Attachment 117492 Details for Bug 91540 – example application

example application

pftest.cpp (text/plain), 3.29 KB, created by Bas Nieuwenhuizen on 2015-08-03 19:11:17 UTC

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Creator: Bas Nieuwenhuizen

Created: 2015-08-03 19:11:17 UTC

Size: 3.29 KB

patch

obsolete

>// compile using
>// g++ -o pftest pftest.cpp  -std=c++11 -lSDL2 -lepoxy
>//
>#include <iostream>
>
>#include <SDL2/SDL.h>
>#include <epoxy/gl.h>
>
>namespace {
>GLAPIENTRY void debugHandler(GLenum source, GLenum type, GLuint id,
>                             GLenum severity, GLsizei length,
>                             GLchar const *message, void const *userParam) {
>  std::cout << "GL message: " << message << '\n';
>}
>
>float const vertices[] = {-1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0};
>
>unsigned short const indices[] = {0, 1, 2, 1, 2, 3};
>
>char const* const vsSource = R"(
>#version 330
>#extension GL_ARB_shading_language_420pack : require
>
>layout(binding = 0) uniform Block {
>    float t;
>};
>layout(location = 0) in vec2 inPos;
>
>void main() {
>    float s = sin(t);
>    float c = cos(t);
>    gl_Position = vec4(inPos.x * c + inPos.y * s, inPos.y * c - inPos.x * s, 0, 2);
>}
>)";
>
>char const* const fsSource = R"(
>#version 330
>#extension GL_ARB_shading_language_420pack : require
>    
>out vec4 color;
>
>void main() {
>    color = vec4(1.0);
>}
>)";
>
>GLuint createShader(GLenum type, char const* source) {
>    auto shader = glCreateShader(type);
>    glShaderSource(shader, 1, &source, 0);
>    glCompileShader(shader);
>    return shader;
>}
>
>}
>
>int main() {
>  SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
>
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
>  SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
>  SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
>
>
>  SDL_Window *window =
>      SDL_CreateWindow("pageflip", 0, 0, 1920, 1080, SDL_WINDOW_OPENGL);
>  SDL_GLContext context = SDL_GL_CreateContext(window);
>
>  glDebugMessageCallbackARB(debugHandler, nullptr);
>
>  glClearColor(0.f, 0.f, 0.f, 0.f);
>
>  auto vs = createShader(GL_VERTEX_SHADER, vsSource);
>  auto fs = createShader(GL_FRAGMENT_SHADER, fsSource);
>  auto prog = glCreateProgram();
>  glAttachShader(prog, vs);
>  glAttachShader(prog, fs);
>  glLinkProgram(prog);
>  glUseProgram(prog);
>  
>  GLuint vao;
>  glGenVertexArrays(1, &vao);
>  glBindVertexArray(vao);
>  
>  GLuint vbo, ibo;
>  glGenBuffers(1, &vbo);
>  glBindBuffer(GL_ARRAY_BUFFER, vbo);
>  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
>  glVertexAttribPointer(0, 2, GL_FLOAT, false, 8, nullptr);
>  glEnableVertexAttribArray(0);
>  
>  glGenBuffers(1, &ibo);
>  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
>  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
>  
>  bool shouldExit = false;
>  
>  float t = 0;
>  for (;;) {
>    SDL_Event event;
>    while (SDL_PollEvent(&event)) {
>      if (event.type == SDL_QUIT ||
>          (event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_ESCAPE))
>        shouldExit = true;
>      if(event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_SPACE)
>          t += 1.0;
>    }
>    if (shouldExit)
>      break;
>
>    glClear(GL_COLOR_BUFFER_BIT);
>    
>    GLuint ubo;
>    glGenBuffers(1, &ubo);
>    glBindBuffer(GL_UNIFORM_BUFFER, ubo);
>    glBufferData(GL_UNIFORM_BUFFER, sizeof(t), &t, GL_STATIC_DRAW);
>    
>    glBindBufferBase(GL_UNIFORM_BUFFER, 0, ubo);
>
>    glDrawElementsInstanced(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, nullptr, 1000);
>
>    SDL_GL_SwapWindow(window);
>  }
>
>  // no cleanup: not needed
>}

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Attachments on bug 91540: 117492 | 117493 | 117494

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