openspades/Sources/Draw/GLCameraBlurFilter.cpp

/*
 Copyright (c) 2013 yvt
 
 This file is part of OpenSpades.
 
 OpenSpades is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 OpenSpades is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with OpenSpades.  If not, see <http://www.gnu.org/licenses/>.
 
 */


#include "GLCameraBlurFilter.h"
#include "IGLDevice.h"
#include "../Core/Math.h"
#include <vector>
#include "GLQuadRenderer.h"
#include "GLProgram.h"
#include "GLProgramAttribute.h"
#include "GLProgramUniform.h"
#include "GLRenderer.h"
#include "../Core/Debug.h"
#include "GLProfiler.h"

namespace spades {
	namespace draw {
		GLCameraBlurFilter::GLCameraBlurFilter(GLRenderer *renderer):
		renderer(renderer){
			prevMatrix = Matrix4::Identity();
			program = renderer->RegisterProgram("Shaders/PostFilters/CameraBlur.program");
		}
		
#define M(r,c) (d.m[(r)+(c)*4])
		
		static Matrix4 ReverseMatrix(Matrix4 d){
			return Matrix4(M(1,2)*M(2,1)-M(1,1)*M(2,2),
						   M(1,0)*M(2,2)-M(1,2)*M(2,0),
						   M(1,1)*M(2,0)-M(1,0)*M(2,1),
						   0,
						   M(0,1)*M(2,2)-M(0,2)*M(2,1),
						   M(0,2)*M(2,0)-M(0,0)*M(2,2),
						   M(0,0)*M(2,1)-M(0,1)*M(2,0),
						   0,
						   0, 0, 0, 0,
						   M(0,2)*M(1,1)-M(0,1)*M(1,2),
						   M(0,0)*M(1,2)-M(0,2)*M(1,0),
						   M(0,1)*M(1,0)-M(0,0)*M(1,1),
						   1);
		}
		
		static float MyACos(float v){
			if(v >= 1.f)
				return 0.f;
			else
				return acosf(v);
		}
		
		GLColorBuffer GLCameraBlurFilter::Filter(GLColorBuffer input, float radialBlur) {
			SPADES_MARK_FUNCTION();
			
			if(radialBlur > 0.f)
				radialBlur = 1.f - radialBlur;
			else
				radialBlur = 1.f;
			
			bool hasRadialBlur = radialBlur < .9999f;
			
			IGLDevice *dev = renderer->GetGLDevice();
			GLQuadRenderer qr(dev);
			
			
			
			dev->Enable(IGLDevice::Blend, false);
			
			static GLProgramAttribute programPosition("positionAttribute");
			static GLProgramUniform programTexture("texture");
			static GLProgramUniform programDepthTexture("depthTexture");
			static GLProgramUniform programReverseMatrix("reverseMatrix");
			static GLProgramUniform programShutterTimeScale("shutterTimeScale");
			
			programPosition(program);
			programTexture(program);
			programDepthTexture(program);
			programReverseMatrix(program);
			programShutterTimeScale(program);
			
			const client::SceneDefinition& def = renderer->GetSceneDef();
			Matrix4 newMatrix = Matrix4::Identity();
			newMatrix.m[0] = def.viewAxis[0].x;
			newMatrix.m[1] = def.viewAxis[1].x;
			newMatrix.m[2] = def.viewAxis[2].x;
			newMatrix.m[4] = def.viewAxis[0].y;
			newMatrix.m[5] = def.viewAxis[1].y;
			newMatrix.m[6] = def.viewAxis[2].y;
			newMatrix.m[8] = def.viewAxis[0].z;
			newMatrix.m[9] = def.viewAxis[1].z;
			newMatrix.m[10] = def.viewAxis[2].z;
			
			// othrogonal matrix can be reversed fast
			Matrix4 inverseNewMatrix = newMatrix.Transposed();
			Matrix4 diffMatrix = prevMatrix * inverseNewMatrix;
			prevMatrix = newMatrix;
			Matrix4 reverseMatrix = ReverseMatrix(diffMatrix);
			
			if(diffMatrix.m[0] < .3f ||
			   diffMatrix.m[5] < .3f ||
			   diffMatrix.m[10] < .3f){
				// too much change
				if(hasRadialBlur) {
					diffMatrix = Matrix4::Identity();
				}else{
					// skip blur
					return input;
				}
			}
			
			float movePixels = MyACos(diffMatrix.m[0]);
			float shutterTimeScale = .3f;
			movePixels = std::max(movePixels, MyACos(diffMatrix.m[5]));
			movePixels = std::max(movePixels, MyACos(diffMatrix.m[10]));
			movePixels = tanf(movePixels) / tanf(def.fovX * .5f);
			movePixels *= (float)dev->ScreenWidth() * .5f;
			movePixels *= shutterTimeScale;
			
			movePixels = std::max(movePixels,
								  (1.f - radialBlur) * dev->ScreenWidth() * 0.5f);
			
			if(movePixels < 1.f){
				// too less change, skip camera blur
				return input;
			}
			
			int levels = (int)ceilf(logf(movePixels) / logf(5.f));
			if(levels <= 0)
				levels = 1;
			
			if(hasRadialBlur)
				radialBlur *= radialBlur;
			reverseMatrix = Matrix4::Scale(radialBlur, radialBlur, 1.f)
				* reverseMatrix;
			
			program->Use();
			
			programTexture.SetValue(0);
			programDepthTexture.SetValue(1);
			programReverseMatrix.SetValue(reverseMatrix);
			
			// composite to the final image
			GLColorBuffer buf = input;
			
			qr.SetCoordAttributeIndex(programPosition());
			dev->ActiveTexture(1);
			dev->BindTexture(IGLDevice::Texture2D, renderer->GetFramebufferManager()->GetDepthTexture());
			dev->ActiveTexture(0);
			
			for(int i = 0; i < levels; i++){
				GLProfiler measure(dev, "Apply [%d / %d]", i+1,levels);
				GLColorBuffer output = input.GetManager()->CreateBufferHandle();
				programShutterTimeScale.SetValue(shutterTimeScale);
				dev->BindTexture(IGLDevice::Texture2D, buf.GetTexture());
				dev->BindFramebuffer(IGLDevice::Framebuffer, output.GetFramebuffer());
				dev->Viewport(0, 0, output.GetWidth(), output.GetHeight());
				qr.Draw();
				dev->BindTexture(IGLDevice::Texture2D, 0);
				shutterTimeScale /= 5.f;
				buf = output;
			}
			
			dev->ActiveTexture(1);
			dev->BindTexture(IGLDevice::Texture2D, 0);
			dev->ActiveTexture(0);
			
			
			return buf;
		}
	}
}