rayjs/examples/textures/textures_textured_curve.c

260 lines
9.4 KiB
C
Raw Normal View History

2023-05-25 21:12:11 +00:00
/*******************************************************************************************
*
* raylib [textures] example - Draw a texture along a segmented curve
*
* Example originally created with raylib 4.5, last time updated with raylib 4.5
*
* Example contributed by Jeffery Myers and reviewed by Ramon Santamaria (@raysan5)
*
* Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
* BSD-like license that allows static linking with closed source software
*
* Copyright (c) 2022-2023 Jeffery Myers and Ramon Santamaria (@raysan5)
*
********************************************************************************************/
#include "raylib.h"
#include "raymath.h"
#include "rlgl.h"
#include <math.h> // Required for: powf()
#include <stdlib.h> // Required for: NULL
//----------------------------------------------------------------------------------
// Global Variables Definition
//----------------------------------------------------------------------------------
static Texture texRoad = { 0 };
static bool showCurve = false;
static float curveWidth = 50;
static int curveSegments = 24;
static Vector2 curveStartPosition = { 0 };
static Vector2 curveStartPositionTangent = { 0 };
static Vector2 curveEndPosition = { 0 };
static Vector2 curveEndPositionTangent = { 0 };
static Vector2 *curveSelectedPoint = NULL;
//----------------------------------------------------------------------------------
// Module Functions Declaration
//----------------------------------------------------------------------------------
static void UpdateOptions(void);
static void UpdateCurve(void);
static void DrawCurve(void);
static void DrawTexturedCurve(void);
//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main()
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
SetConfigFlags(FLAG_VSYNC_HINT | FLAG_MSAA_4X_HINT);
InitWindow(screenWidth, screenHeight, "raylib [textures] examples - textured curve");
// Load the road texture
texRoad = LoadTexture("resources/road.png");
SetTextureFilter(texRoad, TEXTURE_FILTER_BILINEAR);
// Setup the curve
curveStartPosition = (Vector2){ 80, 100 };
curveStartPositionTangent = (Vector2){ 100, 300 };
curveEndPosition = (Vector2){ 700, 350 };
curveEndPositionTangent = (Vector2){ 600, 100 };
SetTargetFPS(60); // Set our game to run at 60 frames-per-second
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
// Update
//----------------------------------------------------------------------------------
UpdateCurve();
UpdateOptions();
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
DrawTexturedCurve();
DrawCurve();
DrawText("Drag points to move curve, press SPACE to show/hide base curve", 10, 10, 10, DARKGRAY);
DrawText(TextFormat("Curve width: %2.0f (Use + and - to adjust)", curveWidth), 10, 30, 10, DARKGRAY);
DrawText(TextFormat("Curve segments: %d (Use LEFT and RIGHT to adjust)", curveSegments), 10, 50, 10, DARKGRAY);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadTexture(texRoad);
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
//----------------------------------------------------------------------------------
// Module Functions Definition
//----------------------------------------------------------------------------------
static void DrawCurve(void)
{
if (showCurve) DrawLineBezierCubic(curveStartPosition, curveEndPosition, curveStartPositionTangent, curveEndPositionTangent, 2, BLUE);
// Draw the various control points and highlight where the mouse is
DrawLineV(curveStartPosition, curveStartPositionTangent, SKYBLUE);
DrawLineV(curveEndPosition, curveEndPositionTangent, PURPLE);
Vector2 mouse = GetMousePosition();
if (CheckCollisionPointCircle(mouse, curveStartPosition, 6)) DrawCircleV(curveStartPosition, 7, YELLOW);
DrawCircleV(curveStartPosition, 5, RED);
if (CheckCollisionPointCircle(mouse, curveStartPositionTangent, 6)) DrawCircleV(curveStartPositionTangent, 7, YELLOW);
