rad4_loop_unrolling.cpp

//code for Windows to run well
#define _USE_MATH_DEFINES
#include <cmath>

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <cassert>
#include <math.h>
#include <time.h>
#include <chrono>
#include <thread>
#include <vector>

#ifdef __MACH__
#include <mach/clock.h>
#include <mach/mach.h>
#endif

//#define __MAC__

#include <winsock2.h>
#ifdef _WIN32
#include <windows.h>
#include <glut.h>
#include <gl\GL.h>
#include <gl\GLU.h>
#endif

#ifdef __MAC__
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#include <GLUT/glut.h>
#endif



// ----------------------------------------------------------
struct RadLight
{
	int tileX;
	int tileY;
};

// ----------------------------------------------------------
const int SCREEN_WIDTH = 800;
const int SCREEN_HEIGHT = 600;
const int SAMPLES_TO_TAKE = 20;

const int TILE_SIZE = 10;
const int TILES_WIDE = SCREEN_WIDTH / TILE_SIZE;
const int TILES_HIGH = SCREEN_HEIGHT / TILE_SIZE;
const int TOTAL_TILES = TILES_WIDE * TILES_HIGH;

int drawSize = 4;

GLubyte *frameBuffer = NULL;
const int RED_OFS = 0;      /* offset to red byte */
const int GREEN_OFS = 1;    /* offset to green byte */
const int BLUE_OFS = 2;     /* offset to blue byte */

GLfloat * tiles = NULL;

// mouse
int LMBDown = 0;
int RMBDown = 0;
int mouseTileX = 0;
int mouseTileY = 0;

bool drawMode = false;
bool eraseMode = false;

// lights
const int NUM_VPLS = 64;
const int TOTAL_LIGHTS = 1 + NUM_VPLS;
RadLight lights[TOTAL_LIGHTS];

const int ONE_BILLION = 1000000000;


typedef __int32 __int32_t;
typedef unsigned __int32 __uint32_t;
typedef __int16 __int16_t;
typedef unsigned __int16 __uint16_t;

// ----------------------------------------------------------
void initGraphics(void)
{
	// set up famebuffer for 2D rendering
	frameBuffer = new GLubyte[SCREEN_WIDTH * SCREEN_HEIGHT * 3];
	memset(frameBuffer, 0, SCREEN_WIDTH * SCREEN_HEIGHT * 3);
	assert(frameBuffer != NULL);

	glViewport(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0.0, SCREEN_WIDTH, 0.0, SCREEN_HEIGHT, 0.0, 1.0);

	glClearColor(1.0, 0.0, 0.0, 1.0);
}

// ----------------------------------------------------------

int random_between(int min, int max) {
	return rand() % (max - min) + min;
}


// ----------------------------------------------------------
void cleanupGraphics(void)
{
	delete(frameBuffer);  frameBuffer = NULL;
}

// ----------------------------------------------------------
void setTile(int tileX, int tileY, GLfloat val)
{
	assert(tileX >= 0);
	assert(tileX < TILES_WIDE);
	assert(tileY >= 0);
	assert(tileY < TILES_HIGH);

	tiles[tileY * TILES_WIDE + tileX] = val;
}

// ----------------------------------------------------------
GLfloat getTile(int tileX, int tileY)
{
	// prevent ray from escaping grid.
	if (tileX < 0) return -1.0;
	if (tileY < 0) return -1.0;
	if (tileX >= TILES_WIDE) return -1.0;
	if (tileY >= TILES_HIGH) return -1.0;

	return tiles[tileY * TILES_WIDE + tileX];
}

// ----------------------------------------------------------
void initScene(void)
{
	tiles = new GLfloat[TILES_WIDE * TILES_HIGH];

	for (int i = 0; i < TILES_WIDE; i++){
		for (int j = 0; j < TILES_HIGH; j++){
			setTile(i, j, 0.0);
		}
	}
	setTile(10, 10, -1.0);
	setTile(10, 9, -1.0);

	setTile(15, 6, -1.0);

	setTile(30, 20, -1.0);
}

// ----------------------------------------------------------
void cleanupScene(void)
{
	delete(tiles);
	tiles = NULL;
}

