portersky
df08210f77
- Add shader class for vertex/fragment program compilation - Add vao class for vertex array object management - Render RGB gradient triangle with interpolated vertex colors
106 lines
2.6 KiB
C++
106 lines
2.6 KiB
C++
#define GLFW_INCLUDE_NONE
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#include "GLFW/glfw3.h"
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#include "cbt/opengl/context.hpp"
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#include "cbt/opengl/shader.hpp"
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#include "cbt/opengl/buffer.hpp"
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#include "cbt/opengl/vao.hpp"
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#include "asio.hpp"
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#include "glad/glad.h"
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auto main([[maybe_unused]]int argc, [[maybe_unused]]char const* argv[]) -> int {
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auto ctx = cbt::opengl::context("cuber", 1280, 720);
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if (!ctx.valid()) {
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return 1;
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}
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// compile shader
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auto prog = cbt::opengl::shader();
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const char* vert_src = R"glsl(
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#version 410 core
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layout(location = 0) in vec3 a_pos;
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layout(location = 1) in vec3 a_color;
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out vec3 v_color;
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void main() {
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gl_Position = vec4(a_pos, 1.0);
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v_color = a_color;
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}
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)glsl";
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const char* frag_src = R"glsl(
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#version 410 core
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in vec3 v_color;
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out vec4 frag_color;
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void main() {
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frag_color = vec4(v_color, 1.0);
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}
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)glsl";
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if (!prog.compile_vertex(vert_src) || !prog.compile_fragment(frag_src) || !prog.link()) {
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return 1;
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}
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// vertex data: triangle with per-vertex colors
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// red, green, blue corners
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std::array<float, 18> vertices = {
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-0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f,
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0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f,
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0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f,
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};
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auto vbo = cbt::opengl::buffer(cbt::opengl::buffer_type::vertex);
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vbo.upload(vertices.data(), vertices.size() * sizeof(float));
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// bind VAO and configure vertex attributes
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auto vao = cbt::opengl::vao();
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vao.bind();
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vbo.bind();
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glEnableVertexAttribArray(0);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), nullptr);
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glEnableVertexAttribArray(1);
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glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float),
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reinterpret_cast<void*>(3 * sizeof(float)));
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vbo.unbind();
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vao.unbind();
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// signal handling
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asio::io_context io;
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asio::signal_set signals(io, SIGINT, SIGTERM);
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bool quit = false;
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signals.async_wait([&](auto, auto) {
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quit = true;
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io.stop();
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});
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auto process_signals = [&]() -> void {
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while (io.poll()) {}
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};
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// render loop
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while (!ctx.should_close()) {
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process_signals();
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if (quit || glfwGetKey(ctx.raw(), GLFW_KEY_Q) == GLFW_PRESS) {
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break;
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}
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glClearColor(0.6f, 0.8f, 1.0f, 1.0f);
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glClear(GL_COLOR_BUFFER_BIT);
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prog.use();
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vao.bind();
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glDrawArrays(GL_TRIANGLES, 0, 3);
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vao.unbind();
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prog.unuse();
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ctx.swap_buffers();
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ctx.poll_events();
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}
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return 0;
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}
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