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https://git.coom.tech/drummyfish/raycastlib.git
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Fix division by 0
This commit is contained in:
Miloslav Číž
parent
8c5231cf9f
commit
c25fdd486b
2 changed files with 117 additions and 37 deletions
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@ -1184,7 +1184,7 @@ PixelInfo mapToScreen(Vector2D worldPosition, Unit height, Camera camera)
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(result.depth * sinInt(HORIZONTAL_FOV_HALF)) / (cos == 0 ? 1 : cos);
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// sin/cos = tan
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result.position.x = (a * middleColumn) / b;
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result.position.x = (a * middleColumn) / (b == 0 ? 1 : b);
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result.position.x = middleColumn - result.position.x;
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return result;
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150
testSDL.c
150
testSDL.c
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@ -1,5 +1,5 @@
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/*
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Raycasting SDL test.
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Raycasting SDL test. This is a port of my Pokitto demo.
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author: Miloslav Ciz
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license: CC0
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@ -25,6 +25,10 @@
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#define SCREEN_HEIGHT 480
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#define MIDDLE_ROW (SCREEN_HEIGHT / 2)
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#define TRANSPARENT_COLOR 0b00000111
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#define max(a,b) ((a) > (b) ? (a) : (b))
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#define KEYS 6
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#define KEY_UP 0
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#define KEY_RIGHT 1
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@ -49,7 +53,7 @@ typedef struct
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Unit mPixelSize;
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} Sprite;
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#define RGB(r,g,b) (0 | ((r << 24) | (g << 16) | (b << 8)))
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uint32_t palette[256];
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#define SPRITES 7
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#define SPRITE_MAX_DISTANCE 5 * UNITS_PER_SQUARE
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@ -750,12 +754,15 @@ Unit floorHeightAt(int16_t x, int16_t y)
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if (x >= 0 && x < LEVEL_X_RES && y >= 0 && y < LEVEL_Y_RES)
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return (levelFloor[(LEVEL_Y_RES - y -1) * LEVEL_X_RES + x] * UNITS_PER_SQUARE) / 8;
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return 0;
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int a = absVal(x - LEVEL_X_RES / 2) - LEVEL_X_RES / 2;
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int b = absVal(y - LEVEL_Y_RES / 2) - LEVEL_Y_RES / 2;
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return (a > b ? a : b) * UNITS_PER_SQUARE;
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}
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Unit ceilingHeightAt(int16_t x, int16_t y)
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{
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signed char v = 127;
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int v = 1024;
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if (x >= 0 && x < LEVEL_X_RES && y >= 0 && y < LEVEL_Y_RES)
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v = levelCeiling[(LEVEL_Y_RES - y -1) * LEVEL_X_RES + x];
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@ -763,6 +770,52 @@ Unit ceilingHeightAt(int16_t x, int16_t y)
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return (v * UNITS_PER_SQUARE) / 8;
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}
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/**
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Draws a scaled sprite on screen in an optimized way. The sprite has to be
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square in resolution.
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*/
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void drawSpriteSquare(const unsigned char *sprite, int16_t x, int16_t y, Unit depth, int16_t size)
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{
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if (size < 0 || size > 200 || // let's not mess up with the incoming array
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sprite[0] != sprite[1]) // only draw square sprites
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return;
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int16_t samplingIndices[size];
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// optimization: precompute the indices
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for (Unit i = 0; i < size; ++i)
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samplingIndices[i] = (i * sprite[0]) / size;
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x -= size / 2;
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y -= size / 2;
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Unit step = UNITS_PER_SQUARE / size;
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uint8_t c;
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int16_t jTo = size - max(0,y + size - 88);
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int16_t iTo = size - max(0,x + size - 110);
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for (Unit i = max(-1 * x,0); i < iTo; ++i)
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{
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int16_t xPos = x + i;
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if (zBuffer[xPos] <= depth)
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continue;
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int16_t columnLocation = 2 + samplingIndices[i] * sprite[0];
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for (Unit j = max(-1 * y,0); j < jTo; ++j)
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{
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c = sprite[columnLocation + samplingIndices[j]];
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if (c != TRANSPARENT_COLOR)
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pixels[j * SCREEN_WIDTH + i] = c | c | c;
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}
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}
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}
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/**
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Function for drawing a single pixel (like fragment shader). Bottleneck =>
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should be as fast as possible.
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@ -774,33 +827,30 @@ void pixelFunc(PixelInfo *pixel)
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uint8_t c;
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Unit depth = pixel->depth - UNITS_PER_SQUARE * 3;
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depth = depth > 0 ? depth : 1;
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int intensity = 7 - (depth * 7) / (UNITS_PER_SQUARE * 5);
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if (intensity < 0)
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intensity = 0;
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//intensity = 5;
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if (pixel->isWall)
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{
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if ((pixel->hit.direction == 0 || pixel->hit.direction == 2))
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intensity -= 2;
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if (intensity < 0)
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intensity = 0;
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c = sampleImage(textures[pixel->hit.type],pixel->hit.textureCoord,pixel->textureCoordY);
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c = addIntensity(c,intensity - 3);
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}
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else
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c = pixel->isFloor ?
