa
 	8.guest/2022/5.computeshader_helloworld
+	8.guest/2022/6.physically_based_bloom
 )
 
 configure_file(configuration/root_directory.h.in configuration/root_directory.h)

src/8.guest/2022/6.physically_based_bloom/6.bloom.fs

@@ -0,0 +1,49 @@
+#version 330 core
+layout (location = 0) out vec4 FragColor;
+layout (location = 1) out vec4 BrightColor;
+
+in VS_OUT {
+    vec3 FragPos;
+    vec3 Normal;
+    vec2 TexCoords;
+} fs_in;
+
+struct Light {
+    vec3 Position;
+    vec3 Color;
+};
+
+uniform Light lights[4];
+uniform sampler2D diffuseTexture;
+uniform vec3 viewPos;
+
+void main()
+{           
+    vec3 color = texture(diffuseTexture, fs_in.TexCoords).rgb;
+    vec3 normal = normalize(fs_in.Normal);
+    // ambient
+    vec3 ambient = 0.0 * color;
+    // lighting
+    vec3 lighting = vec3(0.0);
+    vec3 viewDir = normalize(viewPos - fs_in.FragPos);
+    for(int i = 0; i < 4; i++)
+    {
+        // diffuse
+        vec3 lightDir = normalize(lights[i].Position - fs_in.FragPos);
+        float diff = max(dot(lightDir, normal), 0.0);
+        vec3 result = lights[i].Color * diff * color;      
+        // attenuation (use quadratic as we have gamma correction)
+        float distance = length(fs_in.FragPos - lights[i].Position);
+        result *= 1.0 / (distance * distance);
+        lighting += result;
+                
+    }
+    vec3 result = ambient + lighting;
+    // check whether result is higher than some threshold, if so, output as bloom threshold color
+    float brightness = dot(result, vec3(0.2126, 0.7152, 0.0722));
+    if(brightness > 1.0)
+        BrightColor = vec4(result, 1.0);
+    else
+        BrightColor = vec4(0.0, 0.0, 0.0, 1.0);
+    FragColor = vec4(result, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/6.bloom.vs

@@ -0,0 +1,25 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aNormal;
+layout (location = 2) in vec2 aTexCoords;
+
+out VS_OUT {
+    vec3 FragPos;
+    vec3 Normal;
+    vec2 TexCoords;
+} vs_out;
+
+uniform mat4 projection;
+uniform mat4 view;
+uniform mat4 model;
+
+void main()
+{
+    vs_out.FragPos = vec3(model * vec4(aPos, 1.0));   
+    vs_out.TexCoords = aTexCoords;
+        
+    mat3 normalMatrix = transpose(inverse(mat3(model)));
+    vs_out.Normal = normalize(normalMatrix * aNormal);
+    
+    gl_Position = projection * view * model * vec4(aPos, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/6.bloom_final.fs

@@ -0,0 +1,50 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec2 TexCoords;
+
+uniform sampler2D scene;
+uniform sampler2D bloomBlur;
+uniform float exposure;
+uniform float bloomStrength = 0.04f;
+uniform int programChoice;
+
+vec3 bloom_none()
+{
+    vec3 hdrColor = texture(scene, TexCoords).rgb;
+    return hdrColor;
+}
+
+vec3 bloom_old()
+{
+    vec3 hdrColor = texture(scene, TexCoords).rgb;
+    vec3 bloomColor = texture(bloomBlur, TexCoords).rgb;
+    return hdrColor + bloomColor; // additive blending
+}
+
+vec3 bloom_new()
+{
+    vec3 hdrColor = texture(scene, TexCoords).rgb;
+    vec3 bloomColor = texture(bloomBlur, TexCoords).rgb;
+    return mix(hdrColor, bloomColor, bloomStrength); // linear interpolation
+}
+
+void main()
+{
+    // to bloom or not to bloom
+    vec3 result = vec3(0.0);
+    switch (programChoice)
+    {
+    case 1: result = bloom_none(); break;
+    case 2: result = bloom_old(); break;
+    case 3: result = bloom_new(); break;
+    default:
+        result = bloom_none(); break;
+    }
+    // tone mapping
+    result = vec3(1.0) - exp(-result * exposure);
+    // also gamma correct while we're at it
+    const float gamma = 2.2;
+    result = pow(result, vec3(1.0 / gamma));
+    FragColor = vec4(result, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/6.bloom_final.vs

@@ -0,0 +1,11 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec2 aTexCoords;
+
+out vec2 TexCoords;
+
+void main()
+{
+    TexCoords = aTexCoords;
+    gl_Position = vec4(aPos, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/6.light_box.fs

@@ -0,0 +1,21 @@
+#version 330 core
+layout (location = 0) out vec4 FragColor;
+layout (location = 1) out vec4 BrightColor;
+
+in VS_OUT {
+    vec3 FragPos;
+    vec3 Normal;
+    vec2 TexCoords;
+} fs_in;
+
+uniform vec3 lightColor;
+
+void main()
+{           
+    FragColor = vec4(lightColor, 1.0);
+    float brightness = dot(FragColor.rgb, vec3(0.2126, 0.7152, 0.0722));
+    if(brightness > 1.0)
+        BrightColor = vec4(FragColor.rgb, 1.0);
+	else
+		BrightColor = vec4(0.0, 0.0, 0.0, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/6.new_downsample.fs

