Preliminary entity system

game/Makefile

@@ -1,6 +1,7 @@
 SRC=src/main.c  src/program.c src/resources.c src/camera.c src/chunk/chunk.c \
 	src/chunk/mesh.c src/flags.c src/texture.c src/chunk/manager.c \
-	src/event/manager.c src/event/handlers.c src/state.c src/graphics.c
+	src/event/manager.c src/event/handlers.c src/state.c src/graphics.c \
+	src/entity/meshes.c src/entity/manager.c
 
 OBJ=$(SRC:.c=.o)
 CFLAGS=-Werror -Wextra -Wall `pkg-config --cflags sdl3 sdl3-image cglm gl glib-2.0`

game/res/shaders/billboard.frag

@@ -0,0 +1,8 @@
+#version 100
+
+precision mediump float;
+
+void main ()
+{
+  gl_FragColor = vec4 (1.0, 1.0, 1.0, 1.0);
+}

game/res/shaders/billboard.vert

@@ -0,0 +1,11 @@
+#version 100
+
+attribute vec4 position;
+
+uniform mat4 view;
+uniform mat4 projection;
+
+void main ()
+{
+  gl_Position = projection * view * position;
+}

game/res/shaders/default.frag

@@ -2,7 +2,16 @@
 
 precision mediump float;
 
+uniform sampler2D texture;
+
+varying vec2 f_uv;
+
 void main ()
 {
-  gl_FragColor = vec4 (0.5, 1.0, 0.5, 1.0);
+  if(texture2D (texture, f_uv).a < 0.1)
+    {
+      discard;
+    }
+  
+  gl_FragColor = texture2D (texture, f_uv);
 }

game/res/shaders/default.vert

@@ -1,11 +1,15 @@
 #version 100
 
 attribute vec4 position;
+attribute vec2 uv;
 
 uniform mat4 view;
 uniform mat4 projection;
 
+varying vec2 f_uv;
+
 void main ()
 {
+  f_uv = uv;
   gl_Position = projection * view * position;
 }

game/src/chunk/manager.c

@@ -77,7 +77,7 @@ ChunkManager_render (vec3 camera_position, int program)
 {
   int cx = 0, cz = 0;
   cm_world_to_chunk (camera_position[0], camera_position[2], &cx, &cz);
-  
+
   for (int z = cz - RENDER_DISTANCE; z <= cz + RENDER_DISTANCE; ++z)
     {
       for (int x = cx - RENDER_DISTANCE; x <= cx + RENDER_DISTANCE; ++x)

game/src/chunk/mesh.c

@@ -1,5 +1,8 @@
 #include "mesh.h"
 
+/* No need to bind the elements buffer all the time; it's the same for
+   every single ChunkMesh. */
+
 extern GameFlags game_flags;
 
 ChunkMesh *
@@ -104,7 +107,7 @@ ChunkMesh_render (ChunkMesh *mesh)
   glBindBuffer (GL_ARRAY_BUFFER, mesh->mbo);
   glEnableVertexAttribArray (1);
   glVertexAttribPointer (1, 4, GL_FLOAT, GL_FALSE, sizeof (float) * 4, 0);
-  
+
   glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, mesh->ebo);
   
   if (game_flags.wireframe_enabled)
@@ -115,6 +118,4 @@ ChunkMesh_render (ChunkMesh *mesh)
     {
       glDrawElements (GL_TRIANGLES, CHUNK_SIZE * 6, GL_UNSIGNED_INT, 0);
     }
-
-  glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
 }

game/src/entity/entity.h

@@ -0,0 +1,18 @@
+#pragma once
+
+typedef enum EntityMeshType
+  {
+    ENTITY_MESH_BILLBOARD,
+    ENTITY_MESH_X
+  } EntityMeshType;
+
+typedef struct Entity
+{
+  vec3 position;
+  vec3 rotation; 		/* Unused for now. */
+  vec3 scale;			/* Unused for now. */
+  int texture;
+  EntityMeshType type;
+} Entity;
+
+Entity *Entity_new (vec3 position, int texture, EntityMeshType type);

game/src/entity/manager.c

@@ -0,0 +1,25 @@
+#include "manager.h"
+
+GSequence *entity_manager;
+
+EntityMesh mesh_billboard, mesh_x;
+
+void
+EntityManager_init ()
+{
+  entity_manager = g_sequence_new (NULL);
+  mesh_billboard = EntityMesh_make_billboard ();
+  mesh_x = EntityMesh_make_x ();
+}
+
+void
+EntityManager_tick ()
+{
+  
+}
+
+void
+EntityManager_render ()
+{
+  
+}