// ----------------------------------------------------------
void setPixel(int x, int y, GLfloat r, GLfloat g, GLfloat b)
{
	assert(x >= 0 && x < SCREEN_WIDTH);
	assert(y >= 0 && y < SCREEN_HEIGHT);

	int pos = 3 * SCREEN_WIDTH*y + 3 * x;

	char red = (char)(r * 255);
	char green = (char)(g * 255);
	char blue = (char)(b * 255);

	frameBuffer[pos + RED_OFS] = red;
	frameBuffer[pos + GREEN_OFS] = green;
	frameBuffer[pos + BLUE_OFS] = blue;
}

// ----------------------------------------------------------
bool raycast(int x0, int y0, int x1, int y1, int &xhit, int &yhit)
{
	int dx = abs(x1 - x0), sx = x0 < x1 ? 1 : -1;
	int dy = abs(y1 - y0), sy = y0<y1 ? 1 : -1;
	int err = (dx>dy ? dx : -dy) / 2, e2;

	int x = x0;
	int y = y0;

	int stepped = 0;

	for (;;){
		if (getTile(x, y) < 0.0) {
			xhit = x - stepped*sx;
			yhit = y - stepped*sy;
			return false;

		}

		if (x == x1 && y == y1) break;
		e2 = err;
		if (e2 > -dx) { err -= dy; x += sx; }
		if (e2 < dy) { err += dx; y += sy; }
		stepped = 1;
	}

	return true;
}

// ----------------------------------------------------------
void spawnLights(void)
{
	lights[0].tileX = mouseTileX;
	lights[0].tileY = mouseTileY;

	// *** CAST FIRST BOUNCE ***
	float deltaDegrees = 360.0f / (float)NUM_VPLS;
	float deltaRadians = deltaDegrees * M_PI / 180.0f;
	float twopi = 2.0f * M_PI;

	int vpl = 1;

	float radians = 0.0f;
	while (radians < twopi)
	{
		float xdir = cos(radians);
		float ydir = sin(radians);

		// make it big enough to span the screen
		int destX = mouseTileX + floor(xdir * 5000);
		int destY = mouseTileY + floor(ydir * 5000);

		int hitX;
		int hitY;
		bool rayfree = raycast(mouseTileX, mouseTileY, destX, destY, hitX, hitY);
		assert(!rayfree); // must always hit something

		lights[vpl].tileX = hitX;
		lights[vpl].tileY = hitY;

		radians += deltaRadians;
		vpl++;

	}
}

// ----------------------------------------------------------



void renderScene(void)
{
	// clear screen
	memset(frameBuffer, 0x22, SCREEN_WIDTH * SCREEN_HEIGHT * 3);

	spawnLights();

	// cast light to each pixel
	for (int i = 0; i < TILES_WIDE; i++)
	{
		for (int j = 0; j < TILES_HIGH; j++)
		{
			// only cast from open tiles
			if (getTile(i, j) >= 0.0)
			{
				if (drawMode)
				{
					setTile(i, j, 1.0f);
				}
				else
				{
					int lightsSeen = 0;
					int hitX;
					int hitY;

					for (int n = 0; n < TOTAL_LIGHTS; n++)
					{
						if (raycast(i, j, lights[n].tileX, lights[n].tileY, hitX, hitY))
						{
							lightsSeen++;
						}
					}

					setTile(i, j, 1.0f * lightsSeen / (1.0f * TOTAL_LIGHTS));
				}
			}
		}
	}
	//tile size divisible by 2
	if ((TILE_SIZE % 2) == 0){
		// *** render world pixels based on their intensities ***
		for (int i = 0; i < TILES_WIDE; i += 1)
		{
			for (int j = 0; j < TILES_HIGH; j += 2)
			{
				// convert blocker tiles to black
				float intensity = getTile(i, j);
				float intensity_2 = getTile((i), (j + 1));
				if (intensity < 0.0) {
					intensity = 0.0;
				}
				if (intensity_2 < 0.0){
					intensity_2 = 0.0;
				}
				for (int x = 0; x < TILE_SIZE; x++) {
					for (int y = 0; y < TILE_SIZE; y++) {
						setPixel(i * TILE_SIZE + x, j * TILE_SIZE + y, intensity, intensity, intensity);
						setPixel(i *TILE_SIZE + x, (j + 1) * TILE_SIZE + y, intensity_2, intensity_2, intensity_2);
					}
				}
			}
		}
	}


