Added bloom shaders

src/CMakeLists.txt

@@ -1106,6 +1106,8 @@ set( FASTMATH_SOURCES
 	gl/shaders/gl_texshader.cpp
 	gl/shaders/gl_shaderprogram.cpp
 	gl/shaders/gl_presentshader.cpp
+	gl/shaders/gl_bloomshader.cpp
+	gl/shaders/gl_blurshader.cpp
 	gl/system/gl_interface.cpp
 	gl/system/gl_framebuffer.cpp
 	gl/system/gl_menu.cpp

src/gl/renderer/gl_renderbuffers.cpp

@@ -72,12 +72,37 @@ FGLRenderBuffers::FGLRenderBuffers()
 
 FGLRenderBuffers::~FGLRenderBuffers()
 {
+	Clear();
+}
+
+void FGLRenderBuffers::Clear()
+{
+	for (int i = 0; i < NumBloomLevels; i++)
+	{
+		auto &level = BloomLevels[i];
+		if (level.HFramebuffer != 0)
+			glDeleteFramebuffers(1, &level.HFramebuffer);
+		if (level.VFramebuffer != 0)
+			glDeleteFramebuffers(1, &level.VFramebuffer);
+		if (level.HTexture != 0)
+			glDeleteTextures(1, &level.HTexture);
+		if (level.VTexture != 0)
+			glDeleteTextures(1, &level.VTexture);
+		level = FGLBloomTextureLevel();
+	}
+
 	if (mSceneFB != 0)
 		glDeleteFramebuffers(1, &mSceneFB);
 	if (mSceneTexture != 0)
 		glDeleteTextures(1, &mSceneTexture);
 	if (mSceneDepthStencil != 0)
 		glDeleteRenderbuffers(1, &mSceneDepthStencil);
+
+	mSceneFB = 0;
+	mSceneTexture = 0;
+	mSceneDepthStencil = 0;
+	mWidth = 0;
+	mHeight = 0;
 }
 
 //==========================================================================
@@ -92,12 +117,9 @@ void FGLRenderBuffers::Setup(int width, int height)
 	if (width <= mWidth && height <= mHeight)
 		return;
 
-	if (mSceneFB != 0)
-		glDeleteFramebuffers(1, &mSceneFB);
-	if (mSceneTexture != 0)
-		glDeleteTextures(1, &mSceneTexture);
-	if (mSceneDepthStencil != 0)
-		glDeleteRenderbuffers(1, &mSceneDepthStencil);
+	Clear();
+
+	glActiveTexture(GL_TEXTURE0);
 
 	glGenFramebuffers(1, &mSceneFB);
 	glGenTextures(1, &mSceneTexture);
@@ -109,15 +131,49 @@ void FGLRenderBuffers::Setup(int width, int height)
 	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);
-	glBindTexture(GL_TEXTURE_2D, 0);
 
 	glBindRenderbuffer(GL_RENDERBUFFER, mSceneDepthStencil);
 	glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
-	glBindRenderbuffer(GL_RENDERBUFFER, 0);
 
 	glBindFramebuffer(GL_FRAMEBUFFER, mSceneFB);
 	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mSceneTexture, 0);
 	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, mSceneDepthStencil);
+
+	int bloomWidth = MAX(width / 2, 1);
+	int bloomHeight = MAX(height / 2, 1);
+	for (int i = 0; i < NumBloomLevels; i++)
+	{
+		auto &level = BloomLevels[i];
+		level.Width = MAX(bloomWidth / 2, 1);
+		level.Height = MAX(bloomHeight / 2, 1);
+
+		glGenTextures(1, &level.VTexture);
+		glGenTextures(1, &level.HTexture);
+		glGenFramebuffers(1, &level.VFramebuffer);
+		glGenFramebuffers(1, &level.HFramebuffer);
+
+		glBindTexture(GL_TEXTURE_2D, level.VTexture);
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, level.Width, level.Height, 0, GL_RGBA, GL_FLOAT, nullptr);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+		glBindTexture(GL_TEXTURE_2D, level.HTexture);
+		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, level.Width, level.Height, 0, GL_RGBA, GL_FLOAT, nullptr);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+		glBindFramebuffer(GL_FRAMEBUFFER, level.VFramebuffer);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, level.VTexture, 0);
+
+		glBindFramebuffer(GL_FRAMEBUFFER, level.HFramebuffer);
+		glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, level.HTexture, 0);
+
+		bloomWidth = level.Width;
+		bloomHeight = level.Height;
+	}
+
+	glBindTexture(GL_TEXTURE_2D, 0);
+	glBindRenderbuffer(GL_RENDERBUFFER, 0);
 	glBindFramebuffer(GL_FRAMEBUFFER, mOutputFB);
 
