260 lines
9.4 KiB
C
260 lines
9.4 KiB
C
/*******************************************************************************************
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*
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* raylib [textures] example - Draw a texture along a segmented curve
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*
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* Example originally created with raylib 4.5, last time updated with raylib 4.5
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*
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* Example contributed by Jeffery Myers and reviewed by Ramon Santamaria (@raysan5)
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*
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* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
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* BSD-like license that allows static linking with closed source software
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*
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* Copyright (c) 2022-2023 Jeffery Myers and Ramon Santamaria (@raysan5)
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*
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********************************************************************************************/
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#include "raylib.h"
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#include "raymath.h"
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#include "rlgl.h"
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#include <math.h> // Required for: powf()
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#include <stdlib.h> // Required for: NULL
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//----------------------------------------------------------------------------------
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// Global Variables Definition
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//----------------------------------------------------------------------------------
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static Texture texRoad = { 0 };
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static bool showCurve = false;
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static float curveWidth = 50;
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static int curveSegments = 24;
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static Vector2 curveStartPosition = { 0 };
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static Vector2 curveStartPositionTangent = { 0 };
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static Vector2 curveEndPosition = { 0 };
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static Vector2 curveEndPositionTangent = { 0 };
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static Vector2 *curveSelectedPoint = NULL;
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//----------------------------------------------------------------------------------
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// Module Functions Declaration
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//----------------------------------------------------------------------------------
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static void UpdateOptions(void);
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static void UpdateCurve(void);
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static void DrawCurve(void);
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static void DrawTexturedCurve(void);
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//------------------------------------------------------------------------------------
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// Program main entry point
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//------------------------------------------------------------------------------------
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int main()
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{
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// Initialization
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//--------------------------------------------------------------------------------------
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const int screenWidth = 800;
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const int screenHeight = 450;
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SetConfigFlags(FLAG_VSYNC_HINT | FLAG_MSAA_4X_HINT);
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InitWindow(screenWidth, screenHeight, "raylib [textures] examples - textured curve");
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// Load the road texture
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texRoad = LoadTexture("resources/road.png");
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SetTextureFilter(texRoad, TEXTURE_FILTER_BILINEAR);
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// Setup the curve
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curveStartPosition = (Vector2){ 80, 100 };
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curveStartPositionTangent = (Vector2){ 100, 300 };
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curveEndPosition = (Vector2){ 700, 350 };
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curveEndPositionTangent = (Vector2){ 600, 100 };
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SetTargetFPS(60); // Set our game to run at 60 frames-per-second
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//--------------------------------------------------------------------------------------
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// Main game loop
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while (!WindowShouldClose()) // Detect window close button or ESC key
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{
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// Update
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//----------------------------------------------------------------------------------
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UpdateCurve();
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UpdateOptions();
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//----------------------------------------------------------------------------------
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// Draw
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//----------------------------------------------------------------------------------
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BeginDrawing();
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ClearBackground(RAYWHITE);
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DrawTexturedCurve();
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DrawCurve();
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DrawText("Drag points to move curve, press SPACE to show/hide base curve", 10, 10, 10, DARKGRAY);
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DrawText(TextFormat("Curve width: %2.0f (Use + and - to adjust)", curveWidth), 10, 30, 10, DARKGRAY);
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DrawText(TextFormat("Curve segments: %d (Use LEFT and RIGHT to adjust)", curveSegments), 10, 50, 10, DARKGRAY);
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EndDrawing();
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//----------------------------------------------------------------------------------
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}
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// De-Initialization
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//--------------------------------------------------------------------------------------
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UnloadTexture(texRoad);
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CloseWindow(); // Close window and OpenGL context
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//--------------------------------------------------------------------------------------
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return 0;
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}
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//----------------------------------------------------------------------------------
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// Module Functions Definition
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//----------------------------------------------------------------------------------
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static void DrawCurve(void)
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{
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if (showCurve) DrawLineBezierCubic(curveStartPosition, curveEndPosition, curveStartPositionTangent, curveEndPositionTangent, 2, BLUE);
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// Draw the various control points and highlight where the mouse is
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DrawLineV(curveStartPosition, curveStartPositionTangent, SKYBLUE);
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DrawLineV(curveEndPosition, curveEndPositionTangent, PURPLE);
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Vector2 mouse = GetMousePosition();