@@ -0,0 +1,114 @@
+#version 330 core
+
+// This shader performs downsampling on a texture,
+// as taken from Call Of Duty method, presented at ACM Siggraph 2014.
+// This particular method was customly designed to eliminate
+// "pulsating artifacts and temporal stability issues".
+
+// Remember to add bilinear minification filter for this texture!
+// Remember to use a floating-point texture format (for HDR)!
+// Remember to use edge clamping for this texture!
+uniform sampler2D srcTexture;
+uniform vec2 srcResolution;
+
+// which mip we are writing to, used for Karis average
+uniform int mipLevel = 1;
+
+in vec2 texCoord;
+layout (location = 0) out vec3 downsample;
+
+vec3 PowVec3(vec3 v, float p)
+{
+    return vec3(pow(v.x, p), pow(v.y, p), pow(v.z, p));
+}
+
+const float invGamma = 1.0 / 2.2;
+vec3 ToSRGB(vec3 v)   { return PowVec3(v, invGamma); }
+
+float sRGBToLuma(vec3 col)
+{
+    //return dot(col, vec3(0.2126f, 0.7152f, 0.0722f));
+	return dot(col, vec3(0.299f, 0.587f, 0.114f));
+}
+
+float KarisAverage(vec3 col)
+{
+	// Formula is 1 / (1 + luma)
+	float luma = sRGBToLuma(ToSRGB(col)) * 0.25f;
+	return 1.0f / (1.0f + luma);
+}
+
+// NOTE: This is the readable version of this shader. It will be optimized!
+void main()
+{
+	vec2 srcTexelSize = 1.0 / srcResolution;
+	float x = srcTexelSize.x;
+	float y = srcTexelSize.y;
+
+	// Take 13 samples around current texel:
+	// a - b - c
+	// - j - k -
+	// d - e - f
+	// - l - m -
+	// g - h - i
+	// === ('e' is the current texel) ===
+	vec3 a = texture(srcTexture, vec2(texCoord.x - 2*x, texCoord.y + 2*y)).rgb;
+	vec3 b = texture(srcTexture, vec2(texCoord.x,       texCoord.y + 2*y)).rgb;
+	vec3 c = texture(srcTexture, vec2(texCoord.x + 2*x, texCoord.y + 2*y)).rgb;
+
+	vec3 d = texture(srcTexture, vec2(texCoord.x - 2*x, texCoord.y)).rgb;
+	vec3 e = texture(srcTexture, vec2(texCoord.x,       texCoord.y)).rgb;
+	vec3 f = texture(srcTexture, vec2(texCoord.x + 2*x, texCoord.y)).rgb;
+
+	vec3 g = texture(srcTexture, vec2(texCoord.x - 2*x, texCoord.y - 2*y)).rgb;
+	vec3 h = texture(srcTexture, vec2(texCoord.x,       texCoord.y - 2*y)).rgb;
+	vec3 i = texture(srcTexture, vec2(texCoord.x + 2*x, texCoord.y - 2*y)).rgb;
+
+	vec3 j = texture(srcTexture, vec2(texCoord.x - x, texCoord.y + y)).rgb;
+	vec3 k = texture(srcTexture, vec2(texCoord.x + x, texCoord.y + y)).rgb;
+	vec3 l = texture(srcTexture, vec2(texCoord.x - x, texCoord.y - y)).rgb;
+	vec3 m = texture(srcTexture, vec2(texCoord.x + x, texCoord.y - y)).rgb;
+
+	// Apply weighted distribution:
+	// 0.5 + 0.125 + 0.125 + 0.125 + 0.125 = 1
+	// a,b,d,e * 0.125
+	// b,c,e,f * 0.125
+	// d,e,g,h * 0.125
+	// e,f,h,i * 0.125
+	// j,k,l,m * 0.5
+	// This shows 5 square areas that are being sampled. But some of them overlap,
+	// so to have an energy preserving downsample we need to make some adjustments.
+	// The weights are the distributed, so that the sum of j,k,l,m (e.g.)
+	// contribute 0.5 to the final color output. The code below is written
+	// to effectively yield this sum. We get:
+	// 0.125*5 + 0.03125*4 + 0.0625*4 = 1
+
+	// Check if we need to perform Karis average on each block of 4 samples
+	vec3 groups[5];
+	switch (mipLevel)
+	{
+	case 0:
+	  // We are writing to mip 0, so we need to apply Karis average to each block
+	  // of 4 samples to prevent fireflies (very bright subpixels, leads to pulsating
+	  // artifacts).
+	  groups[0] = (a+b+d+e) * (0.125f/4.0f);
+	  groups[1] = (b+c+e+f) * (0.125f/4.0f);
+	  groups[2] = (d+e+g+h) * (0.125f/4.0f);
+	  groups[3] = (e+f+h+i) * (0.125f/4.0f);
+	  groups[4] = (j+k+l+m) * (0.5f/4.0f);
+	  groups[0] *= KarisAverage(groups[0]);
+	  groups[1] *= KarisAverage(groups[1]);
+	  groups[2] *= KarisAverage(groups[2]);
+	  groups[3] *= KarisAverage(groups[3]);
+	  groups[4] *= KarisAverage(groups[4]);
+	  downsample = groups[0]+groups[1]+groups[2]+groups[3]+groups[4];
+	  downsample = max(downsample, 0.0001f);
+	  break;
+	default:
+	  downsample = e*0.125;                // ok
+	  downsample += (a+c+g+i)*0.03125;     // ok
+	  downsample += (b+d+f+h)*0.0625;      // ok
+	  downsample += (j+k+l+m)*0.125;       // ok
+	  break;
+	}
+}

src/8.guest/2022/6.physically_based_bloom/6.new_downsample.vs

@@ -0,0 +1,12 @@
+#version 330 core
+
+layout (location = 0) in vec2 aPosition;
+layout (location = 1) in vec2 aTexCoord;
+
+out vec2 texCoord;
+
+void main()
+{
+	gl_Position = vec4(aPosition.x, aPosition.y, 0.0, 1.0);
+	texCoord = aTexCoord;
+}