 	mWidth = width;
@@ -154,6 +210,6 @@ void FGLRenderBuffers::BindOutputFB()
 
 void FGLRenderBuffers::BindSceneTexture(int index)
 {
-	glActiveTexture(index);
+	glActiveTexture(GL_TEXTURE0 + index);
 	glBindTexture(GL_TEXTURE_2D, mSceneTexture);
 }

src/gl/renderer/gl_renderbuffers.h

@@ -3,6 +3,17 @@
 
 #include "gl/shaders/gl_shader.h"
 
+class FGLBloomTextureLevel
+{
+public:
+	GLuint VTexture = 0;
+	GLuint VFramebuffer = 0;
+	GLuint HTexture = 0;
+	GLuint HFramebuffer = 0;
+	GLuint Width = 0;
+	GLuint Height = 0;
+};
+
 class FGLRenderBuffers
 {
 public:
@@ -16,7 +27,12 @@ public:
 
 	static bool IsSupported() { return gl.version >= 3.3f; }
 
+	enum { NumBloomLevels = 4 };
+	FGLBloomTextureLevel BloomLevels[NumBloomLevels];
+
 private:
+	void Clear();
+
 	int mWidth = 0;
 	int mHeight = 0;
 

src/gl/renderer/gl_renderer.cpp

@@ -62,6 +62,8 @@
 #include "gl/data/gl_vertexbuffer.h"
 #include "gl/scene/gl_drawinfo.h"
 #include "gl/shaders/gl_shader.h"
+#include "gl/shaders/gl_bloomshader.h"
+#include "gl/shaders/gl_blurshader.h"
 #include "gl/shaders/gl_presentshader.h"
 #include "gl/textures/gl_texture.h"
 #include "gl/textures/gl_translate.h"
@@ -110,6 +112,9 @@ void gl_FlushModels();
 void FGLRenderer::Initialize()
 {
 	mBuffers = new FGLRenderBuffers();
+	mBloomExtractShader = new FBloomExtractShader();
+	mBloomCombineShader = new FBloomCombineShader();
+	mBlurShader = new FBlurShader();
 	mPresentShader = new FPresentShader();
 
 	// Only needed for the core profile, because someone decided it was a good idea to remove the default VAO.
@@ -160,6 +165,9 @@ FGLRenderer::~FGLRenderer()
 	}
 	if (mBuffers) delete mBuffers;
 	if (mPresentShader) delete mPresentShader;
+	if (mBloomExtractShader) delete mBloomExtractShader;
+	if (mBloomCombineShader) delete mBloomCombineShader;
+	if (mBlurShader) delete mBlurShader;
 }
 
 //==========================================================================

src/gl/renderer/gl_renderer.h

@@ -19,6 +19,9 @@ class FLightBuffer;
 class FSamplerManager;
 class DPSprite;
 class FGLRenderBuffers;
+class FBloomExtractShader;
+class FBloomCombineShader;
+class FBlurShader;
 class FPresentShader;
 
 inline float DEG2RAD(float deg)
@@ -82,6 +85,9 @@ public:
 	int mOldFBID;
 
 	FGLRenderBuffers *mBuffers;
+	FBloomExtractShader *mBloomExtractShader;
+	FBloomCombineShader *mBloomCombineShader;
+	FBlurShader *mBlurShader;
 	FPresentShader *mPresentShader;
 
 	FTexture *gllight;
@@ -147,6 +153,7 @@ public:
 	void SetFixedColormap (player_t *player);
 	void WriteSavePic (player_t *player, FILE *file, int width, int height);
 	void EndDrawScene(sector_t * viewsector);
+	void BloomScene();
 	void Flush();
 
 	void SetProjection(float fov, float ratio, float fovratio);

src/gl/scene/gl_scene.cpp

@@ -72,6 +72,8 @@
 #include "gl/scene/gl_drawinfo.h"
 #include "gl/scene/gl_portal.h"
 #include "gl/shaders/gl_shader.h"
+#include "gl/shaders/gl_bloomshader.h"
+#include "gl/shaders/gl_blurshader.h"
 #include "gl/shaders/gl_presentshader.h"
 #include "gl/stereo3d/gl_stereo3d.h"
 #include "gl/stereo3d/scoped_view_shifter.h"
@@ -204,6 +206,130 @@ void FGLRenderer::Set3DViewport()
 	glStencilOp(GL_KEEP,GL_KEEP,GL_REPLACE);
 }
 