	//tile_size is 1
	else {
		// *** render world pixels based on their intensities ***
		for (int i = 0; i < TILES_WIDE; i++)
		{
			for (int j = 0; j < TILES_HIGH; j++)
			{
				// convert blocker tiles to black
				float intensity = getTile(i, j);
				if (intensity < 0.0) intensity = 0.0;

				for (int x = 0; x < TILE_SIZE; x++)
					for (int y = 0; y < TILE_SIZE; y++)
						setPixel(i * TILE_SIZE + x, j * TILE_SIZE + y, intensity, intensity, intensity);
			}
		}
	}
}

// ----------------------------------------------------------

void renderSceneEditable(void)
{
	for (int i = 0; i<TILES_WIDE; i++)
	{
		for (int j = 0; j<TILES_HIGH; j++)
		{
			char intensity = (getTile(i, j) == 1) ? 0 : 255;

			for (int x = 0; x < TILE_SIZE; x++)
				for (int y = 0; y < TILE_SIZE; y++)
					setPixel(i * TILE_SIZE + x, j * TILE_SIZE + y, intensity, intensity, intensity);
		}
	}
}

// ----------------------------------------------------------
void displayCallback() {
	glClear(GL_COLOR_BUFFER_BIT);

	if (drawMode || eraseMode) {
		renderSceneEditable();
	}
	else {
		typedef std::chrono::high_resolution_clock Time;
		typedef std::chrono::nanoseconds ns;
		typedef std::chrono::duration<float> fsec;
		auto t0 = Time::now();

		renderScene();

		auto t1 = Time::now();
		fsec duration = t1 - t0;
		ns nanoseconds = std::chrono::duration_cast<ns>(duration);
		std::cout << "\nRendered " << TOTAL_TILES << "in " << nanoseconds.count() << " nanoseconds";
	}
	// present frame buffer to screen
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
	glRasterPos3f(0.0, 0.0, 0.0);
	glDrawPixels(SCREEN_WIDTH, SCREEN_HEIGHT, GL_RGB, GL_UNSIGNED_BYTE, frameBuffer);

	glFlush();
	glutSwapBuffers();
}

// ----------------------------------------------------------
void mouseCallback(int button, int state, int x, int y)
{
	mouseTileX = x / TILE_SIZE;
	mouseTileY = (SCREEN_HEIGHT - y) / TILE_SIZE;
	printf("mouse move %d %d\n", mouseTileX, mouseTileY);

	LMBDown = (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN);

	if (LMBDown)
	{
		if (drawMode || eraseMode)
		{
			float valueToPlace = drawMode ? 1 : 0;

			int xEnd = mouseTileX + drawSize;
			int yEnd = mouseTileY + drawSize;

			if (xEnd >= TILES_WIDE) xEnd = TILES_WIDE - 1;
			if (yEnd >= TILES_HIGH) yEnd = TILES_HIGH - 1;

			for (int i = mouseTileX; i <= xEnd; i++)
				for (int j = mouseTileY; j <= yEnd; j++)
					setTile(i, j, valueToPlace);

		}
	}

	glutPostRedisplay();
}

// ----------------------------------------------------------
void motionCallback(int x, int y)
{
	mouseCallback(0, 0, x, y);
}

// ----------------------------------------------------------
void fillToDensity(float density)
{
	for (int i = 0; i<TILES_WIDE; i++)
		for (int j = 0; j<TILES_HIGH; j++)
			setTile(i, j, 0);

	int tilesSet = 0;

	while ((1.0f * tilesSet / TOTAL_TILES) < density)
	{
		int i = random_between(0, TILES_WIDE - 1);
		int j = random_between(0, TILES_HIGH - 1);

		if (getTile(i, j) == 0)
		{
			setTile(i, j, 1);
			tilesSet++;
		}
	}

}

// --------------------------------------------------------
void tryLoadMap(const char *mapID)
{
	char filePath[80];
	sprintf(filePath, "maps/%d_%d_%s.map", TILES_WIDE, TILES_HIGH, mapID);
	FILE * fin = fopen(filePath, "rb");

	if (fin == NULL)
	{
		printf("Map %s not found.\n", filePath);
		return;
	}

	int tilesWide = 0;
	int tilesHigh = 0;
	fread(&tilesWide, sizeof(__uint16_t), 1, fin);
	fread(&tilesHigh, sizeof(__uint16_t), 1, fin);

	assert(tilesWide == TILES_WIDE);
	assert(tilesHigh == TILES_HIGH);

	for (int i = 0; i<TILES_WIDE; i++)
		for (int j = 0; j<TILES_HIGH; j++)
		{
			float val;
			fread(&val, sizeof(float), 1, fin);

			setTile(i, j, val);
		}

	fclose(fin);
	fin = NULL;
}

// ----------------------------------------------------------
void saveMap(const char *mapID)
{
	char filePath[80];
	sprintf(filePath, "maps/%d_%d_%s.map", TILES_WIDE, TILES_HIGH, mapID);

