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#include "cglm/cglm.h"
#include "cglm/io.h"
#include "cglm/util.h"
#include "math.h"
#include "glad/glad.h"
#include "block.h"
#include "shader.h"
#include "util.h"
#include "block.h"
#include <math.h>
#include <string.h>
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
int block_init(vec3 pos, struct block* blk) {
// Store buffer data into struct
// Initialize vbo and ebo for block
memcpy(blk->coords, pos, sizeof(vec3));
// ========== Constants of a block ================
// Local world coordinates
float vertices[] = {
0.5f, 0.5f, 0.5f, // top-right
-0.5f, 0.5f, 0.5f, // top-left
-0.5f, -0.5f, 0.5f, // bottom-left
0.5f, -0.5f, 0.5f, // bottom-right
0.5f, 0.5f, -0.5f, // top-right (back plane)
-0.5f, 0.5f, -0.5f, // top-left (back plane)
-0.5f, -0.5f, -0.5f, // bottom-left (back plane)
0.5f, -0.5f, -0.5f, // bottom-right (back plane)
};
int vertex_order[] = {
1, 2, 3, 3, 0, 1, // Front
5, 6, 7, 7, 4, 5, // Back
0, 3, 7, 7, 4, 0, // Right
1, 2, 6, 6, 5, 1, // Left
5, 1, 0, 0, 4, 5, // Top
6, 2, 3, 3, 7, 6, // Bottom
};
// ================ OpenGL work ================
create_vbo(&blk->_vbo, (void*)vertices, sizeof(float) * ARRAY_SIZE(vertices));
create_ebo(&blk->_ebo, (void*)vertex_order, sizeof(int) * ARRAY_SIZE(vertex_order));
blk->_vertex_count = ARRAY_SIZE(vertex_order);
glGenVertexArrays(1, &blk->_vao);
glBindVertexArray(blk->_vao);
// Enable 2 attribs - position
glEnableVertexAttribArray(0);
// set vao_buffer to pos buffer obj
glBindBuffer(GL_ARRAY_BUFFER, blk->_vbo);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
// Set EBO to the vertex_order
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, blk->_ebo);
//NOTE: This is important, otherwise with multiple block_init calls, it
//creates a segfault since the bindings get all messed up. Why it gets
//messed up? Let's say we make 2 blocks. Block 1 creates VBOs, then VAO,
//then binds everything. Now VAO is still bound. Block 2 init starts. First
//call is create_vbo. Since VAO is already bound, it gets bound to the OLD
//VAO!! Always clear before use.
glBindVertexArray(0);
return 0;
}
void block_update(struct block* blk) {
//=============== Matrix Work ==============
// RTS matrix - rotate, translate, scale
glm_mat4_identity(blk->model);
float angle = glm_rad(blk->angle);
vec3 rot_axis = { 1.0f, 1.0f, 0.0f };
vec3 axis_y = { 0.0f, 1.0f, 0.0f };
vec3 pivot = { 0.0f, 0.0f, 0.0f };
vec3 scale = { 0.25f, 0.25f, 0.25f };
glm_translate(blk->model, blk->coords);
glm_scale(blk->model, scale);
glm_rotate_at(blk->model, pivot, angle, rot_axis);
// View matrix (camera)
vec3 camera = { 0.0f, 0.0f, 2.0f };
vec3 camera_direction = { 0.0f, 0.0f, -1.0f };
glm_look(camera, camera_direction, axis_y, blk->view);
// Projection (perspective) matrix
glm_perspective(glm_rad(45.0f), 800.0f / 600.0f, 0.1f, -10.0f, blk->perspective);
blk->angle = fmodf(blk->angle + 0.001f, 360.0f);
}
// Register block vbos and ebos to context
int block_draw(struct block* blk, struct shader* shader) {
glBindVertexArray(blk->_vao);
set_uniform_mat4("model", shader, blk->model);
set_uniform_mat4("view", shader, blk->view);
set_uniform_mat4("perspective", shader, blk->perspective);
GLuint loc = glGetUniformLocation(shader->program, "face_colors");
if (loc == -1) {
fprintf(stderr, "Invalid var %s for get_uniform_mat4: Does not exist\n", "face_colors");
exit(1);
return -1;
}
float colors[] = {
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f,
0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 1.0f,
};
glUniform3fv(loc, 6, (void*)colors);
glDrawElements(GL_TRIANGLES, blk->_vertex_count, GL_UNSIGNED_INT, 0);
block_update(blk);
return 0;
}
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