+//-----------------------------------------------------------------------------
+//
+// Adds bloom contribution to scene texture
+//
+//-----------------------------------------------------------------------------
+
+void FGLRenderer::BloomScene()
+{
+	if (!FGLRenderBuffers::IsSupported())
+		return;
+
+	const float blurAmount = 4.0f;
+	int sampleCount = 5; // Note: must be uneven number 3 to 15
+	float exposure = 2.0f;
+
+	auto vbo = GLRenderer->mVBO;
+
+	// TODO: Need a better way to share state with other parts of the pipeline
+	GLboolean blendEnabled, scissorEnabled;
+	GLint currentProgram, blendEquationRgb, blendEquationAlpha, blendSrcRgb, blendSrcAlpha, blendDestRgb, blendDestAlpha;
+	glGetBooleanv(GL_BLEND, &blendEnabled);
+	glGetBooleanv(GL_SCISSOR_TEST, &scissorEnabled);
+	glGetIntegerv(GL_CURRENT_PROGRAM, &currentProgram);
+	glGetIntegerv(GL_BLEND_EQUATION_RGB, &blendEquationRgb);
+	glGetIntegerv(GL_BLEND_EQUATION_ALPHA, &blendEquationAlpha);
+	glGetIntegerv(GL_BLEND_SRC_RGB, &blendSrcRgb);
+	glGetIntegerv(GL_BLEND_SRC_ALPHA, &blendSrcAlpha);
+	glGetIntegerv(GL_BLEND_DST_RGB, &blendDestRgb);
+	glGetIntegerv(GL_BLEND_DST_ALPHA, &blendDestAlpha);
+
+	glDisable(GL_BLEND);
+	glDisable(GL_SCISSOR_TEST);
+
+	const auto &level0 = mBuffers->BloomLevels[0];
+
+	// Extract blooming pixels from scene texture:
+	glBindFramebuffer(GL_FRAMEBUFFER, level0.VFramebuffer);
+	glViewport(0, 0, level0.Width, level0.Height);
+	mBuffers->BindSceneTexture(0);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	mBloomExtractShader->Bind();
+	mBloomExtractShader->SceneTexture.Set(0);
+	mBloomExtractShader->Exposure.Set(exposure);
+	{
+		FFlatVertex *ptr = vbo->GetBuffer();
+		ptr->Set(-1.0f, -1.0f, 0, 0.0f, 0.0f); ptr++;
+		ptr->Set(-1.0f, 1.0f, 0, 0.0f, 1.0f); ptr++;
+		ptr->Set(1.0f, -1.0f, 0, 1.0f, 0.0f); ptr++;
+		ptr->Set(1.0f, 1.0f, 0, 1.0f, 1.0f); ptr++;
+		vbo->RenderCurrent(ptr, GL_TRIANGLE_STRIP);
+	}
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+
+	// Blur and downscale:
+	for (int i = 0; i < FGLRenderBuffers::NumBloomLevels - 1; i++)
+	{
+		const auto &level = mBuffers->BloomLevels[i];
+		const auto &next = mBuffers->BloomLevels[i + 1];
+		mBlurShader->BlurHorizontal(vbo, blurAmount, sampleCount, level.VTexture, level.HFramebuffer, level.Width, level.Height);
+		mBlurShader->BlurVertical(vbo, blurAmount, sampleCount, level.HTexture, next.VFramebuffer, next.Width, next.Height);
+	}
+
+	// Blur and upscale:
+	for (int i = FGLRenderBuffers::NumBloomLevels - 1; i > 0; i--)
+	{