game/src/entity/manager.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <glib-2.0/glib.h>
+#include <cglm/cglm.h>
+
+#include "entity.h"
+#include "meshes.h"
+
+/* TODO: Sort entities by mesh type AS WELL AS distance. Binding
+   buffers is very performance-sensitive, thus to conserve speed one
+   type should be rendered in one go, then the other type, etc. */
+
+void EntityManager_init ();
+void EntityManager_tick ();
+void EntityManager_render ();

game/src/entity/meshes.c

@@ -0,0 +1,141 @@
+#include "meshes.h"
+
+/* TODO: add back faces. */
+
+extern GameFlags game_flags;
+
+void
+EntityMesh_bind (EntityMesh *mesh)
+{
+  glBindBuffer (GL_ARRAY_BUFFER, mesh->pbo);
+  glEnableVertexAttribArray (0);
+  glVertexAttribPointer (0, 3, GL_FLOAT, GL_FALSE, sizeof (float) * 3, 0);
+
+  glBindBuffer (GL_ARRAY_BUFFER, mesh->uvbo);
+  glEnableVertexAttribArray (1);
+  glVertexAttribPointer (1, 2, GL_FLOAT, GL_FALSE, sizeof (float) * 2, 0);
+  
+  glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, mesh->ebo);
+}
+
+void
+EntityMesh_render (EntityMesh *mesh)
+{
+  if (game_flags.wireframe_enabled)
+    {
+      glDrawElements (GL_LINES, mesh->indices_len, GL_UNSIGNED_INT, 0);
+    }
+  else
+    {
+      glDrawElements (GL_TRIANGLES, mesh->indices_len, GL_UNSIGNED_INT, 0);
+    }
+}
+
+EntityMesh
+EntityMesh_make_billboard ()
+{
+  /* The positions are trivial. */
+  float positions[12] = {
+    -1.0, -1.0, 0.0,
+    +1.0, -1.0, 0.0,
+    -1.0,  1.0, 0.0,
+    +1.0,  1.0, 0.0
+  };
+
+  unsigned int indices[12] = {
+    0, 2, 3, 3, 1, 0,		/* Quad 1 */
+    3, 2, 0, 0, 1, 3,		/* Back of quad 1 */
+  };
+
+  float uvs[8] = {
+    0.0, 1.0,
+    1.0, 1.0,
+    0.0, 0.0,
+    1.0, 0.0,
+  };
+  
+  EntityMesh mesh;
+  mesh.indices_len = 12;
+  glGenBuffers (1, &mesh.pbo);
+  glGenBuffers (1, &mesh.uvbo);
+  glGenBuffers (1, &mesh.ebo);
+
+  glBindBuffer (GL_ARRAY_BUFFER, mesh.pbo);
+  glBufferData (GL_ARRAY_BUFFER, sizeof (float) * 12, positions, GL_STATIC_DRAW);
+  glEnableVertexAttribArray (0);
+  glVertexAttribPointer (0, 3, GL_FLOAT, GL_FALSE, sizeof (float) * 3, 0);
+
+  glBindBuffer (GL_ARRAY_BUFFER, mesh.uvbo);
+  glBufferData (GL_ARRAY_BUFFER, sizeof (float) * 8, uvs, GL_STATIC_DRAW);
+  glEnableVertexAttribArray (1);
+  glVertexAttribPointer (1, 2, GL_FLOAT, GL_FALSE, sizeof (float) * 2, 0);
+
+
+  glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, mesh.ebo);
+  glBufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (unsigned int) * mesh.indices_len, indices, GL_STATIC_DRAW);
+
+  glBindBuffer (GL_ARRAY_BUFFER, 0);
+  glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
+
+  return mesh;
+}
+
+EntityMesh
+EntityMesh_make_x ()
+{
+  /* The positions are trivial. */
+  float positions[24] = {
+    -1.0, -1.0, 0.0,
+    +1.0, -1.0, 0.0,
+    -1.0,  1.0, 0.0,
+    +1.0,  1.0, 0.0,
+
+    0.0, -1.0, -1.0,
+    0.0, -1.0,  1.0,
+    0.0,  1.0, -1.0,
+    0.0,  1.0,  1.0
+  };
+
+  unsigned int indices[24] = {
+    0, 2, 3, 3, 1, 0,		/* Quad 1 */
+    3, 2, 0, 0, 1, 3,		/* Back of quad 1 */
+    4, 6, 7, 7, 5, 4,		/* Quad 2 */
+    7, 6, 4, 4, 5, 7		/* Back of quad 2 */
+  };
+
+  float uvs[16] = {
+    0.0, 1.0,
+    1.0, 1.0,
+    0.0, 0.0,
+    1.0, 0.0,
+    
+    0.0, 1.0,
+    1.0, 1.0,
+    0.0, 0.0,
+    1.0, 0.0
+  };
+  
+  EntityMesh mesh;
+  mesh.indices_len = 24;
+  glGenBuffers (1, &mesh.pbo);
+  glGenBuffers (1, &mesh.uvbo);
+  glGenBuffers (1, &mesh.ebo);
+
+  glBindBuffer (GL_ARRAY_BUFFER, mesh.pbo);
+  glBufferData (GL_ARRAY_BUFFER, sizeof (float) * 24, positions, GL_STATIC_DRAW);
+  glEnableVertexAttribArray (0);
+  glVertexAttribPointer (0, 3, GL_FLOAT, GL_FALSE, sizeof (float) * 3, 0);
+
+  glBindBuffer (GL_ARRAY_BUFFER, mesh.uvbo);
+  glBufferData (GL_ARRAY_BUFFER, sizeof (float) * 16, uvs, GL_STATIC_DRAW);
+  glEnableVertexAttribArray (1);
+  glVertexAttribPointer (1, 2, GL_FLOAT, GL_FALSE, sizeof (float) * 2, 0);
+  
+  glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, mesh.ebo);
+  glBufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (unsigned int) * mesh.indices_len, indices, GL_STATIC_DRAW);
+
+  glBindBuffer (GL_ARRAY_BUFFER, 0);
+  glBindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
+
+  return mesh;
+}

