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241 行
5.8 KiB
241 行
5.8 KiB
/*******************************************************************************************
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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
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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) 2019-2022 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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Texture RoadTexture = { 0 };
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bool ShowCurve = false;
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float Width = 50;
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int Segments = 24;
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Vector2 SP = { 0 };
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Vector2 SPTangent = { 0 };
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Vector2 EP = { 0 };
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Vector2 EPTangent = { 0 };
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Vector2* Selected = NULL;
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void DrawCurve()
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{
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if (ShowCurve)
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DrawLineBezierCubic(SP, EP, SPTangent, EPTangent, 2, BLUE);
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// draw the various control points and highlight where the mouse is
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DrawLineV(SP, SPTangent, SKYBLUE);
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DrawLineV(EP, EPTangent, PURPLE);
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Vector2 mouse = GetMousePosition();
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if (CheckCollisionPointCircle(mouse, SP, 6))
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DrawCircleV(SP, 7, YELLOW);
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DrawCircleV(SP, 5, RED);
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if (CheckCollisionPointCircle(mouse, SPTangent, 6))
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DrawCircleV(SPTangent, 7, YELLOW);
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DrawCircleV(SPTangent, 5, MAROON);
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if (CheckCollisionPointCircle(mouse, EP, 6))
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DrawCircleV(EP, 7, YELLOW);
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DrawCircleV(EP, 5, GREEN);
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if (CheckCollisionPointCircle(mouse, EPTangent, 6))
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DrawCircleV(EPTangent, 7, YELLOW);
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DrawCircleV(EPTangent, 5, DARKGREEN);
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}
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void EditCurve()
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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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Selected = 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 (Selected)
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{
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*Selected = Vector2Add(*Selected, 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, SP, 6))
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Selected = &SP;
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else if (CheckCollisionPointCircle(mouse, SPTangent, 6))
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Selected = &SPTangent;
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else if (CheckCollisionPointCircle(mouse, EP, 6))
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Selected = &EP;
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else if (CheckCollisionPointCircle(mouse, EPTangent, 6))
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Selected = &EPTangent;
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}
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void DrawTexturedCurve()
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{
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const float step = 1.0f / Segments;
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Vector2 previous = SP;
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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 <= Segments; 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 * SP.y + b * SPTangent.y + c * EPTangent.y + d * EP.y;
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current.x = a * SP.x + b * SPTangent.x + c * EPTangent.x + d * EP.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, Width));
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Vector2 prevNegNormal = Vector2Add(previous, Vector2Scale(previousTangent, -Width));
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Vector2 currentPosNormal = Vector2Add(current, Vector2Scale(normal, Width));
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Vector2 currentNegNormal = Vector2Add(current, Vector2Scale(normal, -Width));
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// draw the segment as a quad
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rlSetTexture(RoadTexture.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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void UpdateOptions()
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{
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if (IsKeyPressed(KEY_SPACE))
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ShowCurve = !ShowCurve;
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// width
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if (IsKeyPressed(KEY_EQUAL))
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Width += 2;
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if (IsKeyPressed(KEY_MINUS))
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Width -= 2;
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if (Width < 2)
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Width = 2;
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// segments
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if (IsKeyPressed(KEY_LEFT_BRACKET))
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Segments -= 2;
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if (IsKeyPressed(KEY_RIGHT_BRACKET))
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Segments += 2;
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if (Segments < 2)
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Segments = 2;
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}
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int main ()
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{
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// set up the window
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SetConfigFlags(FLAG_VSYNC_HINT);
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InitWindow(1280, 800, "raylib [textures] examples - textured curve");
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SetTargetFPS(144);
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// load the road texture
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RoadTexture = LoadTexture("resources/roadTexture_01.png");
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// setup the curve
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SP = (Vector2){ 80, 400 };
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SPTangent = (Vector2){ 600, 100 };
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EP = (Vector2){ 1200, 400 };
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EPTangent = (Vector2){ 600, 700 };
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// game loop
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while (!WindowShouldClose())
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{
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EditCurve();
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UpdateOptions();
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BeginDrawing();
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ClearBackground(BLACK);
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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, 0, 20, WHITE);
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DrawText(TextFormat("Width %2.0f + and - to adjust", Width), 10, 20, 20, WHITE);
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DrawText(TextFormat("Segments %d [ and ] to adjust", Segments), 10, 40, 20, WHITE);
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DrawFPS(10, 60);
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EndDrawing();
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}
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// cleanup
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UnloadTexture(RoadTexture);
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CloseWindow();
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return 0;
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}
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