raytracing/Scene.cpp

#include "Scene.h"
#include "util.h"
#include "Camera.h"
#include "Ray.h"
#include "Vector3.h"
#include "Sphere.h"
#pragma comment(lib, "winmm.lib")
static int sTotalPixelCount = 0;
static int sViewportWidth = 0, sViewportHeight = 0;
static Camera* sCamera = nullptr;
Sphere sphere(Vector3(0.0f, 0.0f, -5.0f), 0.5f);
void Init(int width, int height)
{
	sTotalPixelCount = width * height;
	sViewportWidth = width;
	sViewportHeight = height;
	sCamera = new Camera(45.0f, float(width) / float(height));
	sCamera->LookAt(Vector3(0.0f, 0.0f, 0.0f), Vector3(0.0f, 0.0f, -1.0f), Vector3(0.0f, 1.0f, 0.0f));
}

float GetEscaptedTime() {
	static unsigned long sTimeSinceComputerStart = 0;
	static unsigned long sLastFrameTime = 0;
	sTimeSinceComputerStart = timeGetTime();
	unsigned long frame_time = sLastFrameTime == 0 ? 0 : sTimeSinceComputerStart - sLastFrameTime;
	sLastFrameTime = sTimeSinceComputerStart;

	return float(frame_time) / 1000.0f;
}

Vector3 GetEnviromentColor(const Ray& input_ray) {
	Vector3 bottom_color(1.0f, 1.0f, 1.0f);
	Vector3 top_color(0.5f, 0.7f, 1.0f);
	float factor = 0.5f * input_ray.mDirection.y + 0.5f;
	return factor * top_color + (1.0f - factor) * bottom_color;
}

void RenderOnePixel(int pixel_index) {
	int x = pixel_index % sViewportWidth;
	int y = pixel_index / sViewportWidth;
	float u = float(x) / sViewportWidth;
	float v = float(y) / sViewportHeight;
	Ray ray = sCamera->GetRay(u,v);
	HitPoint hit_point;
	if (sphere.HitTest(ray, 0.0f, 100.0f, hit_point)) {
		float rf = hit_point.mNormal.x * 0.5f + 0.5f;
		float gf = hit_point.mNormal.y * 0.5f + 0.5f;
		float bf = hit_point.mNormal.z * 0.5f + 0.5f;
		AByte r = AByte(rf * 255.0f);
		AByte g = AByte(gf * 255.0f);
		AByte b = AByte(bf * 255.0f);
		SetColor(x, y, r, g, b, 255);
	}
	else {
		Vector3 color = GetEnviromentColor(ray);
		AByte r = AByte(color.x * 255.0f);
		AByte g = AByte(color.y * 255.0f);
		AByte b = AByte(color.z * 255.0f);
		SetColor(x, y, r, g, b, 255);
	}
}

void Render()
{
	static int sCurrentRenderPixel = 0;
	float current_render_time = 0.0f;
	while (sCurrentRenderPixel < sTotalPixelCount) {
		RenderOnePixel(sCurrentRenderPixel);
		sCurrentRenderPixel++;
		current_render_time = GetEscaptedTime();
		if (current_render_time > 0.016f) {
			break;
		}
	}
}