	FILE * fout = fopen(filePath, "wb");

	fwrite(&TILES_WIDE, sizeof(__uint16_t), 1, fout);
	fwrite(&TILES_HIGH, sizeof(__uint16_t), 1, fout);

	for (int i = 0; i<TILES_WIDE; i++)
	{
		for (int j = 0; j<TILES_HIGH; j++)
		{
			float val = getTile(i, j);
			if (val != 1) val = 0;

			fwrite(&val, sizeof(float), 1, fout);
		}
	}

	fclose(fout);
	fout = NULL;

	printf("Map saved to %s\n", filePath);
}


// ----------------------------------------------------------
// custom keyFunc with preset keys
void keyCallback(unsigned char ch, int x, int y) {
	switch (ch) {
	case '[':
	{
		drawSize /= 2;
		if (drawSize < 1) drawSize = 1;
		printf("Draw size changed to %d\n", drawSize);
		break;
	}
	case ']':
	{
		drawSize *= 2;
		printf("Draw size changed to %d\n", drawSize);
		break;
	}
	case '1':
	{
		tryLoadMap("1");
		break;
	}
	case '2':
	{
		tryLoadMap("2");
		break;
	}
	case '9':
	{
		saveMap("1");
		break;
	}
	case '0':
	{
		saveMap("2");
		break;
	}
	case 'd':
	case 'D':
	{
		drawMode = true;
		eraseMode = false;

		printf("Draw mode ON.\n");
		break;
	}
	case 'e':
	case 'E':
	{
		drawMode = false;
		eraseMode = true;

		printf("Erase mode ON.\n");
		break;
	}
	case 'r':
	case 'R':
	{
		drawMode = false;
		eraseMode = false;
		printf("Render mode ON.\n");
		break;
	}
	case 'f':
	case 'F':
	{
		fillToDensity(0.01);
		break;
	}
	case 'g':
	case 'G':
	{
		fillToDensity(0.10);
		break;
	}
	case 'h':
	case 'H':
	{
		fillToDensity(0.25);
		break;
	}
	case 't':
	case 'T':
	{
		// --- TIME THE RENDERING FOR THE SCREEN ---
		typedef std::chrono::high_resolution_clock Time;
		typedef std::chrono::nanoseconds ns;
		typedef std::chrono::duration<float> fsec;
		auto t0 = Time::now();

		int samplesTaken = 0;

		while (samplesTaken < SAMPLES_TO_TAKE)
		{
			mouseTileX = random_between(0, TILES_WIDE);
			mouseTileY = random_between(0, TILES_HIGH);

			if (getTile(mouseTileX, mouseTileY) != 1)
			{
				renderScene();
				samplesTaken++;
			}
		}

		auto t1 = Time::now();
		fsec duration = t1 - t0;
		//ns nanoseconds = std::chrono::duration_cast<ns>(duration);

		float avgRenderSec = 1.0f * duration.count() / samplesTaken;
		float secPerTile = avgRenderSec / TOTAL_TILES;

		printf("%d tiles in %f sec =\n\t(%f sec)\n", TOTAL_TILES, avgRenderSec, secPerTile);

		break;
	}
	}

	glutPostRedisplay();
}

// ----------------------------------------------------------
void idleCallback(void)
{
	//no need for this call since any input redraws.
	//we dont care about FPS, just render time for a frame.
	//glutPostRedisplay();
}


// ----------------------------------------------------------
int main(int argc, char **argv)
{
	initScene();
	glutInit(&argc, argv);
	glutInitWindowPosition(100, 100);
	glutInitWindowSize(SCREEN_WIDTH, SCREEN_HEIGHT);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
	int win = glutCreateWindow("2D Radiosity Demo");
	glutSetWindow(win);

	glutKeyboardFunc(keyCallback);
	glutMouseFunc(mouseCallback);
	glutMotionFunc(motionCallback);
	glutDisplayFunc(displayCallback);
	glutIdleFunc(idleCallback);

	initGraphics();


	glutMainLoop();

	cleanupScene();
	cleanupGraphics();
}