path: root/blending/blending.c

#include "GL/glew.h"
#include "GLFW/glfw3.h"

#include "pwyazh.h"

#include "common.h"

#include <unistd.h>

#define WIDTH 1280
#define HEIGHT 720

static V3F camera_pos;
static F32 dt;
static Input input;

void
key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    switch (action)
    {
        case GLFW_PRESS: {
            switch (key)
            {
                case GLFW_KEY_D: {
                    input.move_right.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_W: {
                    input.move_forward.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_A: {
                    input.move_left.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_S: {
                    input.move_backward.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_E: {
                    input.move_up.state = KeyState_PRESS;
                } break;
                case GLFW_KEY_Q: {
                    input.move_down.state = KeyState_PRESS;
                } break;
            }
        } break;

        case GLFW_RELEASE: {
            switch (key)
            {
                case GLFW_KEY_D: {
                    input.move_right.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_W: {
                    input.move_forward.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_A: {
                    input.move_left.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_S: {
                    input.move_backward.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_E: {
                    input.move_up.state = KeyState_RELEASE;
                } break;
                case GLFW_KEY_Q: {
                    input.move_down.state = KeyState_RELEASE;
                } break;
            }
        } break;
    }
}

int
main(void)
{
    GLFWwindow *window;

    if (glfwInit() == GLFW_FALSE)
    {
        fprintf(stderr, "[ERROR] Failed to initialize glfw.\n");
        return(1);
    }

    glfwWindowHint(GLFW_RESIZABLE, 0);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    window = glfwCreateWindow(WIDTH, HEIGHT, "depth testing", 0, 0);
    if (!window)
    {
        fprintf(stderr, "[ERROR] Failed to create window.\n");
        glfwTerminate();
        return(1);
    }

    glfwMakeContextCurrent(window);

    glfwSetKeyCallback(window, key_callback);

    if (glewInit() != GLEW_OK)
    {
        fprintf(stderr, "[ERROR] Failed to initialize glew.\n");
        glfwTerminate();
        return(1);
    }

    glEnable(GL_DEPTH_TEST);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    U32 shader = create_shader_program("shaders/blending.vs", "shaders/blending.fs");
    U32 grass_shader = create_shader_program("shaders/blending.vs", "shaders/grass.fs");
    U32 marble_texture = load_texture("../data/textures/marble.jpg");
    U32 metal_texture = load_texture("../data/textures/metal.png");
    U32 grass_texture = load_texture("../data/textures/grass.png");
    U32 window_texture = load_texture("../data/textures/window.png");

    F32 a = 0.5f;
    F32 vertices[] = {
        -a, -a, -a,  0.0f, 0.0f,
         a, -a, -a,  1.0f, 0.0f,
         a,  a, -a,  1.0f, 1.0f,
         a,  a, -a,  1.0f, 1.0f,
        -a,  a, -a,  0.0f, 1.0f,
        -a, -a, -a,  0.0f, 0.0f,

        -a, -a,  a,  0.0f, 0.0f,
         a, -a,  a,  1.0f, 0.0f,
         a,  a,  a,  1.0f, 1.0f,
         a,  a,  a,  1.0f, 1.0f,
        -a,  a,  a,  0.0f, 1.0f,
        -a, -a,  a,  0.0f, 0.0f,
 
        -a,  a,  a,  1.0f, 0.0f,
        -a,  a, -a,  1.0f, 1.0f,
        -a, -a, -a,  0.0f, 1.0f,
        -a, -a, -a,  0.0f, 1.0f,
        -a, -a,  a,  0.0f, 0.0f,
        -a,  a,  a,  1.0f, 0.0f,

         a,  a,  a,  1.0f, 0.0f,
         a,  a, -a,  1.0f, 1.0f,
         a, -a, -a,  0.0f, 1.0f,
         a, -a, -a,  0.0f, 1.0f,
         a, -a,  a,  0.0f, 0.0f,
         a,  a,  a,  1.0f, 0.0f,

        -a, -a, -a,  0.0f, 1.0f,
         a, -a, -a,  1.0f, 1.0f,
         a, -a,  a,  1.0f, 0.0f,
         a, -a,  a,  1.0f, 0.0f,
        -a, -a,  a,  0.0f, 0.0f,
        -a, -a, -a,  0.0f, 1.0f,