src/8.guest/2022/6.physically_based_bloom/6.new_upsample.fs

@@ -0,0 +1,47 @@
+#version 330 core
+
+// This shader performs upsampling on a texture,
+// as taken from Call Of Duty method, presented at ACM Siggraph 2014.
+
+// Remember to add bilinear minification filter for this texture!
+// Remember to use a floating-point texture format (for HDR)!
+// Remember to use edge clamping for this texture!
+uniform sampler2D srcTexture;
+uniform float filterRadius;
+
+in vec2 texCoord;
+layout (location = 0) out vec3 upsample;
+
+void main()
+{
+	// The filter kernel is applied with a radius, specified in texture
+	// coordinates, so that the radius will vary across mip resolutions.
+	float x = filterRadius;
+	float y = filterRadius;
+
+	// Take 9 samples around current texel:
+	// a - b - c
+	// d - e - f
+	// g - h - i
+	// === ('e' is the current texel) ===
+	vec3 a = texture(srcTexture, vec2(texCoord.x - x, texCoord.y + y)).rgb;
+	vec3 b = texture(srcTexture, vec2(texCoord.x,     texCoord.y + y)).rgb;
+	vec3 c = texture(srcTexture, vec2(texCoord.x + x, texCoord.y + y)).rgb;
+
+	vec3 d = texture(srcTexture, vec2(texCoord.x - x, texCoord.y)).rgb;
+	vec3 e = texture(srcTexture, vec2(texCoord.x,     texCoord.y)).rgb;
+	vec3 f = texture(srcTexture, vec2(texCoord.x + x, texCoord.y)).rgb;
+
+	vec3 g = texture(srcTexture, vec2(texCoord.x - x, texCoord.y - y)).rgb;
+	vec3 h = texture(srcTexture, vec2(texCoord.x,     texCoord.y - y)).rgb;
+	vec3 i = texture(srcTexture, vec2(texCoord.x + x, texCoord.y - y)).rgb;
+
+	// Apply weighted distribution, by using a 3x3 tent filter:
+	//  1   | 1 2 1 |
+	// -- * | 2 4 2 |
+	// 16   | 1 2 1 |
+	upsample = e*4.0;
+	upsample += (b+d+f+h)*2.0;
+	upsample += (a+c+g+i);
+	upsample *= 1.0 / 16.0;
+}

src/8.guest/2022/6.physically_based_bloom/6.new_upsample.vs

@@ -0,0 +1,12 @@
+#version 330 core
+
+layout (location = 0) in vec2 aPosition;
+layout (location = 1) in vec2 aTexCoord;
+
+out vec2 texCoord;
+
+void main()
+{
+	gl_Position = vec4(aPosition.x, aPosition.y, 0.0, 1.0);
+	texCoord = aTexCoord;
+}

src/8.guest/2022/6.physically_based_bloom/6.old_blur.fs

@@ -0,0 +1,32 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec2 TexCoords;
+
+uniform sampler2D image;
+
+uniform bool horizontal;
+uniform float weight[5] = float[] (0.2270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162);
+
+void main()
+{             
+     vec2 tex_offset = 1.0 / textureSize(image, 0); // gets size of single texel
+     vec3 result = texture(image, TexCoords).rgb * weight[0];
+     if(horizontal)
+     {
+         for(int i = 1; i < 5; ++i)
+         {
+            result += texture(image, TexCoords + vec2(tex_offset.x * i, 0.0)).rgb * weight[i];
+            result += texture(image, TexCoords - vec2(tex_offset.x * i, 0.0)).rgb * weight[i];
+         }
+     }
+     else
+     {
+         for(int i = 1; i < 5; ++i)
+         {
+             result += texture(image, TexCoords + vec2(0.0, tex_offset.y * i)).rgb * weight[i];
+             result += texture(image, TexCoords - vec2(0.0, tex_offset.y * i)).rgb * weight[i];
+         }
+     }
+     FragColor = vec4(result, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/6.old_blur.vs

@@ -0,0 +1,11 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec2 aTexCoords;
+
+out vec2 TexCoords;
+
+void main()
+{
+    TexCoords = aTexCoords;
+    gl_Position = vec4(aPos, 1.0);
+}

