browser/external/raylib-4.5.0/examples/others/raylib_opengl_interop.c
2023-09-27 15:02:24 -04:00

166 lines
6.9 KiB
C

/*******************************************************************************************
*
* raylib [shaders] example - OpenGL point particle system
*
* Example originally created with raylib 3.8, last time updated with raylib 2.5
*
* Example contributed by Stephan Soller (@arkanis) 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) 2021-2023 Stephan Soller (@arkanis) and Ramon Santamaria (@raysan5)
*
********************************************************************************************
*
* Mixes raylib and plain OpenGL code to draw a GL_POINTS based particle system. The
* primary point is to demonstrate raylib and OpenGL interop.
*
* rlgl batched draw operations internally so we have to flush the current batch before
* doing our own OpenGL work (rlDrawRenderBatchActive()).
*
* The example also demonstrates how to get the current model view projection matrix of
* raylib. That way raylib cameras and so on work as expected.
*
********************************************************************************************/
#include "raylib.h"
#if defined(PLATFORM_DESKTOP)
#if defined(GRAPHICS_API_OPENGL_ES2)
#include "glad_gles2.h" // Required for: OpenGL functionality
#define glGenVertexArrays glGenVertexArraysOES
#define glBindVertexArray glBindVertexArrayOES
#define glDeleteVertexArrays glDeleteVertexArraysOES
#define GLSL_VERSION 100
#else
#if defined(__APPLE__)
#include <OpenGL/gl3.h> // OpenGL 3 library for OSX
#include <OpenGL/gl3ext.h> // OpenGL 3 extensions library for OSX
#else
#include "glad.h" // Required for: OpenGL functionality
#endif
#define GLSL_VERSION 330
#endif
#else // PLATFORM_RPI, PLATFORM_ANDROID, PLATFORM_WEB
#define GLSL_VERSION 100
#endif
#include "rlgl.h" // Required for: rlDrawRenderBatchActive(), rlGetMatrixModelview(), rlGetMatrixProjection()
#include "raymath.h" // Required for: MatrixMultiply(), MatrixToFloat()
#define MAX_PARTICLES 1000
// Particle type
typedef struct Particle {
float x;
float y;
float period;
} Particle;
//------------------------------------------------------------------------------------
// Program main entry point
//------------------------------------------------------------------------------------
int main(void)
{
// Initialization
//--------------------------------------------------------------------------------------
const int screenWidth = 800;
const int screenHeight = 450;
InitWindow(screenWidth, screenHeight, "raylib - point particles");
Shader shader = LoadShader(TextFormat("resources/shaders/glsl%i/point_particle.vs", GLSL_VERSION),
TextFormat("resources/shaders/glsl%i/point_particle.fs", GLSL_VERSION));
int currentTimeLoc = GetShaderLocation(shader, "currentTime");
int colorLoc = GetShaderLocation(shader, "color");
// Initialize the vertex buffer for the particles and assign each particle random values
Particle particles[MAX_PARTICLES] = { 0 };
for (int i = 0; i < MAX_PARTICLES; i++)
{
particles[i].x = (float)GetRandomValue(20, screenWidth - 20);
particles[i].y = (float)GetRandomValue(50, screenHeight - 20);
// Give each particle a slightly different period. But don't spread it to much.
// This way the particles line up every so often and you get a glimps of what is going on.
particles[i].period = (float)GetRandomValue(10, 30)/10.0f;
}
// Create a plain OpenGL vertex buffer with the data and an vertex array object
// that feeds the data from the buffer into the vertexPosition shader attribute.
GLuint vao = 0;
GLuint vbo = 0;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, MAX_PARTICLES*sizeof(Particle), particles, GL_STATIC_DRAW);
// Note: LoadShader() automatically fetches the attribute index of "vertexPosition" and saves it in shader.locs[SHADER_LOC_VERTEX_POSITION]
glVertexAttribPointer(shader.locs[SHADER_LOC_VERTEX_POSITION], 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
// Allows the vertex shader to set the point size of each particle individually
#ifndef GRAPHICS_API_OPENGL_ES2
glEnable(GL_PROGRAM_POINT_SIZE);
#endif
SetTargetFPS(60);
//--------------------------------------------------------------------------------------
// Main game loop
while (!WindowShouldClose()) // Detect window close button or ESC key
{
// Draw
//----------------------------------------------------------------------------------
BeginDrawing();
ClearBackground(WHITE);
DrawRectangle(10, 10, 210, 30, MAROON);
DrawText(TextFormat("%zu particles in one vertex buffer", MAX_PARTICLES), 20, 20, 10, RAYWHITE);
rlDrawRenderBatchActive(); // Draw iternal buffers data (previous draw calls)
// Switch to plain OpenGL
//------------------------------------------------------------------------------
glUseProgram(shader.id);
glUniform1f(currentTimeLoc, GetTime());
Vector4 color = ColorNormalize((Color){ 255, 0, 0, 128 });
glUniform4fv(colorLoc, 1, (float *)&color);
// Get the current modelview and projection matrix so the particle system is displayed and transformed
Matrix modelViewProjection = MatrixMultiply(rlGetMatrixModelview(), rlGetMatrixProjection());
glUniformMatrix4fv(shader.locs[SHADER_LOC_MATRIX_MVP], 1, false, MatrixToFloat(modelViewProjection));
glBindVertexArray(vao);
glDrawArrays(GL_POINTS, 0, MAX_PARTICLES);
glBindVertexArray(0);
glUseProgram(0);
//------------------------------------------------------------------------------
DrawFPS(screenWidth - 100, 10);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
glDeleteBuffers(1, &vbo);
glDeleteVertexArrays(1, &vao);
UnloadShader(shader); // Unload shader
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}