raytracing/Scene.cpp

#include "Scene.h"
#include "util.h"
#include "Camera.h"
#include "Ray.h"
#pragma comment(lib, "winmm.lib")
static int sTotalPixelCount = 0;
static int sViewportWidth = 0, sViewportHeight = 0;
static Camera* sCamera = nullptr;
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,1.0f), Vector3(0.0f,0.0f,0.0f), 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;
}

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);
	float rf = ray.mDirection.x > 0.0f ? ray.mDirection.x : -ray.mDirection.x;
	float gf = ray.mDirection.y > 0.0f ? ray.mDirection.y : -ray.mDirection.y;
	float bf = ray.mDirection.z > 0.0f ? ray.mDirection.z : -ray.mDirection.z;
	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);
}

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;
		}
	}
}