Fix bloom shader missing its target

src/gl/renderer/gl_postprocess.cpp

@@ -143,6 +143,8 @@ void FGLRenderer::BloomScene()
 	mBloomExtractShader->Bind();
 	mBloomExtractShader->SceneTexture.Set(0);
 	mBloomExtractShader->Exposure.Set(mCameraExposure);
+	mBloomExtractShader->Scale.Set(mSceneViewport.width / (float)mScreenViewport.width, mSceneViewport.height / (float)mScreenViewport.height);
+	mBloomExtractShader->Offset.Set(mSceneViewport.left / (float)mScreenViewport.width, mSceneViewport.top / (float)mScreenViewport.height);
 	RenderScreenQuad();
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
@@ -182,7 +184,7 @@ void FGLRenderer::BloomScene()
 
 	// Add bloom back to scene texture:
 	mBuffers->BindCurrentFB();
-	glViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
+	glViewport(mSceneViewport.left, mSceneViewport.top, mSceneViewport.width, mSceneViewport.height);
 	glEnable(GL_BLEND);
 	glBlendEquation(GL_FUNC_ADD);
 	glBlendFunc(GL_ONE, GL_ONE);
@@ -193,6 +195,7 @@ void FGLRenderer::BloomScene()
 	mBloomCombineShader->Bind();
 	mBloomCombineShader->BloomTexture.Set(0);
 	RenderScreenQuad();
+	glViewport(mScreenViewport.left, mScreenViewport.top, mScreenViewport.width, mScreenViewport.height);
 }
 
 //-----------------------------------------------------------------------------

src/gl/renderer/gl_renderbuffers.cpp

@@ -139,7 +139,7 @@ void FGLRenderBuffers::DeleteFrameBuffer(GLuint &handle)
 //
 //==========================================================================
 
-void FGLRenderBuffers::Setup(int width, int height)
+void FGLRenderBuffers::Setup(int width, int height, int sceneWidth, int sceneHeight)
 {
 	if (!IsEnabled())
 		return;
@@ -151,16 +151,23 @@ void FGLRenderBuffers::Setup(int width, int height)
 		CreateScene(mWidth, mHeight, samples);
 		mSamples = samples;
 	}
-	else if (width > mWidth || height > mHeight)
+	else if (width != mWidth || height != mHeight)
 	{
 		CreatePipeline(width, height);
 		CreateScene(width, height, samples);
-		CreateBloom(width, height);
 		mWidth = width;
 		mHeight = height;
 		mSamples = samples;
 	}
 
+	// Bloom bluring buffers need to match the scene to avoid bloom bleeding artifacts
+	if (mBloomWidth != sceneWidth || mBloomHeight != sceneHeight)
+	{
+		CreateBloom(sceneWidth, sceneHeight);
+		mBloomWidth = sceneWidth;
+		mBloomHeight = sceneHeight;
+	}
+
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, 0);
 	glBindRenderbuffer(GL_RENDERBUFFER, 0);

src/gl/renderer/gl_renderbuffers.h

@@ -20,7 +20,7 @@ public:
 	FGLRenderBuffers();
 	~FGLRenderBuffers();
 
-	void Setup(int width, int height);
+	void Setup(int width, int height, int sceneWidth, int sceneHeight);
 
 	void BindSceneFB();
 	void BlitSceneToTexture();
@@ -64,6 +64,8 @@ private:
 	int mWidth = 0;
 	int mHeight = 0;
 	int mSamples = 0;
+	int mBloomWidth = 0;
+	int mBloomHeight = 0;
 
 	static const int NumPipelineTextures = 2;
 	int mCurrentPipelineTexture = 0;

src/gl/renderer/gl_renderer.cpp

@@ -286,7 +286,7 @@ void FGLRenderer::Begin2D()
 {
 	if (FGLRenderBuffers::IsEnabled())
 	{
-		mBuffers->Setup(framebuffer->GetWidth(), framebuffer->GetHeight());
+		mBuffers->Setup(mScreenViewport.width, mScreenViewport.height, mSceneViewport.width, mSceneViewport.height);
 		if (mDrawingScene2D)
 			mBuffers->BindSceneFB();
 		else

src/gl/scene/gl_scene.cpp

@@ -170,7 +170,7 @@ void FGLRenderer::Set3DViewport(bool mainview)
 {
 	if (mainview && FGLRenderBuffers::IsEnabled())
 	{
-		mBuffers->Setup(mScreenViewport.width, mScreenViewport.height);
+		mBuffers->Setup(mScreenViewport.width, mScreenViewport.height, mSceneViewport.width, mSceneViewport.height);
 		mBuffers->BindSceneFB();
 	}
 

src/gl/shaders/gl_bloomshader.cpp

@@ -60,6 +60,8 @@ void FBloomExtractShader::Bind()
 		mShader.SetAttribLocation(0, "PositionInProjection");
 		SceneTexture.Init(mShader, "SceneTexture");
 		Exposure.Init(mShader, "ExposureAdjustment");
+		Scale.Init(mShader, "Scale");
+		Offset.Init(mShader, "Offset");
 	}
 	mShader.Bind();
 }

src/gl/shaders/gl_bloomshader.h

@@ -10,6 +10,8 @@ public:
 
 	FBufferedUniform1i SceneTexture;
 	FBufferedUniform1f Exposure;
+	FBufferedUniform2f Scale;
+	FBufferedUniform2f Offset;
 
 private:
 	FShaderProgram mShader;

wadsrc/static/shaders/glsl/bloomextract.fp

@@ -4,9 +4,11 @@ out vec4 FragColor;
 
 uniform sampler2D SceneTexture;
 uniform float ExposureAdjustment;
+uniform vec2 Scale;
+uniform vec2 Offset;
 
 void main()
 {
-	vec4 color = texture(SceneTexture, TexCoord);
+	vec4 color = texture(SceneTexture, Offset + TexCoord * Scale);
 	FragColor = max(vec4(color.rgb * ExposureAdjustment - 1, 1), vec4(0));
 }