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rgbToIndex(intensity/2,intensity,intensity/3) :
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rgbToIndex(intensity,intensity/2,0);
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c = pixel->isFloor ? 0b00010001 : 0b00001010;
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pixels[pixel->position.y * SCREEN_WIDTH + pixel->position.x] = RGB( (c & 0b00000111) * 36, ((c & 0b00111000) >> 3) * 36 , ((c & 0b11000000) >> 6) * 85 );
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int intensity = pixel->depth - 8 * UNITS_PER_SQUARE;
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intensity = intensity < 0 ? 0 : intensity;
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intensity = (intensity * 32) / UNITS_PER_SQUARE;
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int32_t color = palette[c];
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int32_t r = ((color & 0xFF000000) >> 24) - intensity;
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r = r > 0 ? r : 0;
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r = r << 24;
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int32_t g = ((color & 0x00FF0000) >> 16) - intensity;
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g = g > 0 ? g : 0;
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g = g << 16;
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int32_t b = ((color & 0x0000FF00) >> 8) - intensity;
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b = b > 0 ? b : 0;
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b = b << 8;
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pixels[pixel->position.y * SCREEN_WIDTH + pixel->position.x] = r | g | b;
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}
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void draw()
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@ -808,7 +858,6 @@ void draw()
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RayConstraints c;
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c.maxHits = 16;
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// c.maxSteps = 10;
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c.maxSteps = 20;
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c.computeTextureCoords = 1;
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@ -816,8 +865,6 @@ c.maxSteps = 20;
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Unit previousDepth;
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// draw sprites
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for (uint8_t i = 0; i < SPRITES; ++i)
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{
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// use Chebyshew distance instead Euclidean, it's faster
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@ -828,6 +875,20 @@ c.maxSteps = 20;
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continue;
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PixelInfo pos = mapToScreen(sprites[i].mPosition,sprites[i].mHeight,camera);
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if (pos.depth > 0)
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drawSpriteSquare(sprites[i].mImage,pos.position.x,pos.position.y,
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pos.depth,perspectiveScale(sprites[i].mPixelSize,pos.depth));
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/* trick: sort the sprites by distance with bubble sort as we draw - the
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order will be correct in a few frames */
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if (i != 0 && pos.depth > previousDepth)
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{
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Sprite tmp = sprites[i];
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sprites[i] = sprites[i - 1];
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sprites[i - 1] = tmp;
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}
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previousDepth = pos.depth;
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}
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}
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@ -837,17 +898,36 @@ int main()
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for (int i = 0; i < SCREEN_WIDTH; ++i)
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zBuffer[i] = 0;
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camera.position.x = 5;
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camera.position.y = 5;
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for (uint8_t r = 0; r < 8; ++r)
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for (uint8_t g = 0; g < 8; ++g)
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for (uint8_t b = 0; b < 4; ++b)
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palette[rgbToIndex(r,g,b)] = ((36 * r) << 24) | ((36 * g) << 16) | ((85 * b) << 8);
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#define placeSprite(i,s,X,Y,z,n)\
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sprites[i].mImage = s;\
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sprites[i].mPosition.x = X * UNITS_PER_SQUARE;\
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sprites[i].mPosition.y = Y * UNITS_PER_SQUARE;\
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sprites[i].mHeight = z;\
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sprites[i].mPixelSize = n;
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placeSprite(0,sprite1,10,5,1,100);
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placeSprite(1,sprite1,14,5,1,100);
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placeSprite(2,sprite2,15,19,1,200);
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placeSprite(3,sprite3,8,2,1,300);
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placeSprite(4,sprite3,20,5,1,300);
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placeSprite(5,sprite3,26,18,1,300);
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placeSprite(6,sprite3,16,12,1,300);
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#undef placeSprite
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camera.position.x = UNITS_PER_SQUARE * 5;
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camera.position.y = UNITS_PER_SQUARE * 4;
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camera.shear = 0;
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camera.direction = 0;
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camera.height = UNITS_PER_SQUARE * 2;
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camera.resolution.x = SCREEN_WIDTH;
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camera.resolution.y = SCREEN_HEIGHT;
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for (int i = 0; i < KEYS; ++i)
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keys[i] = 0;
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SDL_Window *window = SDL_CreateWindow("raycasting", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
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SDL_Renderer *renderer = SDL_CreateRenderer(window,-1,0);
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SDL_Texture *texture = SDL_CreateTexture(renderer,SDL_PIXELFORMAT_RGBX8888, SDL_TEXTUREACCESS_STATIC, SCREEN_WIDTH, SCREEN_HEIGHT);
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