Add basic block textures

- Remove the code that sent colors through uniform variables, instead
  send texture data
- Each vertex now has a texture coordinate
- struct texture is a easy way to represent textures, can be extended
  later
- Shaders updated to use textures

12 files changed, 147 insertions, 48 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9b9cf03..0a7978b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -10,4 +10,5 @@ add_executable(junkcraft
     world.c
     input.c
     camera.c
+    texture.c
 )
diff --git a/src/block.c b/src/block.c
index 56db3f4..14ffa08 100644
--- a/src/block.c
+++ b/src/block.c
@@ -8,6 +8,7 @@
 #include "glad/glad.h"
 #include "block.h"
 #include "shader.h"
+#include "texture.h"
 #include "util.h"
 #include "block.h"
 #include <math.h>
@@ -21,6 +22,7 @@ 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);
@@ -32,58 +34,82 @@ void block_load_gpu(struct block* blk) {
     // Local world coordinates
     float vertices[] = {
         1.0f, 1.0f, 0.0f, // top-right
-        0.0f, 0.0f, 1.0f, // Front
+        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
+        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
+        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
+        0.0f, 0.0f, 1.0f, // Front normal
+        1.0f, 0.0f,
 
         1.0f, 1.0f, -1.0f, // top-right (back plane)
-        0.0f, 0.0f, -1.0f, // Back
+        0.0f, 0.0f, -1.0f, // Back normal
+        1.0f, 1.0f,
         0.0f, 1.0f, -1.0f, // top-left (back plane)
-        0.0f, 0.0f, -1.0f, // Back
+        0.0f, 0.0f, -1.0f, // Back normal
+        0.0f, 1.0f,
         0.0f, 0.0f, -1.0f, // bottom-left (back plane)
-        0.0f, 0.0f, -1.0f, // Back
+        0.0f, 0.0f, -1.0f, // Back normal
+        0.0f, 0.0f,
         1.0f, 0.0f, -1.0f, // bottom-right (back plane)
-        0.0f, 0.0f, -1.0f, // Back
+        0.0f, 0.0f, -1.0f, // Back normal
+        1.0f, 0.0f,
 
         1.0f, 1.0f, -1.0f, // top-right (back plane)
-        1.0f, 0.0f, 0.0f, // Right
+        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
+        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
+        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
+        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
+        -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
+        -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
+        -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
+        -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
+        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
+        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
+        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
+        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
+        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
+        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
+        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
+        0.0f, -1.0f, 0.0f, // Bottom normal
+        1.0f, 0.0f,
     };
     // int vertex_order[] = {
     //     1, 2, 3,  3, 0, 1, // Front
@@ -111,14 +137,17 @@ void block_load_gpu(struct block* blk) {
     blk->_vertex_count = ARRAY_SIZE(vertex_order);
     glGenVertexArrays(1, &blk->_vao);
     glBindVertexArray(blk->_vao);
-    // Enable 2 attribs - position and normals
+    // 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, 6 * sizeof(float), 0);
+    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, 6 * sizeof(float), (GLvoid*)(3*sizeof(float)));
+    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
@@ -145,24 +174,25 @@ void block_update(struct block* blk) {
 }
 
 // Register block vbos and ebos to context
-int block_draw(struct block* blk, struct shader* shader) {
+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);
+    // 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;
diff --git a/src/block.h b/src/block.h
index f55f784..ad81c47 100644
--- a/src/block.h
+++ b/src/block.h
@@ -2,12 +2,14 @@
 #include "cglm/types.h"
 #include "glad/glad.h"
 #include "shader.h"
+#include "texture.h"
 
 struct block {
     vec3 coords; 
     GLuint _vao;
     GLuint _vbo;
     GLuint _ebo;
+    GLuint _tbo;
     int _vertex_count;
     mat4 model;
     float angle;
@@ -21,7 +23,7 @@ struct block {
  *
  */
 int block_init(vec3 pos, struct block* blk);
-int block_draw(struct block* blk, struct shader* shader);
+int block_draw(struct block* blk, struct shader* shader, struct texture* texture);
 void block_debug(struct block* blk);
 void block_update(struct block* blk);
 
diff --git a/src/chunk.c b/src/chunk.c
index 4918d22..3a7b334 100644
--- a/src/chunk.c
+++ b/src/chunk.c
@@ -147,7 +147,7 @@ void chunk_load(struct chunk *chunk, int coord[2]) {
     }
 }
 
-void chunk_draw(struct chunk* chunk, struct shader* shader) {
+void chunk_draw(struct chunk* chunk, struct shader* shader, struct texture* texture) {
     int counter = 0;
     for (int i = 0; i < CHUNK_WIDTH; i++) {
         for (int j = 0; j < CHUNK_LENGTH; j++) {
@@ -156,7 +156,7 @@ void chunk_draw(struct chunk* chunk, struct shader* shader) {
                 if (blk == NULL) {
                     continue;
                 }
-                block_draw(blk, shader);
+                block_draw(blk, shader, texture);
                 counter += 1;
             }
         }
diff --git a/src/chunk.h b/src/chunk.h
index 0122cf9..d49ba80 100644
--- a/src/chunk.h
+++ b/src/chunk.h
@@ -1,5 +1,6 @@
 #pragma once
 #include "block.h"
+#include "texture.h"
 #include "world.h"
 #include <stdint.h>
 #define CHUNK_WIDTH 16
@@ -49,5 +50,6 @@ void chunk_unload(struct chunk* chunk);
  * Technically this wraps block_draw, so block_draw is the one doing all the work
  * @param chunk Chunk to draw
  * @param shader Shader to pass to block_draw
+ * @param texture Textures that block_draw will use
  */
-void chunk_draw(struct chunk* chunk, struct shader* shader);
+void chunk_draw(struct chunk* chunk, struct shader* shader, struct texture* texture);
diff --git a/src/engine.c b/src/engine.c
index ec1d9d3..5b6cf05 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -4,6 +4,7 @@
 #include "cglm/io.h"
 #include "chunk.h"
 #include "input.h"
+#include "texture.h"
 #include "window.h"
 #include "world.h"
 #include <SDL2/SDL_render.h>
@@ -35,6 +36,12 @@ int engine_init(struct engine *engine) {
     };
     engine->shader = shader;
 