+		const auto &level = mBuffers->BloomLevels[i];
+		const auto &next = mBuffers->BloomLevels[i - 1];
+
+		mBlurShader->BlurHorizontal(vbo, blurAmount, sampleCount, level.VTexture, level.HFramebuffer, level.Width, level.Height);
+		mBlurShader->BlurVertical(vbo, blurAmount, sampleCount, level.HTexture, level.VFramebuffer, level.Width, level.Height);
+
+		// Linear upscale:
+		glBindFramebuffer(GL_FRAMEBUFFER, next.VFramebuffer);
+		glViewport(0, 0, next.Width, next.Height);
+		glActiveTexture(GL_TEXTURE0);
+		glBindTexture(GL_TEXTURE_2D, level.VTexture);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+		mBloomCombineShader->Bind();
+		mBloomCombineShader->BloomTexture.Set(0);
+		{
+			FFlatVertex *ptr = vbo->GetBuffer();
+			ptr->Set(-1.0f, -1.0f, 0, 0.0f, 0.0f); ptr++;
+			ptr->Set(-1.0f, 1.0f, 0, 0.0f, 1.0f); ptr++;
+			ptr->Set(1.0f, -1.0f, 0, 1.0f, 0.0f); ptr++;
+			ptr->Set(1.0f, 1.0f, 0, 1.0f, 1.0f); ptr++;
+			vbo->RenderCurrent(ptr, GL_TRIANGLE_STRIP);
+		}
+	}
+
+	mBlurShader->BlurHorizontal(vbo, blurAmount, sampleCount, level0.VTexture, level0.HFramebuffer, level0.Width, level0.Height);
+	mBlurShader->BlurVertical(vbo, blurAmount, sampleCount, level0.HTexture, level0.VFramebuffer, level0.Width, level0.Height);
+
+	// Add bloom back to scene texture:
+	mBuffers->BindSceneFB();
+	glViewport(0, 0, mOutputViewport.width, mOutputViewport.height);
+	glEnable(GL_BLEND);
+	glBlendEquation(GL_FUNC_ADD);
+	glBlendFunc(GL_ONE, GL_ONE);
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, level0.VTexture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	mBloomCombineShader->Bind();
+	mBloomCombineShader->BloomTexture.Set(0);
+	{
+		FFlatVertex *ptr = vbo->GetBuffer();
+		ptr->Set(-1.0f, -1.0f, 0, 0.0f, 0.0f); ptr++;
+		ptr->Set(-1.0f, 1.0f, 0, 0.0f, 1.0f); ptr++;
+		ptr->Set(1.0f, -1.0f, 0, 1.0f, 0.0f); ptr++;
+		ptr->Set(1.0f, 1.0f, 0, 1.0f, 1.0f); ptr++;
+		vbo->RenderCurrent(ptr, GL_TRIANGLE_STRIP);
+	}
+
+	if (blendEnabled)
+		glEnable(GL_BLEND);
+	if (scissorEnabled)
+		glEnable(GL_SCISSOR_TEST);
+	glBlendEquationSeparate(blendEquationRgb, blendEquationAlpha);
+	glBlendFuncSeparate(blendSrcRgb, blendDestRgb, blendSrcAlpha, blendDestAlpha);
+}
+
 //-----------------------------------------------------------------------------
 //
 // Run post processing steps and copy to frame buffer
@@ -810,6 +936,8 @@ void FGLRenderer::EndDrawScene(sector_t * viewsector)
 	gl_RenderState.ResetColor();
 	gl_RenderState.EnableTexture(true);
 	glDisable(GL_SCISSOR_TEST);
+
+	BloomScene();
 }
 
