DSGameEngine/ds_olcEngine3D.cpp

/*---------------------------------------------------------------------------------

	Simple console print demo which prints to bottom screen
	and also has a frame buffer for the top screen to which
	you can draw stuff
	-- iProgramMC - Graphics Engine
	-- dovoto - Console bottom screen print

---------------------------------------------------------------------------------*/
#include <stdio.h>
#include <string.h>
#include <math.h>

#include "block.h"
#include "brick.h"
#include "coin.h"
#include "dirt.h"
#include "door.h"
#include "ground.h"
#include "mariojump.h"
#include "mariostill.h"
#include "question.h"
#include "usedblock.h"

#include <vector>
#include <string>

#include "ds_game_engine.h"

struct vec3d
{
	float x, y, z;
};

struct triangle
{
	vec3d p[3];
};

struct mesh
{
	std::vector<triangle> tris;
};

struct mat4x4
{
	float m[4][4] = {0};
};

mesh meshCube;
mat4x4 matProj;

float fTheta;

void MultiplyMatrixVector (vec3d &i, vec3d &o, mat4x4 &m){
	
		o.x = i.x * m.m[0][0] + i.y * m.m[1][0] + i.z * m.m[2][0] + m.m[3][0];
		o.y = i.x * m.m[0][1] + i.y * m.m[1][1] + i.z * m.m[2][1] + m.m[3][1];
		o.z = i.x * m.m[0][2] + i.y * m.m[1][2] + i.z * m.m[2][2] + m.m[3][2];
		float w = i.x * m.m[0][3] + i.y * m.m[1][3] + i.z * m.m[2][3] + m.m[3][3];

		if (w != 0.0f)
		{
			o.x /= w; o.y /= w; o.z /= w;
		}
}

int ScreenWidth() {return 256;}
int ScreenHeight(){return 192;}


void OnUserCreate()
{
	
		meshCube.tris = {

		// SOUTH
		{ 0.0f, 0.0f, 0.0f,    0.0f, 1.0f, 0.0f,    1.0f, 1.0f, 0.0f },
		{ 0.0f, 0.0f, 0.0f,    1.0f, 1.0f, 0.0f,    1.0f, 0.0f, 0.0f },

		// EAST                                                      
		{ 1.0f, 0.0f, 0.0f,    1.0f, 1.0f, 0.0f,    1.0f, 1.0f, 1.0f },
		{ 1.0f, 0.0f, 0.0f,    1.0f, 1.0f, 1.0f,    1.0f, 0.0f, 1.0f },

		// NORTH                                                     
		{ 1.0f, 0.0f, 1.0f,    1.0f, 1.0f, 1.0f,    0.0f, 1.0f, 1.0f },
		{ 1.0f, 0.0f, 1.0f,    0.0f, 1.0f, 1.0f,    0.0f, 0.0f, 1.0f },

		// WEST                                                      
		{ 0.0f, 0.0f, 1.0f,    0.0f, 1.0f, 1.0f,    0.0f, 1.0f, 0.0f },
		{ 0.0f, 0.0f, 1.0f,    0.0f, 1.0f, 0.0f,    0.0f, 0.0f, 0.0f },

		// TOP                                                       
		{ 0.0f, 1.0f, 0.0f,    0.0f, 1.0f, 1.0f,    1.0f, 1.0f, 1.0f },
		{ 0.0f, 1.0f, 0.0f,    1.0f, 1.0f, 1.0f,    1.0f, 1.0f, 0.0f },

		// BOTTOM                                                    
		{ 1.0f, 0.0f, 1.0f,    0.0f, 0.0f, 1.0f,    0.0f, 0.0f, 0.0f },
		{ 1.0f, 0.0f, 1.0f,    0.0f, 0.0f, 0.0f,    1.0f, 0.0f, 0.0f },

		};
		