+
+    // Load Textures
+    struct texture* texture = { 0 };
+    texture_init(&engine->texture);
+    texture_load(engine->texture, "textures/grass.jpg");
+
     // Setup Objects to draw
     // memset(engine->loaded_chunks, 0, (1 + CHUNK_DISTANCE * 2) * (1 + CHUNK_DISTANCE * 2));
 
@@ -131,7 +138,7 @@ void engine_start(struct engine* engine) {
                 world_get_chunk(engine->world, chunk_coord, &chunk);
                 // Load chunk
                 chunk_load(chunk, chunk_coord);
-                chunk_draw(chunk, engine->shader);
+                chunk_draw(chunk, engine->shader, engine->texture);
             }
         }
         SDL_RenderPresent(engine->window->renderer);
diff --git a/src/engine.h b/src/engine.h
index 92689dd..3248d40 100644
--- a/src/engine.h
+++ b/src/engine.h
@@ -15,6 +15,7 @@ struct engine {
     struct window* window;
     struct shader* shader;
     struct camera* camera;
+    struct texture* texture;
     int game_loop;
     int curr_chunk[2];
     struct world* world;
diff --git a/src/shader.c b/src/shader.c
index 9c36791..c32b12f 100644
--- a/src/shader.c
+++ b/src/shader.c
@@ -82,3 +82,13 @@ int set_uniform_mat4(char* var, struct shader* shader, mat4 matrix) {
     glUniformMatrix4fv(loc, 1, GL_FALSE, (void*)matrix);
     return 0;
 }
+int set_uniform_sampler2d(char* var, struct shader* shader, mat4 matrix) {
+    GLuint loc = glGetUniformLocation(shader->program, var);
+    if (loc == -1) {
+        fprintf(stderr, "Invalid var %s for get_uniform_mat4: Does not exist\n", var);
+        exit(1);
+        return -1;
+    }
+    glUniformMatrix4fv(loc, 1, GL_FALSE, (void*)matrix);
+    return 0;
+}
diff --git a/src/texture.c b/src/texture.c
new file mode 100644
index 0000000..8f2a2a7
--- /dev/null
+++ b/src/texture.c
@@ -0,0 +1,26 @@
+#include "texture.h"
+#include "cglm/io.h"
+#include "util.h"
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb/stb_image.h"
+#include <stdlib.h>
+#include <string.h>
+void texture_init(struct texture** texture) {
+    *texture = malloc(sizeof(struct texture));
+    memset(*texture, 0, sizeof(struct texture));
+}
+
+void texture_load(struct texture* texture, char* path) {
+    int width, height, nr_channels;
+    unsigned char *data = stbi_load(path, &width, &height, &nr_channels, 0);
+    vec2 size = { width, height };
+    glm_vec2_print(size, stderr);
+    create_texture(&texture->_tbo, data, size);
+    stbi_image_free(data);
+    fprintf(stderr, "Loaded texture\n");
+}
+
+void texture_draw(struct texture* texture) {
+    glActiveTexture(GL_TEXTURE0);
+    glBindTexture(GL_TEXTURE_2D, texture->_tbo);
+}
diff --git a/src/texture.h b/src/texture.h
new file mode 100644
index 0000000..721356b
--- /dev/null
+++ b/src/texture.h
@@ -0,0 +1,9 @@
+#pragma once
+#include "glad/glad.h"
+struct texture {
+    GLuint _tbo;
+};
+
+void texture_init(struct texture** texture);
+void texture_load(struct texture* texture, char* path);
+void texture_draw(struct texture* texture);
diff --git a/src/util.c b/src/util.c
index 0a5d983..b296b56 100644
--- a/src/util.c
+++ b/src/util.c
@@ -22,3 +22,12 @@ void create_ebo(GLuint *ebo, void* buf, int size) {
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 }
 
+void create_texture(GLuint* tbo, void* buf, vec2 size) {
+    glGenTextures(1, tbo);
+    glBindTexture(GL_TEXTURE_2D, *tbo);
+    float borderColor[] = { 1.0f, 1.0f, 1.0f, 1.0f };
+    glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR, borderColor);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, size[0], size[1], 0, GL_RGB, GL_UNSIGNED_BYTE, buf);
+    glGenerateMipmap(GL_TEXTURE_2D);
+    // glBindTexture(GL_TEXTURE_2D, 0);
+}
diff --git a/src/util.h b/src/util.h
index 81c9733..721b1a3 100644
--- a/src/util.h
+++ b/src/util.h
@@ -1,4 +1,6 @@
 #pragma once
 #include "glad/glad.h"
+#include "cglm/types.h"
 void create_vbo(GLuint *vbo, void* buf, int size);
 void create_ebo(GLuint *ebo, void* buf, int size);
+void create_texture(GLuint* tbo, void* buf, vec2 size);