 

src/gl/shaders/gl_bloomshader.cpp

@@ -0,0 +1,79 @@
+/*
+** gl_bloomshader.cpp
+** Shaders used to do bloom
+**
+**---------------------------------------------------------------------------
+** Copyright 2016 Magnus Norddahl
+** All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions
+** are met:
+**
+** 1. Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+** 2. Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in the
+**    documentation and/or other materials provided with the distribution.
+** 3. The name of the author may not be used to endorse or promote products
+**    derived from this software without specific prior written permission.
+** 4. When not used as part of GZDoom or a GZDoom derivative, this code will be
+**    covered by the terms of the GNU Lesser General Public License as published
+**    by the Free Software Foundation; either version 2.1 of the License, or (at
+**    your option) any later version.
+** 5. Full disclosure of the entire project's source code, except for third
+**    party libraries is mandatory. (NOTE: This clause is non-negotiable!)
+**
+** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+**---------------------------------------------------------------------------
+**
+*/
+
+#include "gl/system/gl_system.h"
+#include "files.h"
+#include "m_swap.h"
+#include "v_video.h"
+#include "gl/gl_functions.h"
+#include "vectors.h"
+#include "gl/system/gl_interface.h"
+#include "gl/system/gl_framebuffer.h"
+#include "gl/system/gl_cvars.h"
+#include "gl/shaders/gl_bloomshader.h"
+
+void FBloomExtractShader::Bind()
+{
+	if (!mShader)
+	{
+		mShader.Compile(FShaderProgram::Vertex, "shaders/glsl/bloomextract.vp");
+		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/bloomextract.fp");
+		mShader.SetFragDataLocation(0, "FragColor");
+		mShader.Link("shaders/glsl/bloomextract");
+		mShader.SetAttribLocation(0, "PositionInProjection");
+		SceneTexture.Init(mShader, "SceneTexture");
+		Exposure.Init(mShader, "ExposureAdjustment");
+	}
+	mShader.Bind();
+}
+
+void FBloomCombineShader::Bind()
+{
+	if (!mShader)
+	{
+		mShader.Compile(FShaderProgram::Vertex, "shaders/glsl/bloomcombine.vp");
+		mShader.Compile(FShaderProgram::Fragment, "shaders/glsl/bloomcombine.fp");
+		mShader.SetFragDataLocation(0, "FragColor");
+		mShader.Link("shaders/glsl/bloomcombine");
+		mShader.SetAttribLocation(0, "PositionInProjection");
+		BloomTexture.Init(mShader, "Bloom");
+	}
+	mShader.Bind();
+}

src/gl/shaders/gl_bloomshader.h

@@ -0,0 +1,29 @@
+#ifndef __GL_BLOOMSHADER_H
+#define __GL_BLOOMSHADER_H
+
+#include "gl_shaderprogram.h"
+
+class FBloomExtractShader
+{
+public:
+	void Bind();
+
+	FBufferedUniform1i SceneTexture;
+	FBufferedUniform1f Exposure;
+
+private:
+	FShaderProgram mShader;
+};
+
+class FBloomCombineShader
+{
+public:
+	void Bind();
+
+	FBufferedUniform1i BloomTexture;
+
+private:
+	FShaderProgram mShader;
+};
+
+#endif

