1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
/*******************************************************************************************
*
* raylib [shaders] example - OpenGL point particle system
*
* This example has been created using raylib 2ad3eb1 (www.raylib.com)
* raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
*
* Example contributed by Stephan Soller (@arkanis - http://arkanis.de/)
* and reviewed by Ramon Santamaria (@raysan5)
*
* Copyright (c) 2021 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"
#include "rlgl.h"
#include "glad.h"
#if defined(PLATFORM_DESKTOP)
#define GLSL_VERSION 330
#else // PLATFORM_RPI, PLATFORM_ANDROID, PLATFORM_WEB
#define GLSL_VERSION 100
#endif
int main()
{
// 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
struct { float x, y, period; } particles[10000];
const size_t particleCount = sizeof(particles) / sizeof(particles[0]);
for (size_t i = 0; i < particleCount; i++)
{
particles[i].x = GetRandomValue(20, screenWidth - 20);
particles[i].y = 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 = 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, vbo = 0;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(particles), 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
glEnable(GL_PROGRAM_POINT_SIZE);
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", particleCount), 20, 20, 10, RAYWHITE);
// Switch to plain OpenGL
//------------------------------------------------------------------------------
// rlglDraw() in raylib 3.5
rlDrawRenderBatchActive();
glUseProgram(shader.id);
glUniform1f(currentTimeLoc, GetTime());
Vector4 color = ColorNormalize((Color){ 255, 0, 0, 128 });
glUniform4fv(colorLoc, 1, (float*)&color);
// The the current model view projection matrix so the particle system is displayed and transformed
// (e.g. by cameras) just like everything else.
// GetMatrixModelview() and GetMatrixProjection() in raylib 3.5
Matrix modelViewProjection = MatrixMultiply(rlGetMatrixModelview(), rlGetMatrixProjection());
glUniformMatrix4fv(shader.locs[SHADER_LOC_MATRIX_MVP], 1, false, MatrixToFloat(modelViewProjection));
glBindVertexArray(vao);
glDrawArrays(GL_POINTS, 0, particleCount);
glBindVertexArray(0);
glUseProgram(0);
// And back to raylib again
//------------------------------------------------------------------------------
DrawFPS(screenWidth - 100, 10);
EndDrawing();
//----------------------------------------------------------------------------------
}
// De-Initialization
//--------------------------------------------------------------------------------------
glDeleteBuffers(1, &vbo);
glDeleteVertexArrays(1, &vao);
UnloadShader(shader);
CloseWindow(); // Close window and OpenGL context
//--------------------------------------------------------------------------------------
return 0;
}
|
