making a warp

1 files changed, 104 insertions, 6 deletions

diff --git a/polyTest/src/ofApp.cpp b/polyTest/src/ofApp.cpp
index 1553666..7b87c9d 100644
--- a/polyTest/src/ofApp.cpp
+++ b/polyTest/src/ofApp.cpp
@@ -15,6 +15,86 @@ void ofApp::update(){
 	
 }
 
+void gaussianElimination(float * input, int n)
+{
+	auto i = 0;
+	auto j = 0;
+	auto m = n - 1;
+
+	while (i < m && j < n) 
+	{
+		auto iMax = i;
+		for (auto k = i + 1; k < m; ++k)
+		{
+			if (fabs(input[k * n + j]) > fabs(input[iMax * n + j])) 
+			{
+				iMax = k;
+			}
+		}
+
+		if (input[iMax * n + j] != 0) 
+		{
+			if (i != iMax)
+			{
+				for (auto k = 0; k < n; ++k)
+				{
+					auto ikIn = input[i * n + k];
+					input[i * n + k] = input[iMax * n + k];
+					input[iMax * n + k] = ikIn;
+				}
+			}
+
+			float ijIn = input[i * n + j];
+			for (auto k = 0; k < n; ++k)
+			{
+				input[i * n + k] /= ijIn;
+			}
+
+			for (auto u = i + 1; u < m; ++u)
+			{
+				auto ujIn = input[u * n + j];
+				for (auto k = 0; k < n; ++k)
+				{
+					input[u * n + k] -= ujIn * input[i * n + k];
+				}
+			}
+
+			++i;
+		}
+		++j;
+	}
+
+	for (auto i = m - 2; i >= 0; --i)
+	{
+		for (auto j = i + 1; j < n - 1; ++j)
+		{
+			input[i * n + m] -= input[i * n + j] * input[j * n + m];
+		}
+	}
+}
+
+glm::mat4 getPerspectiveTransformMatrix(const glm::vec2 src[4], const glm::vec2 dst[4])
+{
+	float p[8][9] = 
+	{
+		{ -src[0][0], -src[0][1], -1, 0, 0, 0, src[0][0] * dst[0][0], src[0][1] * dst[0][0], -dst[0][0] }, // h11
+		{ 0, 0, 0, -src[0][0], -src[0][1], -1, src[0][0] * dst[0][1], src[0][1] * dst[0][1], -dst[0][1] }, // h12
+		{ -src[1][0], -src[1][1], -1, 0, 0, 0, src[1][0] * dst[1][0], src[1][1] * dst[1][0], -dst[1][0] }, // h13
+		{ 0, 0, 0, -src[1][0], -src[1][1], -1, src[1][0] * dst[1][1], src[1][1] * dst[1][1], -dst[1][1] }, // h21
+		{ -src[2][0], -src[2][1], -1, 0, 0, 0, src[2][0] * dst[2][0], src[2][1] * dst[2][0], -dst[2][0] }, // h22
+		{ 0, 0, 0, -src[2][0], -src[2][1], -1, src[2][0] * dst[2][1], src[2][1] * dst[2][1], -dst[2][1] }, // h23
+		{ -src[3][0], -src[3][1], -1, 0, 0, 0, src[3][0] * dst[3][0], src[3][1] * dst[3][0], -dst[3][0] }, // h31
+		{ 0, 0, 0, -src[3][0], -src[3][1], -1, src[3][0] * dst[3][1], src[3][1] * dst[3][1], -dst[3][1] }, // h32
+	};
+
+	gaussianElimination(&p[0][0], 9);
+
+	return glm::mat4(p[0][8], p[3][8], 0, p[6][8], 
+					 p[1][8], p[4][8], 0, p[7][8], 
+					 0, 0, 1, 0, 
+					 p[2][8], p[5][8], 0, 1);
+}
+
 ofPolyline ofApp::polyLineTransform(const ofPolyline& poly, ofMatrix4x4 xform){
 	ofPolyline tempPoly;
 	for (auto& p:poly){
@@ -48,13 +128,31 @@ void ofApp::draw(){
 	ofBackground(0,0,0);
 	ofSetColor(255,255,255);
 
-	ofTranslate(ofGetWidth()/2,ofGetHeight()/2);
-	ofRotate(0,0,1,ofGetElapsedTimef()*50);
-	drawPoly(makePolygon(4,200),200,200);
-	drawPoly(makePolygon(5,200),-200,200);
-	drawPoly(makePolygon(6,200),-200,-200);
+	ofMatrix4x4 m = ofMatrix4x4::newIdentityMatrix();
+    m.rotateRad(ofGetElapsedTimef(),0,0,1);
+    m.translate(ofGetWidth()/2,ofGetHeight()/2,0);
 
-	
+    glm::vec2 src[]={
+    	glm::vec2(0,0),
+    	glm::vec2(ofGetWidth(),0),
+    	glm::vec2(ofGetWidth(),ofGetHeight()),
+    	glm::vec2(0,ofGetHeight())
+    };
+
+    glm::vec2 dst[]={
+    	glm::vec2(0,0),
+    	glm::vec2(ofGetWidth(),0),
+    	glm::vec2(ofGetWidth()-100,ofGetHeight()),
+    	glm::vec2(100,ofGetHeight())
+    };
+
+    ofMatrix4x4 warp =getPerspectiveTransformMatrix(src,dst);
+
+    //drawPoly(polyLineTransform(makePolygon(4,200),m),200,200);
+    //drawPoly(polyLineTransform(makePolygon(5,200),m),-200,200);
+    //drawPoly(polyLineTransform(makePolygon(6,200),m),-200,-200);
+
+    drawPoly(polyLineTransform(polyLineTransform(makePolygon(6,200),m),warp),0,0);
 
 
 }