/*******************************************************************************************
*
* raylib [models] example - rlgl module usage with push/pop matrix transformations
*
* Example complexity rating: [★★★★] 4/4
*
* NOTE: This example uses [rlgl] module functionality (pseudo-OpenGL 1.1 style coding)
*
* Example originally created with raylib 2.5, last time updated with raylib 4.0
*
* 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) 2018-2025 Ramon Santamaria (@raysan5)
*
********************************************************************************************/
#include "raylib.h"
#include "rlgl.h"
#include <math.h> // Required for: cosf(), sinf()
//------------------------------------------------------------------------------------
// Module Functions Declaration
//------------------------------------------------------------------------------------
void DrawSphereBasic(Color color); // Draw sphere without any matrix transformation
//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
const float sunRadius = 4.0f;
const float earthRadius = 0.6f;
const float earthOrbitRadius = 8.0f;
const float moonRadius = 0.16f;
const float moonOrbitRadius = 1.5f;
InitWindow(screenWidth, screenHeight, "raylib [models] example - rlgl module usage with push/pop matrix transformations");
// Define the camera to look into our 3d world
Camera camera = { 0 };
camera.position = (Vector3){ 16.0f, 16.0f, 16.0f }; // Camera position
camera.target = (Vector3){ 0.0f, 0.0f, 0.0f }; // Camera looking at point
camera.up = (Vector3){ 0.0f, 1.0f, 0.0f }; // Camera up vector (rotation towards target)
camera.fovy = 45.0f; // Camera field-of-view Y
camera.projection = CAMERA_PERSPECTIVE; // Camera projection type
float rotationSpeed = 0.2f; // General system rotation speed
float earthRotation = 0.0f; // Rotation of earth around itself (days) in degrees
float earthOrbitRotation = 0.0f; // Rotation of earth around the Sun (years) in degrees
float moonRotation = 0.0f; // Rotation of moon around itself
float moonOrbitRotation = 0.0f; // Rotation of moon around earth 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
//----------------------------------------------------------------------------------
UpdateCamera(&camera, CAMERA_ORBITAL);
earthRotation += (5.0f*rotationSpeed);
earthOrbitRotation += (365/360.0f*(5.0f*rotationSpeed)*rotationSpeed);
moonRotation += (2.0f*rotationSpeed);
moonOrbitRotation += (8.0f*rotationSpeed);
//----------------------------------------------------------------------------------
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(RAYWHITE);
BeginMode3D(camera);
rlPushMatrix();
rlScalef(sunRadius, sunRadius, sunRadius); // Scale Sun
DrawSphereBasic(GOLD); // Draw the Sun
rlPopMatrix();
rlPushMatrix();
rlRotatef(earthOrbitRotation, 0.0f, 1.0f, 0.0f); // Rotation for Earth orbit around Sun
rlTranslatef(earthOrbitRadius, 0.0f, 0.0f); // Translation for Earth orbit
rlPushMatrix();
rlRotatef(earthRotation, 0.25, 1.0, 0.0); // Rotation for Earth itself
rlScalef(earthRadius, earthRadius, earthRadius);// Scale Earth
DrawSphereBasic(BLUE); // Draw the Earth
rlPopMatrix();
rlRotatef(moonOrbitRotation, 0.0f, 1.0f, 0.0f); // Rotation for Moon orbit around Earth
rlTranslatef(moonOrbitRadius, 0.0f, 0.0f); // Translation for Moon orbit
rlRotatef(moonRotation, 0.0f, 1.0f, 0.0f); // Rotation for Moon itself
rlScalef(moonRadius, moonRadius, moonRadius); // Scale Moon
DrawSphereBasic(LIGHTGRAY); // Draw the Moon
rlPopMatrix();
// Some reference elements (not affected by previous matrix transformations)
DrawCircle3D((Vector3){ 0.0f, 0.0f, 0.0f }, earthOrbitRadius, (Vector3){ 1, 0, 0 }, 90.0f, Fade(RED, 0.5f));
DrawGrid(20, 1.0f);
EndMode3D();
DrawText("EARTH ORBITING AROUND THE SUN!", GetScreenWidth() - 400, 10, 20, MAROON);
DrawFPS(10, 10);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
//--------------------------------------------------------------------------------------------
// Module Functions Definitions (local)
//--------------------------------------------------------------------------------------------
// Draw sphere without any matrix transformation
// NOTE: Sphere is drawn in world position ( 0, 0, 0 ) with radius 1.0f
void DrawSphereBasic(Color color)
{
int rings = 16;
int slices = 16;
// Make sure there is enough space in the internal render batch
// buffer to store all required vertex, batch is reseted if required
rlCheckRenderBatchLimit((rings + 2)*slices*6);
rlBegin(RL_TRIANGLES);
rlColor4ub(color.r, color.g, color.b, color.a);
for (int i = 0; i < (rings + 2); i++)
{
for (int j = 0; j < slices; j++)
{
rlVertex3f(cosf(DEG2RAD*(270+(180/(rings + 1))*i))*sinf(DEG2RAD*(j*360/slices)),
sinf(DEG2RAD*(270+(180/(rings + 1))*i)),
cosf(DEG2RAD*(270+(180/(rings + 1))*i))*cosf(DEG2RAD*(j*360/slices)));
rlVertex3f(cosf(DEG2RAD*(270+(180/(rings + 1))*(i+1)))*sinf(DEG2RAD*((j+1)*360/slices)),
sinf(DEG2RAD*(270+(180/(rings + 1))*(i+1))),
cosf(DEG2RAD*(270+(180/(rings + 1))*(i+1)))*cosf(DEG2RAD*((j+1)*360/slices)));
rlVertex3f(cosf(DEG2RAD*(270+(180/(rings + 1))*(i+1)))*sinf(DEG2RAD*(j*360/slices)),
sinf(DEG2RAD*(270+(180/(rings + 1))*(i+1))),
cosf(DEG2RAD*(270+(180/(rings + 1))*(i+1)))*cosf(DEG2RAD*(j*360/slices)));
rlVertex3f(cosf(DEG2RAD*(270+(180/(rings + 1))*i))*sinf(DEG2RAD*(j*360/slices)),
sinf(DEG2RAD*(270+(180/(rings + 1))*i)),
cosf(DEG2RAD*(270+(180/(rings + 1))*i))*cosf(DEG2RAD*(j*360/slices)));
rlVertex3f(cosf(DEG2RAD*(270+(180/(rings + 1))*(i)))*sinf(DEG2RAD*((j+1)*360/slices)),
sinf(DEG2RAD*(270+(180/(rings + 1))*(i))),
cosf(DEG2RAD*(270+(180/(rings + 1))*(i)))*cosf(DEG2RAD*((j+1)*360/slices)));
rlVertex3f(cosf(DEG2RAD*(270+(180/(rings + 1))*(i+1)))*sinf(DEG2RAD*((j+1)*360/slices)),
sinf(DEG2RAD*(270+(180/(rings + 1))*(i+1))),
cosf(DEG2RAD*(270+(180/(rings + 1))*(i+1)))*cosf(DEG2RAD*((j+1)*360/slices)));
}
}
rlEnd();
}