src/gl/shaders/gl_blurshader.cpp

@@ -0,0 +1,265 @@
+/*
+** gl_blurshader.cpp
+** Gaussian blur shader
+**
+**---------------------------------------------------------------------------
+** Copyright 2016 Magnus Norddahl
+** All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions
+** are met:
+**
+** 1. Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+** 2. Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in the
+**    documentation and/or other materials provided with the distribution.
+** 3. The name of the author may not be used to endorse or promote products
+**    derived from this software without specific prior written permission.
+** 4. When not used as part of GZDoom or a GZDoom derivative, this code will be
+**    covered by the terms of the GNU Lesser General Public License as published
+**    by the Free Software Foundation; either version 2.1 of the License, or (at
+**    your option) any later version.
+** 5. Full disclosure of the entire project's source code, except for third
+**    party libraries is mandatory. (NOTE: This clause is non-negotiable!)
+**
+** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+**---------------------------------------------------------------------------
+**
+*/
+
+#include "gl/system/gl_system.h"
+#include "files.h"
+#include "m_swap.h"
+#include "v_video.h"
+#include "gl/gl_functions.h"
+#include "vectors.h"
+#include "gl/system/gl_interface.h"
+#include "gl/system/gl_framebuffer.h"
+#include "gl/system/gl_cvars.h"
+#include "gl/shaders/gl_blurshader.h"
+#include "gl/data/gl_vertexbuffer.h"
+
+//==========================================================================
+//
+// Performs a vertical gaussian blur pass
+//
+//==========================================================================
+
+void FBlurShader::BlurVertical(FFlatVertexBuffer *vbo, float blurAmount, int sampleCount, GLuint inputTexture, GLuint outputFrameBuffer, int width, int height)
+{
+	Blur(vbo, blurAmount, sampleCount, inputTexture, outputFrameBuffer, width, height, true);
+}
+
+//==========================================================================
+//
+// Performs a horizontal gaussian blur pass
+//
+//==========================================================================
+
+void FBlurShader::BlurHorizontal(FFlatVertexBuffer *vbo, float blurAmount, int sampleCount, GLuint inputTexture, GLuint outputFrameBuffer, int width, int height)
+{
+	Blur(vbo, blurAmount, sampleCount, inputTexture, outputFrameBuffer, width, height, false);
+}
+
+//==========================================================================
+//
+// Helper for BlurVertical and BlurHorizontal. Executes the actual pass
+//
+//==========================================================================
+
+void FBlurShader::Blur(FFlatVertexBuffer *vbo, float blurAmount, int sampleCount, GLuint inputTexture, GLuint outputFrameBuffer, int width, int height, bool vertical)
+{
+	int error = glGetError();
+	BlurSetup *setup = GetSetup(blurAmount, sampleCount);
+	error = glGetError();
+	if (vertical)
+		setup->VerticalShader->Bind();
+	else
+		setup->HorizontalShader->Bind();
+	error = glGetError();
+	glActiveTexture(GL_TEXTURE0);
+	glBindTexture(GL_TEXTURE_2D, inputTexture);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	error = glGetError();
+	glBindFramebuffer(GL_FRAMEBUFFER, outputFrameBuffer);
+	glViewport(0, 0, width, height);
+	glDisable(GL_BLEND);
+	error = glGetError();
+	FFlatVertex *ptr = vbo->GetBuffer();
+	ptr->Set(-1.0f, -1.0f, 0, 0.0f, 0.0f); ptr++;
+	ptr->Set(-1.0f, 1.0f, 0, 0.0f, 1.0f); ptr++;
+	ptr->Set(1.0f, -1.0f, 0, 1.0f, 0.0f); ptr++;
+	ptr->Set(1.0f, 1.0f, 0, 1.0f, 1.0f); ptr++;
+	vbo->RenderCurrent(ptr, GL_TRIANGLE_STRIP);
+	error = glGetError();
+}
+
+//==========================================================================
+//
+// Compiles the blur shaders needed for the specified blur amount and
+// kernel size
+//
+//==========================================================================
+
+FBlurShader::BlurSetup *FBlurShader::GetSetup(float blurAmount, int sampleCount)
+{
+	for (size_t mBlurSetupIndex = 0; mBlurSetupIndex < mBlurSetups.Size(); mBlurSetupIndex++)
+	{
+		if (mBlurSetups[mBlurSetupIndex].blurAmount == blurAmount && mBlurSetups[mBlurSetupIndex].sampleCount == sampleCount)
+		{
+			return &mBlurSetups[mBlurSetupIndex];
+		}
+	}
+
+	BlurSetup blurSetup(blurAmount, sampleCount);
+
+	FString vertexCode = VertexShaderCode();