src/8.guest/2022/6.physically_based_bloom/physically_based_bloom.cpp

@@ -0,0 +1,860 @@
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+#include <stb_image.h>
+
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/type_ptr.hpp>
+
+#include <learnopengl/filesystem.h>
+#include <learnopengl/shader.h>
+#include <learnopengl/camera.h>
+#include <learnopengl/model.h>
+
+#include <iostream>
+#include <vector>
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height);
+void mouse_callback(GLFWwindow* window, double xpos, double ypos);
+void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
+void processInput(GLFWwindow *window);
+unsigned int loadTexture(const char *path, bool gammaCorrection);
+void renderQuad();
+void renderCube();
+
+// settings
+const unsigned int SCR_WIDTH = 800;
+const unsigned int SCR_HEIGHT = 600;
+bool bloom = true;
+float exposure = 1.0f;
+int programChoice = 1;
+float bloomFilterRadius = 0.005f;
+
+// camera
+Camera camera(glm::vec3(0.0f, 0.0f, 5.0f));
+float lastX = (float)SCR_WIDTH / 2.0;
+float lastY = (float)SCR_HEIGHT / 2.0;
+bool firstMouse = true;
+
+// timing
+float deltaTime = 0.0f;
+float lastFrame = 0.0f;
+
+// bloom stuff
+struct bloomMip
+{
+	glm::vec2 size;
+	glm::ivec2 intSize;
+	unsigned int texture;
+};
+
+class bloomFBO
+{
+public:
+	bloomFBO();
+	~bloomFBO();
+	bool Init(unsigned int windowWidth, unsigned int windowHeight, unsigned int mipChainLength);
+	void Destroy();
+	void BindForWriting();
+	const std::vector<bloomMip>& MipChain() const;
+
+private:
+	bool mInit;
+	unsigned int mFBO;
+	std::vector<bloomMip> mMipChain;
+};
+
+bloomFBO::bloomFBO() : mInit(false) {}
+bloomFBO::~bloomFBO() {}
+
+bool bloomFBO::Init(unsigned int windowWidth, unsigned int windowHeight, unsigned int mipChainLength)
+{
+	if (mInit) return true;
+
+	glGenFramebuffers(1, &mFBO);
+	glBindFramebuffer(GL_FRAMEBUFFER, mFBO);
+
+	glm::vec2 mipSize((float)windowWidth, (float)windowHeight);
+	glm::ivec2 mipIntSize((int)windowWidth, (int)windowHeight);
+	// Safety check
+	if (windowWidth > (unsigned int)INT_MAX || windowHeight > (unsigned int)INT_MAX) {
+		std::cerr << "Window size conversion overflow - cannot build bloom FBO!" << std::endl;
+		return false;
+	}
+
+	for (GLuint i = 0; i < mipChainLength; i++)
+	{
+		bloomMip mip;
+
+		mipSize *= 0.5f;
+		mipIntSize /= 2;
+		mip.size = mipSize;
+		mip.intSize = mipIntSize;
+
+		glGenTextures(1, &mip.texture);
+		glBindTexture(GL_TEXTURE_2D, mip.texture);
+		// we are downscaling an HDR color buffer, so we need a float texture format
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_R11F_G11F_B10F,
+		             (int)mipSize.x, (int)mipSize.y,
+		             0, GL_RGB, GL_FLOAT, nullptr);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+		std::cout << "Created bloom mip " << mipIntSize.x << 'x' << mipIntSize.y << std::endl;
+		mMipChain.emplace_back(mip);
+	}
+
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+	                       GL_TEXTURE_2D, mMipChain[0].texture, 0);
+
+	// setup attachments
+	unsigned int attachments[1] = { GL_COLOR_ATTACHMENT0 };
+	glDrawBuffers(1, attachments);
+
+	// check completion status
+	int status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+	if (status != GL_FRAMEBUFFER_COMPLETE)
+	{
+		printf("gbuffer FBO error, status: 0x%x\n", status);
+		glBindFramebuffer(GL_FRAMEBUFFER, 0);
+		return false;
+	}
+
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	mInit = true;
+	return true;
+}
+
+void bloomFBO::Destroy()
+{
+	for (int i = 0; i < (int)mMipChain.size(); i++) {
+		glDeleteTextures(1, &mMipChain[i].texture);
+		mMipChain[i].texture = 0;
+	}
+	glDeleteFramebuffers(1, &mFBO);
+	mFBO = 0;
+	mInit = false;
+}
+
+void bloomFBO::BindForWriting()
+{
+	glBindFramebuffer(GL_FRAMEBUFFER, mFBO);
+}
+
+const std::vector<bloomMip>& bloomFBO::MipChain() const
+{
+	return mMipChain;
+}
+
+
+
+class BloomRenderer
+{
+public:
+	BloomRenderer();
+	~BloomRenderer();
+	bool Init(unsigned int windowWidth, unsigned int windowHeight);
+	void Destroy();
+	void RenderBloomTexture(unsigned int srcTexture, float filterRadius);
+	unsigned int BloomTexture();
+	unsigned int BloomMip_i(int index);
+
+private:
+	void RenderDownsamples(unsigned int srcTexture);
+	void RenderUpsamples(float filterRadius);
+
+	bool mInit;
+	bloomFBO mFBO;
+	glm::ivec2 mSrcViewportSize;
+	glm::vec2 mSrcViewportSizeFloat;
+	Shader* mDownsampleShader;
+	Shader* mUpsampleShader;
+
+	bool mKarisAverageOnDownsample = true;
+};
+
+BloomRenderer::BloomRenderer() : mInit(false) {}
+BloomRenderer::~BloomRenderer() {}
+
+bool BloomRenderer::Init(unsigned int windowWidth, unsigned int windowHeight)
+{
+	if (mInit) return true;
+	mSrcViewportSize = glm::ivec2(windowWidth, windowHeight);
+	mSrcViewportSizeFloat = glm::vec2((float)windowWidth, (float)windowHeight);
+
+	// Framebuffer
+	const unsigned int num_bloom_mips = 6; // TODO: Play around with this value
+	bool status = mFBO.Init(windowWidth, windowHeight, num_bloom_mips);
+	if (!status) {
+		std::cerr << "Failed to initialize bloom FBO - cannot create bloom renderer!\n";
+		return false;
+	}
+
+	// Shaders
+	mDownsampleShader = new Shader("6.new_downsample.vs", "6.new_downsample.fs");
+    mUpsampleShader = new Shader("6.new_upsample.vs", "6.new_upsample.fs");
+
+	// Downsample
+    mDownsampleShader->use();
+    mDownsampleShader->setInt("srcTexture", 0);
+    glUseProgram(0);
+
+    // Upsample
+    mUpsampleShader->use();
+    mUpsampleShader->setInt("srcTexture", 0);
+    glUseProgram(0);
+
+    return true;
+}
+
+void BloomRenderer::Destroy()
+{
+	mFBO.Destroy();
+	delete mDownsampleShader;
+	delete mUpsampleShader;
+}
+
+void BloomRenderer::RenderDownsamples(unsigned int srcTexture)
+{
+	const std::vector<bloomMip>& mipChain = mFBO.MipChain();
+
+	mDownsampleShader->use();
+	mDownsampleShader->setVec2("srcResolution", mSrcViewportSizeFloat);
+	if (mKarisAverageOnDownsample) {
+		mDownsampleShader->setInt("mipLevel", 0);
+	}
+
+	// Bind srcTexture (HDR color buffer) as initial texture input