DrawCircleV(curveStartPositionTangent, 5, MAROON);
if (CheckCollisionPointCircle(mouse, curveEndPosition, 6)) DrawCircleV(curveEndPosition, 7, YELLOW);
DrawCircleV(curveEndPosition, 5, GREEN);
if (CheckCollisionPointCircle(mouse, curveEndPositionTangent, 6)) DrawCircleV(curveEndPositionTangent, 7, YELLOW);
DrawCircleV(curveEndPositionTangent, 5, DARKGREEN);
}
static void UpdateCurve(void)
{
// If the mouse is not down, we are not editing the curve so clear the selection
if (!IsMouseButtonDown(MOUSE_LEFT_BUTTON))
{
curveSelectedPoint = NULL;
return;
}
// If a point was selected, move it
if (curveSelectedPoint)
{
*curveSelectedPoint = Vector2Add(*curveSelectedPoint, GetMouseDelta());
return;
}
// The mouse is down, and nothing was selected, so see if anything was picked
Vector2 mouse = GetMousePosition();
if (CheckCollisionPointCircle(mouse, curveStartPosition, 6)) curveSelectedPoint = &curveStartPosition;
else if (CheckCollisionPointCircle(mouse, curveStartPositionTangent, 6)) curveSelectedPoint = &curveStartPositionTangent;
else if (CheckCollisionPointCircle(mouse, curveEndPosition, 6)) curveSelectedPoint = &curveEndPosition;
else if (CheckCollisionPointCircle(mouse, curveEndPositionTangent, 6)) curveSelectedPoint = &curveEndPositionTangent;
}
static void DrawTexturedCurve(void)
{
const float step = 1.0f/curveSegments;
Vector2 previous = curveStartPosition;
Vector2 previousTangent = { 0 };
float previousV = 0;
// We can't compute a tangent for the first point, so we need to reuse the tangent from the first segment
bool tangentSet = false;
Vector2 current = { 0 };
float t = 0.0f;
for (int i = 1; i <= curveSegments; i++)
{
// Segment the curve
t = step*i;
float a = powf(1 - t, 3);
float b = 3*powf(1 - t, 2)*t;
float c = 3*(1 - t)*powf(t, 2);
float d = powf(t, 3);
// Compute the endpoint for this segment
current.y = a*curveStartPosition.y + b*curveStartPositionTangent.y + c*curveEndPositionTangent.y + d*curveEndPosition.y;
current.x = a*curveStartPosition.x + b*curveStartPositionTangent.x + c*curveEndPositionTangent.x + d*curveEndPosition.x;
// Vector from previous to current
Vector2 delta = { current.x - previous.x, current.y - previous.y };
// The right hand normal to the delta vector
Vector2 normal = Vector2Normalize((Vector2){ -delta.y, delta.x });
// The v texture coordinate of the segment (add up the length of all the segments so far)
float v = previousV + Vector2Length(delta);
// Make sure the start point has a normal
if (!tangentSet)
{
previousTangent = normal;
tangentSet = true;
}
// Extend out the normals from the previous and current points to get the quad for this segment
Vector2 prevPosNormal = Vector2Add(previous, Vector2Scale(previousTangent, curveWidth));
Vector2 prevNegNormal = Vector2Add(previous, Vector2Scale(previousTangent, -curveWidth));
Vector2 currentPosNormal = Vector2Add(current, Vector2Scale(normal, curveWidth));
Vector2 currentNegNormal = Vector2Add(current, Vector2Scale(normal, -curveWidth));
// Draw the segment as a quad
rlSetTexture(texRoad.id);
rlBegin(RL_QUADS);
rlColor4ub(255,255,255,255);
rlNormal3f(0.0f, 0.0f, 1.0f);
rlTexCoord2f(0, previousV);
rlVertex2f(prevNegNormal.x, prevNegNormal.y);
rlTexCoord2f(1, previousV);
rlVertex2f(prevPosNormal.x, prevPosNormal.y);
rlTexCoord2f(1, v);
rlVertex2f(currentPosNormal.x, currentPosNormal.y);
rlTexCoord2f(0, v);
rlVertex2f(currentNegNormal.x, currentNegNormal.y);
rlEnd();
// The current step is the start of the next step
previous = current;
previousTangent = normal;
previousV = v;
}
}
static void UpdateOptions(void)
{
if (IsKeyPressed(KEY_SPACE)) showCurve = !showCurve;
// Update with
if (IsKeyPressed(KEY_EQUAL)) curveWidth += 2;
if (IsKeyPressed(KEY_MINUS)) curveWidth -= 2;
if (curveWidth < 2) curveWidth = 2;
// Update segments
if (IsKeyPressed(KEY_LEFT)) curveSegments -= 2;
if (IsKeyPressed(KEY_RIGHT)) curveSegments += 2;
if (curveSegments < 2) curveSegments = 2;
}