+	FString horizontalCode = FragmentShaderCode(blurAmount, sampleCount, false);
+	FString verticalCode = FragmentShaderCode(blurAmount, sampleCount, true);
+
+	blurSetup.VerticalShader = std::make_shared<FShaderProgram>();
+	blurSetup.VerticalShader->Compile(FShaderProgram::Vertex, "vertical blur vertex shader", vertexCode);
+	blurSetup.VerticalShader->Compile(FShaderProgram::Fragment, "vertical blur fragment shader", verticalCode);
+	blurSetup.VerticalShader->SetFragDataLocation(0, "FragColor");
+	blurSetup.VerticalShader->SetAttribLocation(0, "PositionInProjection");
+	blurSetup.VerticalShader->Link("vertical blur");
+	blurSetup.VerticalShader->Bind();
+	int error = glGetError();
+	glUniform1i(glGetUniformLocation(*blurSetup.VerticalShader.get(), "SourceTexture"), 0);
+	error = glGetError();
+
+	blurSetup.HorizontalShader = std::make_shared<FShaderProgram>();
+	blurSetup.HorizontalShader->Compile(FShaderProgram::Vertex, "horizontal blur vertex shader", vertexCode);
+	blurSetup.HorizontalShader->Compile(FShaderProgram::Fragment, "horizontal blur fragment shader", horizontalCode);
+	blurSetup.HorizontalShader->SetFragDataLocation(0, "FragColor");
+	blurSetup.HorizontalShader->SetAttribLocation(0, "PositionInProjection");
+	blurSetup.HorizontalShader->Link("horizontal blur");
+	blurSetup.HorizontalShader->Bind();
+	glUniform1i(glGetUniformLocation(*blurSetup.HorizontalShader.get(), "SourceTexture"), 0);
+
+	mBlurSetups.Push(blurSetup);
+
+	return &mBlurSetups[mBlurSetups.Size() - 1];
+}
+
+//==========================================================================
+//
+// The vertex shader GLSL code
+//
+//==========================================================================
+
+FString FBlurShader::VertexShaderCode()
+{
+	return R"(
+		#version 330
+
+		in vec4 PositionInProjection;
+		out vec2 TexCoord;
+
+		void main()
+		{
+			gl_Position = PositionInProjection;
+			TexCoord = (gl_Position.xy + 1.0) * 0.5;
+		}
+	)";
+}
+
+//==========================================================================
+//
+// Generates the fragment shader GLSL code for a specific blur setup
+//
+//==========================================================================
+
+FString FBlurShader::FragmentShaderCode(float blurAmount, int sampleCount, bool vertical)
+{
+	TArray<float> sampleWeights;
+	TArray<int> sampleOffsets;
+	ComputeBlurSamples(sampleCount, blurAmount, sampleWeights, sampleOffsets);
+
+	const char *fragmentShader =
+		R"(
+		#version 330
+		in vec2 TexCoord;
+		uniform sampler2D SourceTexture;
+		out vec4 FragColor;
+		void main()
+		{
+			FragColor = %s;
+		}
+		)";
+
+	FString loopCode;
+	for (int i = 0; i < sampleCount; i++)
+	{
+		if (i > 0)
+			loopCode += " + ";
+
+		if (vertical)
+			loopCode.AppendFormat("\r\n\t\t\ttextureOffset(SourceTexture, TexCoord, ivec2(0, %d)) * %f", sampleOffsets[i], (double)sampleWeights[i]);
+		else
+			loopCode.AppendFormat("\r\n\t\t\ttextureOffset(SourceTexture, TexCoord, ivec2(%d, 0)) * %f", sampleOffsets[i], (double)sampleWeights[i]);
+	}
+
+	FString code;
+	code.Format(fragmentShader, loopCode.GetChars());
+	return code;
+}
+
+//==========================================================================
+//
+// Calculates the sample weight for a specific offset in the kernel
+//
+//==========================================================================
+
+float FBlurShader::ComputeGaussian(float n, float theta) // theta = Blur Amount
+{
+	return (float)((1.0f / sqrtf(2 * (float)M_PI * theta)) * expf(-(n * n) / (2.0f * theta * theta)));
+}
+
+//==========================================================================
+//
+// Calculates the sample weights and offsets
+//
+//==========================================================================
+
+void FBlurShader::ComputeBlurSamples(int sampleCount, float blurAmount, TArray<float> &sampleWeights, TArray<int> &sampleOffsets)
+{
+	sampleWeights.Resize(sampleCount);
+	sampleOffsets.Resize(sampleCount);
+
+	sampleWeights[0] = ComputeGaussian(0, blurAmount);
+	sampleOffsets[0] = 0;
+
+	float totalWeights = sampleWeights[0];
+
+	for (int i = 0; i < sampleCount / 2; i++)
+	{
+		float weight = ComputeGaussian(i + 1.0f, blurAmount);
+
+		sampleWeights[i * 2 + 1] = weight;
+		sampleWeights[i * 2 + 2] = weight;
+		sampleOffsets[i * 2 + 1] = i + 1;
+		sampleOffsets[i * 2 + 2] = -i - 1;
+
+		totalWeights += weight * 2;
+	}
+
+	for (int i = 0; i < sampleCount; i++)
+	{
+		sampleWeights[i] /= totalWeights;
+	}
+}