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, srcTexture);
+
+	// Progressively downsample through the mip chain
+	for (int i = 0; i < (int)mipChain.size(); i++)
+	{
+		const bloomMip& mip = mipChain[i];
+		glViewport(0, 0, mip.size.x, mip.size.y);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+		                       GL_TEXTURE_2D, mip.texture, 0);
+
+		// Render screen-filled quad of resolution of current mip
+		renderQuad();
+
+		// Set current mip resolution as srcResolution for next iteration
+		mDownsampleShader->setVec2("srcResolution", mip.size);
+		// Set current mip as texture input for next iteration
+		glBindTexture(GL_TEXTURE_2D, mip.texture);
+		// Disable Karis average for consequent downsamples
+		if (i == 0) { mDownsampleShader->setInt("mipLevel", 1); }
+	}
+
+	glUseProgram(0);
+}
+
+void BloomRenderer::RenderUpsamples(float filterRadius)
+{
+	const std::vector<bloomMip>& mipChain = mFBO.MipChain();
+
+	mUpsampleShader->use();
+	mUpsampleShader->setFloat("filterRadius", filterRadius);
+
+	// Enable additive blending
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_ONE, GL_ONE);
+	glBlendEquation(GL_FUNC_ADD);
+
+	for (int i = (int)mipChain.size() - 1; i > 0; i--)
+	{
+		const bloomMip& mip = mipChain[i];
+		const bloomMip& nextMip = mipChain[i-1];
+
+		// Bind viewport and texture from where to read
+		glActiveTexture(GL_TEXTURE0);
+		glBindTexture(GL_TEXTURE_2D, mip.texture);
+
+		// Set framebuffer render target (we write to this texture)
+		glViewport(0, 0, nextMip.size.x, nextMip.size.y);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+		                       GL_TEXTURE_2D, nextMip.texture, 0);
+
+		// Render screen-filled quad of resolution of current mip
+		renderQuad();
+	}
+
+	// Disable additive blending
+	//glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+	glDisable(GL_BLEND);
+
+	glUseProgram(0);
+}
+
+void BloomRenderer::RenderBloomTexture(unsigned int srcTexture, float filterRadius)
+{
+	mFBO.BindForWriting();
+
+	this->RenderDownsamples(srcTexture);
+	this->RenderUpsamples(filterRadius);
+
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+	// Restore viewport
+	glViewport(0, 0, mSrcViewportSize.x, mSrcViewportSize.y);
+}
+
+GLuint BloomRenderer::BloomTexture()
+{
+	return mFBO.MipChain()[0].texture;
+}
+
+GLuint BloomRenderer::BloomMip_i(int index)
+{
+	const std::vector<bloomMip>& mipChain = mFBO.MipChain();
+	int size = (int)mipChain.size();
+	return mipChain[(index > size-1) ? size-1 : (index < 0) ? 0 : index].texture;
+}
+
+
+
+
+
+int main()
+{
+    // glfw: initialize and configure
+    // ------------------------------
+    glfwInit();
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+
+#ifdef __APPLE__
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
+#endif
+
+    // glfw window creation
+    // --------------------
+    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
+    if (window == NULL)
+    {
+        std::cout << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwMakeContextCurrent(window);
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+    glfwSetCursorPosCallback(window, mouse_callback);
+    glfwSetScrollCallback(window, scroll_callback);
+
+    // tell GLFW to capture our mouse
+    glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
+
+    // glad: load all OpenGL function pointers
+    // ---------------------------------------
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
+    {
+        std::cout << "Failed to initialize GLAD" << std::endl;
+        return -1;
+    }
+
+    // configure global opengl state
+    // -----------------------------
+    glEnable(GL_DEPTH_TEST);
+
+    // build and compile shaders
+    // -------------------------
+    Shader shader("6.bloom.vs", "6.bloom.fs");
+    Shader shaderLight("6.bloom.vs", "6.light_box.fs");
+    Shader shaderBlur("6.old_blur.vs", "6.old_blur.fs");
+    Shader shaderBloomFinal("6.bloom_final.vs", "6.bloom_final.fs");
+
+    // load textures
+    // -------------
+    unsigned int woodTexture      = loadTexture(FileSystem::getPath("resources/textures/wood.png").c_str(), true); // note that we're loading the texture as an SRGB texture
+    unsigned int containerTexture = loadTexture(FileSystem::getPath("resources/textures/container2.png").c_str(), true); // note that we're loading the texture as an SRGB texture
+
+    // configure (floating point) framebuffers
+    // ---------------------------------------
+    unsigned int hdrFBO;
+    glGenFramebuffers(1, &hdrFBO);
+    glBindFramebuffer(GL_FRAMEBUFFER, hdrFBO);
+    // create 2 floating point color buffers (1 for normal rendering, other for brightness threshold values)
+    unsigned int colorBuffers[2];
+    glGenTextures(2, colorBuffers);
+    for (unsigned int i = 0; i < 2; i++)
+    {
+        glBindTexture(GL_TEXTURE_2D, colorBuffers[i]);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, SCR_WIDTH, SCR_HEIGHT, 0, GL_RGBA, GL_FLOAT, NULL);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);  // we clamp to the edge as the blur filter would otherwise sample repeated texture values!
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+        // attach texture to framebuffer
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, GL_TEXTURE_2D, colorBuffers[i], 0);
+    }
+    // create and attach depth buffer (renderbuffer)
+    unsigned int rboDepth;
+    glGenRenderbuffers(1, &rboDepth);
+    glBindRenderbuffer(GL_RENDERBUFFER, rboDepth);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, SCR_WIDTH, SCR_HEIGHT);
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, rboDepth);
+    // tell OpenGL which color attachments we'll use (of this framebuffer) for rendering
+    unsigned int attachments[2] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 };
+    glDrawBuffers(2, attachments);
+    // finally check if framebuffer is complete
+    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+        std::cout << "Framebuffer not complete!" << std::endl;
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+    // ping-pong-framebuffer for blurring
