Rework chunk rendering to get a 100x performance boost!

- Switching to semi-chunk mesh rendering just 100x the framerate, it was
  running at around 100fps for 3 CHUNK_DISTANCE, and pushing it above
  would make it drop to 30. Now it runs at 9000 frames per second with
  CHUNK_DISTANCE of 8, probably can push it even more

- What is bizarre is this is just from the reduction in draw calls,
  I still need to implement face culling for invisible blocks (simple)
  and frustrum culling (using AABB) or maybe octrees

- Block is way way more simplifed, it's just metadata about a coordinate
  in the chunk block array

- All rendering and mesh generation code is handled by chunks. There is
  a VAO, single VBO and EBO for each chunk. The data buffer is loaded
  into the GPU with a chunk_load, and it stays like that until it is
  loaded again. chunk_load is called if we move chunks, in
  engine_update. Here we unload existing chunks, then load the new ones

1 files changed, 2 insertions, 198 deletions

diff --git a/src/block.c b/src/block.c
index d03a137..8911ba3 100644
--- a/src/block.c
+++ b/src/block.c
@@ -15,203 +15,7 @@
 #include <stdio.h>
 #include <string.h>
 
-
-#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
-
-void block_update(struct block* blk);
-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));
-    block_load_gpu(blk);
-    block_update(blk);
+int block_init(struct block* blk, enum BLOCK_ID block_id) {
+    blk->block_id = block_id;
     return 0;
 }
-
-void block_load_gpu(struct block* blk) {
-    // ========== Constants of a block ================
-    // Local world coordinates
-    float vertices[] = {
-        1.0f, 1.0f, 0.0f, // top-right
-        0.0f, 0.0f, 1.0f, // Front normal
-        1.0f, 1.0f,
-        0.0f, 1.0f, 0.0f, // top-left
-        0.0f, 0.0f, 1.0f, // Front normal
-        0.0f, 1.0f,
-        0.0f, 0.0f, 0.0f, // bottom-left
-        0.0f, 0.0f, 1.0f, // Front normal
-        0.0f, 0.0f,
-        1.0f, 0.0f, 0.0f, // bottom-right
-        0.0f, 0.0f, 1.0f, // Front normal
-        1.0f, 0.0f,
-
-        0.0f, 1.0f, -1.0f, // top-left (back plane)
-        0.0f, 0.0f, -1.0f, // Back normal
-        0.0f, 1.0f,
-        1.0f, 1.0f, -1.0f, // top-right (back plane)
-        0.0f, 0.0f, -1.0f, // Back normal
-        1.0f, 1.0f,
-        1.0f, 0.0f, -1.0f, // bottom-right (back plane)
-        0.0f, 0.0f, -1.0f, // Back normal
-        1.0f, 0.0f,
-        0.0f, 0.0f, -1.0f, // bottom-left (back plane)
-        0.0f, 0.0f, -1.0f, // Back normal
-        0.0f, 0.0f,
-
-        1.0f, 1.0f, -1.0f, // top-right (back plane)
-        1.0f, 0.0f, 0.0f, // Right normal
-        1.0f, 1.0f,
-        1.0f, 1.0f, 0.0f, // top-right
-        1.0f, 0.0f, 0.0f, // Right normal
-        0.0f, 1.0f,
-        1.0f, 0.0f, 0.0f, // bottom-right
-        1.0f, 0.0f, 0.0f, // Right normal
-        0.0f, 0.0f,
-        1.0f, 0.0f, -1.0f, // bottom-right (back plane)
-        1.0f, 0.0f, 0.0f, // Right normal
-        1.0f, 0.0f,
-
-        0.0f, 1.0f, 0.0f, // top-left
-        -1.0f, 0.0f, 0.0f, // Left normal
-        1.0f, 1.0f,
-        0.0f, 1.0f, -1.0f, // top-left (back plane)
-        -1.0f, 0.0f, 0.0f, // Left normal
-        0.0f, 1.0f,
-        0.0f, 0.0f, -1.0f, // bottom-left (back plane)
-        -1.0f, 0.0f, 0.0f, // Left normal
-        0.0f, 0.0f,
-        0.0f, 0.0f, 0.0f, // bottom-left
-        -1.0f, 0.0f, 0.0f, // Left normal
-        1.0f, 0.0f,
-
-        1.0f, 1.0f, -1.0f, // top-right (back plane)
-        0.0f, 1.0f, 0.0f, // Top normal
-        1.0f, 1.0f,