        -a,  a, -a,  0.0f, 1.0f,
         a,  a, -a,  1.0f, 1.0f,
         a,  a,  a,  1.0f, 0.0f,
         a,  a,  a,  1.0f, 0.0f,
        -a,  a,  a,  0.0f, 0.0f,
        -a,  a, -a,  0.0f, 1.0f
    };

    Transform cube_positions[] = {
        transform_default(),
        transform_make_translate(v3f(a, 0.0f, -4.0f*a))
    };

    Transform platform_position =
        transform_make_scale_translate(v3f(10.0f, 0.2f, 10.0f),
                                       v3f(0.0f, -(a+(a*0.2f)+0.01f), 0.0f));

    U32 cube_vao, quad_vao, vbo;

    glGenVertexArrays(1, &cube_vao);
    glBindVertexArray(cube_vao);

    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5*sizeof(F32), (void *)0);
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5*sizeof(F32), (void *)(3*sizeof(F32)));
    glBindVertexArray(0);

    F32 quad_side = 1.0f;
    F32 quad_vertices[] = {
        /* NOTE(pryazha): left top triangle */
        -quad_side/2.0f, 0.0f,      0.0f,  0.0f, 0.0f,
        -quad_side/2.0f, quad_side, 0.0f,  0.0f, 1.0f,
         quad_side/2.0f, quad_side, 0.0f,  1.0f, 1.0f,

        /* NOTE(pryazha): right bottom triangle */
        -quad_side/2.0f, 0.0f,      0.0f,  0.0f, 0.0f,
         quad_side/2.0f, quad_side, 0.0f,  1.0f, 1.0f,
         quad_side/2.0f, 0.0f,      0.0f,  1.0f, 0.0f
    };

    glGenVertexArrays(1, &quad_vao);
    glBindVertexArray(quad_vao);
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(quad_vertices), quad_vertices, GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5*sizeof(F32), (void *)0);
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5*sizeof(F32), (void *)(3*sizeof(F32)));
    glBindVertexArray(0);

    Transform grass_positions[] = {
        transform_make_scale_translate(v3f(0.5f, 0.5f, 0.5f), v3f(1.0f, -0.5f, 0.0f)),
        transform_make_scale_translate(v3f(0.5f, 0.5f, 0.5f), v3f(-1.5f, -0.5f, 2.0f)),
        transform_make_scale_translate(v3f(0.5f, 0.5f, 0.5f), v3f(0.0f, -0.5f, -1.0f)),
        transform_make_scale_translate(v3f(0.5f, 0.5f, 0.5f), v3f(3.0f, -0.5f, 1.0f)),
        transform_make_scale_translate(v3f(0.5f, 0.5f, 0.5f), v3f(-2.0f, -0.5f, -3.0f))
    };

    Transform window_transforms[] = {
        transform_make_translate(v3f(0.0f, -0.5f, a+0.1f)),
        transform_make_translate(v3f(0.0f, -0.5f, 2.0f)),
        transform_make_translate(v3f(1.0f, -0.5f, -1.0f)),
        transform_make_translate(v3f(-2.0f, -0.5f, 0.5f)),
        transform_make_translate(v3f(-3.0f, -0.5f, -3.0f)),
        transform_make_translate(v3f(3.0f, -0.5f, 0.2)),
    };

    F32 angle = 0.0f;
    for (S32 window_index = 0;
         window_index < (S32)ArrayCount(window_transforms);
         ++window_index)
    {
        Transform *transform = window_transforms+window_index;
        *transform = transform_rotate(*transform, v3f(0.0f, angle, 0.0f));
        angle += 30.0f;
    }

    F32 target_fps = 60.0f;
    F32 target_spf = 1.0f/target_fps;
    camera_pos = v3f(0.0f, 0.0f, 3.0f);

    /* glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); */

    F32 last_time = glfwGetTime();

    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();

        /* INFO(pryazha): update */
        V3F left, up, forward;
        V3F world_up = v3f(0.0f, 1.0f, 0.0f);

        forward = v3f_norm(v3f_sub(v3f(0.0f, 0.0f, 0.0f), camera_pos));
        left = v3f_norm(v3f_cross(world_up, forward));
        up = v3f_cross(forward, left);

        V3F dp = v3f_zero();