src/gl/shaders/gl_blurshader.h

@@ -0,0 +1,39 @@
+#ifndef __GL_BLURSHADER_H
+#define __GL_BLURSHADER_H
+
+#include "gl_shaderprogram.h"
+#include <memory>
+
+class FFlatVertexBuffer;
+
+class FBlurShader
+{
+public:
+	void BlurVertical(FFlatVertexBuffer *vbo, float blurAmount, int sampleCount, GLuint inputTexture, GLuint outputFrameBuffer, int width, int height);
+	void BlurHorizontal(FFlatVertexBuffer *vbo, float blurAmount, int sampleCount, GLuint inputTexture, GLuint outputFrameBuffer, int width, int height);
+
+private:
+	void Blur(FFlatVertexBuffer *vbo, float blurAmount, int sampleCount, GLuint inputTexture, GLuint outputFrameBuffer, int width, int height, bool vertical);
+
+	struct BlurSetup
+	{
+		BlurSetup(float blurAmount, int sampleCount) : blurAmount(blurAmount), sampleCount(sampleCount) { }
+
+		float blurAmount;
+		int sampleCount;
+		std::shared_ptr<FShaderProgram> VerticalShader;
+		std::shared_ptr<FShaderProgram> HorizontalShader;
+	};
+
+	BlurSetup *GetSetup(float blurAmount, int sampleCount);
+
+	FString VertexShaderCode();
+	FString FragmentShaderCode(float blurAmount, int sampleCount, bool vertical);
+
+	float ComputeGaussian(float n, float theta);
+	void ComputeBlurSamples(int sampleCount, float blurAmount, TArray<float> &sample_weights, TArray<int> &sample_offsets);
+
+	TArray<BlurSetup> mBlurSetups;
+};
+
+#endif

src/gl/shaders/gl_shaderprogram.cpp

@@ -95,13 +95,17 @@ void FShaderProgram::CreateShader(ShaderType type)
 
 void FShaderProgram::Compile(ShaderType type, const char *lumpName)
 {
-	CreateShader(type);
-
-	const auto &handle = mShaders[type];
-
 	int lump = Wads.CheckNumForFullName(lumpName);
 	if (lump == -1) I_Error("Unable to load '%s'", lumpName);
 	FString code = Wads.ReadLump(lump).GetString().GetChars();
+	Compile(type, lumpName, code);
+}
+
+void FShaderProgram::Compile(ShaderType type, const char *name, const FString &code)
+{
+	CreateShader(type);
+
+	const auto &handle = mShaders[type];
 
 	int lengths[1] = { (int)code.Len() };
 	const char *sources[1] = { code.GetChars() };
@@ -113,7 +117,7 @@ void FShaderProgram::Compile(ShaderType type, const char *lumpName)
 	glGetShaderiv(handle, GL_COMPILE_STATUS, &status);
 	if (status == GL_FALSE)
 	{
-		I_Error("Compile Shader '%s':\n%s\n", lumpName, GetShaderInfoLog(handle).GetChars());
+		I_Error("Compile Shader '%s':\n%s\n", name, GetShaderInfoLog(handle).GetChars());
 	}
 	else
 	{

src/gl/shaders/gl_shaderprogram.h

@@ -16,6 +16,7 @@ public:
 	};
 
 	void Compile(ShaderType type, const char *lumpName);
+	void Compile(ShaderType type, const char *name, const FString &code);
 	void SetFragDataLocation(int index, const char *name);
 	void Link(const char *name);
 	void SetAttribLocation(int index, const char *name);

wadsrc/static/shaders/glsl/bloomcombine.fp

@@ -0,0 +1,12 @@
+
+#version 330
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D Bloom;
+
+void main()
+{
+	FragColor = vec4(texture(Bloom, TexCoord).rgb, 0.0);
+}

wadsrc/static/shaders/glsl/bloomcombine.vp

@@ -0,0 +1,11 @@
+
+#version 330
+
+in vec4 PositionInProjection;
+out vec2 TexCoord;
+
+void main()
+{
+	gl_Position = PositionInProjection;
+	TexCoord = PositionInProjection.xy * 0.5 + 0.5;
+}

wadsrc/static/shaders/glsl/bloomextract.fp

@@ -0,0 +1,14 @@
+
+#version 330
+
+in vec2 TexCoord;
+out vec4 FragColor;
+
+uniform sampler2D SceneTexture;
+uniform float ExposureAdjustment;
+
+void main()
+{
+	vec4 color = texture(SceneTexture, TexCoord);
+	FragColor = max(vec4(color.rgb * ExposureAdjustment - 1, 1), vec4(0));
+}

wadsrc/static/shaders/glsl/bloomextract.vp

@@ -0,0 +1,11 @@
+
+#version 330
+
+in vec4 PositionInProjection;
+out vec2 TexCoord;
+
+void main()
+{
+	gl_Position = PositionInProjection;
+	TexCoord = PositionInProjection.xy * 0.5 + 0.5;
+}