raylib/examples/textures/textures_polygon.c
2024-01-02 20:58:12 +01:00

141 lines
5.3 KiB
C

/*******************************************************************************************
*
* raylib [shapes] example - Draw Textured Polygon
*
* Example originally created with raylib 3.7, last time updated with raylib 3.7
*
* Example contributed by Chris Camacho (@codifies) 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) 2021-2024 Chris Camacho (@codifies) and Ramon Santamaria (@raysan5)
*
********************************************************************************************/
#include "raylib.h"
#include "rlgl.h" // Required for: Vertex definition
#include "raymath.h"
#define MAX_POINTS 11 // 10 points and back to the start
// Draw textured polygon, defined by vertex and texture coordinates
void DrawTexturePoly(Texture2D texture, Vector2 center, Vector2 *points, Vector2 *texcoords, int pointCount, Color tint);
//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib [textures] example - textured polygon");
// Define texture coordinates to map our texture to poly
Vector2 texcoords[MAX_POINTS] = {
(Vector2){ 0.75f, 0.0f },
(Vector2){ 0.25f, 0.0f },
(Vector2){ 0.0f, 0.5f },
(Vector2){ 0.0f, 0.75f },
(Vector2){ 0.25f, 1.0f},
(Vector2){ 0.375f, 0.875f},
(Vector2){ 0.625f, 0.875f},
(Vector2){ 0.75f, 1.0f},
(Vector2){ 1.0f, 0.75f},
(Vector2){ 1.0f, 0.5f},
(Vector2){ 0.75f, 0.0f} // Close the poly
};
// Define the base poly vertices from the UV's
// NOTE: They can be specified in any other way
Vector2 points[MAX_POINTS] = { 0 };
for (int i = 0; i < MAX_POINTS; i++)
{
points[i].x = (texcoords[i].x - 0.5f)*256.0f;
points[i].y = (texcoords[i].y - 0.5f)*256.0f;
}
// Define the vertices drawing position
// NOTE: Initially same as points but updated every frame
Vector2 positions[MAX_POINTS] = { 0 };
for (int i = 0; i < MAX_POINTS; i++) positions[i] = points[i];
// Load texture to be mapped to poly
Texture texture = LoadTexture("resources/cat.png");
float angle = 0.0f; // Rotation angle (in degrees)
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
//----------------------------------------------------------------------------------
// Update points rotation with an angle transform
// NOTE: Base points position are not modified
angle++;
for (int i = 0; i < MAX_POINTS; i++) positions[i] = Vector2Rotate(points[i], angle*DEG2RAD);
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
DrawText("textured polygon", 20, 20, 20, DARKGRAY);
DrawTexturePoly(texture, (Vector2){ GetScreenWidth()/2.0f, GetScreenHeight()/2.0f },
positions, texcoords, MAX_POINTS, WHITE);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
UnloadTexture(texture); // Unload texture
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
// Draw textured polygon, defined by vertex and texture coordinates
// NOTE: Polygon center must have straight line path to all points
// without crossing perimeter, points must be in anticlockwise order
void DrawTexturePoly(Texture2D texture, Vector2 center, Vector2 *points, Vector2 *texcoords, int pointCount, Color tint)
{
rlSetTexture(texture.id);
// Texturing is only supported on RL_QUADS
rlBegin(RL_QUADS);
rlColor4ub(tint.r, tint.g, tint.b, tint.a);
for (int i = 0; i < pointCount - 1; i++)
{
rlTexCoord2f(0.5f, 0.5f);
rlVertex2f(center.x, center.y);
rlTexCoord2f(texcoords[i].x, texcoords[i].y);
rlVertex2f(points[i].x + center.x, points[i].y + center.y);
rlTexCoord2f(texcoords[i + 1].x, texcoords[i + 1].y);
rlVertex2f(points[i + 1].x + center.x, points[i + 1].y + center.y);
rlTexCoord2f(texcoords[i + 1].x, texcoords[i + 1].y);
rlVertex2f(points[i + 1].x + center.x, points[i + 1].y + center.y);
}
rlEnd();
rlSetTexture(0);
}