+    unsigned int pingpongFBO[2];
+    unsigned int pingpongColorbuffers[2];
+    glGenFramebuffers(2, pingpongFBO);
+    glGenTextures(2, pingpongColorbuffers);
+    for (unsigned int i = 0; i < 2; i++)
+    {
+        glBindFramebuffer(GL_FRAMEBUFFER, pingpongFBO[i]);
+        glBindTexture(GL_TEXTURE_2D, pingpongColorbuffers[i]);
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, SCR_WIDTH, SCR_HEIGHT, 0, GL_RGBA, GL_FLOAT, NULL);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); // we clamp to the edge as the blur filter would otherwise sample repeated texture values!
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, pingpongColorbuffers[i], 0);
+        // also check if framebuffers are complete (no need for depth buffer)
+        if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
+            std::cout << "Framebuffer not complete!" << std::endl;
+    }
+
+    // lighting info
+    // -------------
+    // positions
+    std::vector<glm::vec3> lightPositions;
+    lightPositions.push_back(glm::vec3( 0.0f, 0.5f,  1.5f));
+    lightPositions.push_back(glm::vec3(-4.0f, 0.5f, -3.0f));
+    lightPositions.push_back(glm::vec3( 3.0f, 0.5f,  1.0f));
+    lightPositions.push_back(glm::vec3(-.8f,  2.4f, -1.0f));
+    // colors
+    std::vector<glm::vec3> lightColors;
+    lightColors.push_back(glm::vec3(5.0f,   5.0f,  5.0f));
+    lightColors.push_back(glm::vec3(10.0f,  0.0f,  0.0f));
+    lightColors.push_back(glm::vec3(0.0f,   0.0f,  15.0f));
+    lightColors.push_back(glm::vec3(0.0f,   5.0f,  0.0f));
+
+
+    // shader configuration
+    // --------------------
+    shader.use();
+    shader.setInt("diffuseTexture", 0);
+    shaderBlur.use();
+    shaderBlur.setInt("image", 0);
+    shaderBloomFinal.use();
+    shaderBloomFinal.setInt("scene", 0);
+    shaderBloomFinal.setInt("bloomBlur", 1);
+
+    // bloom renderer
+    // --------------
+    BloomRenderer bloomRenderer;
+    bloomRenderer.Init(SCR_WIDTH, SCR_HEIGHT);
+
+    // render loop
+    // -----------
+    while (!glfwWindowShouldClose(window))
+    {
+        // per-frame time logic
+        // --------------------
+        float currentFrame = static_cast<float>(glfwGetTime());
+        deltaTime = currentFrame - lastFrame;
+        lastFrame = currentFrame;
+
+        // input
+        // -----
+        processInput(window);
+
+        // render
+        // ------
+        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+        // 1. render scene into floating point framebuffer
+        // -----------------------------------------------
+        glBindFramebuffer(GL_FRAMEBUFFER, hdrFBO);
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+        glm::mat4 projection = glm::perspective(glm::radians(camera.Zoom), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
+        glm::mat4 view = camera.GetViewMatrix();
+        glm::mat4 model = glm::mat4(1.0f);
+        shader.use();
+        shader.setMat4("projection", projection);
+        shader.setMat4("view", view);
+        glActiveTexture(GL_TEXTURE0);
+        glBindTexture(GL_TEXTURE_2D, woodTexture);
+        // set lighting uniforms
+        for (unsigned int i = 0; i < lightPositions.size(); i++)
+        {
+            shader.setVec3("lights[" + std::to_string(i) + "].Position", lightPositions[i]);
+            shader.setVec3("lights[" + std::to_string(i) + "].Color", lightColors[i]);
+        }
+        shader.setVec3("viewPos", camera.Position);
+        // create one large cube that acts as the floor
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(0.0f, -1.0f, 0.0));
+        model = glm::scale(model, glm::vec3(12.5f, 0.5f, 12.5f));
+        shader.setMat4("model", model);
+        renderCube();
+        // then create multiple cubes as the scenery
+        glBindTexture(GL_TEXTURE_2D, containerTexture);
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(0.0f, 1.5f, 0.0));
+        model = glm::scale(model, glm::vec3(0.5f));
+        shader.setMat4("model", model);
+        renderCube();
+
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(2.0f, 0.0f, 1.0));
+        model = glm::scale(model, glm::vec3(0.5f));
+        shader.setMat4("model", model);
+        renderCube();
+
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(-1.0f, -1.0f, 2.0));
+        model = glm::rotate(model, glm::radians(60.0f), glm::normalize(glm::vec3(1.0, 0.0, 1.0)));
+        shader.setMat4("model", model);
+        renderCube();
+
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(0.0f, 2.7f, 4.0));
+        model = glm::rotate(model, glm::radians(23.0f), glm::normalize(glm::vec3(1.0, 0.0, 1.0)));
+        model = glm::scale(model, glm::vec3(1.25));
+        shader.setMat4("model", model);
+        renderCube();
+
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(-2.0f, 1.0f, -3.0));
+        model = glm::rotate(model, glm::radians(124.0f), glm::normalize(glm::vec3(1.0, 0.0, 1.0)));
+        shader.setMat4("model", model);
+        renderCube();
+
+        model = glm::mat4(1.0f);
+        model = glm::translate(model, glm::vec3(-3.0f, 0.0f, 0.0));
+        model = glm::scale(model, glm::vec3(0.5f));
+        shader.setMat4("model", model);
+        renderCube();
+
+        // finally show all the light sources as bright cubes
+        shaderLight.use();
+        shaderLight.setMat4("projection", projection);
+        shaderLight.setMat4("view", view);
+
+        for (unsigned int i = 0; i < lightPositions.size(); i++)
+        {
+            model = glm::mat4(1.0f);
+            model = glm::translate(model, glm::vec3(lightPositions[i]));
+            model = glm::scale(model, glm::vec3(0.25f));
+            shaderLight.setMat4("model", model);
+            shaderLight.setVec3("lightColor", lightColors[i]);
+            renderCube();
+        }
+        glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+        if (programChoice < 1 || programChoice > 3) { programChoice = 1; }
+        bloom = (programChoice == 1) ? false : true;
+        bool horizontal = true;