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if (CheckCollisionPointCircle(mouse, curveStartPosition, 6)) DrawCircleV(curveStartPosition, 7, YELLOW);
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DrawCircleV(curveStartPosition, 5, RED);
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if (CheckCollisionPointCircle(mouse, curveStartPositionTangent, 6)) DrawCircleV(curveStartPositionTangent, 7, YELLOW);
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DrawCircleV(curveStartPositionTangent, 5, MAROON);
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if (CheckCollisionPointCircle(mouse, curveEndPosition, 6)) DrawCircleV(curveEndPosition, 7, YELLOW);
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DrawCircleV(curveEndPosition, 5, GREEN);
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if (CheckCollisionPointCircle(mouse, curveEndPositionTangent, 6)) DrawCircleV(curveEndPositionTangent, 7, YELLOW);
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DrawCircleV(curveEndPositionTangent, 5, DARKGREEN);
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}
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static void UpdateCurve(void)
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{
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// If the mouse is not down, we are not editing the curve so clear the selection
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if (!IsMouseButtonDown(MOUSE_LEFT_BUTTON))
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{
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curveSelectedPoint = NULL;
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return;
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}
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// If a point was selected, move it
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if (curveSelectedPoint)
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{
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*curveSelectedPoint = Vector2Add(*curveSelectedPoint, GetMouseDelta());
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return;
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}
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// The mouse is down, and nothing was selected, so see if anything was picked
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Vector2 mouse = GetMousePosition();
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if (CheckCollisionPointCircle(mouse, curveStartPosition, 6)) curveSelectedPoint = &curveStartPosition;
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else if (CheckCollisionPointCircle(mouse, curveStartPositionTangent, 6)) curveSelectedPoint = &curveStartPositionTangent;
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else if (CheckCollisionPointCircle(mouse, curveEndPosition, 6)) curveSelectedPoint = &curveEndPosition;
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else if (CheckCollisionPointCircle(mouse, curveEndPositionTangent, 6)) curveSelectedPoint = &curveEndPositionTangent;
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}
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static void DrawTexturedCurve(void)
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{
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const float step = 1.0f/curveSegments;
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Vector2 previous = curveStartPosition;
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Vector2 previousTangent = { 0 };
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float previousV = 0;
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// We can't compute a tangent for the first point, so we need to reuse the tangent from the first segment
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bool tangentSet = false;
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Vector2 current = { 0 };
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float t = 0.0f;
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for (int i = 1; i <= curveSegments; i++)
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{
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// Segment the curve
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t = step*i;
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float a = powf(1 - t, 3);
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float b = 3*powf(1 - t, 2)*t;
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float c = 3*(1 - t)*powf(t, 2);
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float d = powf(t, 3);
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// Compute the endpoint for this segment
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current.y = a*curveStartPosition.y + b*curveStartPositionTangent.y + c*curveEndPositionTangent.y + d*curveEndPosition.y;
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current.x = a*curveStartPosition.x + b*curveStartPositionTangent.x + c*curveEndPositionTangent.x + d*curveEndPosition.x;
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// Vector from previous to current
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Vector2 delta = { current.x - previous.x, current.y - previous.y };
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// The right hand normal to the delta vector
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Vector2 normal = Vector2Normalize((Vector2){ -delta.y, delta.x });
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// The v texture coordinate of the segment (add up the length of all the segments so far)
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float v = previousV + Vector2Length(delta);
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// Make sure the start point has a normal
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if (!tangentSet)
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{
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previousTangent = normal;
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tangentSet = true;
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}
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// Extend out the normals from the previous and current points to get the quad for this segment
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Vector2 prevPosNormal = Vector2Add(previous, Vector2Scale(previousTangent, curveWidth));
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Vector2 prevNegNormal = Vector2Add(previous, Vector2Scale(previousTangent, -curveWidth));
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Vector2 currentPosNormal = Vector2Add(current, Vector2Scale(normal, curveWidth));
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Vector2 currentNegNormal = Vector2Add(current, Vector2Scale(normal, -curveWidth));
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// Draw the segment as a quad
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rlSetTexture(texRoad.id);
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rlBegin(RL_QUADS);
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rlColor4ub(255,255,255,255);
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rlNormal3f(0.0f, 0.0f, 1.0f);
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rlTexCoord2f(0, previousV);
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rlVertex2f(prevNegNormal.x, prevNegNormal.y);
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rlTexCoord2f(1, previousV);
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rlVertex2f(prevPosNormal.x, prevPosNormal.y);
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rlTexCoord2f(1, v);
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rlVertex2f(currentPosNormal.x, currentPosNormal.y);
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rlTexCoord2f(0, v);
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rlVertex2f(currentNegNormal.x, currentNegNormal.y);
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rlEnd();
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// The current step is the start of the next step
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previous = current;
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previousTangent = normal;
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previousV = v;
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}
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}
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static void UpdateOptions(void)
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{
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if (IsKeyPressed(KEY_SPACE)) showCurve = !showCurve;
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// Update with
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if (IsKeyPressed(KEY_EQUAL)) curveWidth += 2;
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if (IsKeyPressed(KEY_MINUS)) curveWidth -= 2;
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if (curveWidth < 2) curveWidth = 2;
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// Update segments
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if (IsKeyPressed(KEY_LEFT)) curveSegments -= 2;
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if (IsKeyPressed(KEY_RIGHT)) curveSegments += 2;
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if (curveSegments < 2) curveSegments = 2;
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}
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