raytracing/util.cpp

#include "util.h"
#include<functional>
static RenderableBuffer* sRenderableBuffer = nullptr;
void InitRenderableBuffer(HDC dc, int width, int height)
{
	sRenderableBuffer = new RenderableBuffer();
	sRenderableBuffer->mDC = CreateCompatibleDC(dc);
	BITMAPINFO bitmapinfo = {};
	bitmapinfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
	bitmapinfo.bmiHeader.biPlanes = 1;
	bitmapinfo.bmiHeader.biBitCount = 32;
	bitmapinfo.bmiHeader.biCompression = BI_RGB;
	bitmapinfo.bmiHeader.biWidth = width;
	bitmapinfo.bmiHeader.biHeight = height;
	sRenderableBuffer->mBitmap = CreateDIBSection(sRenderableBuffer->mDC, &bitmapinfo, DIB_RGB_COLORS, (void**)&sRenderableBuffer->mColorBuffer, 0, 0);
	SelectObject(sRenderableBuffer->mDC, sRenderableBuffer->mBitmap);
	sRenderableBuffer->mHeight = height;
	sRenderableBuffer->mWidth = width;
	sRenderableBuffer->mPixelCount = height * width;
}

void SetColor(int x, int y, AByte r, AByte g, AByte b, AByte a)
{
	AUint color = (a << 24) + (r << 16) + (g << 8) + b;
	int pixel_index = y * sRenderableBuffer->mWidth + x;
	if (pixel_index < sRenderableBuffer->mPixelCount) {
		sRenderableBuffer->mColorBuffer[pixel_index] = color;
	}
}

void ASwapBuffers(HDC dc)
{
	BitBlt(dc, 0, 0, sRenderableBuffer->mWidth, sRenderableBuffer->mHeight, sRenderableBuffer->mDC, 0,0, SRCCOPY);
}

float randf()
{
	return float(rand()) / float(RAND_MAX);
}

float srandf()
{
	return randf() * 2.0f - 1.0f;
}

unsigned char* LoadFileContent(const char* path, int& file_size) {
	FILE* file = fopen(path, "rb");
	if (file != nullptr) {
		fseek(file, 0, SEEK_END);
		file_size = ftell(file);
		if (file_size > 0) {
			rewind(file);
			unsigned char* content = new unsigned char[file_size + 1];
			fread(content, 1, file_size, file);
			content[file_size] = 0;
			fclose(file);
			return content;
		}
		fclose(file);
	}
	return nullptr;
}

unsigned char* DecodeBMP(unsigned char* bmp_file_content, int& width, int& height) {
	if (0x4D42 == *((unsigned short*)bmp_file_content)) {
		int pixel_data_offset = *((int*)(bmp_file_content + 10));
		width = *((int*)(bmp_file_content + 18));
		height = *((int*)(bmp_file_content + 22));
		unsigned char * pixel_data = bmp_file_content + pixel_data_offset;
		//bgr->rgb
		for (int i = 0; i < width * height; i++) {
			int pixel_data_start_index = i * 3;
			unsigned char r = pixel_data[pixel_data_start_index + 2];
			pixel_data[pixel_data_start_index + 2] = pixel_data[pixel_data_start_index];
			pixel_data[pixel_data_start_index] = r;
		}
		return pixel_data;
	}
	return nullptr;
}