+
+        // 2.A) bloom is disabled
+        // ----------------------
+        if (programChoice == 1)
+        {
+
+        }
+
+        // 2.B) blur bright fragments with two-pass Gaussian Blur
+        // ------------------------------------------------------
+        else if (programChoice == 2)
+        {
+	        bool first_iteration = true;
+	        unsigned int amount = 10;
+	        shaderBlur.use();
+	        for (unsigned int i = 0; i < amount; i++)
+	        {
+		        glBindFramebuffer(GL_FRAMEBUFFER, pingpongFBO[horizontal]);
+		        shaderBlur.setInt("horizontal", horizontal);
+		        glBindTexture(GL_TEXTURE_2D, first_iteration ? colorBuffers[1] : pingpongColorbuffers[!horizontal]);  // bind texture of other framebuffer (or scene if first iteration)
+		        renderQuad();
+		        horizontal = !horizontal;
+		        if (first_iteration)
+			        first_iteration = false;
+	        }
+	        glBindFramebuffer(GL_FRAMEBUFFER, 0);
+        }
+
+        // 2.C) use unthresholded bloom with progressive downsample/upsampling
+        // -------------------------------------------------------------------
+        else if (programChoice == 3)
+        {
+	        bloomRenderer.RenderBloomTexture(colorBuffers[1], bloomFilterRadius);
+        }
+
+        // 3. now render floating point color buffer to 2D quad and tonemap HDR colors to default framebuffer's (clamped) color range
+        // --------------------------------------------------------------------------------------------------------------------------
+        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+        shaderBloomFinal.use();
+        glActiveTexture(GL_TEXTURE0);
+        glBindTexture(GL_TEXTURE_2D, colorBuffers[0]);
+        glActiveTexture(GL_TEXTURE1);
+        if (programChoice == 1) {
+	        glBindTexture(GL_TEXTURE_2D, 0); // trick to bind invalid texture "0", we don't care either way!
+        }
+        if (programChoice == 2) {
+	        glBindTexture(GL_TEXTURE_2D, pingpongColorbuffers[!horizontal]);
+        }
+        else if (programChoice == 3) {
+	        glBindTexture(GL_TEXTURE_2D, bloomRenderer.BloomTexture());
+        }
+        shaderBloomFinal.setInt("programChoice", programChoice);
+        shaderBloomFinal.setFloat("exposure", exposure);
+        renderQuad();
+
+        //std::cout << "bloom: " << (bloom ? "on" : "off") << "| exposure: " << exposure << std::endl;
+
+        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
+        // -------------------------------------------------------------------------------
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+
+    bloomRenderer.Destroy();
+    glfwTerminate();
+    return 0;
+}
+
+// renderCube() renders a 1x1 3D cube in NDC.
+// -------------------------------------------------
+unsigned int cubeVAO = 0;
+unsigned int cubeVBO = 0;
+void renderCube()
+{
+    // initialize (if necessary)
+    if (cubeVAO == 0)
+    {
+        float vertices[] = {
+            // back face
+            -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 0.0f, 0.0f, // bottom-left
+             1.0f,  1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 1.0f, 1.0f, // top-right
+             1.0f, -1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 1.0f, 0.0f, // bottom-right
+             1.0f,  1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 1.0f, 1.0f, // top-right
+            -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 0.0f, 0.0f, // bottom-left
+            -1.0f,  1.0f, -1.0f,  0.0f,  0.0f, -1.0f, 0.0f, 1.0f, // top-left
+            // front face
+            -1.0f, -1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f, 0.0f, // bottom-left
+             1.0f, -1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f, 0.0f, // bottom-right
+             1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f, 1.0f, // top-right
+             1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 1.0f, 1.0f, // top-right
+            -1.0f,  1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f, 1.0f, // top-left
+            -1.0f, -1.0f,  1.0f,  0.0f,  0.0f,  1.0f, 0.0f, 0.0f, // bottom-left
+            // left face
+            -1.0f,  1.0f,  1.0f, -1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-right
+            -1.0f,  1.0f, -1.0f, -1.0f,  0.0f,  0.0f, 1.0f, 1.0f, // top-left
+            -1.0f, -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-left
+            -1.0f, -1.0f, -1.0f, -1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-left
+            -1.0f, -1.0f,  1.0f, -1.0f,  0.0f,  0.0f, 0.0f, 0.0f, // bottom-right
+            -1.0f,  1.0f,  1.0f, -1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-right
+            // right face
+             1.0f,  1.0f,  1.0f,  1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-left
+             1.0f, -1.0f, -1.0f,  1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-right
+             1.0f,  1.0f, -1.0f,  1.0f,  0.0f,  0.0f, 1.0f, 1.0f, // top-right
+             1.0f, -1.0f, -1.0f,  1.0f,  0.0f,  0.0f, 0.0f, 1.0f, // bottom-right
+             1.0f,  1.0f,  1.0f,  1.0f,  0.0f,  0.0f, 1.0f, 0.0f, // top-left
+             1.0f, -1.0f,  1.0f,  1.0f,  0.0f,  0.0f, 0.0f, 0.0f, // bottom-left
+            // bottom face
+            -1.0f, -1.0f, -1.0f,  0.0f, -1.0f,  0.0f, 0.0f, 1.0f, // top-right
+             1.0f, -1.0f, -1.0f,  0.0f, -1.0f,  0.0f, 1.0f, 1.0f, // top-left
+             1.0f, -1.0f,  1.0f,  0.0f, -1.0f,  0.0f, 1.0f, 0.0f, // bottom-left
+             1.0f, -1.0f,  1.0f,  0.0f, -1.0f,  0.0f, 1.0f, 0.0f, // bottom-left
+            -1.0f, -1.0f,  1.0f,  0.0f, -1.0f,  0.0f, 0.0f, 0.0f, // bottom-right
+            -1.0f, -1.0f, -1.0f,  0.0f, -1.0f,  0.0f, 0.0f, 1.0f, // top-right
+            // top face
+            -1.0f,  1.0f, -1.0f,  0.0f,  1.0f,  0.0f, 0.0f, 1.0f, // top-left
+             1.0f,  1.0f , 1.0f,  0.0f,  1.0f,  0.0f, 1.0f, 0.0f, // bottom-right
+             1.0f,  1.0f, -1.0f,  0.0f,  1.0f,  0.0f, 1.0f, 1.0f, // top-right