-        0.0f, 1.0f, -1.0f, // top-left (back plane)
-        0.0f, 1.0f, 0.0f, // Top normal
-        0.0f, 1.0f,
-        0.0f, 1.0f, 0.0f, // top-left
-        0.0f, 1.0f, 0.0f, // Top normal
-        0.0f, 0.0f,
-        1.0f, 1.0f, 0.0f, // top-right
-        0.0f, 1.0f, 0.0f, // Top normal
-        1.0f, 0.0f,
-
-        1.0f, 0.0f, -1.0f, // bottom-right (back plane)
-        0.0f, -1.0f, 0.0f, // Bottom normal
-        1.0f, 1.0f,
-        0.0f, 0.0f, -1.0f, // bottom-left (back plane)
-        0.0f, -1.0f, 0.0f, // Bottom normal
-        0.0f, 1.0f,
-        0.0f, 0.0f, 0.0f, // bottom-left
-        0.0f, -1.0f, 0.0f, // Bottom normal
-        0.0f, 0.0f,
-        1.0f, 0.0f, 0.0f, // bottom-right
-        0.0f, -1.0f, 0.0f, // Bottom normal
-        1.0f, 0.0f,
-    };
-    // int vertex_order[] = {
-    //     1, 2, 3,  3, 0, 1, // Front
-    //     5, 6, 7,  7, 4, 5, // Back
-    //     9, 10, 11, 11, 8, 9, // Right
-    //     13, 14, 15,   15, 12, 13, // Left
-    //     17, 18, 19,   19, 16, 17, // Top
-    //     21, 22, 23,   23, 20, 21, // Bottom
-    //
-    // };
-    int vertex_order[] = {
-        1, 2, 3,   3, 0, 1, // Front
-        5, 6, 7,   7, 4, 5, // Back
-        9, 10, 11, 11, 8, 9, // Right
-        13, 14, 15,   15, 12, 13, // Left
-        17, 18, 19,   19, 16, 17, // Top
-        21, 22, 23,   23, 20, 21, // 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 3 attribs - position normals texture
-    glEnableVertexAttribArray(0);
-    glEnableVertexAttribArray(1);
-    glEnableVertexAttribArray(2);
-    // set vao_buffer to pos buffer obj
-    glBindBuffer(GL_ARRAY_BUFFER, blk->_vbo);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), 0);
-    // set vao_buffer to normals buffer obj
-    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (GLvoid*)(3*sizeof(float)));
-    // set vao_buffer to texture buffer obj
-    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (GLvoid*)(6*sizeof(float)));
-    // 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);
-}
-
-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 scale = { 0.90f, 0.90f, 0.90f };
-    glm_translate(blk->model, blk->coords);
-    // glm_scale(blk->model, scale);
-    // glm_rotate_at(blk->model, pivot, angle, rot_axis);
-    // View matrix (camera)
-    //blk->angle = fmodf(blk->angle + 0.005f, 360.0f);
-}
-
-// Register block vbos and ebos to context
-int block_draw(struct block* blk, struct shader* shader, struct texture* texture) {
-    glBindVertexArray(blk->_vao);
-    set_uniform_mat4("model", shader, blk->model);
-    // 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[] = {
-    //     0.761f, 0.424f,  0.0f, 
-    //     0.761f, 0.424f,  0.0f, 
-    //     0.761f, 0.424f,  0.0f, 
-    //     0.761f, 0.424f,  0.0f, 
-    //     0.404f, 0.776f,  0.027f, 
-    //     0.761f, 0.424f,  0.0f, 
-    // };
-    // glUniform3fv(loc, 6, (void*)colors);
-    // texture_draw(texture);
-    glDrawElements(GL_TRIANGLES, blk->_vertex_count, GL_UNSIGNED_INT, 0);
-    glBindVertexArray(0);
-    return 0;
-}
-
-void block_debug(struct block *blk) {
-    fprintf(stderr, "==== Block Debug ====\n");
-    fprintf(stderr, "==== Block Coords ====\n");
-    glm_vec3_print(blk->coords, stderr);
-    fprintf(stderr, "==== Block Model ====\n");
-    glm_mat4_print(blk->model, stderr);
-
-}
-
-void block_unload(struct block *blk) {
-    // Clear VBO data
-    glDeleteBuffers(1, &blk->_vbo);
-    // Clear EBO data
-    glDeleteBuffers(1, &blk->_ebo);
-    // Clear VAO
-    glDeleteVertexArrays(1, &blk->_vao);
-}