03_cube.cpp

// Copyright (c), Tamas Csala

#include "oglwrap_example.hpp"

#include <oglwrap/oglwrap.h>
#include <oglwrap/shapes/cube_shape.h>
#include <glm/gtc/matrix_transform.hpp>

class CubeExample : public OglwrapExample {
private:
 // Defines a unit sized cube (see oglwrap/shapes/cube_shape.h)
 gl::CubeShape cube_shape_;

 // A shader program
 gl::Program prog_;

public:
 CubeExample ()
 : cube_shape_({gl::CubeShape::kPosition,
 gl::CubeShape::kNormal})
 {
 // We need to add a few more lines to the shaders
 gl::ShaderSource vs_source;
 vs_source.set_source(R"""(
 #version 330 core
 in vec4 inPos;
 in vec3 inNormal;

 uniform mat4 mvp;

 out vec3 normal;

 void main() {
 normal = inNormal;
 gl_Position = mvp * inPos;
 })""");
 vs_source.set_source_file("example_shader.vert");
 gl::Shader vs(gl::kVertexShader, vs_source);

 gl::ShaderSource fs_source;
 fs_source.set_source(R"""(
 #version 330 core
 in vec3 normal;

 out vec4 fragColor;

 void main() {
 vec3 lightPos = normalize(vec3(0.3, 1, 0.2));
 float diffuseLighting = max(dot(lightPos, normalize(normal)), 0.0);
 vec3 color = vec3(0.1, 0.3, 0.8);
 fragColor = vec4(diffuseLighting * color, 1.0);
 })""");
 fs_source.set_source_file("example_shader.frag");
 gl::Shader fs(gl::kFragmentShader, fs_source);

 // Create a shader program
 prog_.attachShader(vs);
 prog_.attachShader(fs);
 prog_.link();
 gl::Use(prog_);

 // Bind the attribute locations
 (prog_ | "inPos").bindLocation(gl::CubeShape::kPosition);
 (prog_ | "inNormal").bindLocation(gl::CubeShape::kNormal);

 gl::Enable(gl::kDepthTest);

 // Set the clear color
 gl::ClearColor(0.1f, 0.2f, 0.3f, 1.0f);
 }

protected:
 virtual void Render() override {
 float t = glfwGetTime();
 glm::mat4 camera_mat = glm::lookAt(1.5f*glm::vec3{sin(t), 1.0f, cos(t)}, glm::vec3{0.0f, 0.0f, 0.0f}, glm::vec3{0.0f, 1.0f, 0.0f});
 glm::mat4 proj_mat = glm::perspectiveFov<float>(M_PI/3.0, kScreenWidth, kScreenHeight, 0.1, 100);
 gl::Uniform<glm::mat4>(prog_, "mvp") = proj_mat * camera_mat;
 cube_shape_.render();
 }
};

int main() {
 CubeExample().RunMainLoop();
}