        F32 speed = 2.0f;
        if (key_is_pressed(input.move_right))
            dp = v3f_add(dp, v3f_scalef(left, -speed*dt));
        if (key_is_pressed(input.move_forward))
            dp = v3f_add(dp, v3f_scalef(forward, speed*dt));
        if (key_is_pressed(input.move_left))
            dp = v3f_add(dp, v3f_scalef(left, speed*dt));
        if (key_is_pressed(input.move_backward))
            dp = v3f_add(dp, v3f_scalef(forward, -speed*dt));
        if (key_is_pressed(input.move_up))
            dp = v3f_add(dp, v3f_scalef(up, speed*dt));
        if (key_is_pressed(input.move_down))
            dp = v3f_add(dp, v3f_scalef(up, -speed*dt));

        input_update_last_state(&input);

        camera_pos = v3f_add(camera_pos, dp);

        Transform sorted_window_transforms[ArrayCount(window_transforms)];
        MemoryCopyArray(sorted_window_transforms, window_transforms);
        for (S32 i = 0; i < (S32)ArrayCount(sorted_window_transforms); ++i) {
            for (S32 pos_index = 1;
                 pos_index < (S32)ArrayCount(sorted_window_transforms);
                 ++pos_index)
            {
                F32 distance_left = v3f_length(v3f_sub(sorted_window_transforms[pos_index-1].translate, camera_pos));
                F32 distance_right = v3f_length(v3f_sub(sorted_window_transforms[pos_index].translate, camera_pos));
                if (distance_left < distance_right) {
                    Transform temp = sorted_window_transforms[pos_index];
                    sorted_window_transforms[pos_index] = sorted_window_transforms[pos_index-1];
                    sorted_window_transforms[pos_index-1] = temp;
                }
            }
        }

        /* INFO(pryazha): Render */
        glClearColor(0.15f, 0.15f, 0.15f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        MAT4 model, view, projection;
        view = look_at(camera_pos, v3f(0.0f, 0.0f, 0.0f), v3f(0.0f, 1.0f, 0.0f));
        projection = perspective(90.0f, (F32)WIDTH/(F32)HEIGHT, 0.1f, 100.0f);

        glUseProgram(shader);
        shader_set_mat4fv(shader, "view", view);
        shader_set_mat4fv(shader, "projection", projection);

        glBindTexture(GL_TEXTURE_2D, marble_texture);
        glBindVertexArray(cube_vao);
        for (S32 transform_index = 0;
             transform_index < (S32)ArrayCount(cube_positions);
             ++transform_index)
       {
            model = transform_apply(cube_positions[transform_index]);
            shader_set_mat4fv(shader, "model", model);
            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        glBindTexture(GL_TEXTURE_2D, metal_texture);
        model = transform_apply(platform_position);
        shader_set_mat4fv(shader, "model", model);
        glDrawArrays(GL_TRIANGLES, 0, 36);

        glUseProgram(grass_shader);
        glBindTexture(GL_TEXTURE_2D, grass_texture);
        shader_set_mat4fv(shader, "view", view);
        shader_set_mat4fv(shader, "projection", projection);
        glBindVertexArray(quad_vao);

        F32 angle = 0.0f;
        for (S32 transform_index = 0;
             transform_index < (S32)ArrayCount(grass_positions);
             ++transform_index)
        {
            Transform *transform = grass_positions+transform_index;
            Transform new_transform = transform_rotate(*transform, v3f(0.0f, angle, 0.0f));
            shader_set_mat4fv(shader, "model", transform_apply(new_transform));
            glDrawArrays(GL_TRIANGLES, 0, 6);
            angle += 30.0f;
        }

        glUseProgram(shader);
        glBindTexture(GL_TEXTURE_2D, window_texture);
        shader_set_mat4fv(shader, "view", view);
        shader_set_mat4fv(shader, "projection", projection);
        for (S32 window_index = 0;
             window_index < (S32)ArrayCount(sorted_window_transforms);
             ++window_index)
        {
            MAT4 model = transform_apply(sorted_window_transforms[window_index]);
            shader_set_mat4fv(shader, "model", model);
            glDrawArrays(GL_TRIANGLES, 0, 6);
        }

        glBindVertexArray(0);

        glfwSwapBuffers(window);

        F32 elapsed = glfwGetTime()-last_time;
        if (elapsed < target_spf) {
            U32 sleep_time = (U32)(target_spf-elapsed);
            if (sleep_time > 0) {
                sleep(sleep_time);
            }
        }
        F32 current_time = glfwGetTime();
        dt = current_time-last_time;
        last_time = current_time;
    }

    glfwTerminate();
    return(0);
}