+             1.0f,  1.0f,  1.0f,  0.0f,  1.0f,  0.0f, 1.0f, 0.0f, // bottom-right
+            -1.0f,  1.0f, -1.0f,  0.0f,  1.0f,  0.0f, 0.0f, 1.0f, // top-left
+            -1.0f,  1.0f,  1.0f,  0.0f,  1.0f,  0.0f, 0.0f, 0.0f  // bottom-left
+        };
+        glGenVertexArrays(1, &cubeVAO);
+        glGenBuffers(1, &cubeVBO);
+        // fill buffer
+        glBindBuffer(GL_ARRAY_BUFFER, cubeVBO);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+        // link vertex attributes
+        glBindVertexArray(cubeVAO);
+        glEnableVertexAttribArray(0);
+        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
+        glEnableVertexAttribArray(1);
+        glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
+        glEnableVertexAttribArray(2);
+        glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
+        glBindBuffer(GL_ARRAY_BUFFER, 0);
+        glBindVertexArray(0);
+    }
+    // render Cube
+    glBindVertexArray(cubeVAO);
+    glDrawArrays(GL_TRIANGLES, 0, 36);
+    glBindVertexArray(0);
+}
+
+// renderQuad() renders a 1x1 XY quad in NDC
+// -----------------------------------------
+unsigned int quadVAO = 0;
+unsigned int quadVBO;
+void renderQuad()
+{
+    if (quadVAO == 0)
+    {
+        float quadVertices[] = {
+            // positions        // texture Coords
+            -1.0f,  1.0f, 0.0f, 0.0f, 1.0f,
+            -1.0f, -1.0f, 0.0f, 0.0f, 0.0f,
+             1.0f,  1.0f, 0.0f, 1.0f, 1.0f,
+             1.0f, -1.0f, 0.0f, 1.0f, 0.0f,
+        };
+        // setup plane VAO
+        glGenVertexArrays(1, &quadVAO);
+        glGenBuffers(1, &quadVBO);
+        glBindVertexArray(quadVAO);
+        glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
+        glEnableVertexAttribArray(0);
+        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
+        glEnableVertexAttribArray(1);
+        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
+    }
+    glBindVertexArray(quadVAO);
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    glBindVertexArray(0);
+}
+
+// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
+// ---------------------------------------------------------------------------------------------------------
+void processInput(GLFWwindow *window)
+{
+    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, true);
+
+    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
+        camera.ProcessKeyboard(FORWARD, deltaTime);
+    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
+        camera.ProcessKeyboard(BACKWARD, deltaTime);
+    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
+        camera.ProcessKeyboard(LEFT, deltaTime);
+    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
+        camera.ProcessKeyboard(RIGHT, deltaTime);
+
+    if (glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS)
+    {
+        if (exposure > 0.0f)
+            exposure -= 0.001f;
+        else
+            exposure = 0.0f;
+    }
+    else if (glfwGetKey(window, GLFW_KEY_E) == GLFW_PRESS)
+    {
+        exposure += 0.001f;
+    }
+
+    if (glfwGetKey(window, GLFW_KEY_1) == GLFW_PRESS)
+    {
+	    programChoice = 1;
+    }
+    else if (glfwGetKey(window, GLFW_KEY_2) == GLFW_PRESS)
+    {
+	    programChoice = 2;
+    }
+    else if (glfwGetKey(window, GLFW_KEY_3) == GLFW_PRESS)
+    {
+	    programChoice = 3;
+    }
+}
+
+// glfw: whenever the window size changed (by OS or user resize) this callback function executes
+// ---------------------------------------------------------------------------------------------
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
+{
+    // make sure the viewport matches the new window dimensions; note that width and
+    // height will be significantly larger than specified on retina displays.
+    glViewport(0, 0, width, height);
+}
+
+// glfw: whenever the mouse moves, this callback is called
+// -------------------------------------------------------
+void mouse_callback(GLFWwindow* window, double xposIn, double yposIn)
+{
+    float xpos = static_cast<float>(xposIn);
+    float ypos = static_cast<float>(yposIn);
+    if (firstMouse)
+    {
+        lastX = xpos;
+        lastY = ypos;
+        firstMouse = false;
+    }
+
+    float xoffset = xpos - lastX;
+    float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
+
+    lastX = xpos;
+    lastY = ypos;
+
+    camera.ProcessMouseMovement(xoffset, yoffset);
+}
+
+// glfw: whenever the mouse scroll wheel scrolls, this callback is called
+// ----------------------------------------------------------------------
+void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
+{
+    camera.ProcessMouseScroll(static_cast<float>(yoffset));
+}
+
+// utility function for loading a 2D texture from file
+// ---------------------------------------------------
+unsigned int loadTexture(char const * path, bool gammaCorrection)
+{
+    unsigned int textureID;
+    glGenTextures(1, &textureID);
+
+    int width, height, nrComponents;
+    unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
+    if (data)
+    {
+        GLenum internalFormat;
+        GLenum dataFormat;
+        if (nrComponents == 1)
+        {
+            internalFormat = dataFormat = GL_RED;
+        }
+        else if (nrComponents == 3)
+        {
+            internalFormat = gammaCorrection ? GL_SRGB : GL_RGB;
+            dataFormat = GL_RGB;
+        }
+        else if (nrComponents == 4)
+        {
+            internalFormat = gammaCorrection ? GL_SRGB_ALPHA : GL_RGBA;
+            dataFormat = GL_RGBA;
+        }
+
+        glBindTexture(GL_TEXTURE_2D, textureID);
+        glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, width, height, 0, dataFormat, GL_UNSIGNED_BYTE, data);
+        glGenerateMipmap(GL_TEXTURE_2D);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+        stbi_image_free(data);
+    }
+    else
+    {
+        std::cout << "Texture failed to load at path: " << path << std::endl;
+        stbi_image_free(data);
+    }
+
+    return textureID;
+}