		
		// Projection Matrix
		float fNear = 0.1f;
		float fFar = 1000.0f;
		float fFov = 90.0f;
		float fAspectRatio = (float)ScreenHeight() / (float)ScreenWidth();
		float fFovRad = 1.0f / tanf(fFov * 0.5f / 180.0f * 3.14159f);

		matProj.m[0][0] = fAspectRatio * fFovRad;
		matProj.m[1][1] = fFovRad;
		matProj.m[2][2] = fFar / (fFar - fNear);
		matProj.m[3][2] = (-fFar * fNear) / (fFar - fNear);
		matProj.m[2][3] = 1.0f;
		matProj.m[3][3] = 0.0f;
	//iprintf("\n\n\tGraphics Engine\n\tCoded by iProgramMC\n\tMore modern-like\n\tDo whatever you want!");
}

void OnUserUpdate()
{
		clear_screenbuffer(BLACK);
		
		mat4x4 matRotX, matRotZ;
		fTheta += 0.01f;
		
		
		matRotZ.m[0][0] = cosf(fTheta);
		matRotZ.m[0][1] = sinf(fTheta);
		matRotZ.m[1][0] = -sinf(fTheta);
		matRotZ.m[1][1] = cosf(fTheta);
		matRotZ.m[2][2] = 1;
		matRotZ.m[3][3] = 1;

		// Rotation X
		matRotX.m[0][0] = 1;
		matRotX.m[1][1] = cosf(fTheta * 0.5f);
		matRotX.m[1][2] = sinf(fTheta * 0.5f);
		matRotX.m[2][1] = -sinf(fTheta * 0.5f);
		matRotX.m[2][2] = cosf(fTheta * 0.5f);
		matRotX.m[3][3] = 1;
		
		for(auto tri : meshCube.tris){
			
			triangle triProjected, triTranslated, triRotatedZ, triRotatedZX;

			// Rotate in Z-Axis
			MultiplyMatrixVector(tri.p[0], triRotatedZ.p[0], matRotZ);
			MultiplyMatrixVector(tri.p[1], triRotatedZ.p[1], matRotZ);
			MultiplyMatrixVector(tri.p[2], triRotatedZ.p[2], matRotZ);

			// Rotate in X-Axis
			MultiplyMatrixVector(triRotatedZ.p[0], triRotatedZX.p[0], matRotX);
			MultiplyMatrixVector(triRotatedZ.p[1], triRotatedZX.p[1], matRotX);
			MultiplyMatrixVector(triRotatedZ.p[2], triRotatedZX.p[2], matRotX);

			// Offset into the screen
			triTranslated = triRotatedZX;
			triTranslated.p[0].z = triRotatedZX.p[0].z + 3.0f;
			triTranslated.p[1].z = triRotatedZX.p[1].z + 3.0f;
			triTranslated.p[2].z = triRotatedZX.p[2].z + 3.0f;

			// Project triangles from 3D --> 2D
			MultiplyMatrixVector(triTranslated.p[0], triProjected.p[0], matProj);
			MultiplyMatrixVector(triTranslated.p[1], triProjected.p[1], matProj);
			MultiplyMatrixVector(triTranslated.p[2], triProjected.p[2], matProj);

			// Scale into view
			triProjected.p[0].x += 1.0f; triProjected.p[0].y += 1.0f;
			triProjected.p[1].x += 1.0f; triProjected.p[1].y += 1.0f;
			triProjected.p[2].x += 1.0f; triProjected.p[2].y += 1.0f;
			triProjected.p[0].x *= 0.5f * (float)ScreenWidth();
			triProjected.p[0].y *= 0.5f * (float)ScreenHeight();
			triProjected.p[1].x *= 0.5f * (float)ScreenWidth();
			triProjected.p[1].y *= 0.5f * (float)ScreenHeight();
			triProjected.p[2].x *= 0.5f * (float)ScreenWidth();
			triProjected.p[2].y *= 0.5f * (float)ScreenHeight();

			// Rasterize triangle
			draw_triangle(triProjected.p[0].x, triProjected.p[0].y,
				triProjected.p[1].x, triProjected.p[1].y,
				triProjected.p[2].x, triProjected.p[2].y, WHITE);
		}
						
		push_frame();
}