game/src/entity/meshes.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <SDL3/SDL_opengles2.h>
+#include <cglm/cglm.h>
+
+#include "../flags.h"
+
+typedef struct EntityMesh
+{
+  size_t indices_len;
+  unsigned int pbo;
+  unsigned int uvbo;
+  unsigned int ebo;
+} EntityMesh;
+
+void EntityMesh_bind (EntityMesh *mesh);
+void EntityMesh_render (EntityMesh *mesh);
+EntityMesh EntityMesh_make_billboard ();
+EntityMesh EntityMesh_make_x ();

game/src/graphics.c

@@ -6,6 +6,9 @@ extern ChunkManager chunk_manager;
 extern GameState game_state;
 extern Resources resources;
 
+extern EntityMesh mesh_billboard;
+extern EntityMesh mesh_x;
+
 void
 GraphicsContext_init ()
 {
@@ -54,12 +57,11 @@ GraphicsContext_render ()
 {
   glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-  program_use (resources.programs[1]);
-
   mat4 projection, view;
   Camera_get_projection (&game_state.camera, 640.0 / 480.0, projection);
   Camera_get_view (&game_state.camera, view);
   
+  program_use (resources.programs[1]);  
   program_set_mat4 (resources.programs[1], "projection", projection);
   program_set_mat4 (resources.programs[1], "view", view);
 
@@ -71,8 +73,15 @@ GraphicsContext_render ()
 
   ChunkManager_render (game_state.camera.position, resources.programs[1]);
 
-  glBindTexture (GL_TEXTURE_2D, 0);
+  program_use (resources.programs[0]);
+  program_set_mat4 (resources.programs[0], "projection", projection);
+  program_set_mat4 (resources.programs[0], "view", view);
+  glActiveTexture (GL_TEXTURE0);
+  glBindTexture (GL_TEXTURE_2D, resources.textures[5]);
   
+  EntityMesh_bind (&mesh_billboard);
+  EntityMesh_render (&mesh_billboard);
+
   SDL_GL_SwapWindow (gfx.window);
 }
 

game/src/graphics.h

@@ -5,6 +5,7 @@
 
 #include "util.h"
 #include "chunk/manager.h"
+#include "entity/manager.h"
 #include "state.h"
 #include "resources.h"
 

game/src/main.c

@@ -23,6 +23,7 @@ SDL_AppInit (void **appstate, int argc, char **argv)
   handlers_init ();
   Resources_init ();
   ChunkManager_init ();
+  EntityManager_init ();
   GameState_init (SDL_GetTicks ());
   /* Set some basic game flags for testing. */
   game_flags.can_free_look = 1;

game/src/resources.c

@@ -85,6 +85,7 @@ Resources_init ()
   Resources_load_texture ("res/textures/grass.png");
   Resources_load_texture ("res/textures/rock_cement.png");
   Resources_load_texture ("res/textures/asphalt_gravel.png");
+  Resources_load_texture ("res/textures/tree.png");
 }
 
 void

game/src/state.c

@@ -9,6 +9,7 @@ GameState_init (int ticks)
 {
   game_state.last_time = ticks;
   game_state.camera = Camera_default ();
+  game_state.camera.position[2] = -1.0;
 }
 
 void