136 lines
3.4 KiB
C++
136 lines
3.4 KiB
C++
#include <SDL.h>
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#include "glcxx.hpp"
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#include "GL3/gl3w.h"
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#include <iostream>
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#include <stdio.h>
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using namespace std;
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#define WIDTH 800
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#define HEIGHT 800
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std::shared_ptr<glcxx::Program> program;
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std::shared_ptr<glcxx::Buffer> box_buffer;
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std::shared_ptr<glcxx::Array> box_array;
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static struct
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{
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GLint size;
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GLint color;
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GLint position;
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} uniforms;
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int color = 0;
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GLfloat size = 0.2;
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GLfloat position[2] = {0.0, 0.0};
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GLfloat colors[][4] = {
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{1.0, 0.7, 0.0, 1.0},
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{0.0, 0.5, 1.0, 1.0},
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{1.0, 1.0, 0.0, 1.0},
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{0.2, 0.2, 1.0, 1.0},
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};
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bool init(void)
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{
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glClearColor (0.0, 0.0, 0.0, 0.0);
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glViewport(0, 0, WIDTH, HEIGHT);
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try
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{
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program = glcxx::Program::create(
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glcxx::Shader::create_from_file(GL_VERTEX_SHADER, "box.v.glsl"),
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glcxx::Shader::create_from_file(GL_FRAGMENT_SHADER, "box.f.glsl"),
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"coord", 0);
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uniforms.size = program->get_uniform_location("size");
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uniforms.color = program->get_uniform_location("color");
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uniforms.position = program->get_uniform_location("position");
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box_buffer = glcxx::Buffer::create(GL_ARRAY_BUFFER, GL_STATIC_DRAW,
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{-1.0, -1.0,
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1.0, -1.0,
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1.0, 1.0,
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-1.0, 1.0});
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box_array = glcxx::Array::create();
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box_array->bind();
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box_buffer->bind();
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE,
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2 * sizeof(GLfloat), NULL);
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}
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catch (glcxx::Error & e)
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{
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cerr << "glcxx error: " << e.what() << endl;
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return false;
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}
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return true;
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}
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void display(SDL_Window * window)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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program->use();
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box_array->bind();
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glUniform4fv(uniforms.color, 1, colors[color]);
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glUniform2fv(uniforms.position, 1, position);
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glUniform1f(uniforms.size, size);
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glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
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SDL_GL_SwapWindow(window);
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}
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int main(int argc, char *argv[])
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{
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if (SDL_Init(SDL_INIT_VIDEO))
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{
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printf("Failed to initialize SDL!\n");
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return 1;
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}
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atexit(SDL_Quit);
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SDL_Window * window = SDL_CreateWindow(argv[0],
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SDL_WINDOWPOS_UNDEFINED,
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SDL_WINDOWPOS_UNDEFINED,
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WIDTH,
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HEIGHT,
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SDL_WINDOW_OPENGL);
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if (!window)
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{
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printf("Failed to create window!\n");
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SDL_Quit();
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return 2;
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}
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(void)SDL_GL_CreateContext(window);
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if (gl3wInit())
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{
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cerr << "Failed to initialize GL3W" << endl;
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return 2;
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}
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if (!gl3wIsSupported(3, 0))
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{
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cerr << "OpenGL 3.0 is not supported!" << endl;
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return 2;
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}
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if (!init())
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{
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return 2;
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}
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display(window);
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SDL_Event event;
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while (SDL_WaitEvent(&event))
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{
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if (event.type == SDL_QUIT)
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break;
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else if (event.type == SDL_KEYDOWN)
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{
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if (event.key.keysym.sym == SDLK_ESCAPE)
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break;
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if (event.key.keysym.sym == SDLK_RETURN)
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display(window);
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}
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}
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}
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