diff --git a/examples/others/opengl_interop.c b/examples/others/opengl_interop.c new file mode 100644 index 000000000..50003de05 --- /dev/null +++ b/examples/others/opengl_interop.c @@ -0,0 +1,132 @@ +/******************************************************************************************* +* +* 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; +} \ No newline at end of file diff --git a/examples/others/opengl_interop.png b/examples/others/opengl_interop.png new file mode 100644 index 000000000..74d7acaea Binary files /dev/null and b/examples/others/opengl_interop.png differ diff --git a/examples/others/resources/shaders/glsl100/point_particle.fs b/examples/others/resources/shaders/glsl100/point_particle.fs new file mode 100644 index 000000000..cf0fd72c2 --- /dev/null +++ b/examples/others/resources/shaders/glsl100/point_particle.fs @@ -0,0 +1,16 @@ +#version 100 + +precision mediump float; + +// Input uniform values +uniform vec4 color; + +// NOTE: Add here your custom variables + +void main() +{ + // Each point is drawn as a screen space square of gl_PointSize size. gl_PointCoord contains where we are inside of + // it. (0, 0) is the top left, (1, 1) the bottom right corner. + // Draw each point as a colored circle with alpha 1.0 in the center and 0.0 at the outer edges. + gl_FragColor = vec4(color.rgb, color.a * (1.0 - length(gl_PointCoord.xy - vec2(0.5))*2.0)); +} \ No newline at end of file diff --git a/examples/others/resources/shaders/glsl100/point_particle.vs b/examples/others/resources/shaders/glsl100/point_particle.vs new file mode 100644 index 000000000..890834c49 --- /dev/null +++ b/examples/others/resources/shaders/glsl100/point_particle.vs @@ -0,0 +1,24 @@ +#version 100 + +// Input vertex attributes +attribute vec3 vertexPosition; + +// Input uniform values +uniform mat4 mvp; +uniform float currentTime; + +// NOTE: Add here your custom variables + +void main() +{ + // Unpack data from vertexPosition + vec2 pos = vertexPosition.xy; + float period = vertexPosition.z; + + // Calculate final vertex position (jiggle it around a bit horizontally) + pos += vec2(100.0, 0.0) * sin(period * currentTime); + gl_Position = mvp * vec4(pos.x, pos.y, 0.0, 1.0); + + // Calculate the screen space size of this particle (also vary it over time) + gl_PointSize = 10.0 - 5.0 * abs(sin(period * currentTime)); +} \ No newline at end of file diff --git a/examples/others/resources/shaders/glsl330/point_particle.fs b/examples/others/resources/shaders/glsl330/point_particle.fs new file mode 100644 index 000000000..f08462105 --- /dev/null +++ b/examples/others/resources/shaders/glsl330/point_particle.fs @@ -0,0 +1,17 @@ +#version 330 + +// Input uniform values +uniform vec4 color; + +// Output fragment color +out vec4 finalColor; + +// NOTE: Add here your custom variables + +void main() +{ + // Each point is drawn as a screen space square of gl_PointSize size. gl_PointCoord contains where we are inside of + // it. (0, 0) is the top left, (1, 1) the bottom right corner. + // Draw each point as a colored circle with alpha 1.0 in the center and 0.0 at the outer edges. + finalColor = vec4(color.rgb, color.a * (1 - length(gl_PointCoord.xy - vec2(0.5))*2)); +} \ No newline at end of file diff --git a/examples/others/resources/shaders/glsl330/point_particle.vs b/examples/others/resources/shaders/glsl330/point_particle.vs new file mode 100644 index 000000000..e43b91de3 --- /dev/null +++ b/examples/others/resources/shaders/glsl330/point_particle.vs @@ -0,0 +1,24 @@ +#version 330 + +// Input vertex attributes +in vec3 vertexPosition; + +// Input uniform values +uniform mat4 mvp; +uniform float currentTime; + +// NOTE: Add here your custom variables + +void main() +{ + // Unpack data from vertexPosition + vec2 pos = vertexPosition.xy; + float period = vertexPosition.z; + + // Calculate final vertex position (jiggle it around a bit horizontally) + pos += vec2(100, 0) * sin(period * currentTime); + gl_Position = mvp * vec4(pos, 0.0, 1.0); + + // Calculate the screen space size of this particle (also vary it over time) + gl_PointSize = 10 - 5 * abs(sin(period * currentTime)); +} \ No newline at end of file