first commit

3 files changed, 190 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..99b716d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.ppm
+srender
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..ba88ceb
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,178 @@
+#include<fstream>
+#include<cmath>
+
+class Vertice
+{
+public:
+	float x, y, z;
+	float u, v;
+	Vertice(float x, float y, float z, float u, float v)
+	{
+		this->x = x;
+		this->y = y;
+		this->z = z;
+
+		this->u = u;
+		this->v = v;
+	}
+	void project()
+	{
+		x /= z;
+		y /= z;
+		u /= z;
+		v /= z;
+		z = 1.0f / z;
+	}
+	void fitToImage(int imageWidth, int imageHeight)
+	{
+		x = (x * (imageWidth / 2)) + (imageWidth / 2);
+		y = (-y * (imageHeight / 2)) + (imageHeight / 2);
+	}
+};
+
+class Image
+{
+public:
+	int imageWidth, imageHeight;
+	unsigned char* pixels;
+	float* zbuffer;
+	Image(int imageWidth, int imageHeight)
+	{
+		this->imageWidth = imageWidth;
+		this->imageHeight = imageHeight;
+		pixels = new unsigned char[imageWidth * imageHeight * 3];
+		zbuffer = new float[imageWidth * imageHeight];
+		for (int i = 0; i < imageWidth * imageHeight; i++)
+			zbuffer[i] = 1000.0f;
+	}
+	~Image()
+	{
+		delete[] pixels;
+		delete[] zbuffer;
+	}
+	void setPixel(int x, int y, int red, int green, int blue)
+	{
+		int help_var = ((y * imageWidth) + x) * 3;
+		pixels[help_var + 0] = (unsigned char)red;
+		pixels[help_var + 1] = (unsigned char)green;
+		pixels[help_var + 2] = (unsigned char)blue;
+	}
+	void fillPixels(int red, int green, int blue)
+	{
+		int help_var = imageWidth * imageHeight * 3;
+		for (int i = 0; i < help_var; i += 3) {
+			pixels[i + 0] = (unsigned char)red;
+			pixels[i + 1] = (unsigned char)green;
+			pixels[i + 2] = (unsigned char)blue;
+		}
+	}
+	void setZBufferAt(int x, int y, float value)
+	{
+		int hlp_var = ((y * imageWidth) + x);
+		zbuffer[hlp_var] = value;
+	}
+	float getZBufferAt(int x, int y)
+	{
+		int hlp_var = ((y * imageWidth) + x);
+		return zbuffer[hlp_var];
+	}
+
+	float edgeFunction(const Vertice& A, const Vertice& B, const Vertice& P)
+	{
+		return ((P.x - A.x)*(B.y - A.y) - (P.y - A.y)*(B.x - A.x));
+	}	
+
+	void fillTriangleBarycentric(const Vertice& v0, const Vertice& v1, const Vertice& v2)
+	{
+		Vertice p(0.0f, 0.0f, 0.0f, 0.0f, 0.0f);
+		float area = edgeFunction(v0, v1, v2);
+		float edge0[2] = {v2.x - v1.x, v2.y - v1.y};
+		float edge1[2] = {v0.x - v2.x, v0.y - v2.y};
+		float edge2[2] = {v1.x - v0.x, v1.y - v0.y};
+		for (int x = 0; x < imageWidth; x++) {
+			for (int y = 0; y < imageHeight; y++) {
+				p.x = x + 0.5f;	p.y = y + 0.5f;
+				float w0 = edgeFunction(v1, v2, p);
+				float w1 = edgeFunction(v2, v0, p);
+				float w2 = edgeFunction(v0, v1, p);
+				bool inside = true;
+				inside &= ((w0 == 0) ? ((edge0[1] == 0 && edge0[0] > 0) || edge0[1] > 0) : (w0 > 0));
+				inside &= ((w1 == 0) ? ((edge1[1] == 0 && edge1[0] > 0) || edge1[1] > 0) : (w1 > 0));
+				inside &= ((w2 == 0) ? ((edge2[1] == 0 && edge2[0] > 0) || edge2[1] > 0) : (w2 > 0));
+				if (inside) {
+					w0 /= area;
+					w1 /= area;
+					w2 /= area;
+					float z = 1.0f / (w0 * v0.z + w1 * v1.z + w2 * v2.z);	
+					
+					if (z < getZBufferAt(x, y)) {
+						setZBufferAt(x, y, z);
+
+						float u = (w0 * v0.u + w1 * v1.u + w2 * v2.u) * z;
+						float v = (w0 * v0.v + w1 * v1.v + w2 * v2.v) * z;
+					
+						const float M = 8;
+						float p = (fmod(u * M, 1.0f) > 0.5f) ^ (fmod(v * M, 1.0f) < 0.5f);
+
+						int red =   (int)(255.0f * p);
+						int green = (int)(255.0f * p);
+						int blue =  (int)(255.0f * p);
+						setPixel(x, y, red, green, blue);
+					}
+				}
+			}
+		}
+	}
+};
+
+int main()
+{
+	Image image(800, 600);
+	//image.fillPixels(255, 255, 255);
+	float sr = 90.0f, sg = 90.0f, sb = 130.0f;
+	float er = 0.0f, eg = 0.0f, eb = 80.0f;
+	float dr = ((er - sr) / 600.0f); 
+	float dg = ((eg - sg) / 600.0f); 
+	float db = ((eb - sb) / 600.0f);
+	for (int y = 0; y < 600; y++) {
+		sr += dr; sg += dg; sb += db;
+		for (int x = 0; x < 800; x++)
+			image.setPixel(x, y, (int)sr, (int)sg, (int)sb);
+	}
+
+
+	Vertice a(0.2f, 3.5f, 4.0f, 0.0f, 1.0f);
+	Vertice b(-0.8f, 0.0f, 1.0f, 0.0f, 0.0f);
+	Vertice c(1.6f, -1.6f, 2.0f, 1.0f, 0.0f);
+	
+	Vertice d(2.0f, 2.0f, 3.0f, 0.0f, 1.0f);
+	Vertice e(-2.0f, -2.0f, 3.0f, 1.0f, 0.0f);
+	Vertice f(2.0f, -2.0f, 3.0f, 0.0f, 0.0f);
+
+	a.project();
+	b.project();
+	c.project();
+	
+	d.project();
+	e.project();
+	f.project();
+
+	a.fitToImage(image.imageWidth, image.imageHeight);
+	b.fitToImage(image.imageWidth, image.imageHeight);
+	c.fitToImage(image.imageWidth, image.imageHeight);
+	
+	d.fitToImage(image.imageWidth, image.imageHeight);
+	e.fitToImage(image.imageWidth, image.imageHeight);
+	f.fitToImage(image.imageWidth, image.imageHeight);
+
+	image.fillTriangleBarycentric(a, b, c);
+	image.fillTriangleBarycentric(d, e, f);
+
+	std::ofstream imageFile;
+	imageFile.open("./image.ppm");
+	imageFile << "P6\n" << image.imageWidth << " " << image.imageHeight << "\n255\n";
+	imageFile.write((char*)image.pixels, image.imageWidth * image.imageHeight * 3);
+	imageFile.close();
+	
+	return 0;
+}
diff --git a/makefile b/makefile
new file mode 100644
index 0000000..02d5d7c
--- /dev/null
+++ b/makefile
@@ -0,0 +1,10 @@
+srender: main.cpp
+	g++ -o srender main.cpp
+image.ppm: srender
+	./srender
+run: srender
+	./srender
+view: image.ppm
+	feh -. image.ppm
+clean:
+	rm image.ppm